[EXPORTER] Handle OTLP partial success response (#4104)

Author: RaviTriv

CHANGELOG.md

@@ -113,6 +113,9 @@ Increment the:
 * [SEMANTIC CONVENTIONS] Generate event name constants (e.g. `semconv::exception::kException`)
   [#4171](https://github.com/open-telemetry/opentelemetry-cpp/pull/4171)
 
+* [EXPORTER] Handle OTLP partial success response
+  [#4104](https://github.com/open-telemetry/opentelemetry-cpp/pull/4104)
+
 ## [1.27.0] 2026-05-13
 
 * [RELEASE] Bump main branch to 1.27.0-dev

exporters/otlp/BUILD

@@ -209,6 +209,7 @@ cc_library(
         "//sdk/src/common:base64",
         "@com_github_opentelemetry_proto//:common_proto_cc",
         "@com_google_absl//absl/strings",
+        "@com_google_protobuf//:protobuf",
         "@github_nlohmann_json//:json",
     ],
 )
@@ -695,6 +696,7 @@ cc_test(
         ":otlp_grpc_exporter",
         "//api",
         "//sdk/src/metrics",
+        "//test_common:headers",
         "@com_google_googletest//:gtest_main",
     ],
 )
@@ -876,6 +878,7 @@ cc_test(
         "//api",
         "//sdk/src/logs",
         "//sdk/src/metrics",
+        "//test_common:headers",
         "@com_google_googletest//:gtest_main",
     ],
 )
@@ -909,6 +912,7 @@ cc_test(
         ":otlp_grpc_metric_exporter",
         "//api",
         "//sdk/src/metrics",
+        "//test_common:headers",
         "@com_google_googletest//:gtest_main",
     ],
 )

exporters/otlp/CMakeLists.txt

@@ -907,7 +907,7 @@ if(BUILD_TESTING)
     add_executable(otlp_grpc_exporter_test test/otlp_grpc_exporter_test.cc)
     target_link_libraries(
       otlp_grpc_exporter_test ${GTEST_BOTH_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT}
-      ${GMOCK_LIB} opentelemetry_exporter_otlp_grpc)
+      ${GMOCK_LIB} opentelemetry_exporter_otlp_grpc opentelemetry_test_common)
     gtest_add_tests(
       TARGET otlp_grpc_exporter_test
       TEST_PREFIX exporter.otlp.
@@ -942,7 +942,8 @@ if(BUILD_TESTING)
       opentelemetry_exporter_otlp_grpc
       opentelemetry_exporter_otlp_grpc_log
       opentelemetry_trace
-      opentelemetry_logs)
+      opentelemetry_logs
+      opentelemetry_test_common)
     gtest_add_tests(
       TARGET otlp_grpc_log_record_exporter_test
       TEST_PREFIX exporter.otlp.
@@ -962,9 +963,13 @@ if(BUILD_TESTING)
     add_executable(otlp_grpc_metric_exporter_test
                    test/otlp_grpc_metric_exporter_test.cc)
     target_link_libraries(
-      otlp_grpc_metric_exporter_test ${GTEST_BOTH_LIBRARIES}
-      ${CMAKE_THREAD_LIBS_INIT} ${GMOCK_LIB} opentelemetry_exporter_otlp_grpc
-      opentelemetry_exporter_otlp_grpc_metrics)
+      otlp_grpc_metric_exporter_test
+      ${GTEST_BOTH_LIBRARIES}
+      ${CMAKE_THREAD_LIBS_INIT}
+      ${GMOCK_LIB}
+      opentelemetry_exporter_otlp_grpc
+      opentelemetry_exporter_otlp_grpc_metrics
+      opentelemetry_test_common)
     gtest_add_tests(
       TARGET otlp_grpc_metric_exporter_test
       TEST_PREFIX exporter.otlp.
@@ -992,7 +997,8 @@ if(BUILD_TESTING)
       opentelemetry_exporter_otlp_http
       opentelemetry_http_client_nosend
       nlohmann_json::nlohmann_json
-      protobuf::libprotobuf)
+      protobuf::libprotobuf
+      opentelemetry_test_common)
     gtest_add_tests(
       TARGET otlp_http_exporter_test
       TEST_PREFIX exporter.otlp.
@@ -1018,7 +1024,8 @@ if(BUILD_TESTING)
       opentelemetry_exporter_otlp_http_log
       opentelemetry_logs
       opentelemetry_http_client_nosend
-      nlohmann_json::nlohmann_json)
+      nlohmann_json::nlohmann_json
+      opentelemetry_test_common)
     gtest_add_tests(
       TARGET otlp_http_log_record_exporter_test
       TEST_PREFIX exporter.otlp.
@@ -1046,7 +1053,8 @@ if(BUILD_TESTING)
       opentelemetry_metrics
       opentelemetry_http_client_nosend
       nlohmann_json::nlohmann_json
-      protobuf::libprotobuf)
+      protobuf::libprotobuf
+      opentelemetry_test_common)
     gtest_add_tests(
       TARGET otlp_http_metric_exporter_test
       TEST_PREFIX exporter.otlp.

