Feature: Support gRPC protocol in CollectorExporter

Makefile

@@ -7,9 +7,13 @@ init:
 	dart pub get
 	# Generate mocks for unit tests.  For config, see build.yaml.
 	dart run build_runner build --delete-conflicting-outputs
-	dart pub global activate protoc_plugin 21.1.2
+	if dart --version | grep 'Dart SDK version: 2'; then \
+		dart pub global activate protoc_plugin 20.0.1; \
+	else \
+		dart pub global activate protoc_plugin 21.1.2; \
+	fi
 	cd lib/src/sdk/proto && \
-		protoc --proto_path opentelemetry-proto --dart_out . \
+		protoc --proto_path opentelemetry-proto --dart_out grpc:. \
 			opentelemetry-proto/opentelemetry/proto/common/v1/common.proto \
 			opentelemetry-proto/opentelemetry/proto/collector/trace/v1/trace_service.proto \
 			opentelemetry-proto/opentelemetry/proto/trace/v1/trace.proto \

README.md

@@ -29,6 +29,8 @@ import 'package:opentelemetry/sdk.dart' as otel_sdk;
 final exporter = otel_sdk.CollectorExporter(Uri.parse('https://my-collector.com/v1/traces'));
 ```
 
+The CollectorExporter supports transport protocols including `http/protobuf` and `grpc`. The default protocol is `http/protobuf`.
+
 #### ConsoleExporter
 
 The ConsoleExporter has no requirements, and has no configuration options.
@@ -190,6 +192,7 @@ const result = doWork();
 ```
 
 You can also create Span Events with additional Attributes:
+
 ```dart
 span.addEvent('some log', attributes: {
   'log.severity': 'error',
@@ -203,6 +206,7 @@ span.addEvent('some log', attributes: {
 In order to generate protobuf definitions, you must have [protoc](https://github.com/protocolbuffers/protobuf/releases) installed and available in your path.
 
 ### Publishing New Versions
-See https://github.com/Workiva/Observability/blob/master/doc/publishing_opentelemetry_dart.md
+
+See <https://github.com/Workiva/Observability/blob/master/doc/publishing_opentelemetry_dart.md>
 
 Only Workiva maintainers can publish new versions of opentelemetry-dart.

lib/sdk.dart

@@ -9,7 +9,8 @@ export 'src/sdk/time_providers/datetime_time_provider.dart'
     show DateTimeTimeProvider;
 export 'src/sdk/time_providers/time_provider.dart' show TimeProvider;
 export 'src/sdk/trace/exporters/span_exporter.dart' show SpanExporter;
-export 'src/sdk/trace/exporters/collector_exporter.dart' show CollectorExporter;
+export 'src/sdk/trace/exporters/collector_exporter.dart'
+    show CollectorExporter, CollectorExporterProtocol;
 export 'src/sdk/trace/exporters/console_exporter.dart' show ConsoleExporter;
 export 'src/sdk/trace/id_generator.dart' show IdGenerator;
 export 'src/sdk/trace/sampling/always_off_sampler.dart' show AlwaysOffSampler;

lib/src/sdk/proto/opentelemetry/proto/collector/trace/v1/trace_service.pb.dart

@@ -12,17 +12,16 @@
 // ignore_for_file: non_constant_identifier_names, prefer_final_fields
