[EXPORTER] Allow to share gRPC clients between OTLP exporters

CHANGELOG.md

@@ -21,6 +21,9 @@ Increment the:
 * [REMOVAL] Remove build option `WITH_DEPRECATED_SDK_FACTORY`
   [#2717](https://github.com/open-telemetry/opentelemetry-cpp/pull/2717)
 
+* [EXPORTER] Allow to share gRPC clients between OTLP exporters.
+  [#3041](https://github.com/open-telemetry/opentelemetry-cpp/pull/3041)
+
 * [EXPORTER] Add in-memory metric exporter
   [#3043](https://github.com/open-telemetry/opentelemetry-cpp/pull/3043)
 

CMakeLists.txt

@@ -365,7 +365,7 @@ if(WITH_PROMETHEUS)
   endif()
 endif()
 
-if(WITH_ABSEIL)
+if(WITH_ABSEIL OR WITH_OTLP_GRPC)
   if(NOT TARGET absl::strings)
     find_package(absl CONFIG REQUIRED)
   endif()
@@ -376,7 +376,7 @@ if(WITH_OTLP_GRPC
    OR WITH_OTLP_FILE)
   find_package(Protobuf)
   if(Protobuf_VERSION AND Protobuf_VERSION VERSION_GREATER_EQUAL "3.22.0")
-    if(NOT WITH_ABSEIL)
+    if(NOT WITH_ABSEIL AND NOT WITH_OTLP_GRPC)
       message(
         FATAL_ERROR
           "Protobuf 3.22 or upper require abseil-cpp(Recommended version: 20230125 or upper)"

api/CMakeLists.txt

@@ -35,7 +35,7 @@ if(WITH_NO_DEPRECATED_CODE)
                              INTERFACE OPENTELEMETRY_NO_DEPRECATED_CODE)
 endif()
 
-if(WITH_ABSEIL)
+if(WITH_ABSEIL OR WITH_OTLP_GRPC)
   target_compile_definitions(opentelemetry_api INTERFACE HAVE_ABSEIL)
   target_link_libraries(
     opentelemetry_api INTERFACE absl::bad_variant_access absl::any absl::base

cmake/opentelemetry-proto.cmake

@@ -328,12 +328,10 @@ add_library(
 set_target_version(opentelemetry_proto)
 
 # Disable include-what-you-use on generated code.
-set_target_properties(
-  opentelemetry_proto
-  PROPERTIES CXX_INCLUDE_WHAT_YOU_USE ""
-)
+set_target_properties(opentelemetry_proto PROPERTIES CXX_INCLUDE_WHAT_YOU_USE
+                                                     "")
 
-if(WITH_ABSEIL)
+if(WITH_ABSEIL OR WITH_OTLP_GRPC)
   target_link_libraries(opentelemetry_proto PUBLIC absl::bad_variant_access)
 endif()
 
@@ -393,12 +391,10 @@ else() # cmake 3.8 or lower
 endif()
 
 if(WITH_OTLP_GRPC)
-  if(WITH_ABSEIL)
-    find_package(absl CONFIG)
-    if(TARGET absl::synchronization)
-      target_link_libraries(opentelemetry_proto_grpc
-                            PRIVATE absl::synchronization)
-    endif()
+  find_package(absl CONFIG)
+  if(TARGET absl::synchronization)
+    target_link_libraries(opentelemetry_proto_grpc
+                          PRIVATE absl::synchronization)
   endif()
 endif()
 

cmake/patch-imported-config.cmake

@@ -29,7 +29,7 @@ if(TARGET CURL::libcurl
 endif()
 