exporters/otlp/include/opentelemetry/exporters/otlp/otlp_grpc_client.h

@@ -7,6 +7,7 @@
 #include <grpcpp/support/status.h>
 #include <atomic>
 #include <chrono>
+#include <functional>
 #include <memory>
 #include <string>
 
@@ -22,8 +23,6 @@
 // clang-format on
 
 #ifdef ENABLE_ASYNC_EXPORT
-#  include <functional>
-
 #  include "opentelemetry/sdk/common/exporter_utils.h"
 #endif /* ENABLE_ASYNC_EXPORT */
 
@@ -151,21 +150,30 @@ class OtlpGrpcClient
       std::unique_ptr<grpc::ClientContext> &&context,
       std::unique_ptr<google::protobuf::Arena> &&arena,
       proto::collector::trace::v1::ExportTraceServiceRequest *request,
-      proto::collector::trace::v1::ExportTraceServiceResponse *response);
+      proto::collector::trace::v1::ExportTraceServiceResponse *response,
+      std::function<void(std::unique_ptr<google::protobuf::Arena> &&,
+                         proto::collector::trace::v1::ExportTraceServiceResponse *)> &&on_complete =
+          {});
 
   static grpc::Status DelegateExport(
       proto::collector::metrics::v1::MetricsService::StubInterface *stub,
       std::unique_ptr<grpc::ClientContext> &&context,
       std::unique_ptr<google::protobuf::Arena> &&arena,
       proto::collector::metrics::v1::ExportMetricsServiceRequest *request,
-      proto::collector::metrics::v1::ExportMetricsServiceResponse *response);
+      proto::collector::metrics::v1::ExportMetricsServiceResponse *response,
+      std::function<void(std::unique_ptr<google::protobuf::Arena> &&,
+                         proto::collector::metrics::v1::ExportMetricsServiceResponse *)>
+          &&on_complete = {});
 
   static grpc::Status DelegateExport(
       proto::collector::logs::v1::LogsService::StubInterface *stub,
       std::unique_ptr<grpc::ClientContext> &&context,
       std::unique_ptr<google::protobuf::Arena> &&arena,
       proto::collector::logs::v1::ExportLogsServiceRequest *request,
-      proto::collector::logs::v1::ExportLogsServiceResponse *response);
+      proto::collector::logs::v1::ExportLogsServiceResponse *response,
+      std::function<void(std::unique_ptr<google::protobuf::Arena> &&,
+                         proto::collector::logs::v1::ExportLogsServiceResponse *)> &&on_complete =
+          {});
 
   void AddReference(OtlpGrpcClientReferenceGuard &guard,
                     const OtlpGrpcClientOptions &options) noexcept;

exporters/otlp/include/opentelemetry/exporters/otlp/otlp_http_client.h

@@ -24,13 +24,14 @@
 #include "opentelemetry/sdk/common/thread_instrumentation.h"
 #include "opentelemetry/version.h"
 