 // ignore_for_file: unnecessary_import, unnecessary_this, unused_import
 
-import 'dart:async' as $async;
 import 'dart:core' as $core;
 
 import 'package:fixnum/fixnum.dart' as $fixnum;
 import 'package:protobuf/protobuf.dart' as $pb;
 
-import '../../../trace/v1/trace.pb.dart' as $2;
+import '../../../trace/v1/trace.pb.dart' as $3;
 
 class ExportTraceServiceRequest extends $pb.GeneratedMessage {
   factory ExportTraceServiceRequest({
-    $core.Iterable<$2.ResourceSpans>? resourceSpans,
+    $core.Iterable<$3.ResourceSpans>? resourceSpans,
   }) {
     final $result = create();
     if (resourceSpans != null) {
@@ -35,7 +34,7 @@ class ExportTraceServiceRequest extends $pb.GeneratedMessage {
   factory ExportTraceServiceRequest.fromJson($core.String i, [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) => create()..mergeFromJson(i, r);
 
   static final $pb.BuilderInfo _i = $pb.BuilderInfo(_omitMessageNames ? '' : 'ExportTraceServiceRequest', package: const $pb.PackageName(_omitMessageNames ? '' : 'opentelemetry.proto.collector.trace.v1'), createEmptyInstance: create)
-    ..pc<$2.ResourceSpans>(1, _omitFieldNames ? '' : 'resourceSpans', $pb.PbFieldType.PM, subBuilder: $2.ResourceSpans.create)
+    ..pc<$3.ResourceSpans>(1, _omitFieldNames ? '' : 'resourceSpans', $pb.PbFieldType.PM, subBuilder: $3.ResourceSpans.create)
     ..hasRequiredFields = false
   ;
 
@@ -66,7 +65,7 @@ class ExportTraceServiceRequest extends $pb.GeneratedMessage {
   /// data from multiple origins typically batch the data before forwarding further and
   /// in that case this array will contain multiple elements.
   @$pb.TagNumber(1)
-  $core.List<$2.ResourceSpans> get resourceSpans => $_getList(0);
+  $core.List<$3.ResourceSpans> get resourceSpans => $_getList(0);
 }
 
 class ExportTraceServiceResponse extends $pb.GeneratedMessage {
@@ -211,15 +210,6 @@ class ExportTracePartialSuccess extends $pb.GeneratedMessage {
   void clearErrorMessage() => clearField(2);
 }
 
-class TraceServiceApi {
-  $pb.RpcClient _client;
-  TraceServiceApi(this._client);
-
-  $async.Future<ExportTraceServiceResponse> export($pb.ClientContext? ctx, ExportTraceServiceRequest request) =>
-    _client.invoke<ExportTraceServiceResponse>(ctx, 'TraceService', 'Export', request, ExportTraceServiceResponse())
-  ;
-}
-
 
 const _omitFieldNames = $core.bool.fromEnvironment('protobuf.omit_field_names');
 const _omitMessageNames = $core.bool.fromEnvironment('protobuf.omit_message_names');

lib/src/sdk/proto/opentelemetry/proto/collector/trace/v1/trace_service.pbgrpc.dart

@@ -0,0 +1,62 @@
+// Copyright 2021-2022 Workiva.
+// Licensed under the Apache License, Version 2.0. Please see https://github.com/Workiva/opentelemetry-dart/blob/master/LICENSE for more information
+
+//
+//  Generated code. Do not modify.
