From 31437c36d4fd2d8db05685d5511e6f1588cac828 Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Tue, 18 Feb 2025 11:02:17 -0500
Subject: [PATCH 01/31] initial commit of instance object

---
 src/viam/sdk/CMakeLists.txt      |  2 ++
 src/viam/sdk/common/instance.cpp | 11 +++++++++++
 src/viam/sdk/common/instance.hpp | 24 ++++++++++++++++++++++++
 3 files changed, 37 insertions(+)
 create mode 100644 src/viam/sdk/common/instance.cpp
 create mode 100644 src/viam/sdk/common/instance.hpp

diff --git a/src/viam/sdk/CMakeLists.txt b/src/viam/sdk/CMakeLists.txt
index cd7992f2a..e42db9ae5 100644
--- a/src/viam/sdk/CMakeLists.txt
+++ b/src/viam/sdk/CMakeLists.txt
@@ -50,6 +50,7 @@ target_sources(viamsdk
   PRIVATE
     common/client_helper.cpp
     common/exception.cpp
+    common/instance.cpp
     common/linear_algebra.cpp
     common/pose.cpp
     common/proto_value.cpp
@@ -142,6 +143,7 @@ target_sources(viamsdk
     FILES
       ../../viam/sdk/common/client_helper.hpp
       ../../viam/sdk/common/exception.hpp
+      ../../viam/sdk/common/instance.hpp
       ../../viam/sdk/common/linear_algebra.hpp
       ../../viam/sdk/common/pose.hpp
       ../../viam/sdk/common/proto_convert.hpp
diff --git a/src/viam/sdk/common/instance.cpp b/src/viam/sdk/common/instance.cpp
new file mode 100644
index 000000000..1ec93d01f
--- /dev/null
+++ b/src/viam/sdk/common/instance.cpp
@@ -0,0 +1,11 @@
+#include <viam/sdk/common/instance.hpp>
+
+namespace viam {
+namespace sdk {
+
+Instance::Instance() {
+    registry_.initialize();
+}
+
+}  // namespace sdk
+}  // namespace viam
diff --git a/src/viam/sdk/common/instance.hpp b/src/viam/sdk/common/instance.hpp
new file mode 100644
index 000000000..8297b74e4
--- /dev/null
+++ b/src/viam/sdk/common/instance.hpp
@@ -0,0 +1,24 @@
+#pragma once
+
+#include <viam/sdk/registry/registry.hpp>
+
+namespace viam {
+namespace sdk {
+
+/// @brief Instance management for Viam C++ SDK applications.
+/// This is a single instance class which is responsible for global setup and teardown related to
+/// the SDK. An Instance must be constructed before doing anything else in a program, and it must
+/// remain alive in a valid state for the duration of the program. Creating multiple overlapping
+/// Instance objects is an error.
+class Instance {
+   public:
+    Instance();
+
+    Registry& registry();
+
+   private:
+    Registry registry_;
+};
+
+}  // namespace sdk
+}  // namespace viam

From 932ebaa1885b2e238cf339d0642c681ebf653b7a Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Tue, 18 Feb 2025 11:04:40 -0500
Subject: [PATCH 02/31] wip: initial commit to get sdk building with instance

---
 src/viam/sdk/module/service.cpp    | 38 ++++++++++--------
 src/viam/sdk/module/service.hpp    |  7 +++-
 src/viam/sdk/registry/registry.cpp | 62 ++++++++++++++----------------
 src/viam/sdk/registry/registry.hpp | 51 ++++++++++++------------
 src/viam/sdk/robot/client.cpp      | 27 +++++++------
 src/viam/sdk/robot/client.hpp      | 21 ++++++++--
 src/viam/sdk/rpc/server.cpp        |  5 +--
 src/viam/sdk/rpc/server.hpp        |  4 +-
 8 files changed, 119 insertions(+), 96 deletions(-)

diff --git a/src/viam/sdk/module/service.cpp b/src/viam/sdk/module/service.cpp
index 53f1fe9bc..526beecb5 100644
--- a/src/viam/sdk/module/service.cpp
+++ b/src/viam/sdk/module/service.cpp
@@ -57,7 +57,7 @@ struct ModuleService::ServiceImpl : viam::module::v1::ModuleService::Service {
         std::shared_ptr<Resource> res;
         const Dependencies deps = parent.get_dependencies_(&request->dependencies(), cfg.name());
         const std::shared_ptr<const ModelRegistration> reg =
-            Registry::lookup_model(cfg.api(), cfg.model());
+            parent.registry_.lookup_model(cfg.api(), cfg.model());
         if (reg) {
             try {
                 res = reg->construct_resource(deps, cfg);
@@ -111,7 +111,8 @@ struct ModuleService::ServiceImpl : viam::module::v1::ModuleService::Service {
             BOOST_LOG_TRIVIAL(error) << "unable to stop resource: " << err.what();
         }
 
-        const std::shared_ptr<const ModelRegistration> reg = Registry::lookup_model(cfg.name());
+        const std::shared_ptr<const ModelRegistration> reg =
+            parent.registry_.lookup_model(cfg.name());
         if (reg) {
             try {
                 const std::shared_ptr<Resource> res = reg->construct_resource(deps, cfg);
@@ -131,7 +132,7 @@ struct ModuleService::ServiceImpl : viam::module::v1::ModuleService::Service {
         ResourceConfig cfg = from_proto(proto);
 
         const std::shared_ptr<const ModelRegistration> reg =
-            Registry::lookup_model(cfg.api(), cfg.model());
+            parent.registry_.lookup_model(cfg.api(), cfg.model());
         if (!reg) {
             return grpc::Status(grpc::UNKNOWN,
                                 "unable to validate resource " + cfg.resource_name().name() +
@@ -207,31 +208,36 @@ Dependencies ModuleService::get_dependencies_(
 
 std::shared_ptr<Resource> ModuleService::get_parent_resource_(const Name& name) {
     if (!parent_) {
-        parent_ = RobotClient::at_local_socket(parent_addr_, {0, boost::none});
+        parent_ = RobotClient::at_local_socket(parent_addr_, {0, boost::none}, registry_);
     }
 
     return parent_->resource_by_name(name);
 }
 
-ModuleService::ModuleService(std::string addr)
-    : module_(std::make_unique<Module>(std::move(addr))), server_(std::make_unique<Server>()) {
+ModuleService::ModuleService(std::string addr, Registry& registry)
+    : registry_(registry),
+      module_(std::make_unique<Module>(std::move(addr))),
+      server_(std::make_unique<Server>(&registry_)) {
     impl_ = std::make_unique<ServiceImpl>(*this);
 }
 
 ModuleService::ModuleService(int argc,
                              char** argv,
-                             const std::vector<std::shared_ptr<ModelRegistration>>& registrations)
-    : ModuleService([argc, argv] {
-          if (argc < 2) {
-              throw Exception(ErrorCondition::k_connection,
-                              "Need socket path as command line argument");
-          }
-          return argv[1];
-      }()) {
+                             const std::vector<std::shared_ptr<ModelRegistration>>& registrations,
+                             Registry& registry)
+    : ModuleService(
+          [argc, argv] {
+              if (argc < 2) {
+                  throw Exception(ErrorCondition::k_connection,
+                                  "Need socket path as command line argument");
+              }
+              return argv[1];
+          }(),
+          registry) {
     set_logger_severity_from_args(argc, argv);
 
     for (auto&& mr : registrations) {
-        Registry::register_model(mr);
+        registry_.register_model(mr);
         add_model_from_registry(mr->api(), mr->model());
     }
 }
@@ -274,7 +280,7 @@ void ModuleService::add_model_from_registry_inlock_(API api,
                                                     Model model,
                                                     const std::lock_guard<std::mutex>&) {
     const std::shared_ptr<const ResourceServerRegistration> creator =
-        Registry::lookup_resource_server(api);
+        registry_.lookup_resource_server(api);
     std::string name;
     if (creator && creator->service_descriptor()) {
         name = creator->service_descriptor()->full_name();
diff --git a/src/viam/sdk/module/service.hpp b/src/viam/sdk/module/service.hpp
index 799ba1ab5..cffc47fe7 100644
--- a/src/viam/sdk/module/service.hpp
+++ b/src/viam/sdk/module/service.hpp
@@ -31,7 +31,7 @@ class ModuleService {
    public:
     /// @brief Creates a new ModuleService that can serve on the provided socket.
     /// @param addr Address of socket to serve on.
-    explicit ModuleService(std::string addr);
+    explicit ModuleService(std::string addr, Registry& registry);
 
     /// @brief Creates a new ModuleService. Socket path and log level will be
     /// inferred from passed in command line arguments, and passed in model
@@ -41,7 +41,8 @@ class ModuleService {
     /// @param registrations Models to register and add to the module.
     explicit ModuleService(int argc,
                            char** argv,
-                           const std::vector<std::shared_ptr<ModelRegistration>>& registrations);
+                           const std::vector<std::shared_ptr<ModelRegistration>>& registrations,
+                           Registry& registry);
     ~ModuleService();
 
     /// @brief Starts module. serve will return when SIGINT or SIGTERM is received
@@ -64,6 +65,8 @@ class ModuleService {
                                    std::string const& resource_name);
     std::shared_ptr<Resource> get_parent_resource_(const Name& name);
 
+    Registry& registry_;
+
     std::mutex lock_;
     std::unique_ptr<Module> module_;
     std::shared_ptr<RobotClient> parent_;
diff --git a/src/viam/sdk/registry/registry.cpp b/src/viam/sdk/registry/registry.cpp
index 57e857f00..71e3e7711 100644
--- a/src/viam/sdk/registry/registry.cpp
+++ b/src/viam/sdk/registry/registry.cpp
@@ -122,7 +122,7 @@ void Registry::register_resource_client_(
 }
 
 std::shared_ptr<const ModelRegistration> Registry::lookup_model_inlock_(
-    const std::string& name, const std::lock_guard<std::mutex>&) {
+    const std::string& name, const std::lock_guard<std::mutex>&) const {
     if (resources_.find(name) == resources_.end()) {
         return nullptr;
     }
@@ -130,19 +130,20 @@ std::shared_ptr<const ModelRegistration> Registry::lookup_model_inlock_(
     return resources_.at(name);
 }
 
-std::shared_ptr<const ModelRegistration> Registry::lookup_model(const std::string& name) {
+std::shared_ptr<const ModelRegistration> Registry::lookup_model(const std::string& name) const {
     const std::lock_guard<std::mutex> lock(lock_);
     return lookup_model_inlock_(name, lock);
 }
 
 std::shared_ptr<const ModelRegistration> Registry::lookup_model(const API& api,
-                                                                const Model& model) {
+                                                                const Model& model) const {
     const std::lock_guard<std::mutex> lock(lock_);
     const std::string name = api.to_string() + "/" + model.to_string();
     return lookup_model_inlock_(name, lock);
 }
 
-std::shared_ptr<const ResourceServerRegistration> Registry::lookup_resource_server(const API& api) {
+std::shared_ptr<const ResourceServerRegistration> Registry::lookup_resource_server(
+    const API& api) const {
     const std::lock_guard<std::mutex> lock(lock_);
     if (server_apis_.find(api) == server_apis_.end()) {
         return nullptr;
@@ -151,7 +152,8 @@ std::shared_ptr<const ResourceServerRegistration> Registry::lookup_resource_serv
     return server_apis_.at(api);
 }
 
-std::shared_ptr<const ResourceClientRegistration> Registry::lookup_resource_client(const API& api) {
+std::shared_ptr<const ResourceClientRegistration> Registry::lookup_resource_client(
+    const API& api) const {
     const std::lock_guard<std::mutex> lock(lock_);
     if (client_apis_.find(api) == client_apis_.end()) {
         return nullptr;
@@ -161,7 +163,7 @@ std::shared_ptr<const ResourceClientRegistration> Registry::lookup_resource_clie
 }
 
 const google::protobuf::ServiceDescriptor* Registry::get_service_descriptor_(
-    const char* service_full_name) {
+    const char* service_full_name) const {
     const google::protobuf::DescriptorPool* p = google::protobuf::DescriptorPool::generated_pool();
     const google::protobuf::ServiceDescriptor* sd = p->FindServiceByName(service_full_name);
     if (!sd) {
@@ -171,12 +173,12 @@ const google::protobuf::ServiceDescriptor* Registry::get_service_descriptor_(
 }
 
 const std::unordered_map<API, std::shared_ptr<const ResourceServerRegistration>>&
-Registry::registered_resource_servers() {
+Registry::registered_resource_servers() const {
     return server_apis_;
 }
 
 const std::unordered_map<std::string, std::shared_ptr<const ModelRegistration>>&
-Registry::registered_models() {
+Registry::registered_models() const {
     return resources_;
 }
 
@@ -184,28 +186,28 @@ const google::protobuf::ServiceDescriptor* ResourceServerRegistration::service_d
     return service_descriptor_;
 }
 
-void register_resources() {
+void Registry::register_resources() {
     // Register all components
-    Registry::register_resource<impl::ArmClient, impl::ArmServer>();
-    Registry::register_resource<impl::BaseClient, impl::BaseServer>();
-    Registry::register_resource<impl::BoardClient, impl::BoardServer>();
-    Registry::register_resource<impl::CameraClient, impl::CameraServer>();
-    Registry::register_resource<impl::EncoderClient, impl::EncoderServer>();
-    Registry::register_resource<impl::GantryClient, impl::GantryServer>();
-    Registry::register_resource<impl::GenericComponentClient, impl::GenericComponentServer>();
-    Registry::register_resource<impl::GripperClient, impl::GripperServer>();
-    Registry::register_resource<impl::MotorClient, impl::MotorServer>();
-    Registry::register_resource<impl::MovementSensorClient, impl::MovementSensorServer>();
-    Registry::register_resource<impl::PoseTrackerClient, impl::PoseTrackerServer>();
-    Registry::register_resource<impl::PowerSensorClient, impl::PowerSensorServer>();
-    Registry::register_resource<impl::SensorClient, impl::SensorServer>();
-    Registry::register_resource<impl::ServoClient, impl::ServoServer>();
+    register_resource<impl::ArmClient, impl::ArmServer>();
+    register_resource<impl::BaseClient, impl::BaseServer>();
+    register_resource<impl::BoardClient, impl::BoardServer>();
+    register_resource<impl::CameraClient, impl::CameraServer>();
+    register_resource<impl::EncoderClient, impl::EncoderServer>();
+    register_resource<impl::GantryClient, impl::GantryServer>();
+    register_resource<impl::GenericComponentClient, impl::GenericComponentServer>();
+    register_resource<impl::GripperClient, impl::GripperServer>();
+    register_resource<impl::MotorClient, impl::MotorServer>();
+    register_resource<impl::MovementSensorClient, impl::MovementSensorServer>();
+    register_resource<impl::PoseTrackerClient, impl::PoseTrackerServer>();
+    register_resource<impl::PowerSensorClient, impl::PowerSensorServer>();
+    register_resource<impl::SensorClient, impl::SensorServer>();
+    register_resource<impl::ServoClient, impl::ServoServer>();
 
     // Register all services
-    Registry::register_resource<impl::GenericServiceClient, impl::GenericServiceServer>();
-    Registry::register_resource<impl::MLModelServiceClient, impl::MLModelServiceServer>();
-    Registry::register_resource<impl::MotionClient, impl::MotionServer>();
-    Registry::register_resource<impl::NavigationClient, impl::NavigationServer>();
+    register_resource<impl::GenericServiceClient, impl::GenericServiceServer>();
+    register_resource<impl::MLModelServiceClient, impl::MLModelServiceServer>();
+    register_resource<impl::MotionClient, impl::MotionServer>();
+    register_resource<impl::NavigationClient, impl::NavigationServer>();
 }
 
 void Registry::initialize() {
@@ -220,11 +222,5 @@ void Registry::initialize() {
     grpc::reflection::InitProtoReflectionServerBuilderPlugin();
 }
 
-std::unordered_map<std::string, std::shared_ptr<const ModelRegistration>> Registry::resources_;
-std::unordered_map<API, std::shared_ptr<const ResourceClientRegistration>> Registry::client_apis_;
-std::unordered_map<API, std::shared_ptr<const ResourceServerRegistration>> Registry::server_apis_;
-std::mutex Registry::lock_;
-bool Registry::initialized_{false};
-
 }  // namespace sdk
 }  // namespace viam
diff --git a/src/viam/sdk/registry/registry.hpp b/src/viam/sdk/registry/registry.hpp
index b00d98833..4431575d6 100644
--- a/src/viam/sdk/registry/registry.hpp
+++ b/src/viam/sdk/registry/registry.hpp
@@ -106,23 +106,22 @@ class Registry {
     /// @brief Registers a resource with the Registry.
     /// @param resource An object containing resource registration information.
     /// @throws `Exception` if the resource has already been registered.
-    static void register_model(std::shared_ptr<const ModelRegistration> resource);
+    void register_model(std::shared_ptr<const ModelRegistration> resource);
 
     /// @brief Lookup a given registered resource.
     /// @param name The name of the resource to lookup.
     /// @return a `shared_ptr` to the resource's registration data.
-    static std::shared_ptr<const ModelRegistration> lookup_model(const std::string& name);
+    std::shared_ptr<const ModelRegistration> lookup_model(const std::string& name) const;
 
     /// @brief Lookup a given registered resource.
     /// @param api The api of the resource to lookup.
     /// @param model The model of the resource to lookup.
     /// @return a `shared_ptr` to the resource's registration data.
-    static std::shared_ptr<const ModelRegistration> lookup_model(const API& api,
-                                                                 const Model& model);
+    std::shared_ptr<const ModelRegistration> lookup_model(const API& api, const Model& model) const;
 
     /// @brief Register a resource client constructor
     template <typename ResourceClientT>
-    static void register_resource_client() {
+    void register_resource_client() {
         class ResourceClientRegistration2 final : public ResourceClientRegistration {
            public:
             using ResourceClientRegistration::ResourceClientRegistration;
@@ -139,7 +138,7 @@ class Registry {
 
     /// @brief Register a resource server constructor.
     template <typename ResourceServerT>
-    static void register_resource_server() {
+    void register_resource_server() {
         class ResourceServerRegistration2 final : public ResourceServerRegistration {
            public:
             using ResourceServerRegistration::ResourceServerRegistration;
@@ -159,7 +158,7 @@ class Registry {
 
     /// @brief Register resource client and server constructors
     template <typename ResourceClientT, typename ResourceServerT>
-    static void register_resource() {
+    void register_resource() {
         register_resource_client<ResourceClientT>();
         register_resource_server<ResourceServerT>();
     }
@@ -167,44 +166,46 @@ class Registry {
     /// @brief Lookup a registered server api.
     /// @param api The api to lookup.
     /// @return A `shared_ptr` to the registered api's `ResourceServerRegistration`.
-    static std::shared_ptr<const ResourceServerRegistration> lookup_resource_server(const API& api);
+    std::shared_ptr<const ResourceServerRegistration> lookup_resource_server(const API& api) const;
 
     /// @brief Lookup a registered client api.
     /// @param api The api to lookup.
     /// @return A `shared_ptr` to the registered api's `ResourceClientRegistration`.
-    static std::shared_ptr<const ResourceClientRegistration> lookup_resource_client(const API& api);
+    std::shared_ptr<const ResourceClientRegistration> lookup_resource_client(const API& api) const;
 
     /// @brief Provide information on registered resource models.
     /// @return A map from name to `ModelRegistration` of all registered resource models.
-    static const std::unordered_map<std::string, std::shared_ptr<const ModelRegistration>>&
-    registered_models();
+    const std::unordered_map<std::string, std::shared_ptr<const ModelRegistration>>&
+    registered_models() const;
 
     /// @brief Provide access to registered resources.
     /// @return A map from `API` to `ResourceServerRegistration` of all registered resources.
-    static const std::unordered_map<API, std::shared_ptr<const ResourceServerRegistration>>&
-    registered_resource_servers();
+    const std::unordered_map<API, std::shared_ptr<const ResourceServerRegistration>>&
+    registered_resource_servers() const;
 