-// forward declare google::protobuf::Message
+// forward declare google::protobuf::Message and google::protobuf::Arena
 namespace google
 {
 namespace protobuf
 {
+class Arena;
 class Message;
-}
+}  // namespace protobuf
 }  // namespace google
 
 OPENTELEMETRY_BEGIN_NAMESPACE
@@ -183,35 +184,23 @@ class OtlpHttpClient
   OtlpHttpClient &operator=(OtlpHttpClient &&)      = delete;
 
   /**
-   * Sync export
-   * @param message message to export, it should be ExportTraceServiceRequest,
-   * ExportMetricsServiceRequest or ExportLogsServiceRequest
-   * @return return the status of this operation
-   */
-  sdk::common::ExportResult Export(const google::protobuf::Message &message) noexcept;
-
-  /**
-   * Async export
-   * @param message message to export, it should be ExportTraceServiceRequest,
-   * ExportMetricsServiceRequest or ExportLogsServiceRequest
-   * @param result_callback callback to call when the exporting is done
-   * @return return the status of this operation
-   */
-  sdk::common::ExportResult Export(
-      const google::protobuf::Message &message,
-      std::function<bool(opentelemetry::sdk::common::ExportResult)> &&result_callback) noexcept;
-
-  /**
-   * Async export
+   * Export message with typed response. Synchronous when max_running_requests is 0,
+   * asynchronous otherwise.
    * @param message message to export, it should be ExportTraceServiceRequest,
    * ExportMetricsServiceRequest or ExportLogsServiceRequest
+   * @param arena protobuf arena that owns response
+   * @param response the parsed body is written here on 2xx
    * @param result_callback callback to call when the exporting is done
    * @param max_running_requests wait for at most max_running_requests running requests
-   * @return return the status of this operation
+   * @return the export result; kSuccess for asynchronous exports (final result via
+   * result_callback)
    */
   sdk::common::ExportResult Export(
       const google::protobuf::Message &message,
-      std::function<bool(opentelemetry::sdk::common::ExportResult)> &&result_callback,
+      std::unique_ptr<google::protobuf::Arena> &&arena,
+      google::protobuf::Message *response,
+      std::function<bool(opentelemetry::sdk::common::ExportResult, google::protobuf::Message *)>
+          &&result_callback,
       std::size_t max_running_requests) noexcept;
 
   /**
@@ -252,23 +241,36 @@ class OtlpHttpClient
     std::shared_ptr<opentelemetry::ext::http::client::Session> session;
     std::shared_ptr<opentelemetry::ext::http::client::EventHandler> event_handle;
 
-    HttpSessionData() = default;
+    std::unique_ptr<google::protobuf::Arena> arena;
+    google::protobuf::Message *response = nullptr;
+
+    HttpSessionData() noexcept;
+    HttpSessionData(std::shared_ptr<opentelemetry::ext::http::client::Session> &&input_session,
+                    std::shared_ptr<opentelemetry::ext::http::client::EventHandler> &&input_handle,
+                    std::unique_ptr<google::protobuf::Arena> &&input_arena,
+                    google::protobuf::Message *input_response) noexcept;
 
-    explicit HttpSessionData(
-        std::shared_ptr<opentelemetry::ext::http::client::Session> &&input_session,
-        std::shared_ptr<opentelemetry::ext::http::client::EventHandler> &&input_handle)
-        : session(std::move(input_session)), event_handle(std::move(input_handle))
-    {}
+    ~HttpSessionData();
+    HttpSessionData(HttpSessionData &&) noexcept;
+    HttpSessionData &operator=(HttpSessionData &&) noexcept;
+    HttpSessionData(const HttpSessionData &)            = delete;
+    HttpSessionData &operator=(const HttpSessionData &) = delete;
   };
 
