RSDK-6158 - initial connection options (#376)

Author: stuqdog

src/viam/examples/modules/complex/proto/buf.lock

@@ -4,5 +4,5 @@ deps:
   - remote: buf.build
     owner: googleapis
     repository: googleapis
-    commit: 546238c53f7340c6a2a6099fb863bc1b
-    digest: shake256:8d75c12f391e392b24c076d05117b47aeddb090add99c70247a8f4389b906a65f61a933c68e54ed8b73a050b967b6b712ba194348b67c3ab3ee26cc2cb25852c
+    commit: 751cbe31638d43a9bfb6162cd2352e67
+    digest: shake256:87f55470d9d124e2d1dedfe0231221f4ed7efbc55bc5268917c678e2d9b9c41573a7f9a557f6d8539044524d9fc5ca8fbb7db05eb81379d168285d76b57eb8a4

src/viam/sdk/robot/client.cpp

@@ -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) {
     const char* uri = address.c_str();
-    auto channel = ViamChannel::dial(uri, options.dial_options());
+    auto channel = ViamChannel::dial_initial(uri, options.dial_options());
     std::shared_ptr<RobotClient> robot = RobotClient::with_channel(channel, options);
     robot->should_close_channel_ = true;
 

src/viam/sdk/rpc/dial.cpp

@@ -3,6 +3,7 @@
 #include <istream>
 #include <string>
 
+#include <boost/config.hpp>
 #include <boost/none.hpp>
 #include <boost/optional.hpp>
 #include <grpcpp/channel.h>
@@ -52,16 +53,35 @@ ViamChannel::ViamChannel(std::shared_ptr<grpc::Channel> channel, const char* pat
 
 DialOptions::DialOptions() = default;
 
-void DialOptions::set_credentials(boost::optional<Credentials> creds) {
+DialOptions& DialOptions::set_credentials(boost::optional<Credentials> creds) {
     credentials_ = std::move(creds);
+
+    return *this;
 }
 
-void DialOptions::set_entity(boost::optional<std::string> entity) {
+DialOptions& DialOptions::set_entity(boost::optional<std::string> entity) {
     auth_entity_ = std::move(entity);
+
+    return *this;
+}
+
+DialOptions& DialOptions::set_initial_connection_attempts(int attempts) {
+    initial_connection_attempts_ = attempts;
+
+    return *this;
 }
 
-void DialOptions::set_timeout(std::chrono::duration<float> timeout) {
-    timeout_ = std::move(timeout);
+DialOptions& DialOptions::set_timeout(std::chrono::duration<float> timeout) {
+    timeout_ = timeout;
+
+    return *this;
+}
+
+DialOptions& DialOptions::set_initial_connection_attempt_timeout(
+    std::chrono::duration<float> timeout) {
+    initial_connection_attempt_timeout_ = timeout;
+
+    return *this;
 }
 
 const boost::optional<std::string>& DialOptions::entity() const {
@@ -72,18 +92,55 @@ const boost::optional<Credentials>& DialOptions::credentials() const {
     return credentials_;
 }
 
+int DialOptions::initial_connection_attempts() const {
+    return initial_connection_attempts_;
+}
+
 const std::chrono::duration<float>& DialOptions::timeout() const {
     return timeout_;
 }
 
-void DialOptions::set_allow_insecure_downgrade(bool allow) {
+std::chrono::duration<float> DialOptions::initial_connection_attempt_timeout() const {
+    return initial_connection_attempt_timeout_;
+}
+
+DialOptions& DialOptions::set_allow_insecure_downgrade(bool allow) {
     allow_insecure_downgrade_ = allow;
+
+    return *this;
 }
 
 bool DialOptions::allows_insecure_downgrade() const {
     return allow_insecure_downgrade_;
 }
 