     /// @brief Initialized the Viam registry. No-op if it has already been called.
-    static void initialize();
+    void initialize();
 
    private:
-    static std::mutex lock_;
-    static bool initialized_;
-    static std::unordered_map<std::string, std::shared_ptr<const ModelRegistration>> resources_;
-    static std::unordered_map<API, std::shared_ptr<const ResourceClientRegistration>> client_apis_;
-    static std::unordered_map<API, std::shared_ptr<const ResourceServerRegistration>> server_apis_;
+    mutable std::mutex lock_;
+    bool initialized_{false};
+    std::unordered_map<std::string, std::shared_ptr<const ModelRegistration>> resources_;
+    std::unordered_map<API, std::shared_ptr<const ResourceClientRegistration>> client_apis_;
+    std::unordered_map<API, std::shared_ptr<const ResourceServerRegistration>> server_apis_;
 
-    static void register_resource_server_(
+    void register_resources();
+
+    void register_resource_server_(
         API api, std::shared_ptr<ResourceServerRegistration> resource_registration);
 
-    static void register_resource_client_(
+    void register_resource_client_(
         API api, std::shared_ptr<ResourceClientRegistration> resource_registration);
 
-    static const google::protobuf::ServiceDescriptor* get_service_descriptor_(
-        const char* service_full_name);
+    const google::protobuf::ServiceDescriptor* get_service_descriptor_(
+        const char* service_full_name) const;
 
-    static std::shared_ptr<const ModelRegistration> lookup_model_inlock_(
-        const std::string& name, const std::lock_guard<std::mutex>&);
+    std::shared_ptr<const ModelRegistration> lookup_model_inlock_(
+        const std::string& name, const std::lock_guard<std::mutex>&) const;
 };
 
 }  // namespace sdk
diff --git a/src/viam/sdk/robot/client.cpp b/src/viam/sdk/robot/client.cpp
index fff691fd2..6ac049eba 100644
--- a/src/viam/sdk/robot/client.cpp
+++ b/src/viam/sdk/robot/client.cpp
@@ -178,7 +178,7 @@ void RobotClient::refresh() {
         // are being properly registered from name.subtype(), or update what we're
         // using for lookup
         const std::shared_ptr<const ResourceClientRegistration> rs =
-            Registry::lookup_resource_client({name.namespace_(), name.type(), name.subtype()});
+            registry_.lookup_resource_client({name.namespace_(), name.type(), name.subtype()});
         if (rs) {
             try {
                 const std::shared_ptr<Resource> rpc_client =
@@ -221,13 +221,12 @@ void RobotClient::refresh_every() {
     }
 };
 
-RobotClient::RobotClient(std::shared_ptr<ViamChannel> channel)
-    : channel_(channel->channel()),
+RobotClient::RobotClient(std::shared_ptr<ViamChannel> channel, Registry& registry)
+    : registry_(registry),
+      channel_(channel->channel()),
       viam_channel_(std::move(channel)),
       should_close_channel_(false),
-      impl_(std::make_unique<impl>(RobotService::NewStub(channel_))) {
-    Registry::initialize();
-}
+      impl_(std::make_unique<impl>(RobotService::NewStub(channel_))) {}
 
 std::vector<Name> RobotClient::resource_names() const {
     const std::lock_guard<std::mutex> lock(lock_);
@@ -235,8 +234,10 @@ std::vector<Name> RobotClient::resource_names() const {
 }
 
 std::shared_ptr<RobotClient> RobotClient::with_channel(std::shared_ptr<ViamChannel> channel,
-                                                       const Options& options) {
-    std::shared_ptr<RobotClient> robot = std::make_shared<RobotClient>(std::move(channel));
+                                                       const Options& options,
+                                                       Registry& registry) {
+    std::shared_ptr<RobotClient> robot =
+        std::make_shared<RobotClient>(std::move(channel), registry);
     robot->refresh_interval_ = options.refresh_interval();
     robot->should_refresh_ = (robot->refresh_interval_ > 0);
     if (robot->should_refresh_) {
@@ -254,23 +255,25 @@ std::shared_ptr<RobotClient> RobotClient::with_channel(std::shared_ptr<ViamChann
 };
 
 std::shared_ptr<RobotClient> RobotClient::at_address(const std::string& address,
-                                                     const Options& options) {
+                                                     const Options& options,
+                                                     Registry& registry) {
     const char* uri = address.c_str();
     auto channel = ViamChannel::dial(uri, options.dial_options());
-    std::shared_ptr<RobotClient> robot = RobotClient::with_channel(channel, options);
+    std::shared_ptr<RobotClient> robot = RobotClient::with_channel(channel, options, registry);
     robot->should_close_channel_ = true;
 
     return robot;
 };
 
 std::shared_ptr<RobotClient> RobotClient::at_local_socket(const std::string& address,
-                                                          const Options& options) {
+                                                          const Options& options,
+                                                          Registry& registry) {
     const std::string addr = "unix://" + address;
     const char* uri = addr.c_str();
     const std::shared_ptr<grpc::Channel> channel =
         sdk::impl::create_viam_channel(uri, grpc::InsecureChannelCredentials());
     auto viam_channel = std::make_shared<ViamChannel>(channel, address.c_str(), nullptr);
-    std::shared_ptr<RobotClient> robot = RobotClient::with_channel(viam_channel, options);
+    std::shared_ptr<RobotClient> robot = RobotClient::with_channel(viam_channel, options, registry);
     robot->should_close_channel_ = true;
 
     return robot;
diff --git a/src/viam/sdk/robot/client.hpp b/src/viam/sdk/robot/client.hpp
index 9d63bd14b..09834e1d8 100644
--- a/src/viam/sdk/robot/client.hpp
+++ b/src/viam/sdk/robot/client.hpp
@@ -68,7 +68,8 @@ class RobotClient {
     /// @param address The address of the robot (IP address, URI, URL, etc.)
     /// @param options Options for connecting and refreshing.
     static std::shared_ptr<RobotClient> at_address(const std::string& address,
-                                                   const Options& options);
+                                                   const Options& options,
+                                                   Registry& registry);
 
     /// @brief Creates a robot client connected to the robot at the provided local socket.
     /// @param address The local socket of the robot (a .sock file, etc.).
@@ -76,7 +77,8 @@ class RobotClient {
     /// Creates a direct connection to the robot using the `unix://` scheme.
     /// Only useful for connecting to robots across Unix sockets.
     static std::shared_ptr<RobotClient> at_local_socket(const std::string& address,
-                                                        const Options& options);
+                                                        const Options& options,
+                                                        Registry& registry);
 
     /// @brief Creates a robot client connected to the provided channel.
     /// @param channel The channel to connect with.
@@ -84,8 +86,11 @@ class RobotClient {
     /// Connects directly to a pre-existing channel. A robot created this way must be
     /// `close()`d manually.
     static std::shared_ptr<RobotClient> with_channel(std::shared_ptr<ViamChannel> channel,
-                                                     const Options& options);
-    RobotClient(std::shared_ptr<ViamChannel> channel);
+                                                     const Options& options,
+                                                     Registry& registry);
+
+    RobotClient(std::shared_ptr<ViamChannel> channel, Registry& registry);
+
     std::vector<Name> resource_names() const;
 
     /// @brief Lookup and return a `shared_ptr` to a resource.
@@ -147,17 +152,25 @@ class RobotClient {
     status get_machine_status() const;
 
    private:
+    Registry& registry_;
+
     std::vector<std::shared_ptr<std::thread>> threads_;
+
     std::atomic<bool> should_refresh_;
     unsigned int refresh_interval_;
+
     std::shared_ptr<GrpcChannel> channel_;
     std::shared_ptr<ViamChannel> viam_channel_;
     bool should_close_channel_;
+
     struct impl;
     std::unique_ptr<impl> impl_;
+
     mutable std::mutex lock_;
+
     std::vector<Name> resource_names_;
     ResourceManager resource_manager_;
+
     void refresh_every();
 };
 
diff --git a/src/viam/sdk/rpc/server.cpp b/src/viam/sdk/rpc/server.cpp
index 408f23bf6..b2c46c695 100644
--- a/src/viam/sdk/rpc/server.cpp
+++ b/src/viam/sdk/rpc/server.cpp
@@ -15,12 +15,11 @@
 namespace viam {
 namespace sdk {
 
-Server::Server() : builder_(std::make_unique<grpc::ServerBuilder>()) {
+Server::Server(const Registry* registry) : builder_(std::make_unique<grpc::ServerBuilder>()) {
     builder_->SetMaxReceiveMessageSize(kMaxMessageSize);
     builder_->SetMaxSendMessageSize(kMaxMessageSize);
     builder_->SetMaxMessageSize(kMaxMessageSize);
-    Registry::initialize();
-    for (const auto& rr : Registry::registered_resource_servers()) {
+    for (const auto& rr : registry->registered_resource_servers()) {
         auto new_manager = std::make_shared<ResourceManager>();
         auto server = rr.second->create_resource_server(new_manager, *this);
         managed_servers_.emplace(rr.first, std::move(server));
diff --git a/src/viam/sdk/rpc/server.hpp b/src/viam/sdk/rpc/server.hpp
index e735a6351..5f868b779 100644
--- a/src/viam/sdk/rpc/server.hpp
+++ b/src/viam/sdk/rpc/server.hpp
@@ -23,11 +23,13 @@ class TestServer;
 
 namespace sdk {
 
+class Registry;
+
 /// @class Server server.hpp "rpc/server.hpp"
 /// @brief Defines gRPC `Server` functionality.
 class Server {
    public:
-    Server();
+    Server(const Registry* registry);
     ~Server();
 
     /// @brief Starts the grpc server. Can only be called once.

From 04d0158412c31836d226576668c90ce36234d4f0 Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Tue, 18 Feb 2025 14:14:58 -0500
Subject: [PATCH 03/31] add missing implementation

---
 src/viam/sdk/common/instance.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/viam/sdk/common/instance.cpp b/src/viam/sdk/common/instance.cpp
index 1ec93d01f..3c277273d 100644
--- a/src/viam/sdk/common/instance.cpp
+++ b/src/viam/sdk/common/instance.cpp
@@ -7,5 +7,9 @@ Instance::Instance() {
     registry_.initialize();
 }
 
+Registry& Instance::registry() {
+    return registry_;
+}
+
 }  // namespace sdk
 }  // namespace viam

From a105cef7426252039a7917153e0a34d3afc0a5a2 Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Tue, 18 Feb 2025 14:15:56 -0500
Subject: [PATCH 04/31] update examples to use instance

---
 src/viam/examples/modules/simple/client.cpp | 5 ++++-
 src/viam/examples/modules/simple/main.cpp   | 5 ++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/viam/examples/modules/simple/client.cpp b/src/viam/examples/modules/simple/client.cpp
index fcaab5eff..ac014d1e7 100644
--- a/src/viam/examples/modules/simple/client.cpp
+++ b/src/viam/examples/modules/simple/client.cpp
@@ -2,6 +2,7 @@
 #include <memory>
 #include <string>
 
+#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/common/proto_value.hpp>
 #include <viam/sdk/components/sensor.hpp>
 #include <viam/sdk/robot/client.hpp>
@@ -10,6 +11,8 @@
 using namespace viam::sdk;
 
 int main() {
+    Instance inst;
+
     const char* uri = "http://localhost:8080/";  // replace with your URI if connecting securely
     DialOptions dial_options;
     dial_options.set_allow_insecure_downgrade(true);  // set to false if connecting securely
@@ -24,7 +27,7 @@ int main() {
     std::string address(uri);
     Options options(1, opts);
 
-    std::shared_ptr<RobotClient> robot = RobotClient::at_address(address, options);
+    std::shared_ptr<RobotClient> robot = RobotClient::at_address(address, options, inst.registry());
 
     // Print resources
     std::cout << "Resources\n";
diff --git a/src/viam/examples/modules/simple/main.cpp b/src/viam/examples/modules/simple/main.cpp
index cfd783f66..b899d3b44 100644
--- a/src/viam/examples/modules/simple/main.cpp
+++ b/src/viam/examples/modules/simple/main.cpp
@@ -3,6 +3,7 @@
 #include <sstream>
 
 #include <viam/sdk/common/exception.hpp>
+#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/common/proto_value.hpp>
 #include <viam/sdk/components/sensor.hpp>
 #include <viam/sdk/config/resource.hpp>
@@ -75,6 +76,8 @@ ProtoStruct MySensor::get_readings(const ProtoStruct&) {
 }
 
 int main(int argc, char** argv) try {
+    Instance inst;
+
     Model mysensor_model("viam", "sensor", "mysensor");
 
     std::shared_ptr<ModelRegistration> mr = std::make_shared<ModelRegistration>(
@@ -84,7 +87,7 @@ int main(int argc, char** argv) try {
         &MySensor::validate);
 
     std::vector<std::shared_ptr<ModelRegistration>> mrs = {mr};
-    auto my_mod = std::make_shared<ModuleService>(argc, argv, mrs);
+    auto my_mod = std::make_shared<ModuleService>(argc, argv, mrs, inst.registry());
     my_mod->serve();
 
     return EXIT_SUCCESS;

From 403f31610d1b95a705b466fad0b0873934acec0c Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Tue, 18 Feb 2025 16:21:21 -0500
Subject: [PATCH 05/31] only instance can construct registry

---
 src/viam/sdk/registry/registry.hpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/viam/sdk/registry/registry.hpp b/src/viam/sdk/registry/registry.hpp
index 4431575d6..a98e05c6e 100644
--- a/src/viam/sdk/registry/registry.hpp
+++ b/src/viam/sdk/registry/registry.hpp
@@ -187,6 +187,10 @@ class Registry {
     void initialize();
 
    private:
+    friend class Instance;
+
+    Registry() = default;
+
     mutable std::mutex lock_;
     bool initialized_{false};
     std::unordered_map<std::string, std::shared_ptr<const ModelRegistration>> resources_;

From 27eeb1331c28810243859a7c5f0f5606a4e69ba6 Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Fri, 21 Feb 2025 12:55:42 -0500
Subject: [PATCH 06/31] make tests work with registry member approach

---
 src/viam/sdk/registry/registry.hpp      |  6 +++---
 src/viam/sdk/tests/mocks/mock_robot.cpp |  2 +-
 src/viam/sdk/tests/test_robot.cpp       | 19 +++++++++++--------
 src/viam/sdk/tests/test_utils.hpp       | 17 +++++++++++++++--
 4 files changed, 30 insertions(+), 14 deletions(-)

diff --git a/src/viam/sdk/registry/registry.hpp b/src/viam/sdk/registry/registry.hpp
index a98e05c6e..75e2324e3 100644
--- a/src/viam/sdk/registry/registry.hpp
+++ b/src/viam/sdk/registry/registry.hpp
@@ -183,14 +183,14 @@ class Registry {
     const std::unordered_map<API, std::shared_ptr<const ResourceServerRegistration>>&
     registered_resource_servers() const;
 
-    /// @brief Initialized the Viam registry. No-op if it has already been called.
-    void initialize();
-
    private:
     friend class Instance;
 
     Registry() = default;
 
+    /// @brief Initialized the Viam registry. No-op if it has already been called.
+    void initialize();
+
     mutable std::mutex lock_;
     bool initialized_{false};
     std::unordered_map<std::string, std::shared_ptr<const ModelRegistration>> resources_;
diff --git a/src/viam/sdk/tests/mocks/mock_robot.cpp b/src/viam/sdk/tests/mocks/mock_robot.cpp
index cdef0fe78..8e28b944b 100644
--- a/src/viam/sdk/tests/mocks/mock_robot.cpp
+++ b/src/viam/sdk/tests/mocks/mock_robot.cpp
@@ -26,7 +26,7 @@ std::vector<Name> registered_models_for_resource(const std::shared_ptr<Resource>
     std::string resource_type;
     std::string resource_subtype;
     std::vector<Name> resource_names;
-    for (const auto& kv : Registry::registered_models()) {
+    for (const auto& kv : GlobalInstance::registry().registered_models()) {
         const std::shared_ptr<const ModelRegistration> reg = kv.second;
         if (reg->api() == resource->api()) {
             resource_type = reg->api().resource_type();
diff --git a/src/viam/sdk/tests/test_robot.cpp b/src/viam/sdk/tests/test_robot.cpp
index 9f1093d49..e7ccc0de1 100644
--- a/src/viam/sdk/tests/test_robot.cpp
+++ b/src/viam/sdk/tests/test_robot.cpp
@@ -42,7 +42,7 @@ void robot_client_to_mocks_pipeline(F&& test_case) {
     rm->add(std::string("mock_generic"), generic::MockGenericComponent::get_mock_generic());
     rm->add(std::string("mock_motor"), motor::MockMotor::get_mock_motor());
     rm->add(std::string("mock_camera"), camera::MockCamera::get_mock_camera());
-    auto server = std::make_shared<sdk::Server>();
+    auto server = std::make_shared<sdk::Server>(&GlobalInstance::registry());
     MockRobotService service(rm, *server);
     server->start();
 
@@ -51,7 +51,8 @@ void robot_client_to_mocks_pipeline(F&& test_case) {
     auto test_server = TestServer(server);
     auto grpc_channel = test_server.grpc_in_process_channel();
     auto viam_channel = std::make_shared<ViamChannel>(grpc_channel, "", nullptr);
-    auto client = RobotClient::with_channel(viam_channel, Options(0, boost::none));
+    auto client = RobotClient::with_channel(
+        viam_channel, Options(0, boost::none), GlobalInstance::registry());
 
     // Run the passed-in test case on the created stack and give access to the
     // created RobotClient and MockRobotService.
@@ -62,6 +63,8 @@ void robot_client_to_mocks_pipeline(F&& test_case) {
 }
 
 BOOST_AUTO_TEST_CASE(test_registering_resources) {
+    auto& registry = GlobalInstance::registry();
+
     // To test with mock resources we need to be able to create them, which means registering
     // constructors. This tests that we register correctly.
     Model camera_model("fake", "fake", "mock_camera");
@@ -70,7 +73,7 @@ BOOST_AUTO_TEST_CASE(test_registering_resources) {
         camera_model,
         [](Dependencies, ResourceConfig cfg) { return camera::MockCamera::get_mock_camera(); },
         [](ResourceConfig cfg) -> std::vector<std::string> { return {}; });
-    Registry::register_model(cr);
+    registry.register_model(cr);
 
     Model generic_model("fake", "fake", "mock_generic");
     std::shared_ptr<ModelRegistration> gr = std::make_shared<ModelRegistration>(
@@ -80,7 +83,7 @@ BOOST_AUTO_TEST_CASE(test_registering_resources) {
             return generic::MockGenericComponent::get_mock_generic();
         },
         [](ResourceConfig cfg) -> std::vector<std::string> { return {}; });
-    Registry::register_model(gr);
+    registry.register_model(gr);
 
     Model motor_model("fake", "fake", "mock_motor");
     std::shared_ptr<ModelRegistration> mr = std::make_shared<ModelRegistration>(
@@ -88,11 +91,11 @@ BOOST_AUTO_TEST_CASE(test_registering_resources) {
         motor_model,
         [](Dependencies, ResourceConfig cfg) { return motor::MockMotor::get_mock_motor(); },
         [](ResourceConfig cfg) -> std::vector<std::string> { return {}; });
-    Registry::register_model(mr);
+    registry.register_model(mr);
 
-    BOOST_CHECK(Registry::lookup_model(API::get<Camera>(), camera_model));
-    BOOST_CHECK(Registry::lookup_model(API::get<GenericComponent>(), generic_model));
-    BOOST_CHECK(Registry::lookup_model(API::get<Motor>(), motor_model));
+    BOOST_CHECK(registry.lookup_model(API::get<Camera>(), camera_model));
+    BOOST_CHECK(registry.lookup_model(API::get<GenericComponent>(), generic_model));
+    BOOST_CHECK(registry.lookup_model(API::get<Motor>(), motor_model));
 }
 
 BOOST_AUTO_TEST_CASE(test_resource_names) {
diff --git a/src/viam/sdk/tests/test_utils.hpp b/src/viam/sdk/tests/test_utils.hpp
index 400bc54a2..c24bed482 100644
--- a/src/viam/sdk/tests/test_utils.hpp
+++ b/src/viam/sdk/tests/test_utils.hpp
@@ -2,6 +2,7 @@
 
 #include <grpcpp/grpcpp.h>
 
+#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/config/resource.hpp>
 #include <viam/sdk/registry/registry.hpp>
 #include <viam/sdk/resource/resource.hpp>
@@ -10,6 +11,17 @@
 namespace viam {
 namespace sdktests {
 