   /**
-   * @brief Create a Session object or return a error result
+   * @brief Create a Session object that deserializes the response body or return an error result.
    *
    * @param message The message to send
+   * @param arena Protobuf arena that owns response
+   * @param response the parsed body is written here on 2xx
+   * @param result_callback Callback for the export result; receives the populated response
    */
   nostd::variant<sdk::common::ExportResult, HttpSessionData> createSession(
       const google::protobuf::Message &message,
-      std::function<bool(opentelemetry::sdk::common::ExportResult)> &&result_callback) noexcept;
+      std::unique_ptr<google::protobuf::Arena> &&arena,
+      google::protobuf::Message *response,
+      std::function<bool(opentelemetry::sdk::common::ExportResult, google::protobuf::Message *)>
+          &&result_callback) noexcept;
 
   /**
    * Add http session and hold it's lifetime.

exporters/otlp/src/otlp_grpc_client.cc

@@ -514,35 +514,60 @@ grpc::Status OtlpGrpcClient::DelegateExport(
     std::unique_ptr<grpc::ClientContext> &&context,
     std::unique_ptr<google::protobuf::Arena> &&arena,
     proto::collector::trace::v1::ExportTraceServiceRequest *request,
-    proto::collector::trace::v1::ExportTraceServiceResponse *response)
+    proto::collector::trace::v1::ExportTraceServiceResponse *response,
+    std::function<void(std::unique_ptr<google::protobuf::Arena> &&,
+                       proto::collector::trace::v1::ExportTraceServiceResponse *)> &&on_complete)
 {
   auto trace_grpc_context = std::move(context);
   auto trace_arena        = std::move(arena);
-  return stub->Export(trace_grpc_context.get(), *request, response);
+  auto status             = stub->Export(trace_grpc_context.get(), *request, response);
+  if (status.ok() && on_complete)
+  {
+    auto callback = std::move(on_complete);
+    callback(std::move(trace_arena), response);
+  }
+  return status;
 }
 
 grpc::Status OtlpGrpcClient::DelegateExport(
     proto::collector::metrics::v1::MetricsService::StubInterface *stub,
     std::unique_ptr<grpc::ClientContext> &&context,
     std::unique_ptr<google::protobuf::Arena> &&arena,
     proto::collector::metrics::v1::ExportMetricsServiceRequest *request,
-    proto::collector::metrics::v1::ExportMetricsServiceResponse *response)
+    proto::collector::metrics::v1::ExportMetricsServiceResponse *response,
+    std::function<void(std::unique_ptr<google::protobuf::Arena> &&,
+                       proto::collector::metrics::v1::ExportMetricsServiceResponse *)>
+        &&on_complete)
 {
   auto metrics_grpc_context = std::move(context);
   auto metrics_arena        = std::move(arena);
-  return stub->Export(metrics_grpc_context.get(), *request, response);
+  auto status               = stub->Export(metrics_grpc_context.get(), *request, response);
+  if (status.ok() && on_complete)
+  {
+    auto callback = std::move(on_complete);
+    callback(std::move(metrics_arena), response);
+  }
+  return status;
 }
 
 grpc::Status OtlpGrpcClient::DelegateExport(
     proto::collector::logs::v1::LogsService::StubInterface *stub,
     std::unique_ptr<grpc::ClientContext> &&context,
     std::unique_ptr<google::protobuf::Arena> &&arena,
     proto::collector::logs::v1::ExportLogsServiceRequest *request,
-    proto::collector::logs::v1::ExportLogsServiceResponse *response)
+    proto::collector::logs::v1::ExportLogsServiceResponse *response,
+    std::function<void(std::unique_ptr<google::protobuf::Arena> &&,
+                       proto::collector::logs::v1::ExportLogsServiceResponse *)> &&on_complete)
 {
   auto logs_grpc_context = std::move(context);
   auto logs_arena        = std::move(arena);
-  return stub->Export(logs_grpc_context.get(), *request, response);
+  auto status            = stub->Export(logs_grpc_context.get(), *request, response);
+  if (status.ok() && on_complete)
+  {
+    auto callback = std::move(on_complete);
+    callback(std::move(logs_arena), response);
+  }
+  return status;
 }
 
 void OtlpGrpcClient::AddReference(OtlpGrpcClientReferenceGuard &guard,