Make opencensus Stackdriver exporter respects initial_metadata option…

bazel/repository_locations.bzl

@@ -269,10 +269,10 @@ REPOSITORY_LOCATIONS = dict(
         urls = ["https://github.com/WAVM/WAVM/archive/1ec06cd202a922015c9041c5ed84f875453c4dc7.tar.gz"],
     ),
     io_opencensus_cpp = dict(
-        sha256 = "193ffb4e13bd7886757fd22b61b7f7a400634412ad8e7e1071e73f57bedd7fc6",
-        strip_prefix = "opencensus-cpp-04ed0211931f12b03c1a76b3907248ca4db7bc90",
-        # 2020-03-24
-        urls = ["https://github.com/census-instrumentation/opencensus-cpp/archive/04ed0211931f12b03c1a76b3907248ca4db7bc90.tar.gz"],
+        sha256 = "12ff300fa804f97bd07e2ff071d969e09d5f3d7bbffeac438c725fa52a51a212",
+        strip_prefix = "opencensus-cpp-7877337633466358ed680f9b26967da5b310d7aa",
+        # 2020-06-01
+        urls = ["https://github.com/census-instrumentation/opencensus-cpp/archive/7877337633466358ed680f9b26967da5b310d7aa.tar.gz"],
     ),
     com_github_curl = dict(
         sha256 = "01ae0c123dee45b01bbaef94c0bc00ed2aec89cb2ee0fd598e0d302a6b5e0a98",

source/extensions/tracers/opencensus/opencensus_tracer_impl.cc

@@ -275,7 +275,17 @@ Driver::Driver(const envoy::config::trace::v3::OpenCensusConfig& oc_config,
         stackdriver_service.mutable_google_grpc()->set_target_uri(GoogleStackdriverTraceAddress);
       }
       auto channel = Envoy::Grpc::GoogleGrpcUtils::createChannel(stackdriver_service, api);
+      // TODO(bianpengyuan): add tests for trace_service_stub and initial_metadata options with mock
+      // stubs.
       opts.trace_service_stub = ::google::devtools::cloudtrace::v2::TraceService::NewStub(channel);
+      const auto& initial_metadata = stackdriver_service.initial_metadata();
+      if (!initial_metadata.empty()) {
+        opts.prepare_client_context = [initial_metadata](grpc::ClientContext* ctx) {
+          for (const auto& metadata : initial_metadata) {
+            ctx->AddMetadata(metadata.key(), metadata.value());
+          }
+        };
+      }
     }
     ::opencensus::exporters::trace::StackdriverExporter::Register(std::move(opts));
   }

test/extensions/tracers/opencensus/config_test.cc

@@ -303,6 +303,33 @@ TEST(OpenCensusTracerConfigTest, DoubleRegistrationTest) {
       EnvoyException, "Double registration for name: 'envoy.tracers.opencensus'");
 }
 
+TEST(OpenCensusTracerConfigTest, OpenCensusHttpTracerStackdriverGrpc) {
+  NiceMock<Server::Configuration::MockTracerFactoryContext> context;
+  const std::string yaml_string = R"EOF(
+  http:
+    name: opencensus
+    typed_config:
+      "@type": type.googleapis.com/envoy.config.trace.v2.OpenCensusConfig
+      stackdriver_exporter_enabled: true
+      stackdriver_grpc_service:
+        google_grpc:
+          target_uri: 127.0.0.1:55678
+          stat_prefix: test
+        initial_metadata:
+        - key: foo
+          value: bar
+  )EOF";
+
+  envoy::config::trace::v3::Tracing configuration;
+  TestUtility::loadFromYaml(yaml_string, configuration);
+
+  OpenCensusTracerFactory factory;
+  auto message = Config::Utility::translateToFactoryConfig(
+      configuration.http(), ProtobufMessage::getStrictValidationVisitor(), factory);
+  Tracing::HttpTracerSharedPtr tracer = factory.createHttpTracer(*message, context);
+  EXPECT_NE(nullptr, tracer);
+}
+
 } // namespace OpenCensus
 } // namespace Tracers
 } // namespace Extensions