+struct GlobalInstance {
+    static sdk::Instance& get() {
+        static sdk::Instance inst;
+        return inst;
+    }
+
+    static sdk::Registry& registry() {
+        return get().registry();
+    }
+};
+
 using namespace viam::sdk;
 
 ProtoStruct fake_map();
@@ -49,7 +61,7 @@ class TestServer {
 // The passed in test_case function will have access to the created ResourceClient.
 template <typename ResourceType, typename F>
 void client_to_mock_pipeline(std::shared_ptr<Resource> mock, F&& test_case) {
-    auto server = std::make_shared<sdk::Server>();
+    auto server = std::make_shared<sdk::Server>(&GlobalInstance::registry());
 
     // normally the high level server service (either robot or module) handles adding managed
     // resources, but in this case we must do it ourselves.
@@ -61,7 +73,8 @@ void client_to_mock_pipeline(std::shared_ptr<Resource> mock, F&& test_case) {
     auto test_server = TestServer(server);
     auto grpc_channel = test_server.grpc_in_process_channel();
 
-    auto resource_client = Registry::lookup_resource_client(API::get<ResourceType>())
+    auto resource_client = GlobalInstance::registry()
+                               .lookup_resource_client(API::get<ResourceType>())
                                ->create_rpc_client(mock->name(), std::move(grpc_channel));
 
     // Run the passed-in test case on the created stack and give access to the

From ce2aa8c54852cb2e88ff53dbc831331dd0081e02 Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Mon, 24 Feb 2025 16:17:18 -0500
Subject: [PATCH 07/31] pimpl registry and update examples

---
 src/viam/examples/camera/example_camera.cpp      |  8 +++++++-
 src/viam/examples/dial/example_dial.cpp          |  7 ++++++-
 .../dial_api_key/example_dial_api_key.cpp        |  7 ++++++-
 .../example_audio_classification_client.cpp      |  9 +++++++--
 src/viam/examples/modules/complex/client.cpp     | 11 ++++++++---
 src/viam/examples/modules/complex/main.cpp       | 11 ++++++++---
 .../modules/complex/test_complex_module.cpp      |  5 +++--
 src/viam/examples/motor/example_motor.cpp        |  8 +++++++-
 src/viam/sdk/common/instance.cpp                 | 16 ++++++++++++----
 src/viam/sdk/common/instance.hpp                 | 10 +++++++---
 src/viam/sdk/module/service.cpp                  | 16 ++++++++--------
 src/viam/sdk/module/service.hpp                  |  6 +++---
 src/viam/sdk/registry/registry.hpp               |  1 -
 src/viam/sdk/robot/client.cpp                    | 10 +++++-----
 src/viam/sdk/robot/client.hpp                    | 14 ++++++++------
 src/viam/sdk/tests/mocks/mock_robot.cpp          |  2 +-
 src/viam/sdk/tests/test_robot.cpp                |  4 ++--
 src/viam/sdk/tests/test_utils.hpp                |  6 +++---
 18 files changed, 101 insertions(+), 50 deletions(-)

diff --git a/src/viam/examples/camera/example_camera.cpp b/src/viam/examples/camera/example_camera.cpp
index bc1b0ab9a..b0202a27e 100644
--- a/src/viam/examples/camera/example_camera.cpp
+++ b/src/viam/examples/camera/example_camera.cpp
@@ -3,6 +3,7 @@
 #include <unistd.h>
 #include <vector>
 
+#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/components/camera.hpp>
 #include <viam/sdk/robot/client.hpp>
 #include <viam/sdk/rpc/dial.hpp>
@@ -13,6 +14,11 @@ int main() {
     using std::endl;
     namespace vs = ::viam::sdk;
     try {
+        // Every Viam C++ SDK program must have one and only one Instance object which is created
+        // before
+        // any other C++ SDK objects and stays alive until all Viam C++ SDK objects are destroyed.
+        vs::Instance inst;
+
         // If you want to connect to a remote robot, this should be the url of the robot
         // Ex: xxx.xxx.viam.cloud
         std::string robot_address("localhost:8080");
@@ -35,7 +41,7 @@ int main() {
 
         std::shared_ptr<vs::RobotClient> robot;
         try {
-            robot = vs::RobotClient::at_address(robot_address, options);
+            robot = vs::RobotClient::at_address(robot_address, options, inst.registry());
             cout << "Successfully connected to the robot" << endl;
         } catch (const std::exception& e) {
             cerr << "Failed to connect to the robot. Exiting." << endl;
diff --git a/src/viam/examples/dial/example_dial.cpp b/src/viam/examples/dial/example_dial.cpp
index efa783dfb..28ccd7659 100644
--- a/src/viam/examples/dial/example_dial.cpp
+++ b/src/viam/examples/dial/example_dial.cpp
@@ -9,6 +9,7 @@
 
 #include <boost/optional.hpp>
 
+#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/components/generic.hpp>
 #include <viam/sdk/robot/client.hpp>
 #include <viam/sdk/rpc/dial.hpp>
@@ -16,6 +17,10 @@
 using namespace viam::sdk;
 
 int main() {
+    // Every Viam C++ SDK program must have one and only one Instance object which is created before
+    // any other C++ SDK objects and stays alive until all Viam C++ SDK objects are destroyed.
+    Instance inst;
+
     const char* uri = "<your robot URI here>";
     DialOptions dial_options;
     std::string type = "<your authentication type>";
@@ -27,7 +32,7 @@ int main() {
     Options options(1, opts);
 
     // connect to robot, ensure we can refresh it
-    std::shared_ptr<RobotClient> robot = RobotClient::at_address(address, options);
+    std::shared_ptr<RobotClient> robot = RobotClient::at_address(address, options, inst.registry());
 
     // ensure we can query resources
     std::vector<Name> resource_names = robot->resource_names();
diff --git a/src/viam/examples/dial_api_key/example_dial_api_key.cpp b/src/viam/examples/dial_api_key/example_dial_api_key.cpp
index 4c47beffe..7c9e82fef 100644
--- a/src/viam/examples/dial_api_key/example_dial_api_key.cpp
+++ b/src/viam/examples/dial_api_key/example_dial_api_key.cpp
@@ -10,6 +10,7 @@
 #include <boost/optional.hpp>
 #include <boost/program_options.hpp>
 
+#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/robot/client.hpp>
 #include <viam/sdk/rpc/dial.hpp>
 
@@ -18,6 +19,10 @@ using namespace viam::sdk;
 namespace po = boost::program_options;
 
 int main(int argc, char* argv[]) {
+    // Every Viam C++ SDK program must have one and only one Instance object which is created before
+    // any other C++ SDK objects and stays alive until all Viam C++ SDK objects are destroyed.
+    Instance inst;
+
     po::options_description desc("Allowed options");
     desc.add_options()("help", "List options and exit")(
         "uri", po::value<std::string>(), "URI of robot")(
@@ -41,7 +46,7 @@ int main(int argc, char* argv[]) {
 
     // connect to robot, ensure we can refresh it
     std::shared_ptr<RobotClient> robot =
-        RobotClient::at_address(vm["uri"].as<std::string>(), options);
+        RobotClient::at_address(vm["uri"].as<std::string>(), options, inst.registry());
 
     // ensure we can query resources
     std::vector<Name> resource_names = robot->resource_names();
diff --git a/src/viam/examples/mlmodel/example_audio_classification_client.cpp b/src/viam/examples/mlmodel/example_audio_classification_client.cpp
index 95e26f57c..ab06a082e 100644
--- a/src/viam/examples/mlmodel/example_audio_classification_client.cpp
+++ b/src/viam/examples/mlmodel/example_audio_classification_client.cpp
@@ -29,6 +29,7 @@
 #include <boost/program_options.hpp>
 #include <boost/variant/get.hpp>
 
+#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/robot/client.hpp>
 #include <viam/sdk/services/mlmodel.hpp>
 
@@ -78,6 +79,10 @@ constexpr char kRobotConfigTemplate[] = R"(
 }  // namespace
 
 int main(int argc, char* argv[]) try {
+    // Every Viam C++ SDK program must have one and only one Instance object which is created before
+    // any other C++ SDK objects and stays alive until all Viam C++ SDK objects are destroyed.
+    viam::sdk::Instance inst;
+
     // Build up our command line options. The example operates in two
     // modes. In the "--generate" mode, it takes command line
     // parameters needed to satisfy the interpolation points in the
@@ -234,8 +239,8 @@ int main(int argc, char* argv[]) try {
         dial_options.set_entity(opt_api_key_id.get());
         dial_options.set_credentials(viam::sdk::Credentials("api-key", opt_api_key.get()));
 
-        auto robot =
-            vsdk::RobotClient::at_address(opt_robot_host.get(), {0, {std::move(dial_options)}});
+        auto robot = vsdk::RobotClient::at_address(
+            opt_robot_host.get(), {0, {std::move(dial_options)}}, inst.registry());
 
         // Obtain a handle to the MLModelService module on the robot. Note that the string
         // `yamnet_classification_tflite` is arbitrary. It just matches what was used to name the
diff --git a/src/viam/examples/modules/complex/client.cpp b/src/viam/examples/modules/complex/client.cpp
index ed321abd5..ea3444844 100644
--- a/src/viam/examples/modules/complex/client.cpp
+++ b/src/viam/examples/modules/complex/client.cpp
@@ -11,6 +11,7 @@
 #include <grpcpp/grpcpp.h>
 #include <grpcpp/support/status.h>
 
+#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/components/motor.hpp>
 #include <viam/sdk/robot/client.hpp>
 #include <viam/sdk/rpc/dial.hpp>
@@ -21,6 +22,10 @@
 using namespace viam::sdk;
 
 int main() {
+    // Every Viam C++ SDK program must have one and only one Instance object which is created before
+    // any other C++ SDK objects and stays alive until all Viam C++ SDK objects are destroyed.
+    Instance inst;
+
     const char* uri = "http://localhost:8080/";  // replace with your URI if connecting securely
     DialOptions dial_options;
     dial_options.set_allow_insecure_downgrade(true);  // set to false if connecting securely
@@ -37,11 +42,11 @@ int main() {
 
     // Register custom gizmo and summation clients so robot client can access resources
     // of that type from the server.
-    Registry::register_resource_client<GizmoClient>();
-    Registry::register_resource_client<SummationClient>();
+    inst.registry()->register_resource_client<GizmoClient>();
+    inst.registry()->register_resource_client<SummationClient>();
 
     // Connect to robot.
-    std::shared_ptr<RobotClient> robot = RobotClient::at_address(address, options);
+    std::shared_ptr<RobotClient> robot = RobotClient::at_address(address, options, inst.registry());
     // Print resources.
     std::cout << "Resources" << std::endl;
     std::vector<Name> resource_names = robot->resource_names();
diff --git a/src/viam/examples/modules/complex/main.cpp b/src/viam/examples/modules/complex/main.cpp
index 59f590733..5d3f85f67 100644
--- a/src/viam/examples/modules/complex/main.cpp
+++ b/src/viam/examples/modules/complex/main.cpp
@@ -5,6 +5,7 @@
 #include <grpcpp/grpcpp.h>
 #include <grpcpp/server_context.h>
 
+#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/components/base.hpp>
 #include <viam/sdk/components/component.hpp>
 #include <viam/sdk/config/resource.hpp>
@@ -24,11 +25,15 @@
 using namespace viam::sdk;
 
 int main(int argc, char** argv) {
+    // Every Viam C++ SDK program must have one and only one Instance object which is created before
+    // any other C++ SDK objects and stays alive until all Viam C++ SDK objects are destroyed.
+    Instance inst;
+
     Model mybase_model("viam", "base", "mybase");
 
     // Make sure to explicity register resources with custom APIs.
-    Registry::register_resource_server<GizmoServer>();
-    Registry::register_resource_server<SummationServer>();
+    inst.registry()->register_resource_server<GizmoServer>();
+    inst.registry()->register_resource_server<SummationServer>();
 
     std::shared_ptr<ModelRegistration> mybase_mr = std::make_shared<ModelRegistration>(
         API::get<Base>(),
@@ -51,7 +56,7 @@ int main(int argc, char** argv) {
         });
 
     std::vector<std::shared_ptr<ModelRegistration>> mrs = {mybase_mr, mygizmo_mr, mysummation_mr};
-    auto my_mod = std::make_shared<ModuleService>(argc, argv, mrs);
+    auto my_mod = std::make_shared<ModuleService>(argc, argv, mrs, inst.registry());
     my_mod->serve();
 
     return EXIT_SUCCESS;
diff --git a/src/viam/examples/modules/complex/test_complex_module.cpp b/src/viam/examples/modules/complex/test_complex_module.cpp
index 4984df8f0..228ef96c7 100644
--- a/src/viam/examples/modules/complex/test_complex_module.cpp
+++ b/src/viam/examples/modules/complex/test_complex_module.cpp
@@ -24,8 +24,9 @@ using namespace viam::sdktests;
 
 struct RegisterGizmoAndSummationFixture {
     RegisterGizmoAndSummationFixture() {
-        Registry::register_resource<GizmoClient, GizmoServer>();
-        Registry::register_resource<SummationClient, SummationServer>();
+        auto* registry = GlobalInstance::registry();
+        registry->register_resource<GizmoClient, GizmoServer>();
+        registry->register_resource<SummationClient, SummationServer>();
     }
 
     // Test teardown is a noop;
diff --git a/src/viam/examples/motor/example_motor.cpp b/src/viam/examples/motor/example_motor.cpp
index c4d8023d5..1a5ff50b7 100644
--- a/src/viam/examples/motor/example_motor.cpp
+++ b/src/viam/examples/motor/example_motor.cpp
@@ -6,6 +6,7 @@
 #include <string>
 #include <vector>
 
+#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/components/motor.hpp>
 #include <viam/sdk/robot/client.hpp>
 #include <viam/sdk/rpc/dial.hpp>
@@ -27,6 +28,11 @@ int main() {
     namespace vs = ::viam::sdk;
 
     try {
+        // Every Viam C++ SDK program must have one and only one Instance object which is created
+        // before any other C++ SDK objects and stays alive until all Viam C++ SDK objects are
+        // destroyed.
+        vs::Instance inst;
+
         // If you want to connect to a remote robot, this should be the url of the robot
         // Ex: xxx.xxx.viam.cloud
         std::string robot_address("localhost:8080");
@@ -49,7 +55,7 @@ int main() {
 
         std::shared_ptr<vs::RobotClient> robot;
         try {
-            robot = vs::RobotClient::at_address(robot_address, options);
+            robot = vs::RobotClient::at_address(robot_address, options, inst.registry());
             cout << "Successfully connected to the robot" << endl;
         } catch (const std::exception& e) {
             cerr << "Failed to connect to the robot. Exiting." << endl;
diff --git a/src/viam/sdk/common/instance.cpp b/src/viam/sdk/common/instance.cpp
index 3c277273d..c356aee54 100644
--- a/src/viam/sdk/common/instance.cpp
+++ b/src/viam/sdk/common/instance.cpp
@@ -1,14 +1,22 @@
 #include <viam/sdk/common/instance.hpp>
 
+#include <viam/sdk/registry/registry.hpp>
+
 namespace viam {
 namespace sdk {
 
-Instance::Instance() {
-    registry_.initialize();
+struct Instance::Impl {
+    Registry registry;
+};
+
+Instance::Instance() : impl_(std::make_unique<Instance::Impl>()) {
+    impl_->registry.initialize();
 }
 
-Registry& Instance::registry() {
-    return registry_;
+Instance::~Instance() = default;
+
+Registry* Instance::registry() {
+    return &(impl_->registry);
 }
 
 }  // namespace sdk
diff --git a/src/viam/sdk/common/instance.hpp b/src/viam/sdk/common/instance.hpp
index 8297b74e4..0702d513f 100644
--- a/src/viam/sdk/common/instance.hpp
+++ b/src/viam/sdk/common/instance.hpp
@@ -1,10 +1,12 @@
 #pragma once
 
-#include <viam/sdk/registry/registry.hpp>
+#include <memory>
 
 namespace viam {
 namespace sdk {
 
+class Registry;
+
 /// @brief Instance management for Viam C++ SDK applications.
 /// This is a single instance class which is responsible for global setup and teardown related to
 /// the SDK. An Instance must be constructed before doing anything else in a program, and it must
@@ -13,11 +15,13 @@ namespace sdk {
 class Instance {
    public:
     Instance();
+    ~Instance();
 
-    Registry& registry();
+    Registry* registry();
 
    private:
-    Registry registry_;
+    struct Impl;
+    std::unique_ptr<Impl> impl_;
 };
 
 }  // namespace sdk
diff --git a/src/viam/sdk/module/service.cpp b/src/viam/sdk/module/service.cpp
index 526beecb5..041fb90b3 100644
--- a/src/viam/sdk/module/service.cpp
+++ b/src/viam/sdk/module/service.cpp
@@ -57,7 +57,7 @@ struct ModuleService::ServiceImpl : viam::module::v1::ModuleService::Service {
         std::shared_ptr<Resource> res;
         const Dependencies deps = parent.get_dependencies_(&request->dependencies(), cfg.name());
         const std::shared_ptr<const ModelRegistration> reg =
-            parent.registry_.lookup_model(cfg.api(), cfg.model());
+            parent.registry_->lookup_model(cfg.api(), cfg.model());
         if (reg) {
             try {
                 res = reg->construct_resource(deps, cfg);
@@ -112,7 +112,7 @@ struct ModuleService::ServiceImpl : viam::module::v1::ModuleService::Service {
         }
 
         const std::shared_ptr<const ModelRegistration> reg =
-            parent.registry_.lookup_model(cfg.name());
+            parent.registry_->lookup_model(cfg.name());
         if (reg) {
             try {
                 const std::shared_ptr<Resource> res = reg->construct_resource(deps, cfg);
@@ -132,7 +132,7 @@ struct ModuleService::ServiceImpl : viam::module::v1::ModuleService::Service {
         ResourceConfig cfg = from_proto(proto);
 
         const std::shared_ptr<const ModelRegistration> reg =
-            parent.registry_.lookup_model(cfg.api(), cfg.model());
+            parent.registry_->lookup_model(cfg.api(), cfg.model());
         if (!reg) {
             return grpc::Status(grpc::UNKNOWN,
                                 "unable to validate resource " + cfg.resource_name().name() +
@@ -214,17 +214,17 @@ std::shared_ptr<Resource> ModuleService::get_parent_resource_(const Name& name)
     return parent_->resource_by_name(name);
 }
 
-ModuleService::ModuleService(std::string addr, Registry& registry)
+ModuleService::ModuleService(std::string addr, Registry* registry)
     : registry_(registry),
       module_(std::make_unique<Module>(std::move(addr))),
-      server_(std::make_unique<Server>(&registry_)) {
+      server_(std::make_unique<Server>(registry_)) {
     impl_ = std::make_unique<ServiceImpl>(*this);
 }
 
 ModuleService::ModuleService(int argc,
                              char** argv,
                              const std::vector<std::shared_ptr<ModelRegistration>>& registrations,
-                             Registry& registry)
+                             Registry* registry)
     : ModuleService(
           [argc, argv] {
               if (argc < 2) {
@@ -237,7 +237,7 @@ ModuleService::ModuleService(int argc,
     set_logger_severity_from_args(argc, argv);
 
     for (auto&& mr : registrations) {
-        registry_.register_model(mr);
+        registry_->register_model(mr);
         add_model_from_registry(mr->api(), mr->model());
     }
 }
@@ -280,7 +280,7 @@ void ModuleService::add_model_from_registry_inlock_(API api,
                                                     Model model,
                                                     const std::lock_guard<std::mutex>&) {
     const std::shared_ptr<const ResourceServerRegistration> creator =
-        registry_.lookup_resource_server(api);
+        registry_->lookup_resource_server(api);
     std::string name;
     if (creator && creator->service_descriptor()) {
         name = creator->service_descriptor()->full_name();
diff --git a/src/viam/sdk/module/service.hpp b/src/viam/sdk/module/service.hpp
index cffc47fe7..0927d26a8 100644
--- a/src/viam/sdk/module/service.hpp
+++ b/src/viam/sdk/module/service.hpp
@@ -31,7 +31,7 @@ class ModuleService {
    public:
     /// @brief Creates a new ModuleService that can serve on the provided socket.
     /// @param addr Address of socket to serve on.
-    explicit ModuleService(std::string addr, Registry& registry);
+    explicit ModuleService(std::string addr, Registry* registry);
 