+//  source: opentelemetry/proto/collector/trace/v1/trace_service.proto
+//
+// @dart = 2.12
+
+// ignore_for_file: annotate_overrides, camel_case_types, comment_references
+// ignore_for_file: constant_identifier_names, library_prefixes
+// ignore_for_file: non_constant_identifier_names, prefer_final_fields
+// ignore_for_file: unnecessary_import, unnecessary_this, unused_import
+
+import 'dart:async' as $async;
+import 'dart:core' as $core;
+
+import 'package:grpc/service_api.dart' as $grpc;
+import 'package:protobuf/protobuf.dart' as $pb;
+
+import 'trace_service.pb.dart' as $0;
+
+export 'trace_service.pb.dart';
+
+@$pb.GrpcServiceName('opentelemetry.proto.collector.trace.v1.TraceService')
+class TraceServiceClient extends $grpc.Client {
+  static final _$export = $grpc.ClientMethod<$0.ExportTraceServiceRequest, $0.ExportTraceServiceResponse>(
+      '/opentelemetry.proto.collector.trace.v1.TraceService/Export',
+      ($0.ExportTraceServiceRequest value) => value.writeToBuffer(),
+      ($core.List<$core.int> value) => $0.ExportTraceServiceResponse.fromBuffer(value));
+
+  TraceServiceClient($grpc.ClientChannel channel,
+      {$grpc.CallOptions? options,
+      $core.Iterable<$grpc.ClientInterceptor>? interceptors})
+      : super(channel, options: options,
+        interceptors: interceptors);
+
+  $grpc.ResponseFuture<$0.ExportTraceServiceResponse> export($0.ExportTraceServiceRequest request, {$grpc.CallOptions? options}) {
+    return $createUnaryCall(_$export, request, options: options);
+  }
+}
+
+@$pb.GrpcServiceName('opentelemetry.proto.collector.trace.v1.TraceService')
+abstract class TraceServiceBase extends $grpc.Service {
+  $core.String get $name => 'opentelemetry.proto.collector.trace.v1.TraceService';
+
+  TraceServiceBase() {
+    $addMethod($grpc.ServiceMethod<$0.ExportTraceServiceRequest, $0.ExportTraceServiceResponse>(
+        'Export',
+        export_Pre,
+        false,
+        false,
+        ($core.List<$core.int> value) => $0.ExportTraceServiceRequest.fromBuffer(value),
+        ($0.ExportTraceServiceResponse value) => value.writeToBuffer()));
+  }
+
+  $async.Future<$0.ExportTraceServiceResponse> export_Pre($grpc.ServiceCall call, $async.Future<$0.ExportTraceServiceRequest> request) async {
+    return export(call, await request);
+  }
+
+  $async.Future<$0.ExportTraceServiceResponse> export($grpc.ServiceCall call, $0.ExportTraceServiceRequest request);
+}

lib/src/sdk/proto/opentelemetry/proto/collector/trace/v1/trace_service.pbjson.dart

@@ -16,10 +16,6 @@ import 'dart:convert' as $convert;
 import 'dart:core' as $core;
 import 'dart:typed_data' as $typed_data;
 
-import '../../../common/v1/common.pbjson.dart' as $0;
-import '../../../resource/v1/resource.pbjson.dart' as $1;
-import '../../../trace/v1/trace.pbjson.dart' as $2;
-
 @$core.Deprecated('Use exportTraceServiceRequestDescriptor instead')
 const ExportTraceServiceRequest$json = {
   '1': 'ExportTraceServiceRequest',
@@ -61,35 +57,3 @@ final $typed_data.Uint8List exportTracePartialSuccessDescriptor = $convert.base6
     'ChlFeHBvcnRUcmFjZVBhcnRpYWxTdWNjZXNzEiUKDnJlamVjdGVkX3NwYW5zGAEgASgDUg1yZW'
     'plY3RlZFNwYW5zEiMKDWVycm9yX21lc3NhZ2UYAiABKAlSDGVycm9yTWVzc2FnZQ==');
 
-const $core.Map<$core.String, $core.dynamic> TraceServiceBase$json = {
-  '1': 'TraceService',
-  '2': [
-    {'1': 'Export', '2': '.opentelemetry.proto.collector.trace.v1.ExportTraceServiceRequest', '3': '.opentelemetry.proto.collector.trace.v1.ExportTraceServiceResponse', '4': {}},
-  ],
-};
-
-@$core.Deprecated('Use traceServiceDescriptor instead')
-const $core.Map<$core.String, $core.Map<$core.String, $core.dynamic>> TraceServiceBase$messageJson = {
-  '.opentelemetry.proto.collector.trace.v1.ExportTraceServiceRequest': ExportTraceServiceRequest$json,
-  '.opentelemetry.proto.trace.v1.ResourceSpans': $2.ResourceSpans$json,
-  '.opentelemetry.proto.resource.v1.Resource': $1.Resource$json,
-  '.opentelemetry.proto.common.v1.KeyValue': $0.KeyValue$json,
-  '.opentelemetry.proto.common.v1.AnyValue': $0.AnyValue$json,
-  '.opentelemetry.proto.common.v1.ArrayValue': $0.ArrayValue$json,
-  '.opentelemetry.proto.common.v1.KeyValueList': $0.KeyValueList$json,
-  '.opentelemetry.proto.trace.v1.ScopeSpans': $2.ScopeSpans$json,
-  '.opentelemetry.proto.common.v1.InstrumentationScope': $0.InstrumentationScope$json,
-  '.opentelemetry.proto.trace.v1.Span': $2.Span$json,
-  '.opentelemetry.proto.trace.v1.Span.Event': $2.Span_Event$json,
-  '.opentelemetry.proto.trace.v1.Span.Link': $2.Span_Link$json,
-  '.opentelemetry.proto.trace.v1.Status': $2.Status$json,
-  '.opentelemetry.proto.collector.trace.v1.ExportTraceServiceResponse': ExportTraceServiceResponse$json,
-  '.opentelemetry.proto.collector.trace.v1.ExportTracePartialSuccess': ExportTracePartialSuccess$json,
-};
-
-/// Descriptor for `TraceService`. Decode as a `google.protobuf.ServiceDescriptorProto`.
