tracing: google grpc service support for ocagent/opencensus

api/envoy/config/trace/v2/trace.proto

@@ -142,7 +142,7 @@ message DatadogConfig {
 }
 
 // Configuration for the OpenCensus tracer.
-// [#next-free-field: 14]
+// [#next-free-field: 15]
 // [#extension: envoy.tracers.opencensus]
 message OpenCensusConfig {
   enum TraceContext {
@@ -196,14 +196,19 @@ message OpenCensusConfig {
   // The URL to Zipkin, e.g. "http://127.0.0.1:9411/api/v2/spans"
   string zipkin_url = 6;
 
-  // Enables the OpenCensus Agent exporter if set to true. The address must also
-  // be set.
+  // Enables the OpenCensus Agent exporter if set to true. The ocagent_address or
+  // ocagent_grpc_service must also be set.
   bool ocagent_exporter_enabled = 11;
 
   // The address of the OpenCensus Agent, if its exporter is enabled, in gRPC
   // format: https://github.com/grpc/grpc/blob/master/doc/naming.md
+  // [#comment:TODO: deprecate this field]
   string ocagent_address = 12;
 
+  // (optional) The gRPC server hosted by the OpenCensus Agent. Only Google gRPC is supported.
+  // This is only used if the ocagent_address is left empty.
+  api.v2.core.GrpcService ocagent_grpc_service = 14;
+
   // List of incoming trace context headers we will accept. First one found
   // wins.
   repeated TraceContext incoming_trace_context = 8;

api/envoy/config/trace/v3/trace.proto

@@ -162,7 +162,7 @@ message DatadogConfig {
 }
 
 // Configuration for the OpenCensus tracer.
-// [#next-free-field: 14]
+// [#next-free-field: 15]
 // [#extension: envoy.tracers.opencensus]
 message OpenCensusConfig {
   option (udpa.annotations.versioning).previous_message_type =
@@ -219,14 +219,19 @@ message OpenCensusConfig {
   // The URL to Zipkin, e.g. "http://127.0.0.1:9411/api/v2/spans"
   string zipkin_url = 6;
 
-  // Enables the OpenCensus Agent exporter if set to true. The address must also
-  // be set.
+  // Enables the OpenCensus Agent exporter if set to true. The ocagent_address or
+  // ocagent_grpc_service must also be set.
   bool ocagent_exporter_enabled = 11;
 
   // The address of the OpenCensus Agent, if its exporter is enabled, in gRPC
   // format: https://github.com/grpc/grpc/blob/master/doc/naming.md
+  // [#comment:TODO: deprecate this field]
   string ocagent_address = 12;
 
+  // (optional) The gRPC server hosted by the OpenCensus Agent. Only Google gRPC is supported.
+  // This is only used if the ocagent_address is left empty.
+  core.v3.GrpcService ocagent_grpc_service = 14;
+
   // List of incoming trace context headers we will accept. First one found
   // wins.
   repeated TraceContext incoming_trace_context = 8;

docs/root/intro/version_history.rst

@@ -22,7 +22,7 @@ Version history
 * thrift_proxy: add router filter stats to docs.
 * tracers: tracer extensions use the "envoy.tracers" name space. A mapping of extension names is
   available in the :ref:`deprecated <deprecated>` documentation.
-* tracing: added gRPC service configuration to the OpenCensus Stackdriver tracer.
+* tracing: added gRPC service configuration to the OpenCensus Stackdriver and OpenCensus Agent tracers.
 * upstream: combined HTTP/1 and HTTP/2 connection pool code. This means that circuit breaker
   limits for both requests and connections apply to both pool types. Also, HTTP/2 now has
   the option to limit concurrent requests on a connection, and allow multiple draining

source/extensions/tracers/opencensus/opencensus_tracer_impl.cc

@@ -277,7 +277,17 @@ Driver::Driver(const envoy::config::trace::v3::OpenCensusConfig& oc_config,
   }
   if (oc_config.ocagent_exporter_enabled()) {
     ::opencensus::exporters::trace::OcAgentOptions opts;
-    opts.address = oc_config.ocagent_address();
+    if (!oc_config.ocagent_address().empty()) {
+      opts.address = oc_config.ocagent_address();
+    } else if (oc_config.has_ocagent_grpc_service()) {
+      if (!oc_config.ocagent_grpc_service().has_google_grpc()) {
+        throw EnvoyException("Opencensus ocagent tracer only supports GoogleGrpc.");
+      }
+      envoy::config::core::v3::GrpcService ocagent_service = oc_config.ocagent_grpc_service();
+      auto channel = Envoy::Grpc::GoogleGrpcUtils::createChannel(ocagent_service, api);
+      opts.trace_service_stub =
+          ::opencensus::proto::agent::trace::v1::TraceService::NewStub(channel);
+    }
     opts.service_name = local_info_.clusterName();
     ::opencensus::exporters::trace::OcAgentExporter::Register(std::move(opts));
   }

test/extensions/tracers/opencensus/config_test.cc

@@ -75,6 +75,46 @@ TEST(OpenCensusTracerConfigTest, OpenCensusHttpTracerWithTypedConfig) {
       {32, 32, 128, 32, ::opencensus::trace::ProbabilitySampler(1e-4)});
 }
 
+TEST(OpenCensusTracerConfigTest, OpenCensusHttpTracerGrpc) {
+  NiceMock<Server::MockInstance> server;
+  const std::string yaml_string = R"EOF(
+  http:
+    name: envoy.tracers.opencensus
+    typed_config:
+      "@type": type.googleapis.com/envoy.config.trace.v2.OpenCensusConfig
+      trace_config:
+        rate_limiting_sampler:
+          qps: 123
+        max_number_of_attributes: 12
+        max_number_of_annotations: 34
+        max_number_of_message_events: 56
+        max_number_of_links: 78
+      ocagent_exporter_enabled: true
+      ocagent_grpc_service:
+        google_grpc:
+          target_uri: 127.0.0.1:55678
+          stat_prefix: test
+      incoming_trace_context: b3
+      incoming_trace_context: trace_context
+      incoming_trace_context: grpc_trace_bin
+      incoming_trace_context: cloud_trace_context
+      outgoing_trace_context: trace_context
+  )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::HttpTracerPtr tracer = factory.createHttpTracer(*message, server);
+  EXPECT_NE(nullptr, tracer);
+
+  // Reset TraceParams back to default.
+  ::opencensus::trace::TraceConfig::SetCurrentTraceParams(
+      {32, 32, 128, 32, ::opencensus::trace::ProbabilitySampler(1e-4)});
+}
+
 TEST(OpenCensusTracerConfigTest, DoubleRegistrationTest) {
   EXPECT_THROW_WITH_MESSAGE(
       (Registry::RegisterFactory<OpenCensusTracerFactory, Server::Configuration::TracerFactory>()),

tools/spelling/spelling_dictionary.txt

@@ -784,6 +784,7 @@ nullptr
 num
 numkeys
 observability
+ocagent
 offsetof
 oneof
 oneway