     /// @brief Creates a new ModuleService. Socket path and log level will be
     /// inferred from passed in command line arguments, and passed in model
@@ -42,7 +42,7 @@ class ModuleService {
     explicit ModuleService(int argc,
                            char** argv,
                            const std::vector<std::shared_ptr<ModelRegistration>>& registrations,
-                           Registry& registry);
+                           Registry* registry);
     ~ModuleService();
 
     /// @brief Starts module. serve will return when SIGINT or SIGTERM is received
@@ -65,7 +65,7 @@ class ModuleService {
                                    std::string const& resource_name);
     std::shared_ptr<Resource> get_parent_resource_(const Name& name);
 
-    Registry& registry_;
+    Registry* registry_;
 
     std::mutex lock_;
     std::unique_ptr<Module> module_;
diff --git a/src/viam/sdk/registry/registry.hpp b/src/viam/sdk/registry/registry.hpp
index 75e2324e3..43fa5c38f 100644
--- a/src/viam/sdk/registry/registry.hpp
+++ b/src/viam/sdk/registry/registry.hpp
@@ -185,7 +185,6 @@ class Registry {
 
    private:
     friend class Instance;
-
     Registry() = default;
 
     /// @brief Initialized the Viam registry. No-op if it has already been called.
diff --git a/src/viam/sdk/robot/client.cpp b/src/viam/sdk/robot/client.cpp
index 6ac049eba..cb72451c7 100644
--- a/src/viam/sdk/robot/client.cpp
+++ b/src/viam/sdk/robot/client.cpp
@@ -178,7 +178,7 @@ void RobotClient::refresh() {
         // are being properly registered from name.subtype(), or update what we're
         // using for lookup
         const std::shared_ptr<const ResourceClientRegistration> rs =
-            registry_.lookup_resource_client({name.namespace_(), name.type(), name.subtype()});
+            registry_->lookup_resource_client({name.namespace_(), name.type(), name.subtype()});
         if (rs) {
             try {
                 const std::shared_ptr<Resource> rpc_client =
@@ -221,7 +221,7 @@ void RobotClient::refresh_every() {
     }
 };
 
-RobotClient::RobotClient(std::shared_ptr<ViamChannel> channel, Registry& registry)
+RobotClient::RobotClient(std::shared_ptr<ViamChannel> channel, Registry* registry)
     : registry_(registry),
       channel_(channel->channel()),
       viam_channel_(std::move(channel)),
@@ -235,7 +235,7 @@ std::vector<Name> RobotClient::resource_names() const {
 
 std::shared_ptr<RobotClient> RobotClient::with_channel(std::shared_ptr<ViamChannel> channel,
                                                        const Options& options,
-                                                       Registry& registry) {
+                                                       Registry* registry) {
     std::shared_ptr<RobotClient> robot =
         std::make_shared<RobotClient>(std::move(channel), registry);
     robot->refresh_interval_ = options.refresh_interval();
@@ -256,7 +256,7 @@ std::shared_ptr<RobotClient> RobotClient::with_channel(std::shared_ptr<ViamChann
 
 std::shared_ptr<RobotClient> RobotClient::at_address(const std::string& address,
                                                      const Options& options,
-                                                     Registry& registry) {
+                                                     Registry* registry) {
     const char* uri = address.c_str();
     auto channel = ViamChannel::dial(uri, options.dial_options());
     std::shared_ptr<RobotClient> robot = RobotClient::with_channel(channel, options, registry);
@@ -267,7 +267,7 @@ std::shared_ptr<RobotClient> RobotClient::at_address(const std::string& address,
 
 std::shared_ptr<RobotClient> RobotClient::at_local_socket(const std::string& address,
                                                           const Options& options,
-                                                          Registry& registry) {
+                                                          Registry* registry) {
     const std::string addr = "unix://" + address;
     const char* uri = addr.c_str();
     const std::shared_ptr<grpc::Channel> channel =
diff --git a/src/viam/sdk/robot/client.hpp b/src/viam/sdk/robot/client.hpp
index 09834e1d8..0a9610ac2 100644
--- a/src/viam/sdk/robot/client.hpp
+++ b/src/viam/sdk/robot/client.hpp
@@ -12,14 +12,16 @@
 #include <viam/sdk/common/utils.hpp>
 #include <viam/sdk/common/world_state.hpp>
 #include <viam/sdk/components/component.hpp>
-#include <viam/sdk/registry/registry.hpp>
 #include <viam/sdk/resource/resource.hpp>
+#include <viam/sdk/resource/resource_manager.hpp>
 #include <viam/sdk/rpc/dial.hpp>
 #include <viam/sdk/services/service.hpp>
 
 namespace viam {
 namespace sdk {
 
+class Registry;
+
 /// @defgroup Robot Classes related to a Robot representation.
 
 /// @class RobotClient client.hpp "robot/client.hpp"
@@ -69,7 +71,7 @@ class RobotClient {
     /// @param options Options for connecting and refreshing.
     static std::shared_ptr<RobotClient> at_address(const std::string& address,
                                                    const Options& options,
-                                                   Registry& registry);
+                                                   Registry* registry);
 
     /// @brief Creates a robot client connected to the robot at the provided local socket.
     /// @param address The local socket of the robot (a .sock file, etc.).
@@ -78,7 +80,7 @@ class RobotClient {
     /// Only useful for connecting to robots across Unix sockets.
     static std::shared_ptr<RobotClient> at_local_socket(const std::string& address,
                                                         const Options& options,
-                                                        Registry& registry);
+                                                        Registry* registry);
 
     /// @brief Creates a robot client connected to the provided channel.
     /// @param channel The channel to connect with.
@@ -87,9 +89,9 @@ class RobotClient {
     /// `close()`d manually.
     static std::shared_ptr<RobotClient> with_channel(std::shared_ptr<ViamChannel> channel,
                                                      const Options& options,
-                                                     Registry& registry);
+                                                     Registry* registry);
 
-    RobotClient(std::shared_ptr<ViamChannel> channel, Registry& registry);
+    RobotClient(std::shared_ptr<ViamChannel> channel, Registry* registry);
 
     std::vector<Name> resource_names() const;
 
@@ -152,7 +154,7 @@ class RobotClient {
     status get_machine_status() const;
 
    private:
-    Registry& registry_;
+    Registry* registry_;
 
     std::vector<std::shared_ptr<std::thread>> threads_;
 
diff --git a/src/viam/sdk/tests/mocks/mock_robot.cpp b/src/viam/sdk/tests/mocks/mock_robot.cpp
index 8e28b944b..fdc068ec3 100644
--- a/src/viam/sdk/tests/mocks/mock_robot.cpp
+++ b/src/viam/sdk/tests/mocks/mock_robot.cpp
@@ -26,7 +26,7 @@ std::vector<Name> registered_models_for_resource(const std::shared_ptr<Resource>
     std::string resource_type;
     std::string resource_subtype;
     std::vector<Name> resource_names;
-    for (const auto& kv : GlobalInstance::registry().registered_models()) {
+    for (const auto& kv : GlobalInstance::registry()->registered_models()) {
         const std::shared_ptr<const ModelRegistration> reg = kv.second;
         if (reg->api() == resource->api()) {
             resource_type = reg->api().resource_type();
diff --git a/src/viam/sdk/tests/test_robot.cpp b/src/viam/sdk/tests/test_robot.cpp
index e7ccc0de1..a7b403359 100644
--- a/src/viam/sdk/tests/test_robot.cpp
+++ b/src/viam/sdk/tests/test_robot.cpp
@@ -42,7 +42,7 @@ void robot_client_to_mocks_pipeline(F&& test_case) {
     rm->add(std::string("mock_generic"), generic::MockGenericComponent::get_mock_generic());
     rm->add(std::string("mock_motor"), motor::MockMotor::get_mock_motor());
     rm->add(std::string("mock_camera"), camera::MockCamera::get_mock_camera());
-    auto server = std::make_shared<sdk::Server>(&GlobalInstance::registry());
+    auto server = std::make_shared<sdk::Server>(GlobalInstance::registry());
     MockRobotService service(rm, *server);
     server->start();
 
@@ -63,7 +63,7 @@ void robot_client_to_mocks_pipeline(F&& test_case) {
 }
 
 BOOST_AUTO_TEST_CASE(test_registering_resources) {
-    auto& registry = GlobalInstance::registry();
+    auto& registry = *GlobalInstance::registry();
 
     // To test with mock resources we need to be able to create them, which means registering
     // constructors. This tests that we register correctly.
diff --git a/src/viam/sdk/tests/test_utils.hpp b/src/viam/sdk/tests/test_utils.hpp
index c24bed482..655b34904 100644
--- a/src/viam/sdk/tests/test_utils.hpp
+++ b/src/viam/sdk/tests/test_utils.hpp
@@ -17,7 +17,7 @@ struct GlobalInstance {
         return inst;
     }
 
-    static sdk::Registry& registry() {
+    static sdk::Registry* registry() {
         return get().registry();
     }
 };
@@ -61,7 +61,7 @@ class TestServer {
 // The passed in test_case function will have access to the created ResourceClient.
 template <typename ResourceType, typename F>
 void client_to_mock_pipeline(std::shared_ptr<Resource> mock, F&& test_case) {
-    auto server = std::make_shared<sdk::Server>(&GlobalInstance::registry());
+    auto server = std::make_shared<sdk::Server>(GlobalInstance::registry());
 
     // normally the high level server service (either robot or module) handles adding managed
     // resources, but in this case we must do it ourselves.
@@ -74,7 +74,7 @@ void client_to_mock_pipeline(std::shared_ptr<Resource> mock, F&& test_case) {
     auto grpc_channel = test_server.grpc_in_process_channel();
 
     auto resource_client = GlobalInstance::registry()
-                               .lookup_resource_client(API::get<ResourceType>())
+                               ->lookup_resource_client(API::get<ResourceType>())
                                ->create_rpc_client(mock->name(), std::move(grpc_channel));
 
     // Run the passed-in test case on the created stack and give access to the

From e5cf6d054c82a4dff634ec64b5eb95e3c2a5426c Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Tue, 25 Feb 2025 15:37:51 -0500
Subject: [PATCH 08/31] add instance management infra

---
 .../modules/complex/test_complex_module.cpp   |  2 +-
 src/viam/sdk/common/instance.cpp              | 41 ++++++++++++++++++-
 src/viam/sdk/common/instance.hpp              |  2 +
 src/viam/sdk/tests/mocks/mock_robot.cpp       |  2 +-
 src/viam/sdk/tests/test_robot.cpp             |  6 +--
 src/viam/sdk/tests/test_utils.hpp             | 16 ++------
 6 files changed, 49 insertions(+), 20 deletions(-)

diff --git a/src/viam/examples/modules/complex/test_complex_module.cpp b/src/viam/examples/modules/complex/test_complex_module.cpp
index 228ef96c7..3f4d4ee3d 100644
--- a/src/viam/examples/modules/complex/test_complex_module.cpp
+++ b/src/viam/examples/modules/complex/test_complex_module.cpp
@@ -24,7 +24,7 @@ using namespace viam::sdktests;
 
 struct RegisterGizmoAndSummationFixture {
     RegisterGizmoAndSummationFixture() {
-        auto* registry = GlobalInstance::registry();
+        auto* registry = Instance::current().registry();
         registry->register_resource<GizmoClient, GizmoServer>();
         registry->register_resource<SummationClient, SummationServer>();
     }
diff --git a/src/viam/sdk/common/instance.cpp b/src/viam/sdk/common/instance.cpp
index c356aee54..9b6a7eccc 100644
--- a/src/viam/sdk/common/instance.cpp
+++ b/src/viam/sdk/common/instance.cpp
@@ -1,19 +1,56 @@
 #include <viam/sdk/common/instance.hpp>
 
+#include <viam/sdk/common/exception.hpp>
 #include <viam/sdk/registry/registry.hpp>
 
+#include <atomic>
+
 namespace viam {
 namespace sdk {
 
+namespace {
+
+// Memory region sentinel to check if object is being destroyed.
+std::aligned_storage_t<sizeof(Instance), alignof(Instance)> sentinel;
+
+std::atomic<Instance*> current_instance{nullptr};
+
+}  // namespace
+
 struct Instance::Impl {
     Registry registry;
 };
 
-Instance::Instance() : impl_(std::make_unique<Instance::Impl>()) {
+Instance::Instance() {
+    Instance* expected = nullptr;
+
+    if (!current_instance.compare_exchange_strong(expected, this)) {
+        throw Exception("tried to create duplicate instance");
+    }
+
+    impl_ = std::make_unique<Instance::Impl>();
     impl_->registry.initialize();
 }
 
-Instance::~Instance() = default;
+Instance::~Instance() {
+    current_instance.store(reinterpret_cast<Instance*>(&sentinel));
+    impl_.reset();
+}
+
+Instance& Instance::current() {
+    if (!current_instance.load()) {
+        // This variable declaration calls the default ctor, storing a current instance.
+        static Instance inst;
+    }
+
+    Instance* current = current_instance.load();
+
+    if (current == reinterpret_cast<Instance*>(&sentinel)) {
+        throw Exception("instance was destroyed");
+    }
+
+    return *current;
+}
 
 Registry* Instance::registry() {
     return &(impl_->registry);
diff --git a/src/viam/sdk/common/instance.hpp b/src/viam/sdk/common/instance.hpp
index 0702d513f..c1ab0961f 100644
--- a/src/viam/sdk/common/instance.hpp
+++ b/src/viam/sdk/common/instance.hpp
@@ -17,6 +17,8 @@ class Instance {
     Instance();
     ~Instance();
 
+    static Instance& current();
+
     Registry* registry();
 
    private:
diff --git a/src/viam/sdk/tests/mocks/mock_robot.cpp b/src/viam/sdk/tests/mocks/mock_robot.cpp
index fdc068ec3..5dc03fcc2 100644
--- a/src/viam/sdk/tests/mocks/mock_robot.cpp
+++ b/src/viam/sdk/tests/mocks/mock_robot.cpp
@@ -26,7 +26,7 @@ std::vector<Name> registered_models_for_resource(const std::shared_ptr<Resource>
     std::string resource_type;
     std::string resource_subtype;
     std::vector<Name> resource_names;
-    for (const auto& kv : GlobalInstance::registry()->registered_models()) {
+    for (const auto& kv : Instance::current().registry()->registered_models()) {
         const std::shared_ptr<const ModelRegistration> reg = kv.second;
         if (reg->api() == resource->api()) {
             resource_type = reg->api().resource_type();
diff --git a/src/viam/sdk/tests/test_robot.cpp b/src/viam/sdk/tests/test_robot.cpp
index a7b403359..e3bead0c9 100644
--- a/src/viam/sdk/tests/test_robot.cpp
+++ b/src/viam/sdk/tests/test_robot.cpp
@@ -42,7 +42,7 @@ void robot_client_to_mocks_pipeline(F&& test_case) {
     rm->add(std::string("mock_generic"), generic::MockGenericComponent::get_mock_generic());
     rm->add(std::string("mock_motor"), motor::MockMotor::get_mock_motor());
     rm->add(std::string("mock_camera"), camera::MockCamera::get_mock_camera());
-    auto server = std::make_shared<sdk::Server>(GlobalInstance::registry());
+    auto server = std::make_shared<sdk::Server>(Instance::current().registry());
     MockRobotService service(rm, *server);
     server->start();
 
@@ -52,7 +52,7 @@ void robot_client_to_mocks_pipeline(F&& test_case) {
     auto grpc_channel = test_server.grpc_in_process_channel();
     auto viam_channel = std::make_shared<ViamChannel>(grpc_channel, "", nullptr);
     auto client = RobotClient::with_channel(
-        viam_channel, Options(0, boost::none), GlobalInstance::registry());
+        viam_channel, Options(0, boost::none), Instance::current().registry());
 
     // Run the passed-in test case on the created stack and give access to the
     // created RobotClient and MockRobotService.
@@ -63,7 +63,7 @@ void robot_client_to_mocks_pipeline(F&& test_case) {
 }
 
 BOOST_AUTO_TEST_CASE(test_registering_resources) {
-    auto& registry = *GlobalInstance::registry();
+    auto& registry = *Instance::current().registry();
 
     // To test with mock resources we need to be able to create them, which means registering
     // constructors. This tests that we register correctly.
diff --git a/src/viam/sdk/tests/test_utils.hpp b/src/viam/sdk/tests/test_utils.hpp
index 655b34904..e5c6fb729 100644
--- a/src/viam/sdk/tests/test_utils.hpp
+++ b/src/viam/sdk/tests/test_utils.hpp
@@ -11,17 +11,6 @@
 namespace viam {
 namespace sdktests {
 
-struct GlobalInstance {
-    static sdk::Instance& get() {
-        static sdk::Instance inst;
-        return inst;
-    }
-
-    static sdk::Registry* registry() {
-        return get().registry();
-    }
-};
-
 using namespace viam::sdk;
 
 ProtoStruct fake_map();
@@ -61,7 +50,7 @@ class TestServer {
 // The passed in test_case function will have access to the created ResourceClient.
 template <typename ResourceType, typename F>
 void client_to_mock_pipeline(std::shared_ptr<Resource> mock, F&& test_case) {
-    auto server = std::make_shared<sdk::Server>(GlobalInstance::registry());
+    auto server = std::make_shared<sdk::Server>(sdk::Instance::current().registry());
 
     // normally the high level server service (either robot or module) handles adding managed
     // resources, but in this case we must do it ourselves.
@@ -73,7 +62,8 @@ void client_to_mock_pipeline(std::shared_ptr<Resource> mock, F&& test_case) {
     auto test_server = TestServer(server);
     auto grpc_channel = test_server.grpc_in_process_channel();
 
-    auto resource_client = GlobalInstance::registry()
+    auto resource_client = sdk::Instance::current()
+                               .registry()
                                ->lookup_resource_client(API::get<ResourceType>())
                                ->create_rpc_client(mock->name(), std::move(grpc_channel));
 

From 5024d3a2d6be053ee8b088ede5746475c2298477 Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Tue, 25 Feb 2025 15:43:04 -0500
Subject: [PATCH 09/31] update tflite module

---
 src/viam/examples/modules/tflite/main.cpp | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/viam/examples/modules/tflite/main.cpp b/src/viam/examples/modules/tflite/main.cpp
index 44cd8e284..e1c806354 100644
--- a/src/viam/examples/modules/tflite/main.cpp
+++ b/src/viam/examples/modules/tflite/main.cpp
@@ -23,6 +23,7 @@
 
 #include <tensorflow/lite/c/c_api.h>
 
+#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/common/proto_value.hpp>
 #include <viam/sdk/components/component.hpp>
 #include <viam/sdk/config/resource.hpp>
@@ -723,6 +724,10 @@ class MLModelServiceTFLite : public vsdk::MLModelService,
 };
 
 int serve(const std::string& socket_path) try {
+    // Every Viam C++ SDK program must have one and only one Instance object which is created before
+    // any other C++ SDK objects and stays alive until all Viam C++ SDK objects are destroyed.
+    vsdk::Instance inst;
+
     // Create a new model registration for the service.
     auto module_registration = std::make_shared<vsdk::ModelRegistration>(
         // Identify that this resource offers the MLModelService API
@@ -737,10 +742,10 @@ int serve(const std::string& socket_path) try {
         });
 
     // Register the newly created registration with the Registry.
-    vsdk::Registry::register_model(module_registration);
+    inst.registry()->register_model(module_registration);
 
     // Construct the module service and tell it where to place the socket path.
-    auto module_service = std::make_shared<vsdk::ModuleService>(socket_path);
+    auto module_service = std::make_shared<vsdk::ModuleService>(socket_path, inst.registry());
 
     // Add the server as providing the API and model declared in the
     // registration.