+std::shared_ptr<ViamChannel> ViamChannel::dial_initial(
+    const char* uri, const boost::optional<DialOptions>& options) {
+    DialOptions opts = options.get_value_or(DialOptions());
+    auto timeout = opts.timeout();
+    auto attempts_remaining = opts.initial_connection_attempts();
+    if (attempts_remaining == 0) {
+        attempts_remaining = -1;
+    }
+    opts.set_timeout(opts.initial_connection_attempt_timeout());
+
+    while (attempts_remaining != 0) {
+        try {
+            auto connection = dial(uri, opts);
+            opts.set_timeout(timeout);
+            return connection;
+        } catch (const std::exception& e) {
+            attempts_remaining -= 1;
+            if (attempts_remaining == 0) {
+                throw e;
+            }
+        }
+    }
+    // the while loop will run until we either return or throw an error, so we can never reach this
+    // point
+    BOOST_UNREACHABLE_RETURN(nullptr)
+}
+
 std::shared_ptr<ViamChannel> ViamChannel::dial(const char* uri,
                                                const boost::optional<DialOptions>& options) {
     void* ptr = init_rust_runtime();

src/viam/sdk/rpc/dial.hpp

@@ -16,9 +16,26 @@ class ViamChannel {
    public:
     void close();
     ViamChannel(std::shared_ptr<GrpcChannel> channel, const char* path, void* runtime);
+
+    /// @brief Connects to a robot at the given URI address, using the provided dial options (or
+    /// default options is none are provided). Ignores initial connection options specifying
+    /// how many times to attempt to connect and with what timeout.
+    /// In general, use of this method is discouraged. `RobotClient::at_address(...)` is the
+    /// preferred method to connect to a robot, and creates the channel itself.
+    /// @throws Exception if it is unable to establish a connection to the provided URI
     static std::shared_ptr<ViamChannel> dial(const char* uri,
                                              const boost::optional<DialOptions>& options);
 
+    // @brief Dials to a robot at the given URI address, using the provided dial options (or default
+    // options is none are provided). Additionally specifies that this dial is an initial connection
+    // attempt and so uses the initial connection options.
+    /// In general, use of this method is discouraged. `RobotClient::at_address(...)` is the
+    /// preferred method to connect to a robot, and creates the channel itself.
+    /// @throws Exception if it is unable to establish a connection to the provided URI within
+    /// the given number of initial connection attempts
+    static std::shared_ptr<ViamChannel> dial_initial(const char* uri,
+                                                     const boost::optional<DialOptions>& options);
+
     const std::shared_ptr<GrpcChannel>& channel() const;
 
    private:
@@ -49,11 +66,15 @@ class DialOptions {
     const boost::optional<std::string>& entity() const;
     bool allows_insecure_downgrade() const;
     const std::chrono::duration<float>& timeout() const;
+    int initial_connection_attempts() const;
+    std::chrono::duration<float> initial_connection_attempt_timeout() const;
 
-    void set_entity(boost::optional<std::string> entity);
-    void set_credentials(boost::optional<Credentials> creds);
-    void set_allow_insecure_downgrade(bool allow);
-    void set_timeout(std::chrono::duration<float> timeout);
+    DialOptions& set_entity(boost::optional<std::string> entity);
+    DialOptions& set_credentials(boost::optional<Credentials> creds);
+    DialOptions& set_allow_insecure_downgrade(bool allow);
+    DialOptions& set_timeout(std::chrono::duration<float> timeout);
+    DialOptions& set_initial_connection_attempts(int attempts);
+    DialOptions& set_initial_connection_attempt_timeout(std::chrono::duration<float> timeout);
 
    private:
     // TODO (RSDK-917): We currently don't provide a flag for disabling webRTC, instead relying on a
@@ -72,6 +93,14 @@ class DialOptions {
     /// @brief Duration before the dial connection times out
     /// Set to 20sec to match _defaultOfferDeadline in goutils/rpc/wrtc_call_queue.go
     std::chrono::duration<float> timeout_{20};
+
+    /// @brief Number of attempts to make when initially connecting to a robot
+    /// If set to 0 or a negative integer, will attempt to reconnect forever.
+    int initial_connection_attempts_ = 3;
+
+    /// @brief Timeout of connection attempts when initially dialing a robot
+    /// Defaults to 20sec to match the default timeout duration
+    std::chrono::duration<float> initial_connection_attempt_timeout_{20};
 };
 
 class Options {