-final $typed_data.Uint8List traceServiceDescriptor = $convert.base64Decode(
-    'CgxUcmFjZVNlcnZpY2USkQEKBkV4cG9ydBJBLm9wZW50ZWxlbWV0cnkucHJvdG8uY29sbGVjdG'
-    '9yLnRyYWNlLnYxLkV4cG9ydFRyYWNlU2VydmljZVJlcXVlc3QaQi5vcGVudGVsZW1ldHJ5LnBy'
-    'b3RvLmNvbGxlY3Rvci50cmFjZS52MS5FeHBvcnRUcmFjZVNlcnZpY2VSZXNwb25zZSIA');
-

lib/src/sdk/proto/opentelemetry/proto/resource/v1/resource.pb.dart

@@ -16,12 +16,12 @@ import 'dart:core' as $core;
 
 import 'package:protobuf/protobuf.dart' as $pb;
 
-import '../../common/v1/common.pb.dart' as $0;
+import '../../common/v1/common.pb.dart' as $1;
 
 /// Resource information.
 class Resource extends $pb.GeneratedMessage {
   factory Resource({
-    $core.Iterable<$0.KeyValue>? attributes,
+    $core.Iterable<$1.KeyValue>? attributes,
     $core.int? droppedAttributesCount,
   }) {
     final $result = create();
@@ -38,7 +38,7 @@ class Resource extends $pb.GeneratedMessage {
   factory Resource.fromJson($core.String i, [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) => create()..mergeFromJson(i, r);
 
   static final $pb.BuilderInfo _i = $pb.BuilderInfo(_omitMessageNames ? '' : 'Resource', package: const $pb.PackageName(_omitMessageNames ? '' : 'opentelemetry.proto.resource.v1'), createEmptyInstance: create)
-    ..pc<$0.KeyValue>(1, _omitFieldNames ? '' : 'attributes', $pb.PbFieldType.PM, subBuilder: $0.KeyValue.create)
+    ..pc<$1.KeyValue>(1, _omitFieldNames ? '' : 'attributes', $pb.PbFieldType.PM, subBuilder: $1.KeyValue.create)
     ..a<$core.int>(2, _omitFieldNames ? '' : 'droppedAttributesCount', $pb.PbFieldType.OU3)
     ..hasRequiredFields = false
   ;
@@ -68,7 +68,7 @@ class Resource extends $pb.GeneratedMessage {
   /// Attribute keys MUST be unique (it is not allowed to have more than one
   /// attribute with the same key).
   @$pb.TagNumber(1)
-  $core.List<$0.KeyValue> get attributes => $_getList(0);
+  $core.List<$1.KeyValue> get attributes => $_getList(0);
 
   /// dropped_attributes_count is the number of dropped attributes. If the value is 0, then
   /// no attributes were dropped.