 # abseil targets
-if(WITH_ABSEIL)
+if(WITH_ABSEIL OR WITH_OTLP_GRPC)
   project_build_tools_patch_default_imported_config(
     absl::bad_variant_access
     absl::raw_logging_internal

examples/grpc/CMakeLists.txt

@@ -39,7 +39,7 @@ else()
   target_link_libraries(example_grpc_proto PUBLIC gRPC::grpc++
                                                   ${Protobuf_LIBRARIES})
 endif()
-if(WITH_ABSEIL)
+if(WITH_ABSEIL OR WITH_OTLP_GRPC)
   target_link_libraries(example_grpc_proto PUBLIC absl::bad_variant_access)
 endif()
 

exporters/otlp/BUILD

@@ -42,11 +42,13 @@ cc_library(
     name = "otlp_grpc_client",
     srcs = [
         "src/otlp_grpc_client.cc",
+        "src/otlp_grpc_client_factory.cc",
         "src/otlp_grpc_utils.cc",
     ],
     hdrs = [
         "include/opentelemetry/exporters/otlp/otlp_environment.h",
         "include/opentelemetry/exporters/otlp/otlp_grpc_client.h",
+        "include/opentelemetry/exporters/otlp/otlp_grpc_client_factory.h",
         "include/opentelemetry/exporters/otlp/otlp_grpc_client_options.h",
         "include/opentelemetry/exporters/otlp/otlp_grpc_utils.h",
         "include/opentelemetry/exporters/otlp/protobuf_include_prefix.h",

exporters/otlp/CMakeLists.txt

@@ -23,8 +23,10 @@ target_link_libraries(opentelemetry_otlp_recordable
 
 if(WITH_OTLP_GRPC)
   find_package(gRPC REQUIRED)
-  add_library(opentelemetry_exporter_otlp_grpc_client src/otlp_grpc_client.cc
-                                                      src/otlp_grpc_utils.cc)
+  add_library(
+    opentelemetry_exporter_otlp_grpc_client
+    src/otlp_grpc_client.cc src/otlp_grpc_client_factory.cc
+    src/otlp_grpc_utils.cc)
   set_target_properties(opentelemetry_exporter_otlp_grpc_client
                         PROPERTIES EXPORT_NAME otlp_grpc_client)
   set_target_version(opentelemetry_exporter_otlp_grpc_client)

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

@@ -13,34 +13,52 @@
 
 #include "opentelemetry/exporters/otlp/otlp_grpc_client_options.h"
 
+// clang-format off
 #include "opentelemetry/exporters/otlp/protobuf_include_prefix.h"
+// clang-format on
 
 #include "google/protobuf/arena.h"
 #include "opentelemetry/proto/collector/logs/v1/logs_service.grpc.pb.h"
 #include "opentelemetry/proto/collector/metrics/v1/metrics_service.grpc.pb.h"
 #include "opentelemetry/proto/collector/trace/v1/trace_service.grpc.pb.h"
 
+// clang-format off
 #include "opentelemetry/exporters/otlp/protobuf_include_suffix.h"
+// clang-format on
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace exporter
 {
 namespace otlp
 {
 
+class OtlpGrpcClient;
 struct OtlpGrpcClientOptions;
-
-#ifdef ENABLE_ASYNC_EXPORT
 struct OtlpGrpcClientAsyncData;
-#endif
+
+class OtlpGrpcClientReferenceGuard
+{
+public:
+  OtlpGrpcClientReferenceGuard() noexcept;
+  ~OtlpGrpcClientReferenceGuard() noexcept;
+
+  OtlpGrpcClientReferenceGuard(const OtlpGrpcClientReferenceGuard &)            = delete;
+  OtlpGrpcClientReferenceGuard(OtlpGrpcClientReferenceGuard &&)                 = delete;
+  OtlpGrpcClientReferenceGuard &operator=(const OtlpGrpcClientReferenceGuard &) = delete;
+  OtlpGrpcClientReferenceGuard &operator=(OtlpGrpcClientReferenceGuard &&)      = delete;
+
+private:
+  friend class OtlpGrpcClient;
+  std::atomic<bool> has_value_;
+};
 
 /**
  * The OTLP gRPC client contains utility functions of gRPC.
  */
 class OtlpGrpcClient
 {
 public:
-  OtlpGrpcClient();
+  OtlpGrpcClient(const OtlpGrpcClientOptions &options);
 
   ~OtlpGrpcClient();
 
