[EXPORTER] support unix sockets in grpc client (open-telemetry#3410)

Author: ethandmd

bazel/extra_deps.bzl

@@ -3,8 +3,8 @@
 
 # Load prometheus C++ dependencies.
 
-load("@com_github_jupp0r_prometheus_cpp//bazel:repositories.bzl", "prometheus_cpp_repositories")
 load("@bazel_skylib//:workspace.bzl", "bazel_skylib_workspace")
+load("@com_github_jupp0r_prometheus_cpp//bazel:repositories.bzl", "prometheus_cpp_repositories")
 load("@rules_foreign_cc//foreign_cc:repositories.bzl", "rules_foreign_cc_dependencies")
 
 def opentelemetry_extra_deps():

examples/grpc/BUILD

@@ -1,10 +1,10 @@
 # Copyright The OpenTelemetry Authors
 # SPDX-License-Identifier: Apache-2.0
 
-package(default_visibility = ["//visibility:public"])
-
-load("@rules_proto//proto:defs.bzl", "proto_library")
 load("@com_github_grpc_grpc//bazel:cc_grpc_library.bzl", "cc_grpc_library")
+load("@rules_proto//proto:defs.bzl", "proto_library")
+
+package(default_visibility = ["//visibility:public"])
 
 proto_library(
     name = "messages_proto",

exporters/otlp/BUILD

@@ -1,10 +1,10 @@
 # Copyright The OpenTelemetry Authors
 # SPDX-License-Identifier: Apache-2.0
 
-package(default_visibility = ["//visibility:public"])
-
 load("//bazel:otel_cc_benchmark.bzl", "otel_cc_benchmark")
 
+package(default_visibility = ["//visibility:public"])
+
 cc_library(
     name = "otlp_recordable",
     srcs = [
@@ -474,6 +474,20 @@ cc_test(
     ],
 )
 
+cc_test(
+    name = "otlp_grpc_target_test",
+    srcs = ["test/otlp_grpc_target_test.cc"],
+    tags = [
+        "otlp",
+        "otlp_grpc",
+        "test",
+    ],
+    deps = [
+        ":otlp_grpc_client",
+        "@com_google_googletest//:gtest_main",
+    ],
+)
+
 cc_test(
     name = "otlp_grpc_exporter_factory_test",
     srcs = ["test/otlp_grpc_exporter_factory_test.cc"],

exporters/otlp/CMakeLists.txt

@@ -377,6 +377,15 @@ if(BUILD_TESTING)
       TEST_PREFIX exporter.otlp.
       TEST_LIST otlp_grpc_exporter_test)
 
+    add_executable(otlp_grpc_target_test test/otlp_grpc_target_test.cc)
+    target_link_libraries(
+      otlp_grpc_target_test ${GTEST_BOTH_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT}
+      ${GMOCK_LIB} opentelemetry_exporter_otlp_grpc)
+    gtest_add_tests(
+      TARGET otlp_grpc_target_test
+      TEST_PREFIX exporter.otlp.
+      TEST_LIST otlp_grpc_target_test)
+
     add_executable(otlp_grpc_exporter_factory_test
                    test/otlp_grpc_exporter_factory_test.cc)
     target_link_libraries(

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

@@ -62,6 +62,8 @@ class OtlpGrpcClient
 
   ~OtlpGrpcClient();
 
+  static std::string GetGrpcTarget(const std::string &endpoint);
+
   /**
    * Create gRPC channel from the exporter options.
    */

exporters/otlp/src/otlp_grpc_client.cc

@@ -309,6 +309,32 @@ OtlpGrpcClient::~OtlpGrpcClient()
 #endif
 }
 
+std::string OtlpGrpcClient::GetGrpcTarget(const std::string &endpoint)
+{
+  //
+  // Scheme is allowed in OTLP endpoint definition, but is not allowed for creating gRPC
+  // channel. Passing URI with scheme to grpc::CreateChannel could resolve the endpoint to some
+  // unexpected address.
+  //
+  ext::http::common::UrlParser url(endpoint);
+  if (!url.success_)
+  {
+    OTEL_INTERNAL_LOG_ERROR("[OTLP GRPC Client] invalid endpoint: " << endpoint);
+    return "";
+  }
+
+  std::string grpc_target;
+  if (url.scheme_ == "unix")
+  {
+    grpc_target = "unix:" + url.path_;
+  }
+  else
+  {
+    grpc_target = url.host_ + ":" + std::to_string(static_cast<int>(url.port_));
+  }
+  return grpc_target;
+}
+
 std::shared_ptr<grpc::Channel> OtlpGrpcClient::MakeChannel(const OtlpGrpcClientOptions &options)
 {
 
@@ -318,22 +344,16 @@ std::shared_ptr<grpc::Channel> OtlpGrpcClient::MakeChannel(const OtlpGrpcClientO
 
     return nullptr;
   }
-  //
-  // Scheme is allowed in OTLP endpoint definition, but is not allowed for creating gRPC
-  // channel. Passing URI with scheme to grpc::CreateChannel could resolve the endpoint to some
-  // unexpected address.
-  //
 
-  ext::http::common::UrlParser url(options.endpoint);
-  if (!url.success_)
+  std::shared_ptr<grpc::Channel> channel;
+  std::string grpc_target = GetGrpcTarget(options.endpoint);
+
+  if (grpc_target.empty())
   {
     OTEL_INTERNAL_LOG_ERROR("[OTLP GRPC Client] invalid endpoint: " << options.endpoint);
-
     return nullptr;
   }
 
-  std::shared_ptr<grpc::Channel> channel;
-  std::string grpc_target = url.host_ + ":" + std::to_string(static_cast<int>(url.port_));
   grpc::ChannelArguments grpc_arguments;
   grpc_arguments.SetUserAgentPrefix(options.user_agent);
 

exporters/otlp/test/otlp_grpc_target_test.cc

@@ -0,0 +1,37 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#include <grpcpp/grpcpp.h>
+#include <gtest/gtest.h>
+
+#include "opentelemetry/exporters/otlp/otlp_grpc_client.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace exporter
+{
+namespace otlp
+{
+
+TEST(OtlpGrpcClientEndpointTest, GrpcClientTest)
+{
+  OtlpGrpcClientOptions opts1;
+  opts1.endpoint = "unix:///tmp/otel1.sock";
+
+  OtlpGrpcClientOptions opts2;
+  opts2.endpoint = "unix:tmp/otel2.sock";
+
+  OtlpGrpcClientOptions opts3;
+  opts3.endpoint = "localhost:4317";
+
+  auto target1 = OtlpGrpcClient::GetGrpcTarget(opts1.endpoint);
+  auto target2 = OtlpGrpcClient::GetGrpcTarget(opts2.endpoint);
+  auto target3 = OtlpGrpcClient::GetGrpcTarget(opts3.endpoint);
+
+  EXPECT_EQ(target1, "unix:/tmp/otel1.sock");
+  EXPECT_EQ(target2, "");
+  EXPECT_EQ(target3, "localhost:4317");
+}
+
+}  // namespace otlp
+}  // namespace exporter
+OPENTELEMETRY_END_NAMESPACE