This doesn't pass unit tests, but now I am writing some more helpful logs into our error logging so I can debug why this isn't working in system-tests

Author: zacharycmontoya

src/datadog/datadog_agent.cpp

@@ -171,7 +171,7 @@ DatadogAgent::DatadogAgent(
   // Origin Detection headers are not necessary when Unix Domain Socket (UDS)
   // is used to communicate with the Datadog Agent.
   if (!contains(config.url.scheme, "unix")) {
-    if (auto container_id = container::get_id()) {
+    if (auto container_id = container::get_id(logger_)) {
       if (container_id->type == container::ContainerID::Type::container_id) {
         headers_.emplace("Datadog-Container-ID", container_id->value);
         headers_.emplace("Datadog-Entity-Id", "ci-" + container_id->value);

src/datadog/platform_util.cpp

@@ -4,6 +4,7 @@
 #include <cstdint>
 #include <fstream>
 #include <iostream>
+#include <memory>
 #include <regex>
 
 // clang-format off
@@ -45,6 +46,8 @@
 #endif
 // clang-format on
 
+#include <datadog/logger.h>
+
 namespace datadog {
 namespace tracing {
 namespace {
@@ -341,19 +344,21 @@ Optional<Cgroup> get_cgroup_version() {
   return nullopt;
 }
 
-Optional<std::string> find_container_id_from_cgroup() {
+Optional<std::string> find_container_id_from_cgroup(
+    const std::shared_ptr<tracing::Logger>& logger) {
   auto cgroup_fd = std::ifstream("/proc/self/cgroup", std::ios::in);
   if (!cgroup_fd.is_open()) {
-    std::cerr << "failed to open /proc/self/cgroup" << std::endl;
+    logger->log_error("failed to open /proc/self/cgroup");
     return nullopt;
   }
 
-  return find_container_id(cgroup_fd);
+  return find_container_id(cgroup_fd, logger);
 }
 #endif
 }  // namespace
 
-Optional<std::string> find_container_id(std::istream& source) {
+Optional<std::string> find_container_id(std::istream& source,
+                                        const std::shared_ptr<tracing::Logger>& logger) {
   static const std::string uuid_regex_str =
       "[0-9a-f]{8}[-_][0-9a-f]{4}[-_][0-9a-f]{4}[-_][0-9a-f]{4}[-_][0-9a-f]{12}"
       "|(?:[0-9a-f]{8}(?:-[0-9a-f]{4}){4}$)";
@@ -365,37 +370,41 @@ Optional<std::string> find_container_id(std::istream& source) {
 
   std::string line;
   while (std::getline(source, line)) {
-    std::cout << "Reading line: " << line << std::endl;
+    logger->log_error("Reading line: " + line);
     // Example:
     // `0::/system.slice/docker-abcdef0123456789abcdef0123456789.scope`
     std::smatch match;
     if (std::regex_match(line, match, path_reg)) {
       assert(match.ready());
       assert(match.size() == 2);
 
-      std::cout << "Found container ID: " << match.str(1) << std::endl;
+      logger->log_error("Found container ID: " + match.str(1));
       return match.str(1);
     }
   }
 
-  std::cout << "No container ID found" << std::endl;
+  logger->log_error("No container ID found");
   return nullopt;
 }
 
-Optional<ContainerID> get_id() {
+Optional<ContainerID> get_id(const std::shared_ptr<tracing::Logger>& logger) {
 #if defined(__linux__) || defined(__unix__)
   if (is_running_in_host_namespace()) {
     // Not in a container, no need to continue.
+    logger->log_error("Not in a container, no need to continue.");
     return nullopt;
   }
 
   auto maybe_cgroup = get_cgroup_version();
-  if (!maybe_cgroup) return nullopt;
+  if (!maybe_cgroup) {
+    logger->log_error("Failed to get cgroup version.");
+    return nullopt;
+  }
 
   ContainerID id;
   switch (*maybe_cgroup) {
     case Cgroup::v1: {
-      if (auto maybe_id = find_container_id_from_cgroup()) {
+      if (auto maybe_id = find_container_id_from_cgroup(logger)) {
         id.value = *maybe_id;
         id.type = ContainerID::Type::container_id;
         break;

src/datadog/platform_util.h

@@ -3,8 +3,10 @@
 // This component provides platform-dependent miscellanea.
 
 #include <datadog/expected.h>
+#include <datadog/logger.h>
 #include <datadog/string_view.h>
 
+#include <memory>
 #include <string>
 
 namespace datadog {
@@ -90,13 +92,14 @@ struct ContainerID final {
 /// @param source The input from which to read the container ID.
 /// @return An Optional containing the container ID if found, otherwise
 /// nothing.
-Optional<std::string> find_container_id(std::istream& source);
+Optional<std::string> find_container_id(std::istream& source,
+                                        const std::shared_ptr<tracing::Logger>& logger);
 
 /// Function to retrieve the container metadata.
 ///
 /// @return A `ContainerID` object containing id of the container in
 /// which the current process is running.
-Optional<ContainerID> get_id();
+Optional<ContainerID> get_id(const std::shared_ptr<tracing::Logger>& logger);
 
 }  // namespace container
 

test/test_platform_util.cpp

@@ -2,6 +2,7 @@
 
 #include "platform_util.h"
 #include "test.h"
+#include "null_logger.h"
 
 using namespace datadog::tracing;
 
@@ -58,7 +59,7 @@ PLATFORM_UTIL_TEST("find docker container ID") {
 
   std::istringstream is(test_case.input);
 
-  auto maybe_container_id = container::find_container_id(is);
+  auto maybe_container_id = container::find_container_id(is, std::make_shared<NullLogger>());
   if (test_case.expected_container_id.has_value()) {
     REQUIRE(maybe_container_id.has_value());
     CHECK(*maybe_container_id == *test_case.expected_container_id);
@@ -186,7 +187,7 @@ PLATFORM_UTIL_TEST("find multiline container IDs") {
 
   std::istringstream is(test_case.input);
 
-  auto maybe_container_id = container::find_container_id(is);
+  auto maybe_container_id = container::find_container_id(is, std::make_shared<NullLogger>());
   if (test_case.expected_container_id.has_value()) {
     REQUIRE(maybe_container_id.has_value());
     CHECK(*maybe_container_id == *test_case.expected_container_id);