@@ -58,20 +76,18 @@ class OtlpGrpcClient
   /**
    * Create trace service stub to communicate with the OpenTelemetry Collector.
    */
-  static std::unique_ptr<proto::collector::trace::v1::TraceService::StubInterface>
-  MakeTraceServiceStub(const OtlpGrpcClientOptions &options);
+  std::unique_ptr<proto::collector::trace::v1::TraceService::StubInterface> MakeTraceServiceStub();
 
   /**
    * Create metrics service stub to communicate with the OpenTelemetry Collector.
    */
-  static std::unique_ptr<proto::collector::metrics::v1::MetricsService::StubInterface>
-  MakeMetricsServiceStub(const OtlpGrpcClientOptions &options);
+  std::unique_ptr<proto::collector::metrics::v1::MetricsService::StubInterface>
+  MakeMetricsServiceStub();
 
   /**
    * Create logs service stub to communicate with the OpenTelemetry Collector.
    */
-  static std::unique_ptr<proto::collector::logs::v1::LogsService::StubInterface>
-  MakeLogsServiceStub(const OtlpGrpcClientOptions &options);
+  std::unique_ptr<proto::collector::logs::v1::LogsService::StubInterface> MakeLogsServiceStub();
 
   static grpc::Status DelegateExport(
       proto::collector::trace::v1::TraceService::StubInterface *stub,
@@ -94,8 +110,18 @@ class OtlpGrpcClient
       proto::collector::logs::v1::ExportLogsServiceRequest &&request,
       proto::collector::logs::v1::ExportLogsServiceResponse *response);
 
-#ifdef ENABLE_ASYNC_EXPORT
+  void AddReference(OtlpGrpcClientReferenceGuard &guard,
+                    const OtlpGrpcClientOptions &options) noexcept;
 
+  /**
+   * Reomve reference fro a guard object
+   *
+   * @param guard guard object to remove reference from
+   * @return true if there is no more reference to this gRPC client
+   */
+  bool RemoveReference(OtlpGrpcClientReferenceGuard &guard) noexcept;
+
+#ifdef ENABLE_ASYNC_EXPORT
   /**
    * Async export
    * @param options Options used to message to create gRPC context and stub(if necessary)
@@ -155,6 +181,7 @@ class OtlpGrpcClient
                          const proto::collector::logs::v1::ExportLogsServiceRequest &,
                          proto::collector::logs::v1::ExportLogsServiceResponse *)>
           &&result_callback) noexcept;
+#endif
 
   /**
    * Force flush the gRPC client.
@@ -167,17 +194,19 @@ class OtlpGrpcClient
    * timeout is applied.
    * @return return the status of this operation
    */
-  bool Shutdown(std::chrono::microseconds timeout = std::chrono::microseconds(0)) noexcept;
+  bool Shutdown(OtlpGrpcClientReferenceGuard &guard,
+                std::chrono::microseconds timeout = std::chrono::microseconds(0)) noexcept;
 
   std::shared_ptr<OtlpGrpcClientAsyncData> MutableAsyncData(const OtlpGrpcClientOptions &options);
 
+  bool IsShutdown() const noexcept;
+
 private:
   // Stores if this gRPC client had its Shutdown() method called
   std::atomic<bool> is_shutdown_;
 
   // Stores shared data between threads of this gRPC client
   std::shared_ptr<OtlpGrpcClientAsyncData> async_data_;
-#endif
 };
 }  // namespace otlp
 }  // namespace exporter

exporters/otlp/include/opentelemetry/exporters/otlp/otlp_grpc_client_factory.h

@@ -0,0 +1,36 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include <memory>
+
+#include "opentelemetry/exporters/otlp/otlp_grpc_client_options.h"
+#include "opentelemetry/nostd/shared_ptr.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace exporter
+{
+namespace otlp
+{
+
+class OtlpGrpcClientReferenceGuard;
+class OtlpGrpcClient;
+
+/**
+ * Factory class for OtlpGrpcClient.
+ */
+class OPENTELEMETRY_EXPORT OtlpGrpcClientFactory
+{
+public:
+  /**
+   * Create an OtlpGrpcClient using all default options.
+   */
+  static nostd::shared_ptr<OtlpGrpcClient> Create(const OtlpGrpcClientOptions &options);
+
+  static nostd::shared_ptr<OtlpGrpcClientReferenceGuard> CreateReferenceGuard();
+};
+
+}  // namespace otlp
+}  // namespace exporter
+OPENTELEMETRY_END_NAMESPACE

exporters/otlp/include/opentelemetry/exporters/otlp/otlp_grpc_exporter.h

@@ -6,12 +6,17 @@
 #include <atomic>
 #include <chrono>
 
+// clang-format off
 #include "opentelemetry/exporters/otlp/protobuf_include_prefix.h"
+// clang-format on
 