From ef8ec8eff50e91c87c23dcc3a34f26611fe48ccc Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Tue, 25 Feb 2025 15:59:35 -0500
Subject: [PATCH 10/31] silence spurious const warning

---
 src/viam/sdk/common/instance.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/viam/sdk/common/instance.cpp b/src/viam/sdk/common/instance.cpp
index 9b6a7eccc..c366ad6c6 100644
--- a/src/viam/sdk/common/instance.cpp
+++ b/src/viam/sdk/common/instance.cpp
@@ -40,7 +40,7 @@ Instance::~Instance() {
 Instance& Instance::current() {
     if (!current_instance.load()) {
         // This variable declaration calls the default ctor, storing a current instance.
-        static Instance inst;
+        static Instance inst;  // NOLINT (misc-const-correctness)
     }
 
     Instance* current = current_instance.load();

From 16113fd4dd38f44e8481c3468eba258b22296941 Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Tue, 25 Feb 2025 16:27:29 -0500
Subject: [PATCH 11/31] make method static

---
 src/viam/sdk/registry/registry.cpp | 2 +-
 src/viam/sdk/registry/registry.hpp | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/viam/sdk/registry/registry.cpp b/src/viam/sdk/registry/registry.cpp
index 71e3e7711..db28f628b 100644
--- a/src/viam/sdk/registry/registry.cpp
+++ b/src/viam/sdk/registry/registry.cpp
@@ -163,7 +163,7 @@ std::shared_ptr<const ResourceClientRegistration> Registry::lookup_resource_clie
 }
 
 const google::protobuf::ServiceDescriptor* Registry::get_service_descriptor_(
-    const char* service_full_name) const {
+    const char* service_full_name) {
     const google::protobuf::DescriptorPool* p = google::protobuf::DescriptorPool::generated_pool();
     const google::protobuf::ServiceDescriptor* sd = p->FindServiceByName(service_full_name);
     if (!sd) {
diff --git a/src/viam/sdk/registry/registry.hpp b/src/viam/sdk/registry/registry.hpp
index 43fa5c38f..db476be97 100644
--- a/src/viam/sdk/registry/registry.hpp
+++ b/src/viam/sdk/registry/registry.hpp
@@ -204,8 +204,8 @@ class Registry {
     void register_resource_client_(
         API api, std::shared_ptr<ResourceClientRegistration> resource_registration);
 
-    const google::protobuf::ServiceDescriptor* get_service_descriptor_(
-        const char* service_full_name) const;
+    static const google::protobuf::ServiceDescriptor* get_service_descriptor_(
+        const char* service_full_name);
 
     std::shared_ptr<const ModelRegistration> lookup_model_inlock_(
         const std::string& name, const std::lock_guard<std::mutex>&) const;

From 4771390555ed6fdad2220d138e4ab770bb8b7b43 Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Thu, 27 Feb 2025 13:48:18 -0500
Subject: [PATCH 12/31] use static current to populate registry member

---
 src/viam/examples/camera/example_camera.cpp   |  8 +-----
 src/viam/examples/dial/example_dial.cpp       |  7 +----
 .../dial_api_key/example_dial_api_key.cpp     |  7 +----
 .../example_audio_classification_client.cpp   |  9 ++-----
 src/viam/examples/modules/complex/client.cpp  | 11 +++-----
 src/viam/examples/modules/complex/main.cpp    | 11 +++-----
 .../modules/complex/test_complex_module.cpp   |  5 ++--
 src/viam/examples/modules/simple/client.cpp   |  5 +---
 src/viam/examples/modules/simple/main.cpp     |  5 +---
 src/viam/examples/modules/tflite/main.cpp     |  9 ++-----
 src/viam/examples/motor/example_motor.cpp     |  8 +-----
 src/viam/sdk/module/service.cpp               | 27 +++++++++----------
 src/viam/sdk/module/service.hpp               |  5 ++--
 src/viam/sdk/registry/registry.cpp            |  5 ++++
 src/viam/sdk/registry/registry.hpp            |  3 +++
 src/viam/sdk/robot/client.cpp                 | 20 ++++++--------
 src/viam/sdk/robot/client.hpp                 | 24 ++++-------------
 src/viam/sdk/rpc/server.cpp                   |  4 +--
 src/viam/sdk/rpc/server.hpp                   |  4 +--
 src/viam/sdk/tests/test_robot.cpp             |  7 +++--
 src/viam/sdk/tests/test_utils.hpp             |  7 +++--
 21 files changed, 62 insertions(+), 129 deletions(-)

diff --git a/src/viam/examples/camera/example_camera.cpp b/src/viam/examples/camera/example_camera.cpp
index b0202a27e..bc1b0ab9a 100644
--- a/src/viam/examples/camera/example_camera.cpp
+++ b/src/viam/examples/camera/example_camera.cpp
@@ -3,7 +3,6 @@
 #include <unistd.h>
 #include <vector>
 
-#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/components/camera.hpp>
 #include <viam/sdk/robot/client.hpp>
 #include <viam/sdk/rpc/dial.hpp>
@@ -14,11 +13,6 @@ int main() {
     using std::endl;
     namespace vs = ::viam::sdk;
     try {
-        // Every Viam C++ SDK program must have one and only one Instance object which is created
-        // before
-        // any other C++ SDK objects and stays alive until all Viam C++ SDK objects are destroyed.
-        vs::Instance inst;
-
         // If you want to connect to a remote robot, this should be the url of the robot
         // Ex: xxx.xxx.viam.cloud
         std::string robot_address("localhost:8080");
@@ -41,7 +35,7 @@ int main() {
 
         std::shared_ptr<vs::RobotClient> robot;
         try {
-            robot = vs::RobotClient::at_address(robot_address, options, inst.registry());
+            robot = vs::RobotClient::at_address(robot_address, options);
             cout << "Successfully connected to the robot" << endl;
         } catch (const std::exception& e) {
             cerr << "Failed to connect to the robot. Exiting." << endl;
diff --git a/src/viam/examples/dial/example_dial.cpp b/src/viam/examples/dial/example_dial.cpp
index 28ccd7659..efa783dfb 100644
--- a/src/viam/examples/dial/example_dial.cpp
+++ b/src/viam/examples/dial/example_dial.cpp
@@ -9,7 +9,6 @@
 
 #include <boost/optional.hpp>
 
-#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/components/generic.hpp>
 #include <viam/sdk/robot/client.hpp>
 #include <viam/sdk/rpc/dial.hpp>
@@ -17,10 +16,6 @@
 using namespace viam::sdk;
 
 int main() {
-    // Every Viam C++ SDK program must have one and only one Instance object which is created before
-    // any other C++ SDK objects and stays alive until all Viam C++ SDK objects are destroyed.
-    Instance inst;
-
     const char* uri = "<your robot URI here>";
     DialOptions dial_options;
     std::string type = "<your authentication type>";
@@ -32,7 +27,7 @@ int main() {
     Options options(1, opts);
 
     // connect to robot, ensure we can refresh it
-    std::shared_ptr<RobotClient> robot = RobotClient::at_address(address, options, inst.registry());
+    std::shared_ptr<RobotClient> robot = RobotClient::at_address(address, options);
 
     // ensure we can query resources
     std::vector<Name> resource_names = robot->resource_names();
diff --git a/src/viam/examples/dial_api_key/example_dial_api_key.cpp b/src/viam/examples/dial_api_key/example_dial_api_key.cpp
index 7c9e82fef..4c47beffe 100644
--- a/src/viam/examples/dial_api_key/example_dial_api_key.cpp
+++ b/src/viam/examples/dial_api_key/example_dial_api_key.cpp
@@ -10,7 +10,6 @@
 #include <boost/optional.hpp>
 #include <boost/program_options.hpp>
 
-#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/robot/client.hpp>
 #include <viam/sdk/rpc/dial.hpp>
 
@@ -19,10 +18,6 @@ using namespace viam::sdk;
 namespace po = boost::program_options;
 
 int main(int argc, char* argv[]) {
-    // Every Viam C++ SDK program must have one and only one Instance object which is created before
-    // any other C++ SDK objects and stays alive until all Viam C++ SDK objects are destroyed.
-    Instance inst;
-
     po::options_description desc("Allowed options");
     desc.add_options()("help", "List options and exit")(
         "uri", po::value<std::string>(), "URI of robot")(
@@ -46,7 +41,7 @@ int main(int argc, char* argv[]) {
 
     // connect to robot, ensure we can refresh it
     std::shared_ptr<RobotClient> robot =
-        RobotClient::at_address(vm["uri"].as<std::string>(), options, inst.registry());
+        RobotClient::at_address(vm["uri"].as<std::string>(), options);
 
     // ensure we can query resources
     std::vector<Name> resource_names = robot->resource_names();
diff --git a/src/viam/examples/mlmodel/example_audio_classification_client.cpp b/src/viam/examples/mlmodel/example_audio_classification_client.cpp
index ab06a082e..95e26f57c 100644
--- a/src/viam/examples/mlmodel/example_audio_classification_client.cpp
+++ b/src/viam/examples/mlmodel/example_audio_classification_client.cpp
@@ -29,7 +29,6 @@
 #include <boost/program_options.hpp>
 #include <boost/variant/get.hpp>
 
-#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/robot/client.hpp>
 #include <viam/sdk/services/mlmodel.hpp>
 
@@ -79,10 +78,6 @@ constexpr char kRobotConfigTemplate[] = R"(
 }  // namespace
 
 int main(int argc, char* argv[]) try {
-    // Every Viam C++ SDK program must have one and only one Instance object which is created before
-    // any other C++ SDK objects and stays alive until all Viam C++ SDK objects are destroyed.
-    viam::sdk::Instance inst;
-
     // Build up our command line options. The example operates in two
     // modes. In the "--generate" mode, it takes command line
     // parameters needed to satisfy the interpolation points in the
@@ -239,8 +234,8 @@ int main(int argc, char* argv[]) try {
         dial_options.set_entity(opt_api_key_id.get());
         dial_options.set_credentials(viam::sdk::Credentials("api-key", opt_api_key.get()));
 
-        auto robot = vsdk::RobotClient::at_address(
-            opt_robot_host.get(), {0, {std::move(dial_options)}}, inst.registry());
+        auto robot =
+            vsdk::RobotClient::at_address(opt_robot_host.get(), {0, {std::move(dial_options)}});
 
         // Obtain a handle to the MLModelService module on the robot. Note that the string
         // `yamnet_classification_tflite` is arbitrary. It just matches what was used to name the
diff --git a/src/viam/examples/modules/complex/client.cpp b/src/viam/examples/modules/complex/client.cpp
index ea3444844..ac85c9f00 100644
--- a/src/viam/examples/modules/complex/client.cpp
+++ b/src/viam/examples/modules/complex/client.cpp
@@ -11,7 +11,6 @@
 #include <grpcpp/grpcpp.h>
 #include <grpcpp/support/status.h>
 
-#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/components/motor.hpp>
 #include <viam/sdk/robot/client.hpp>
 #include <viam/sdk/rpc/dial.hpp>
@@ -22,10 +21,6 @@
 using namespace viam::sdk;
 
 int main() {
-    // Every Viam C++ SDK program must have one and only one Instance object which is created before
-    // any other C++ SDK objects and stays alive until all Viam C++ SDK objects are destroyed.
-    Instance inst;
-
     const char* uri = "http://localhost:8080/";  // replace with your URI if connecting securely
     DialOptions dial_options;
     dial_options.set_allow_insecure_downgrade(true);  // set to false if connecting securely
@@ -42,11 +37,11 @@ int main() {
 
     // Register custom gizmo and summation clients so robot client can access resources
     // of that type from the server.
-    inst.registry()->register_resource_client<GizmoClient>();
-    inst.registry()->register_resource_client<SummationClient>();
+    Registry::get().register_resource_client<GizmoClient>();
+    Registry::get().register_resource_client<SummationClient>();
 
     // Connect to robot.
-    std::shared_ptr<RobotClient> robot = RobotClient::at_address(address, options, inst.registry());
+    std::shared_ptr<RobotClient> robot = RobotClient::at_address(address, options);
     // Print resources.
     std::cout << "Resources" << std::endl;
     std::vector<Name> resource_names = robot->resource_names();
diff --git a/src/viam/examples/modules/complex/main.cpp b/src/viam/examples/modules/complex/main.cpp
index 5d3f85f67..da80453e6 100644
--- a/src/viam/examples/modules/complex/main.cpp
+++ b/src/viam/examples/modules/complex/main.cpp
@@ -5,7 +5,6 @@
 #include <grpcpp/grpcpp.h>
 #include <grpcpp/server_context.h>
 
-#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/components/base.hpp>
 #include <viam/sdk/components/component.hpp>
 #include <viam/sdk/config/resource.hpp>
@@ -25,15 +24,11 @@
 using namespace viam::sdk;
 
 int main(int argc, char** argv) {
-    // Every Viam C++ SDK program must have one and only one Instance object which is created before
-    // any other C++ SDK objects and stays alive until all Viam C++ SDK objects are destroyed.
-    Instance inst;
-
     Model mybase_model("viam", "base", "mybase");
 
     // Make sure to explicity register resources with custom APIs.
-    inst.registry()->register_resource_server<GizmoServer>();
-    inst.registry()->register_resource_server<SummationServer>();
+    Registry::get().register_resource_server<GizmoServer>();
+    Registry::get().register_resource_server<SummationServer>();
 
     std::shared_ptr<ModelRegistration> mybase_mr = std::make_shared<ModelRegistration>(
         API::get<Base>(),
@@ -56,7 +51,7 @@ int main(int argc, char** argv) {
         });
 
     std::vector<std::shared_ptr<ModelRegistration>> mrs = {mybase_mr, mygizmo_mr, mysummation_mr};
-    auto my_mod = std::make_shared<ModuleService>(argc, argv, mrs, inst.registry());
+    auto my_mod = std::make_shared<ModuleService>(argc, argv, mrs);
     my_mod->serve();
 
     return EXIT_SUCCESS;
diff --git a/src/viam/examples/modules/complex/test_complex_module.cpp b/src/viam/examples/modules/complex/test_complex_module.cpp
index 3f4d4ee3d..14d68a8cf 100644
--- a/src/viam/examples/modules/complex/test_complex_module.cpp
+++ b/src/viam/examples/modules/complex/test_complex_module.cpp
@@ -24,9 +24,8 @@ using namespace viam::sdktests;
 
 struct RegisterGizmoAndSummationFixture {
     RegisterGizmoAndSummationFixture() {
-        auto* registry = Instance::current().registry();
-        registry->register_resource<GizmoClient, GizmoServer>();
-        registry->register_resource<SummationClient, SummationServer>();
+        Registry::get().register_resource<GizmoClient, GizmoServer>();
+        Registry::get().register_resource<SummationClient, SummationServer>();
     }
 
     // Test teardown is a noop;
diff --git a/src/viam/examples/modules/simple/client.cpp b/src/viam/examples/modules/simple/client.cpp
index ac014d1e7..fcaab5eff 100644
--- a/src/viam/examples/modules/simple/client.cpp
+++ b/src/viam/examples/modules/simple/client.cpp
@@ -2,7 +2,6 @@
 #include <memory>
 #include <string>
 
-#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/common/proto_value.hpp>
 #include <viam/sdk/components/sensor.hpp>
 #include <viam/sdk/robot/client.hpp>
@@ -11,8 +10,6 @@
 using namespace viam::sdk;
 
 int main() {
-    Instance inst;
-
     const char* uri = "http://localhost:8080/";  // replace with your URI if connecting securely
     DialOptions dial_options;
     dial_options.set_allow_insecure_downgrade(true);  // set to false if connecting securely
@@ -27,7 +24,7 @@ int main() {
     std::string address(uri);
     Options options(1, opts);
 
-    std::shared_ptr<RobotClient> robot = RobotClient::at_address(address, options, inst.registry());
+    std::shared_ptr<RobotClient> robot = RobotClient::at_address(address, options);
 
     // Print resources
     std::cout << "Resources\n";
diff --git a/src/viam/examples/modules/simple/main.cpp b/src/viam/examples/modules/simple/main.cpp
index b899d3b44..cfd783f66 100644
--- a/src/viam/examples/modules/simple/main.cpp
+++ b/src/viam/examples/modules/simple/main.cpp
@@ -3,7 +3,6 @@
 #include <sstream>
 
 #include <viam/sdk/common/exception.hpp>
-#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/common/proto_value.hpp>
 #include <viam/sdk/components/sensor.hpp>
 #include <viam/sdk/config/resource.hpp>
@@ -76,8 +75,6 @@ ProtoStruct MySensor::get_readings(const ProtoStruct&) {
 }
 
 int main(int argc, char** argv) try {
-    Instance inst;
-
     Model mysensor_model("viam", "sensor", "mysensor");
 
     std::shared_ptr<ModelRegistration> mr = std::make_shared<ModelRegistration>(
@@ -87,7 +84,7 @@ int main(int argc, char** argv) try {
         &MySensor::validate);
 
     std::vector<std::shared_ptr<ModelRegistration>> mrs = {mr};
-    auto my_mod = std::make_shared<ModuleService>(argc, argv, mrs, inst.registry());
+    auto my_mod = std::make_shared<ModuleService>(argc, argv, mrs);
     my_mod->serve();
 
     return EXIT_SUCCESS;
diff --git a/src/viam/examples/modules/tflite/main.cpp b/src/viam/examples/modules/tflite/main.cpp
index e1c806354..44cd8e284 100644
--- a/src/viam/examples/modules/tflite/main.cpp
+++ b/src/viam/examples/modules/tflite/main.cpp
@@ -23,7 +23,6 @@
 
 #include <tensorflow/lite/c/c_api.h>
 
-#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/common/proto_value.hpp>
 #include <viam/sdk/components/component.hpp>
 #include <viam/sdk/config/resource.hpp>
@@ -724,10 +723,6 @@ class MLModelServiceTFLite : public vsdk::MLModelService,
 };
 
 int serve(const std::string& socket_path) try {
-    // Every Viam C++ SDK program must have one and only one Instance object which is created before
-    // any other C++ SDK objects and stays alive until all Viam C++ SDK objects are destroyed.
-    vsdk::Instance inst;
-
     // Create a new model registration for the service.
     auto module_registration = std::make_shared<vsdk::ModelRegistration>(
         // Identify that this resource offers the MLModelService API
@@ -742,10 +737,10 @@ int serve(const std::string& socket_path) try {
         });
 
     // Register the newly created registration with the Registry.
-    inst.registry()->register_model(module_registration);
+    vsdk::Registry::register_model(module_registration);
 
     // Construct the module service and tell it where to place the socket path.
-    auto module_service = std::make_shared<vsdk::ModuleService>(socket_path, inst.registry());
+    auto module_service = std::make_shared<vsdk::ModuleService>(socket_path);
 
     // Add the server as providing the API and model declared in the
     // registration.
diff --git a/src/viam/examples/motor/example_motor.cpp b/src/viam/examples/motor/example_motor.cpp
index 1a5ff50b7..c4d8023d5 100644
--- a/src/viam/examples/motor/example_motor.cpp
+++ b/src/viam/examples/motor/example_motor.cpp
@@ -6,7 +6,6 @@
 #include <string>
 #include <vector>
 
-#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/components/motor.hpp>
 #include <viam/sdk/robot/client.hpp>
 #include <viam/sdk/rpc/dial.hpp>
@@ -28,11 +27,6 @@ int main() {
     namespace vs = ::viam::sdk;
 
     try {
-        // Every Viam C++ SDK program must have one and only one Instance object which is created
-        // before any other C++ SDK objects and stays alive until all Viam C++ SDK objects are
-        // destroyed.
-        vs::Instance inst;
-
         // If you want to connect to a remote robot, this should be the url of the robot
         // Ex: xxx.xxx.viam.cloud
         std::string robot_address("localhost:8080");
@@ -55,7 +49,7 @@ int main() {
 
         std::shared_ptr<vs::RobotClient> robot;
         try {
-            robot = vs::RobotClient::at_address(robot_address, options, inst.registry());
+            robot = vs::RobotClient::at_address(robot_address, options);
             cout << "Successfully connected to the robot" << endl;
         } catch (const std::exception& e) {
             cerr << "Failed to connect to the robot. Exiting." << endl;
diff --git a/src/viam/sdk/module/service.cpp b/src/viam/sdk/module/service.cpp
index 041fb90b3..d644b5420 100644
--- a/src/viam/sdk/module/service.cpp
+++ b/src/viam/sdk/module/service.cpp
@@ -208,32 +208,29 @@ Dependencies ModuleService::get_dependencies_(
 
 std::shared_ptr<Resource> ModuleService::get_parent_resource_(const Name& name) {
     if (!parent_) {
-        parent_ = RobotClient::at_local_socket(parent_addr_, {0, boost::none}, registry_);
+        parent_ = RobotClient::at_local_socket(parent_addr_, {0, boost::none});
     }
 
     return parent_->resource_by_name(name);
 }
 
-ModuleService::ModuleService(std::string addr, Registry* registry)
-    : registry_(registry),
+ModuleService::ModuleService(std::string addr)
+    : registry_(&Registry::get()),
       module_(std::make_unique<Module>(std::move(addr))),
-      server_(std::make_unique<Server>(registry_)) {
+      server_(std::make_unique<Server>()) {
     impl_ = std::make_unique<ServiceImpl>(*this);
 }
 
 ModuleService::ModuleService(int argc,
                              char** argv,
-                             const std::vector<std::shared_ptr<ModelRegistration>>& registrations,
-                             Registry* registry)
-    : ModuleService(
-          [argc, argv] {
-              if (argc < 2) {
-                  throw Exception(ErrorCondition::k_connection,
-                                  "Need socket path as command line argument");
-              }
-              return argv[1];
-          }(),
-          registry) {
+                             const std::vector<std::shared_ptr<ModelRegistration>>& registrations)
+    : ModuleService([argc, argv] {
+          if (argc < 2) {
+              throw Exception(ErrorCondition::k_connection,
+                              "Need socket path as command line argument");
+          }
+          return argv[1];
+      }()) {
     set_logger_severity_from_args(argc, argv);
 
     for (auto&& mr : registrations) {
diff --git a/src/viam/sdk/module/service.hpp b/src/viam/sdk/module/service.hpp
index 0927d26a8..95a7ad4f3 100644
--- a/src/viam/sdk/module/service.hpp
+++ b/src/viam/sdk/module/service.hpp
@@ -31,7 +31,7 @@ class ModuleService {
    public:
     /// @brief Creates a new ModuleService that can serve on the provided socket.
     /// @param addr Address of socket to serve on.
-    explicit ModuleService(std::string addr, Registry* registry);
+    explicit ModuleService(std::string addr);
 
     /// @brief Creates a new ModuleService. Socket path and log level will be
     /// inferred from passed in command line arguments, and passed in model
@@ -41,8 +41,7 @@ class ModuleService {
     /// @param registrations Models to register and add to the module.
     explicit ModuleService(int argc,
                            char** argv,
-                           const std::vector<std::shared_ptr<ModelRegistration>>& registrations,
-                           Registry* registry);
+                           const std::vector<std::shared_ptr<ModelRegistration>>& registrations);
     ~ModuleService();
 
     /// @brief Starts module. serve will return when SIGINT or SIGTERM is received
diff --git a/src/viam/sdk/registry/registry.cpp b/src/viam/sdk/registry/registry.cpp
index 8f7209adf..1ee9b5533 100644
--- a/src/viam/sdk/registry/registry.cpp
+++ b/src/viam/sdk/registry/registry.cpp
@@ -12,6 +12,7 @@
 #include <grpcpp/ext/proto_server_reflection_plugin.h>
 
 #include <viam/sdk/common/exception.hpp>
+#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/components/private/arm_client.hpp>
 #include <viam/sdk/components/private/arm_server.hpp>
 #include <viam/sdk/components/private/base_client.hpp>
@@ -90,6 +91,10 @@ const Model& ModelRegistration::model() const {
     return model_;
 };
 
+Registry& Registry::get() {
+    return *Instance::current().registry();
+}
+
 void Registry::register_model(std::shared_ptr<const ModelRegistration> resource) {
     std::string reg_key = resource->api().to_string() + "/" + resource->model().to_string();
     if (resources_.find(reg_key) != resources_.end()) {
diff --git a/src/viam/sdk/registry/registry.hpp b/src/viam/sdk/registry/registry.hpp
index db476be97..f09ee2d62 100644
--- a/src/viam/sdk/registry/registry.hpp
+++ b/src/viam/sdk/registry/registry.hpp
@@ -103,6 +103,9 @@ class ModelRegistration {
 /// @brief A registry of known resources.
 class Registry {
    public:
+    /// @brief Get the application-wide instance of Registry.
+    static Registry& get();
+
     /// @brief Registers a resource with the Registry.
     /// @param resource An object containing resource registration information.
     /// @throws `Exception` if the resource has already been registered.
diff --git a/src/viam/sdk/robot/client.cpp b/src/viam/sdk/robot/client.cpp
index cb72451c7..a8cb16c75 100644
--- a/src/viam/sdk/robot/client.cpp
+++ b/src/viam/sdk/robot/client.cpp
@@ -221,8 +221,8 @@ void RobotClient::refresh_every() {
     }
 };
 
-RobotClient::RobotClient(std::shared_ptr<ViamChannel> channel, Registry* registry)
-    : registry_(registry),
+RobotClient::RobotClient(std::shared_ptr<ViamChannel> channel)
+    : registry_(&Registry::get()),
       channel_(channel->channel()),
       viam_channel_(std::move(channel)),
       should_close_channel_(false),
@@ -234,10 +234,8 @@ std::vector<Name> RobotClient::resource_names() const {
 }
 
 std::shared_ptr<RobotClient> RobotClient::with_channel(std::shared_ptr<ViamChannel> channel,
-                                                       const Options& options,
-                                                       Registry* registry) {
-    std::shared_ptr<RobotClient> robot =
-        std::make_shared<RobotClient>(std::move(channel), registry);
+                                                       const Options& options) {
+    std::shared_ptr<RobotClient> robot = std::make_shared<RobotClient>(std::move(channel));
     robot->refresh_interval_ = options.refresh_interval();
     robot->should_refresh_ = (robot->refresh_interval_ > 0);
     if (robot->should_refresh_) {
@@ -255,25 +253,23 @@ std::shared_ptr<RobotClient> RobotClient::with_channel(std::shared_ptr<ViamChann
 };
 
 std::shared_ptr<RobotClient> RobotClient::at_address(const std::string& address,
-                                                     const Options& options,
-                                                     Registry* registry) {
+                                                     const Options& options) {
     const char* uri = address.c_str();
     auto channel = ViamChannel::dial(uri, options.dial_options());
-    std::shared_ptr<RobotClient> robot = RobotClient::with_channel(channel, options, registry);
+    std::shared_ptr<RobotClient> robot = RobotClient::with_channel(channel, options);
     robot->should_close_channel_ = true;
 
     return robot;
 };
 
 std::shared_ptr<RobotClient> RobotClient::at_local_socket(const std::string& address,
-                                                          const Options& options,
-                                                          Registry* registry) {
+                                                          const Options& options) {
     const std::string addr = "unix://" + address;
     const char* uri = addr.c_str();
     const std::shared_ptr<grpc::Channel> channel =
         sdk::impl::create_viam_channel(uri, grpc::InsecureChannelCredentials());
     auto viam_channel = std::make_shared<ViamChannel>(channel, address.c_str(), nullptr);
-    std::shared_ptr<RobotClient> robot = RobotClient::with_channel(viam_channel, options, registry);
+    std::shared_ptr<RobotClient> robot = RobotClient::with_channel(viam_channel, options);
     robot->should_close_channel_ = true;
 
     return robot;
diff --git a/src/viam/sdk/robot/client.hpp b/src/viam/sdk/robot/client.hpp
index 0a9610ac2..410abca28 100644
--- a/src/viam/sdk/robot/client.hpp
+++ b/src/viam/sdk/robot/client.hpp
@@ -12,16 +12,14 @@
 #include <viam/sdk/common/utils.hpp>
 #include <viam/sdk/common/world_state.hpp>
 #include <viam/sdk/components/component.hpp>
+#include <viam/sdk/registry/registry.hpp>
 #include <viam/sdk/resource/resource.hpp>
-#include <viam/sdk/resource/resource_manager.hpp>
 #include <viam/sdk/rpc/dial.hpp>
 #include <viam/sdk/services/service.hpp>
 
 namespace viam {
 namespace sdk {
 
-class Registry;
-
 /// @defgroup Robot Classes related to a Robot representation.
 
 /// @class RobotClient client.hpp "robot/client.hpp"
@@ -70,8 +68,7 @@ class RobotClient {
     /// @param address The address of the robot (IP address, URI, URL, etc.)
     /// @param options Options for connecting and refreshing.
     static std::shared_ptr<RobotClient> at_address(const std::string& address,
-                                                   const Options& options,
-                                                   Registry* registry);
+                                                   const Options& options);
 
     /// @brief Creates a robot client connected to the robot at the provided local socket.
     /// @param address The local socket of the robot (a .sock file, etc.).
@@ -79,8 +76,7 @@ class RobotClient {
     /// Creates a direct connection to the robot using the `unix://` scheme.
     /// Only useful for connecting to robots across Unix sockets.
     static std::shared_ptr<RobotClient> at_local_socket(const std::string& address,
-                                                        const Options& options,
-                                                        Registry* registry);
+                                                        const Options& options);
 
     /// @brief Creates a robot client connected to the provided channel.
     /// @param channel The channel to connect with.
@@ -88,11 +84,8 @@ class RobotClient {
     /// Connects directly to a pre-existing channel. A robot created this way must be
     /// `close()`d manually.
     static std::shared_ptr<RobotClient> with_channel(std::shared_ptr<ViamChannel> channel,
-                                                     const Options& options,
-                                                     Registry* registry);
-
-    RobotClient(std::shared_ptr<ViamChannel> channel, Registry* registry);
-
+                                                     const Options& options);
+    RobotClient(std::shared_ptr<ViamChannel> channel);
     std::vector<Name> resource_names() const;
 
     /// @brief Lookup and return a `shared_ptr` to a resource.
@@ -155,24 +148,17 @@ class RobotClient {
 
    private:
     Registry* registry_;
-
     std::vector<std::shared_ptr<std::thread>> threads_;
-
     std::atomic<bool> should_refresh_;
     unsigned int refresh_interval_;
-
     std::shared_ptr<GrpcChannel> channel_;
     std::shared_ptr<ViamChannel> viam_channel_;
     bool should_close_channel_;
-
     struct impl;
     std::unique_ptr<impl> impl_;
-
     mutable std::mutex lock_;
-
     std::vector<Name> resource_names_;
     ResourceManager resource_manager_;
-
     void refresh_every();
 };
 
diff --git a/src/viam/sdk/rpc/server.cpp b/src/viam/sdk/rpc/server.cpp
index b2c46c695..9964abbac 100644
--- a/src/viam/sdk/rpc/server.cpp
+++ b/src/viam/sdk/rpc/server.cpp
@@ -15,11 +15,11 @@
 namespace viam {
 namespace sdk {
 
-Server::Server(const Registry* registry) : builder_(std::make_unique<grpc::ServerBuilder>()) {
+Server::Server() : builder_(std::make_unique<grpc::ServerBuilder>()) {
     builder_->SetMaxReceiveMessageSize(kMaxMessageSize);
     builder_->SetMaxSendMessageSize(kMaxMessageSize);
     builder_->SetMaxMessageSize(kMaxMessageSize);
-    for (const auto& rr : registry->registered_resource_servers()) {
+    for (const auto& rr : Registry::get().registered_resource_servers()) {
         auto new_manager = std::make_shared<ResourceManager>();
         auto server = rr.second->create_resource_server(new_manager, *this);
         managed_servers_.emplace(rr.first, std::move(server));
diff --git a/src/viam/sdk/rpc/server.hpp b/src/viam/sdk/rpc/server.hpp
index 5f868b779..e735a6351 100644
--- a/src/viam/sdk/rpc/server.hpp
+++ b/src/viam/sdk/rpc/server.hpp
@@ -23,13 +23,11 @@ class TestServer;
 
 namespace sdk {
 
-class Registry;
-
 /// @class Server server.hpp "rpc/server.hpp"
 /// @brief Defines gRPC `Server` functionality.
 class Server {
    public:
-    Server(const Registry* registry);
+    Server();
     ~Server();
 
     /// @brief Starts the grpc server. Can only be called once.
diff --git a/src/viam/sdk/tests/test_robot.cpp b/src/viam/sdk/tests/test_robot.cpp
index e3bead0c9..2018ed36b 100644
--- a/src/viam/sdk/tests/test_robot.cpp
+++ b/src/viam/sdk/tests/test_robot.cpp
@@ -42,7 +42,7 @@ void robot_client_to_mocks_pipeline(F&& test_case) {
     rm->add(std::string("mock_generic"), generic::MockGenericComponent::get_mock_generic());
     rm->add(std::string("mock_motor"), motor::MockMotor::get_mock_motor());
     rm->add(std::string("mock_camera"), camera::MockCamera::get_mock_camera());
-    auto server = std::make_shared<sdk::Server>(Instance::current().registry());
+    auto server = std::make_shared<sdk::Server>();
     MockRobotService service(rm, *server);
     server->start();
 
@@ -51,8 +51,7 @@ void robot_client_to_mocks_pipeline(F&& test_case) {
     auto test_server = TestServer(server);
     auto grpc_channel = test_server.grpc_in_process_channel();
     auto viam_channel = std::make_shared<ViamChannel>(grpc_channel, "", nullptr);
-    auto client = RobotClient::with_channel(
-        viam_channel, Options(0, boost::none), Instance::current().registry());
+    auto client = RobotClient::with_channel(viam_channel, Options(0, boost::none));
 
     // Run the passed-in test case on the created stack and give access to the
     // created RobotClient and MockRobotService.
@@ -63,7 +62,7 @@ void robot_client_to_mocks_pipeline(F&& test_case) {
 }
 
 BOOST_AUTO_TEST_CASE(test_registering_resources) {
-    auto& registry = *Instance::current().registry();
+    auto& registry = Registry::get();
 
     // To test with mock resources we need to be able to create them, which means registering
     // constructors. This tests that we register correctly.
diff --git a/src/viam/sdk/tests/test_utils.hpp b/src/viam/sdk/tests/test_utils.hpp
index 3de43aed8..26a51444e 100644
--- a/src/viam/sdk/tests/test_utils.hpp
+++ b/src/viam/sdk/tests/test_utils.hpp
@@ -51,7 +51,7 @@ class TestServer {
 // The passed in test_case function will have access to the created ResourceClient.
 template <typename ResourceType, typename F>
 void client_to_mock_pipeline(std::shared_ptr<Resource> mock, F&& test_case) {
-    auto server = std::make_shared<sdk::Server>(sdk::Instance::current().registry());
+    auto server = std::make_shared<sdk::Server>();
 
     // normally the high level server service (either robot or module) handles adding managed
     // resources, but in this case we must do it ourselves.
@@ -63,9 +63,8 @@ void client_to_mock_pipeline(std::shared_ptr<Resource> mock, F&& test_case) {
     auto test_server = TestServer(server);
     auto grpc_channel = test_server.grpc_in_process_channel();
 
-    auto resource_client = sdk::Instance::current()
-                               .registry()
-                               ->lookup_resource_client(API::get<ResourceType>())
+    auto resource_client = sdk::Registry::get()
+                               .lookup_resource_client(API::get<ResourceType>())
                                ->create_rpc_client(mock->name(), std::move(grpc_channel));
 
     // Run the passed-in test case on the created stack and give access to the

From 18d26c92c4a0b39dc785c9306a3fcd803c736f0b Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Thu, 27 Feb 2025 13:51:47 -0500
Subject: [PATCH 13/31] revert and adapt examples

---
 src/viam/examples/camera/example_camera.cpp              | 6 ++++++
 src/viam/examples/dial/example_dial.cpp                  | 5 +++++
 src/viam/examples/dial_api_key/example_dial_api_key.cpp  | 5 +++++
 .../mlmodel/example_audio_classification_client.cpp      | 5 +++++
 src/viam/examples/modules/complex/client.cpp             | 5 +++++
 src/viam/examples/modules/complex/main.cpp               | 9 +++++++--
 .../examples/modules/complex/test_complex_module.cpp     | 5 +++--
 src/viam/examples/modules/simple/client.cpp              | 3 +++
 src/viam/examples/modules/simple/main.cpp                | 3 +++
 src/viam/examples/modules/tflite/main.cpp                | 9 +++++++--
 src/viam/examples/motor/example_motor.cpp                | 6 ++++++
 11 files changed, 55 insertions(+), 6 deletions(-)

diff --git a/src/viam/examples/camera/example_camera.cpp b/src/viam/examples/camera/example_camera.cpp
index bc1b0ab9a..d1eb9b80c 100644
--- a/src/viam/examples/camera/example_camera.cpp
+++ b/src/viam/examples/camera/example_camera.cpp
@@ -3,6 +3,7 @@
 #include <unistd.h>
 #include <vector>
 
+#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/components/camera.hpp>
 #include <viam/sdk/robot/client.hpp>
 #include <viam/sdk/rpc/dial.hpp>
@@ -13,6 +14,11 @@ int main() {
     using std::endl;
     namespace vs = ::viam::sdk;
     try {
+        // Every Viam C++ SDK program must have one and only one Instance object which is created
+        // before
+        // any other C++ SDK objects and stays alive until all Viam C++ SDK objects are destroyed.
+        vs::Instance inst;
+
         // If you want to connect to a remote robot, this should be the url of the robot
         // Ex: xxx.xxx.viam.cloud
         std::string robot_address("localhost:8080");
diff --git a/src/viam/examples/dial/example_dial.cpp b/src/viam/examples/dial/example_dial.cpp
index efa783dfb..f39522c26 100644
--- a/src/viam/examples/dial/example_dial.cpp
+++ b/src/viam/examples/dial/example_dial.cpp
@@ -9,6 +9,7 @@
 
 #include <boost/optional.hpp>
 
+#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/components/generic.hpp>
 #include <viam/sdk/robot/client.hpp>
 #include <viam/sdk/rpc/dial.hpp>
@@ -16,6 +17,10 @@
 using namespace viam::sdk;
 
 int main() {
+    // Every Viam C++ SDK program must have one and only one Instance object which is created before
+    // any other C++ SDK objects and stays alive until all Viam C++ SDK objects are destroyed.
+    Instance inst;
+
     const char* uri = "<your robot URI here>";
     DialOptions dial_options;
     std::string type = "<your authentication type>";
diff --git a/src/viam/examples/dial_api_key/example_dial_api_key.cpp b/src/viam/examples/dial_api_key/example_dial_api_key.cpp
index 4c47beffe..b723e4227 100644
--- a/src/viam/examples/dial_api_key/example_dial_api_key.cpp
+++ b/src/viam/examples/dial_api_key/example_dial_api_key.cpp
@@ -10,6 +10,7 @@
 #include <boost/optional.hpp>
 #include <boost/program_options.hpp>
 
+#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/robot/client.hpp>
 #include <viam/sdk/rpc/dial.hpp>
 
@@ -18,6 +19,10 @@ using namespace viam::sdk;
 namespace po = boost::program_options;
 
 int main(int argc, char* argv[]) {
+    // Every Viam C++ SDK program must have one and only one Instance object which is created before
+    // any other C++ SDK objects and stays alive until all Viam C++ SDK objects are destroyed.
+    Instance inst;
+
     po::options_description desc("Allowed options");
     desc.add_options()("help", "List options and exit")(
         "uri", po::value<std::string>(), "URI of robot")(
diff --git a/src/viam/examples/mlmodel/example_audio_classification_client.cpp b/src/viam/examples/mlmodel/example_audio_classification_client.cpp
index 95e26f57c..6be570449 100644
--- a/src/viam/examples/mlmodel/example_audio_classification_client.cpp
+++ b/src/viam/examples/mlmodel/example_audio_classification_client.cpp
@@ -29,6 +29,7 @@
 #include <boost/program_options.hpp>
 #include <boost/variant/get.hpp>
 
+#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/robot/client.hpp>
 #include <viam/sdk/services/mlmodel.hpp>
 
@@ -78,6 +79,10 @@ constexpr char kRobotConfigTemplate[] = R"(
 }  // namespace
 
 int main(int argc, char* argv[]) try {
+    // Every Viam C++ SDK program must have one and only one Instance object which is created before
+    // any other C++ SDK objects and stays alive until all Viam C++ SDK objects are destroyed.
+    viam::sdk::Instance inst;
+
     // Build up our command line options. The example operates in two
     // modes. In the "--generate" mode, it takes command line
     // parameters needed to satisfy the interpolation points in the
diff --git a/src/viam/examples/modules/complex/client.cpp b/src/viam/examples/modules/complex/client.cpp
index ac85c9f00..4c26f055f 100644
--- a/src/viam/examples/modules/complex/client.cpp
+++ b/src/viam/examples/modules/complex/client.cpp
@@ -11,6 +11,7 @@
 #include <grpcpp/grpcpp.h>
 #include <grpcpp/support/status.h>
 