 #include "opentelemetry/proto/collector/trace/v1/trace_service.grpc.pb.h"
 
+// clang-format off
 #include "opentelemetry/exporters/otlp/protobuf_include_suffix.h"
+// clang-format on
 
+#include "opentelemetry/nostd/shared_ptr.h"
 #include "opentelemetry/sdk/trace/exporter.h"
 
 #include "opentelemetry/exporters/otlp/otlp_environment.h"
@@ -23,6 +28,8 @@ namespace exporter
 namespace otlp
 {
 
+class OtlpGrpcClientReferenceGuard;
+
 class OtlpGrpcClient;
 
 /**
@@ -36,11 +43,22 @@ class OtlpGrpcExporter final : public opentelemetry::sdk::trace::SpanExporter
    */
   OtlpGrpcExporter();
 
+  /**
+   * Create an OtlpGrpcExporter using specified OtlpGrpcClient.
+   *
+   * @param options options to create exporter
+   * @param client the gRPC client to use
+   */
+  OtlpGrpcExporter(const OtlpGrpcExporterOptions &options,
+                   nostd::shared_ptr<OtlpGrpcClient> client);
+
   /**
    * Create an OtlpGrpcExporter using the given options.
    */
   explicit OtlpGrpcExporter(const OtlpGrpcExporterOptions &options);
 
+  ~OtlpGrpcExporter() override;
+
   /**
    * Create a span recordable.
    * @return a newly initialized Recordable object
@@ -71,27 +89,43 @@ class OtlpGrpcExporter final : public opentelemetry::sdk::trace::SpanExporter
   bool Shutdown(
       std::chrono::microseconds timeout = (std::chrono::microseconds::max)()) noexcept override;
 
+  /**
+   * Get the Client object
+   *
+   * @return return binded gRPC client
+   */
+  const nostd::shared_ptr<OtlpGrpcClient> &GetClient() const noexcept;
+
 private:
   // The configuration options associated with this exporter.
   const OtlpGrpcExporterOptions options_;
 
-#ifdef ENABLE_ASYNC_EXPORT
-  std::shared_ptr<OtlpGrpcClient> client_;
-#endif
+  nostd::shared_ptr<OtlpGrpcClient> client_;
+  nostd::shared_ptr<OtlpGrpcClientReferenceGuard> client_reference_guard_;
 
   // For testing
   friend class OtlpGrpcExporterTestPeer;
   friend class OtlpGrpcLogRecordExporterTestPeer;
 
   // Store service stub internally. Useful for testing.
-  std::unique_ptr<proto::collector::trace::v1::TraceService::StubInterface> trace_service_stub_;
+  nostd::shared_ptr<proto::collector::trace::v1::TraceService::StubInterface> trace_service_stub_;
 
   /**
    * Create an OtlpGrpcExporter using the specified service stub.
    * Only tests can call this constructor directly.
    * @param stub the service stub to be used for exporting
    */
   OtlpGrpcExporter(std::unique_ptr<proto::collector::trace::v1::TraceService::StubInterface> stub);
+
+  /**
+   * Create an OtlpGrpcExporter using the specified service stub and gRPC client.
+   * Only tests can call this constructor directly.
+   * @param stub the service stub to be used for exporting
+   * @param client the gRPC client to use
+   */
+  OtlpGrpcExporter(std::unique_ptr<proto::collector::trace::v1::TraceService::StubInterface> stub,
+                   nostd::shared_ptr<OtlpGrpcClient> client);
+
   std::atomic<bool> is_shutdown_{false};
   bool isShutdown() const noexcept;
 };