+#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/components/motor.hpp>
 #include <viam/sdk/robot/client.hpp>
 #include <viam/sdk/rpc/dial.hpp>
@@ -21,6 +22,10 @@
 using namespace viam::sdk;
 
 int main() {
+    // Every Viam C++ SDK program must have one and only one Instance object which is created before
+    // any other C++ SDK objects and stays alive until all Viam C++ SDK objects are destroyed.
+    Instance inst;
+
     const char* uri = "http://localhost:8080/";  // replace with your URI if connecting securely
     DialOptions dial_options;
     dial_options.set_allow_insecure_downgrade(true);  // set to false if connecting securely
diff --git a/src/viam/examples/modules/complex/main.cpp b/src/viam/examples/modules/complex/main.cpp
index da80453e6..c6a1e7532 100644
--- a/src/viam/examples/modules/complex/main.cpp
+++ b/src/viam/examples/modules/complex/main.cpp
@@ -5,6 +5,7 @@
 #include <grpcpp/grpcpp.h>
 #include <grpcpp/server_context.h>
 
+#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/components/base.hpp>
 #include <viam/sdk/components/component.hpp>
 #include <viam/sdk/config/resource.hpp>
@@ -24,11 +25,15 @@
 using namespace viam::sdk;
 
 int main(int argc, char** argv) {
+    // Every Viam C++ SDK program must have one and only one Instance object which is created before
+    // any other C++ SDK objects and stays alive until all Viam C++ SDK objects are destroyed.
+    Instance inst;
+
     Model mybase_model("viam", "base", "mybase");
 
     // Make sure to explicity register resources with custom APIs.
-    Registry::get().register_resource_server<GizmoServer>();
-    Registry::get().register_resource_server<SummationServer>();
+    inst.registry()->register_resource_server<GizmoServer>();
+    inst.registry()->register_resource_server<SummationServer>();
 
     std::shared_ptr<ModelRegistration> mybase_mr = std::make_shared<ModelRegistration>(
         API::get<Base>(),
diff --git a/src/viam/examples/modules/complex/test_complex_module.cpp b/src/viam/examples/modules/complex/test_complex_module.cpp
index 14d68a8cf..3f4d4ee3d 100644
--- a/src/viam/examples/modules/complex/test_complex_module.cpp
+++ b/src/viam/examples/modules/complex/test_complex_module.cpp
@@ -24,8 +24,9 @@ using namespace viam::sdktests;
 
 struct RegisterGizmoAndSummationFixture {
     RegisterGizmoAndSummationFixture() {
-        Registry::get().register_resource<GizmoClient, GizmoServer>();
-        Registry::get().register_resource<SummationClient, SummationServer>();
+        auto* registry = Instance::current().registry();
+        registry->register_resource<GizmoClient, GizmoServer>();
+        registry->register_resource<SummationClient, SummationServer>();
     }
 
     // Test teardown is a noop;
diff --git a/src/viam/examples/modules/simple/client.cpp b/src/viam/examples/modules/simple/client.cpp
index fcaab5eff..09e510636 100644
--- a/src/viam/examples/modules/simple/client.cpp
+++ b/src/viam/examples/modules/simple/client.cpp
@@ -2,6 +2,7 @@
 #include <memory>
 #include <string>
 
+#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/common/proto_value.hpp>
 #include <viam/sdk/components/sensor.hpp>
 #include <viam/sdk/robot/client.hpp>
@@ -10,6 +11,8 @@
 using namespace viam::sdk;
 
 int main() {
+    Instance inst;
+
     const char* uri = "http://localhost:8080/";  // replace with your URI if connecting securely
     DialOptions dial_options;
     dial_options.set_allow_insecure_downgrade(true);  // set to false if connecting securely
diff --git a/src/viam/examples/modules/simple/main.cpp b/src/viam/examples/modules/simple/main.cpp
index cfd783f66..0df75464b 100644
--- a/src/viam/examples/modules/simple/main.cpp
+++ b/src/viam/examples/modules/simple/main.cpp
@@ -3,6 +3,7 @@
 #include <sstream>
 
 #include <viam/sdk/common/exception.hpp>
+#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/common/proto_value.hpp>
 #include <viam/sdk/components/sensor.hpp>
 #include <viam/sdk/config/resource.hpp>
@@ -75,6 +76,8 @@ ProtoStruct MySensor::get_readings(const ProtoStruct&) {
 }
 
 int main(int argc, char** argv) try {
+    Instance inst;
+
     Model mysensor_model("viam", "sensor", "mysensor");
 
     std::shared_ptr<ModelRegistration> mr = std::make_shared<ModelRegistration>(
diff --git a/src/viam/examples/modules/tflite/main.cpp b/src/viam/examples/modules/tflite/main.cpp
index 44cd8e284..e1c806354 100644
--- a/src/viam/examples/modules/tflite/main.cpp
+++ b/src/viam/examples/modules/tflite/main.cpp
@@ -23,6 +23,7 @@
 
 #include <tensorflow/lite/c/c_api.h>
 
+#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/common/proto_value.hpp>
 #include <viam/sdk/components/component.hpp>
 #include <viam/sdk/config/resource.hpp>
@@ -723,6 +724,10 @@ class MLModelServiceTFLite : public vsdk::MLModelService,
 };
 
 int serve(const std::string& socket_path) try {
+    // Every Viam C++ SDK program must have one and only one Instance object which is created before
+    // any other C++ SDK objects and stays alive until all Viam C++ SDK objects are destroyed.
+    vsdk::Instance inst;
+
     // Create a new model registration for the service.
     auto module_registration = std::make_shared<vsdk::ModelRegistration>(
         // Identify that this resource offers the MLModelService API
@@ -737,10 +742,10 @@ int serve(const std::string& socket_path) try {
         });
 
     // Register the newly created registration with the Registry.
-    vsdk::Registry::register_model(module_registration);
+    inst.registry()->register_model(module_registration);
 
     // Construct the module service and tell it where to place the socket path.
-    auto module_service = std::make_shared<vsdk::ModuleService>(socket_path);
+    auto module_service = std::make_shared<vsdk::ModuleService>(socket_path, inst.registry());
 
     // Add the server as providing the API and model declared in the
     // registration.
diff --git a/src/viam/examples/motor/example_motor.cpp b/src/viam/examples/motor/example_motor.cpp
index c4d8023d5..3d5a640ef 100644
--- a/src/viam/examples/motor/example_motor.cpp
+++ b/src/viam/examples/motor/example_motor.cpp
@@ -6,6 +6,7 @@
 #include <string>
 #include <vector>
 
+#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/components/motor.hpp>
 #include <viam/sdk/robot/client.hpp>
 #include <viam/sdk/rpc/dial.hpp>
@@ -27,6 +28,11 @@ int main() {
     namespace vs = ::viam::sdk;
 
     try {
+        // Every Viam C++ SDK program must have one and only one Instance object which is created
+        // before any other C++ SDK objects and stays alive until all Viam C++ SDK objects are
+        // destroyed.
+        vs::Instance inst;
+
         // If you want to connect to a remote robot, this should be the url of the robot
         // Ex: xxx.xxx.viam.cloud
         std::string robot_address("localhost:8080");

From 60183237def4a3aff5c2163efd31ce86630b45c6 Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Thu, 27 Feb 2025 14:26:16 -0500
Subject: [PATCH 14/31] make instance more of a black box

---
 src/viam/examples/modules/complex/main.cpp               | 4 ++--
 .../examples/modules/complex/test_complex_module.cpp     | 6 +++---
 src/viam/examples/modules/tflite/main.cpp                | 2 +-
 src/viam/sdk/common/instance.cpp                         | 9 +--------
 src/viam/sdk/common/instance.hpp                         | 6 ++----
 src/viam/sdk/registry/registry.cpp                       | 4 ++--
 src/viam/sdk/tests/mocks/mock_robot.cpp                  | 2 +-
 7 files changed, 12 insertions(+), 21 deletions(-)

diff --git a/src/viam/examples/modules/complex/main.cpp b/src/viam/examples/modules/complex/main.cpp
index c6a1e7532..253e69d78 100644
--- a/src/viam/examples/modules/complex/main.cpp
+++ b/src/viam/examples/modules/complex/main.cpp
@@ -32,8 +32,8 @@ int main(int argc, char** argv) {
     Model mybase_model("viam", "base", "mybase");
 
     // Make sure to explicity register resources with custom APIs.
-    inst.registry()->register_resource_server<GizmoServer>();
-    inst.registry()->register_resource_server<SummationServer>();
+    Registry::get().register_resource_server<GizmoServer>();
+    Registry::get().register_resource_server<SummationServer>();
 
     std::shared_ptr<ModelRegistration> mybase_mr = std::make_shared<ModelRegistration>(
         API::get<Base>(),
diff --git a/src/viam/examples/modules/complex/test_complex_module.cpp b/src/viam/examples/modules/complex/test_complex_module.cpp
index 3f4d4ee3d..4a178271f 100644
--- a/src/viam/examples/modules/complex/test_complex_module.cpp
+++ b/src/viam/examples/modules/complex/test_complex_module.cpp
@@ -24,9 +24,9 @@ using namespace viam::sdktests;
 
 struct RegisterGizmoAndSummationFixture {
     RegisterGizmoAndSummationFixture() {
-        auto* registry = Instance::current().registry();
-        registry->register_resource<GizmoClient, GizmoServer>();
-        registry->register_resource<SummationClient, SummationServer>();
+        auto& registry = Registry::get();
+        registry.register_resource<GizmoClient, GizmoServer>();
+        registry.register_resource<SummationClient, SummationServer>();
     }
 
     // Test teardown is a noop;
diff --git a/src/viam/examples/modules/tflite/main.cpp b/src/viam/examples/modules/tflite/main.cpp
index e1c806354..c1224266f 100644
--- a/src/viam/examples/modules/tflite/main.cpp
+++ b/src/viam/examples/modules/tflite/main.cpp
@@ -742,7 +742,7 @@ int serve(const std::string& socket_path) try {
         });
 
     // Register the newly created registration with the Registry.
-    inst.registry()->register_model(module_registration);
+    Registry::get().register_model(module_registration);
 
     // Construct the module service and tell it where to place the socket path.
     auto module_service = std::make_shared<vsdk::ModuleService>(socket_path, inst.registry());
diff --git a/src/viam/sdk/common/instance.cpp b/src/viam/sdk/common/instance.cpp
index c366ad6c6..bc52367f6 100644
--- a/src/viam/sdk/common/instance.cpp
+++ b/src/viam/sdk/common/instance.cpp
@@ -1,6 +1,7 @@
 #include <viam/sdk/common/instance.hpp>
 
 #include <viam/sdk/common/exception.hpp>
+#include <viam/sdk/common/private/instance.hpp>
 #include <viam/sdk/registry/registry.hpp>
 
 #include <atomic>
@@ -17,10 +18,6 @@ std::atomic<Instance*> current_instance{nullptr};
 
 }  // namespace
 
-struct Instance::Impl {
-    Registry registry;
-};
-
 Instance::Instance() {
     Instance* expected = nullptr;
 
@@ -52,9 +49,5 @@ Instance& Instance::current() {
     return *current;
 }
 
-Registry* Instance::registry() {
-    return &(impl_->registry);
-}
-
 }  // namespace sdk
 }  // namespace viam
diff --git a/src/viam/sdk/common/instance.hpp b/src/viam/sdk/common/instance.hpp
index c1ab0961f..1c97a2479 100644
--- a/src/viam/sdk/common/instance.hpp
+++ b/src/viam/sdk/common/instance.hpp
@@ -5,8 +5,6 @@
 namespace viam {
 namespace sdk {
 
-class Registry;
-
 /// @brief Instance management for Viam C++ SDK applications.
 /// This is a single instance class which is responsible for global setup and teardown related to
 /// the SDK. An Instance must be constructed before doing anything else in a program, and it must
@@ -19,9 +17,9 @@ class Instance {
 
     static Instance& current();
 
-    Registry* registry();
-
    private:
+    friend class Registry;
+
     struct Impl;
     std::unique_ptr<Impl> impl_;
 };
diff --git a/src/viam/sdk/registry/registry.cpp b/src/viam/sdk/registry/registry.cpp
index 1ee9b5533..b1e8fb604 100644
--- a/src/viam/sdk/registry/registry.cpp
+++ b/src/viam/sdk/registry/registry.cpp
@@ -12,7 +12,7 @@
 #include <grpcpp/ext/proto_server_reflection_plugin.h>
 
 #include <viam/sdk/common/exception.hpp>
-#include <viam/sdk/common/instance.hpp>
+#include <viam/sdk/common/private/instance.hpp>
 #include <viam/sdk/components/private/arm_client.hpp>
 #include <viam/sdk/components/private/arm_server.hpp>
 #include <viam/sdk/components/private/base_client.hpp>
@@ -92,7 +92,7 @@ const Model& ModelRegistration::model() const {
 };
 
 Registry& Registry::get() {
-    return *Instance::current().registry();
+    return Instance::current().impl_->registry;
 }
 
 void Registry::register_model(std::shared_ptr<const ModelRegistration> resource) {
diff --git a/src/viam/sdk/tests/mocks/mock_robot.cpp b/src/viam/sdk/tests/mocks/mock_robot.cpp
index 5dc03fcc2..ce9a62884 100644
--- a/src/viam/sdk/tests/mocks/mock_robot.cpp
+++ b/src/viam/sdk/tests/mocks/mock_robot.cpp
@@ -26,7 +26,7 @@ std::vector<Name> registered_models_for_resource(const std::shared_ptr<Resource>
     std::string resource_type;
     std::string resource_subtype;
     std::vector<Name> resource_names;
-    for (const auto& kv : Instance::current().registry()->registered_models()) {
+    for (const auto& kv : Registry::get().registered_models()) {
         const std::shared_ptr<const ModelRegistration> reg = kv.second;
         if (reg->api() == resource->api()) {
             resource_type = reg->api().resource_type();

From 5535616d43a2fabe14e9c5a5a7d5b5718252a924 Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Thu, 27 Feb 2025 14:40:39 -0500
Subject: [PATCH 15/31] add impl instance to git

---
 src/viam/sdk/common/private/instance.hpp | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
 create mode 100644 src/viam/sdk/common/private/instance.hpp

diff --git a/src/viam/sdk/common/private/instance.hpp b/src/viam/sdk/common/private/instance.hpp
new file mode 100644
index 000000000..b1728de8c
--- /dev/null
+++ b/src/viam/sdk/common/private/instance.hpp
@@ -0,0 +1,14 @@
+#pragma once
+
+#include <viam/sdk/common/instance.hpp>
+#include <viam/sdk/registry/registry.hpp>
+
+namespace viam {
+namespace sdk {
+
+struct Instance::Impl {
+    Registry registry;
+};
+
+}  // namespace sdk
+}  // namespace viam

From eeac195427f24641a37fceccaf4aa87fd4df6385 Mon Sep 17 00:00:00 2001
From: lia <167905060+lia-viam@users.noreply.github.com>
Date: Mon, 3 Mar 2025 10:05:20 -0500
Subject: [PATCH 16/31] Add instance comment boilerplate

Co-authored-by: Ethan <ethanrodkin@proton.me>
---
 src/viam/examples/modules/simple/client.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/viam/examples/modules/simple/client.cpp b/src/viam/examples/modules/simple/client.cpp
index 09e510636..f08410336 100644
--- a/src/viam/examples/modules/simple/client.cpp
+++ b/src/viam/examples/modules/simple/client.cpp
@@ -11,6 +11,8 @@
 using namespace viam::sdk;
 
 int main() {
+    // Every Viam C++ SDK program must have one and only one Instance object which is created before
+    // any other C++ SDK objects and stays alive until all Viam C++ SDK objects are destroyed.
     Instance inst;
 
     const char* uri = "http://localhost:8080/";  // replace with your URI if connecting securely

From 7560f6d0c965939d5ae388bd49766aa268c19e67 Mon Sep 17 00:00:00 2001
From: lia <167905060+lia-viam@users.noreply.github.com>
Date: Mon, 3 Mar 2025 10:05:49 -0500
Subject: [PATCH 17/31] Add instance comment boilerplate

Co-authored-by: Ethan <ethanrodkin@proton.me>
---
 src/viam/examples/modules/simple/main.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/viam/examples/modules/simple/main.cpp b/src/viam/examples/modules/simple/main.cpp
index 0df75464b..e85c2fe3a 100644
--- a/src/viam/examples/modules/simple/main.cpp
+++ b/src/viam/examples/modules/simple/main.cpp
@@ -76,6 +76,8 @@ ProtoStruct MySensor::get_readings(const ProtoStruct&) {
 }
 
 int main(int argc, char** argv) try {
+    // Every Viam C++ SDK program must have one and only one Instance object which is created before
+    // any other C++ SDK objects and stays alive until all Viam C++ SDK objects are destroyed.
     Instance inst;
 
     Model mysensor_model("viam", "sensor", "mysensor");

From 4e25d35b30bfaa3fae2452576e23c32da9c57690 Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Mon, 3 Mar 2025 14:52:30 -0500
Subject: [PATCH 18/31] remove old ctor arg

---
 src/viam/examples/modules/tflite/main.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/viam/examples/modules/tflite/main.cpp b/src/viam/examples/modules/tflite/main.cpp
index c1224266f..65ca8c191 100644
--- a/src/viam/examples/modules/tflite/main.cpp
+++ b/src/viam/examples/modules/tflite/main.cpp
@@ -745,7 +745,7 @@ int serve(const std::string& socket_path) try {
     Registry::get().register_model(module_registration);
 
     // Construct the module service and tell it where to place the socket path.
-    auto module_service = std::make_shared<vsdk::ModuleService>(socket_path, inst.registry());
+    auto module_service = std::make_shared<vsdk::ModuleService>(socket_path);
 
     // Add the server as providing the API and model declared in the
     // registration.

From 55baa6c00d4d3de8eeaaeb2befb13423db23c143 Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Mon, 3 Mar 2025 14:53:26 -0500
Subject: [PATCH 19/31] prohibit multi instance

---
 src/viam/sdk/common/instance.hpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/viam/sdk/common/instance.hpp b/src/viam/sdk/common/instance.hpp
index 1c97a2479..64bb430c2 100644
--- a/src/viam/sdk/common/instance.hpp
+++ b/src/viam/sdk/common/instance.hpp
@@ -8,8 +8,8 @@ namespace sdk {
 /// @brief Instance management for Viam C++ SDK applications.
 /// This is a single instance class which is responsible for global setup and teardown related to
 /// the SDK. An Instance must be constructed before doing anything else in a program, and it must
-/// remain alive in a valid state for the duration of the program. Creating multiple overlapping
-/// Instance objects is an error.
+/// remain alive in a valid state for the duration of the program. Creating multiple Instance
+/// objects in the same program is an error.
 class Instance {
    public:
     Instance();

From 10cd711441b03ea12bea259ba27013d622a0a8a3 Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Mon, 3 Mar 2025 14:54:54 -0500
Subject: [PATCH 20/31] remove initialized flag

---
 src/viam/sdk/registry/registry.cpp | 7 -------
 src/viam/sdk/registry/registry.hpp | 3 ++-
 2 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/src/viam/sdk/registry/registry.cpp b/src/viam/sdk/registry/registry.cpp
index b1e8fb604..15b1f118b 100644
--- a/src/viam/sdk/registry/registry.cpp
+++ b/src/viam/sdk/registry/registry.cpp
@@ -219,13 +219,6 @@ void Registry::register_resources() {
 }
 
 void Registry::initialize() {
-    const std::lock_guard<std::mutex> lock(lock_);
-    if (initialized_) {
-        BOOST_LOG_TRIVIAL(warning)
-            << "Attempted to initialize the Registry but it was already initialized.";
-        return;
-    }
-    initialized_ = true;
     register_resources();
     grpc::reflection::InitProtoReflectionServerBuilderPlugin();
 }
diff --git a/src/viam/sdk/registry/registry.hpp b/src/viam/sdk/registry/registry.hpp
index f09ee2d62..c1a5055a3 100644
--- a/src/viam/sdk/registry/registry.hpp
+++ b/src/viam/sdk/registry/registry.hpp
@@ -194,8 +194,9 @@ class Registry {
     void initialize();
 
     mutable std::mutex lock_;
-    bool initialized_{false};
+
     std::unordered_map<std::string, std::shared_ptr<const ModelRegistration>> resources_;
+
     std::unordered_map<API, std::shared_ptr<const ResourceClientRegistration>> client_apis_;
     std::unordered_map<API, std::shared_ptr<const ResourceServerRegistration>> server_apis_;
 

From c74542296e2513e09281450fdb6e1452b72129a5 Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Mon, 3 Mar 2025 14:55:54 -0500
Subject: [PATCH 21/31] meyers singleton registry

---
 src/viam/sdk/registry/registry.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/viam/sdk/registry/registry.cpp b/src/viam/sdk/registry/registry.cpp
index 15b1f118b..e538d2ec2 100644
--- a/src/viam/sdk/registry/registry.cpp
+++ b/src/viam/sdk/registry/registry.cpp
@@ -92,7 +92,9 @@ const Model& ModelRegistration::model() const {
 };
 
 Registry& Registry::get() {
-    return Instance::current().impl_->registry;
+    static Registry& result = Instance::current().impl_->registry;
+
+    return result;
 }
 
 void Registry::register_model(std::shared_ptr<const ModelRegistration> resource) {

From 75ab450a7fa122ff93e50ff9226ab9c49f003177 Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Mon, 3 Mar 2025 15:13:33 -0500
Subject: [PATCH 22/31] remove registry member and fix member spacing/ordering

---
 src/viam/sdk/module/service.cpp | 14 ++++++--------
 src/viam/sdk/module/service.hpp |  2 --
 src/viam/sdk/robot/client.cpp   |  6 +++---
 src/viam/sdk/robot/client.hpp   |  9 +++++++--
 4 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/src/viam/sdk/module/service.cpp b/src/viam/sdk/module/service.cpp
index d644b5420..911be9bb3 100644
--- a/src/viam/sdk/module/service.cpp
+++ b/src/viam/sdk/module/service.cpp
@@ -57,7 +57,7 @@ struct ModuleService::ServiceImpl : viam::module::v1::ModuleService::Service {
         std::shared_ptr<Resource> res;
         const Dependencies deps = parent.get_dependencies_(&request->dependencies(), cfg.name());
         const std::shared_ptr<const ModelRegistration> reg =
-            parent.registry_->lookup_model(cfg.api(), cfg.model());
+            Registry::get().lookup_model(cfg.api(), cfg.model());
         if (reg) {
             try {
                 res = reg->construct_resource(deps, cfg);
@@ -112,7 +112,7 @@ struct ModuleService::ServiceImpl : viam::module::v1::ModuleService::Service {
         }
 
         const std::shared_ptr<const ModelRegistration> reg =
-            parent.registry_->lookup_model(cfg.name());
+            Registry::get().lookup_model(cfg.name());
         if (reg) {
             try {
                 const std::shared_ptr<Resource> res = reg->construct_resource(deps, cfg);
@@ -132,7 +132,7 @@ struct ModuleService::ServiceImpl : viam::module::v1::ModuleService::Service {
         ResourceConfig cfg = from_proto(proto);
 
         const std::shared_ptr<const ModelRegistration> reg =
-            parent.registry_->lookup_model(cfg.api(), cfg.model());
+            Registry::get().lookup_model(cfg.api(), cfg.model());
         if (!reg) {
             return grpc::Status(grpc::UNKNOWN,
                                 "unable to validate resource " + cfg.resource_name().name() +
@@ -215,9 +215,7 @@ std::shared_ptr<Resource> ModuleService::get_parent_resource_(const Name& name)
 }
 
 ModuleService::ModuleService(std::string addr)
-    : registry_(&Registry::get()),
-      module_(std::make_unique<Module>(std::move(addr))),
-      server_(std::make_unique<Server>()) {
+    : module_(std::make_unique<Module>(std::move(addr))), server_(std::make_unique<Server>()) {
     impl_ = std::make_unique<ServiceImpl>(*this);
 }
 
@@ -234,7 +232,7 @@ ModuleService::ModuleService(int argc,
     set_logger_severity_from_args(argc, argv);
 
     for (auto&& mr : registrations) {
-        registry_->register_model(mr);
+        Registry::get().register_model(mr);
         add_model_from_registry(mr->api(), mr->model());
     }
 }
@@ -277,7 +275,7 @@ void ModuleService::add_model_from_registry_inlock_(API api,
                                                     Model model,
                                                     const std::lock_guard<std::mutex>&) {
     const std::shared_ptr<const ResourceServerRegistration> creator =
-        registry_->lookup_resource_server(api);
+        Registry::get().lookup_resource_server(api);
     std::string name;
     if (creator && creator->service_descriptor()) {
         name = creator->service_descriptor()->full_name();
diff --git a/src/viam/sdk/module/service.hpp b/src/viam/sdk/module/service.hpp
index 95a7ad4f3..799ba1ab5 100644
--- a/src/viam/sdk/module/service.hpp
+++ b/src/viam/sdk/module/service.hpp
@@ -64,8 +64,6 @@ class ModuleService {
                                    std::string const& resource_name);
     std::shared_ptr<Resource> get_parent_resource_(const Name& name);
 
-    Registry* registry_;
-
     std::mutex lock_;
     std::unique_ptr<Module> module_;
     std::shared_ptr<RobotClient> parent_;
diff --git a/src/viam/sdk/robot/client.cpp b/src/viam/sdk/robot/client.cpp
index a8cb16c75..6c2f0f0fe 100644
--- a/src/viam/sdk/robot/client.cpp
+++ b/src/viam/sdk/robot/client.cpp
@@ -178,7 +178,8 @@ void RobotClient::refresh() {
         // are being properly registered from name.subtype(), or update what we're
         // using for lookup
         const std::shared_ptr<const ResourceClientRegistration> rs =
-            registry_->lookup_resource_client({name.namespace_(), name.type(), name.subtype()});
+            Registry::get().lookup_resource_client(
+                {name.namespace_(), name.type(), name.subtype()});
         if (rs) {
             try {
                 const std::shared_ptr<Resource> rpc_client =
@@ -222,8 +223,7 @@ void RobotClient::refresh_every() {
 };
 
 RobotClient::RobotClient(std::shared_ptr<ViamChannel> channel)
-    : registry_(&Registry::get()),
-      channel_(channel->channel()),
+    : channel_(channel->channel()),
       viam_channel_(std::move(channel)),
       should_close_channel_(false),
       impl_(std::make_unique<impl>(RobotService::NewStub(channel_))) {}
diff --git a/src/viam/sdk/robot/client.hpp b/src/viam/sdk/robot/client.hpp
index 410abca28..50fda612c 100644
--- a/src/viam/sdk/robot/client.hpp
+++ b/src/viam/sdk/robot/client.hpp
@@ -147,19 +147,24 @@ class RobotClient {
     status get_machine_status() const;
 
    private:
-    Registry* registry_;
+    void refresh_every();
+
     std::vector<std::shared_ptr<std::thread>> threads_;
+
     std::atomic<bool> should_refresh_;
     unsigned int refresh_interval_;
+
     std::shared_ptr<GrpcChannel> channel_;
     std::shared_ptr<ViamChannel> viam_channel_;
     bool should_close_channel_;
+
     struct impl;
     std::unique_ptr<impl> impl_;
+
     mutable std::mutex lock_;
+
     std::vector<Name> resource_names_;
     ResourceManager resource_manager_;
-    void refresh_every();
 };
 
 }  // namespace sdk

From fc21c356bf455947c5cd8d3dd68b174b354a5766 Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Mon, 3 Mar 2025 15:19:14 -0500
Subject: [PATCH 23/31] remove unused include

---
 src/viam/sdk/tests/test_utils.hpp | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/viam/sdk/tests/test_utils.hpp b/src/viam/sdk/tests/test_utils.hpp
index 26a51444e..11519a551 100644
--- a/src/viam/sdk/tests/test_utils.hpp
+++ b/src/viam/sdk/tests/test_utils.hpp
@@ -2,7 +2,6 @@
 
 #include <grpcpp/grpcpp.h>
 
-#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/config/resource.hpp>
 #include <viam/sdk/registry/registry.hpp>
 #include <viam/sdk/resource/resource.hpp>

From f02ce0f75d81baa28d62e88f9771e46132cab562 Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Wed, 12 Mar 2025 13:44:21 -0400
Subject: [PATCH 24/31] reorder includes

---
 src/viam/sdk/tests/test_mlmodel.cpp | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/viam/sdk/tests/test_mlmodel.cpp b/src/viam/sdk/tests/test_mlmodel.cpp
index 5d2db8010..8bc6a62f0 100644
--- a/src/viam/sdk/tests/test_mlmodel.cpp
+++ b/src/viam/sdk/tests/test_mlmodel.cpp
@@ -12,20 +12,19 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#define BOOST_TEST_MODULE test module test_mlmodel
 #include <viam/sdk/services/mlmodel.hpp>
 
 #include <memory>
 #include <tuple>
 #include <unordered_map>
 
+#include <boost/test/included/unit_test.hpp>
 #include <boost/variant/get.hpp>
 
 #include <viam/sdk/tests/mocks/mlmodel_mocks.hpp>
 #include <viam/sdk/tests/test_utils.hpp>
 
-#define BOOST_TEST_MODULE test module test_mlmodel
-#include <boost/test/included/unit_test.hpp>
-
 namespace viam {
 namespace sdk {
 

From e80bf807136a7b956d1744ac204e27fe6fd39f14 Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Wed, 12 Mar 2025 13:45:01 -0400
Subject: [PATCH 25/31] conditionally find unit test framework and link it to
 tests

---
 CMakeLists.txt                    | 6 +++++-
 src/viam/sdk/tests/CMakeLists.txt | 1 +
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4bebd7564..c025261b6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -324,7 +324,11 @@ set(VIAMCPPSDK_XTL_VERSION_MINIMUM 0.7.2)
 set(VIAMCPPSDK_XTENSOR_VERSION_MINIMUM 0.24.3)
 
 # Time to find `BOOST`.
-find_package(Boost ${VIAMCPPSDK_BOOST_VERSION_MINIMUM} REQUIRED COMPONENTS headers log program_options)
+if (VIAMCPPSDK_BUILD_TESTS)
+  set(VIAMCPPSDK_BOOST_TEST "unit_test_framework")
+endif()
+
+find_package(Boost ${VIAMCPPSDK_BOOST_VERSION_MINIMUM} REQUIRED COMPONENTS headers log program_options ${VIAMCPPSDK_BOOST_TEST})
 
 # Time to find `protobuf` and `gRPC[++]`. Normally this would just be
 # something like `find_package(gRPC <version> CONFIG REQUIRED)`, and
diff --git a/src/viam/sdk/tests/CMakeLists.txt b/src/viam/sdk/tests/CMakeLists.txt
index de1fbf0b7..fa2d1560d 100644
--- a/src/viam/sdk/tests/CMakeLists.txt
+++ b/src/viam/sdk/tests/CMakeLists.txt
@@ -47,6 +47,7 @@ target_include_directories(viamsdk_test
 
 target_link_libraries(viamsdk_test
   PUBLIC viam-cpp-sdk::viamsdk
+  PUBLIC Boost::unit_test_framework
 )
 
 viamcppsdk_link_viam_api(viamsdk_test PUBLIC)

From 185121ae13f80aa0c84858e7130349b7a46afd99 Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Wed, 12 Mar 2025 13:45:44 -0400
Subject: [PATCH 26/31] registry get cannot create instance by default

---
 src/viam/sdk/common/instance.cpp   | 10 +++++++---
 src/viam/sdk/common/instance.hpp   | 11 ++++++++++-
 src/viam/sdk/registry/registry.cpp |  2 +-
 src/viam/sdk/tests/test_utils.cpp  |  2 +-
 src/viam/sdk/tests/test_utils.hpp  | 12 ++++++++++++
 5 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/src/viam/sdk/common/instance.cpp b/src/viam/sdk/common/instance.cpp
index bc52367f6..86443f458 100644
--- a/src/viam/sdk/common/instance.cpp
+++ b/src/viam/sdk/common/instance.cpp
@@ -34,10 +34,14 @@ Instance::~Instance() {
     impl_.reset();
 }
 
-Instance& Instance::current() {
+Instance& Instance::current(Instance::Creation creation) {
     if (!current_instance.load()) {
-        // This variable declaration calls the default ctor, storing a current instance.
-        static Instance inst;  // NOLINT (misc-const-correctness)
+        if (creation == Creation::if_needed) {
+            // This variable declaration calls the default ctor, storing a current instance.
+            static Instance inst;  // NOLINT (misc-const-correctness)
+        } else {
+            throw Exception("Instance has not yet been created");
+        }
     }
 
     Instance* current = current_instance.load();
diff --git a/src/viam/sdk/common/instance.hpp b/src/viam/sdk/common/instance.hpp
index 64bb430c2..1dd0901df 100644
--- a/src/viam/sdk/common/instance.hpp
+++ b/src/viam/sdk/common/instance.hpp
@@ -12,10 +12,19 @@ namespace sdk {
 /// objects in the same program is an error.
 class Instance {
    public:
+    /// @brief Enumeration for creation behavior of @ref current
+    enum class Creation {
+        open_existing,  ///< Instance must already exist
+        if_needed       ///< Use existing instance if present, else create one.
+    };
+
     Instance();
     ~Instance();
 
-    static Instance& current();
+    /// @brief Get the current Instance according to the Creation behavior.
+    /// Calling current(Creation::open_existing) when an instance has not yet been constructed is an
+    /// error.
+    static Instance& current(Creation);
 
    private:
     friend class Registry;
diff --git a/src/viam/sdk/registry/registry.cpp b/src/viam/sdk/registry/registry.cpp
index e538d2ec2..de74d314d 100644
--- a/src/viam/sdk/registry/registry.cpp
+++ b/src/viam/sdk/registry/registry.cpp
@@ -92,7 +92,7 @@ const Model& ModelRegistration::model() const {
 };
 
 Registry& Registry::get() {
-    static Registry& result = Instance::current().impl_->registry;
+    static Registry& result = Instance::current(Instance::Creation::open_existing).impl_->registry;
 
     return result;
 }
diff --git a/src/viam/sdk/tests/test_utils.cpp b/src/viam/sdk/tests/test_utils.cpp
index 0ce5c83ca..c83e59580 100644
--- a/src/viam/sdk/tests/test_utils.cpp
+++ b/src/viam/sdk/tests/test_utils.cpp
@@ -10,8 +10,8 @@
 #include <viam/sdk/spatialmath/orientation_types.hpp>
 
 namespace viam {
-namespace sdktests {
 
+namespace sdktests {
 using namespace viam::sdk;
 
 ProtoStruct fake_map() {
diff --git a/src/viam/sdk/tests/test_utils.hpp b/src/viam/sdk/tests/test_utils.hpp
index 11519a551..201451188 100644
--- a/src/viam/sdk/tests/test_utils.hpp
+++ b/src/viam/sdk/tests/test_utils.hpp
@@ -2,6 +2,9 @@
 
 #include <grpcpp/grpcpp.h>
 
+#include <boost/test/unit_test.hpp>
+
+#include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/config/resource.hpp>
 #include <viam/sdk/registry/registry.hpp>
 #include <viam/sdk/resource/resource.hpp>
@@ -10,6 +13,15 @@
 namespace viam {
 namespace sdktests {
 
+struct GlobalFixture {
+    GlobalFixture() {
+        BOOST_TEST_MESSAGE("Creating instance");
+        (void)sdk::Instance::current(sdk::Instance::Creation::if_needed);
+    }
+};
+
+BOOST_TEST_GLOBAL_FIXTURE(GlobalFixture);
+
 using namespace viam::sdk;
 
 ProtoStruct fake_map();

From 7a747ec8f99fd9d529db8c37f3713b9d7a6bc7dc Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Wed, 12 Mar 2025 13:48:39 -0400
Subject: [PATCH 27/31] instance models fixture

---
 src/viam/sdk/tests/test_utils.hpp | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/src/viam/sdk/tests/test_utils.hpp b/src/viam/sdk/tests/test_utils.hpp
index 201451188..43825b8e2 100644
--- a/src/viam/sdk/tests/test_utils.hpp
+++ b/src/viam/sdk/tests/test_utils.hpp
@@ -13,16 +13,8 @@
 namespace viam {
 namespace sdktests {
 
-struct GlobalFixture {
-    GlobalFixture() {
-        BOOST_TEST_MESSAGE("Creating instance");
-        (void)sdk::Instance::current(sdk::Instance::Creation::if_needed);
-    }
-};
-
-BOOST_TEST_GLOBAL_FIXTURE(GlobalFixture);
-
 using namespace viam::sdk;
+BOOST_TEST_GLOBAL_FIXTURE(Instance);
 
 ProtoStruct fake_map();
 std::vector<GeometryConfig> fake_geometries();

From 9c4dc97111a2ce43bd8f0f917e0b3566601e0bdd Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Wed, 12 Mar 2025 14:05:15 -0400
Subject: [PATCH 28/31] create if needed instance in fixture

---
 src/viam/sdk/tests/test_utils.hpp | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/viam/sdk/tests/test_utils.hpp b/src/viam/sdk/tests/test_utils.hpp
index 43825b8e2..bb69e2499 100644
--- a/src/viam/sdk/tests/test_utils.hpp
+++ b/src/viam/sdk/tests/test_utils.hpp
@@ -13,8 +13,15 @@
 namespace viam {
 namespace sdktests {
 
+struct GlobalFixture {
+    GlobalFixture() {
+        (void)sdk::Instance::current(sdk::Instance::Creation::if_needed);
+    }
+};
+
+BOOST_TEST_GLOBAL_FIXTURE(GlobalFixture);
+
 using namespace viam::sdk;
-BOOST_TEST_GLOBAL_FIXTURE(Instance);
 
 ProtoStruct fake_map();
 std::vector<GeometryConfig> fake_geometries();

From 7409dc78319586f9141d4070f61b1f30f0b95cab Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Wed, 12 Mar 2025 14:08:11 -0400
Subject: [PATCH 29/31] revert namespace ws

---
 src/viam/sdk/tests/test_utils.cpp | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/viam/sdk/tests/test_utils.cpp b/src/viam/sdk/tests/test_utils.cpp
index c83e59580..9e76e2568 100644
--- a/src/viam/sdk/tests/test_utils.cpp
+++ b/src/viam/sdk/tests/test_utils.cpp
@@ -10,7 +10,6 @@
 #include <viam/sdk/spatialmath/orientation_types.hpp>
 
 namespace viam {
-
 namespace sdktests {
 using namespace viam::sdk;
 

From c4aaadfa92bccfd8dcade7d4a45587177f5e3cb4 Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Thu, 13 Mar 2025 13:02:19 -0400
Subject: [PATCH 30/31] code review: update doc comment

---
 src/viam/sdk/common/instance.hpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/viam/sdk/common/instance.hpp b/src/viam/sdk/common/instance.hpp
index 1dd0901df..096815943 100644
--- a/src/viam/sdk/common/instance.hpp
+++ b/src/viam/sdk/common/instance.hpp
@@ -22,8 +22,8 @@ class Instance {
     ~Instance();
 
     /// @brief Get the current Instance according to the Creation behavior.
-    /// Calling current(Creation::open_existing) when an instance has not yet been constructed is an
-    /// error.
+    /// @throws an @ref Exception if current(Creation::open_existing) is called when an instance has
+    /// not yet been constructed.
     static Instance& current(Creation);
 
    private:

From d2ae2d71cb61d44789cb17ee9b9f881bb414a68d Mon Sep 17 00:00:00 2001
From: Lia Stratopoulos <167905060+lia-viam@users.noreply.github.com>
Date: Thu, 13 Mar 2025 13:02:43 -0400
Subject: [PATCH 31/31] code review: include order

---
 src/viam/sdk/common/instance.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/viam/sdk/common/instance.cpp b/src/viam/sdk/common/instance.cpp
index 86443f458..e3a84ea65 100644
--- a/src/viam/sdk/common/instance.cpp
+++ b/src/viam/sdk/common/instance.cpp
@@ -1,11 +1,11 @@
 #include <viam/sdk/common/instance.hpp>
 
+#include <atomic>
+
 #include <viam/sdk/common/exception.hpp>
 #include <viam/sdk/common/private/instance.hpp>
 #include <viam/sdk/registry/registry.hpp>
 
-#include <atomic>
-
 namespace viam {
 namespace sdk {