O11Y-992: OTEL Dart: Implement OTLP HTTP Reporter

.gitignore

@@ -1,3 +1,4 @@
 .dart_tool
 .packages
-pubspec.lock
+pubspec.lock
+lib/src/sdk/trace/exporters/opentelemetry

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "lib/src/sdk/trace/exporters/opentelemetry-proto"]
+	path = lib/src/sdk/trace/exporters/opentelemetry-proto
+	url = [email protected]:open-telemetry/opentelemetry-proto.git

Makefile

@@ -1,13 +1,20 @@
-deps:
-	@pub get
+init:
+	git submodule update --init
+	pub get
+	pub global activate protoc_plugin
+	cd lib/src/sdk/trace/exporters && \
+		protoc --proto_path opentelemetry-proto \
+		--dart_out . \
+		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 \
+		opentelemetry-proto/opentelemetry/proto/resource/v1/resource.proto
 
-analyze-lib:
+analyze:
 	@dart analyze ./lib
-
-analyze-test:
 	@dart analyze ./test
 
-test: analyze-lib
+test:
 	@dart test ./test --chain-stack-traces
 
-.PHONY: deps analyze-lib analyze-test test
+.PHONY: init analyze test

README.md

@@ -63,4 +63,8 @@ main() async {
 
   span.end();
 }
-```
+```
+
+## Development
+
+In order to generate protobuf definitions, you must have [protoc](https://github.com/protocolbuffers/protobuf/releases) installed and available in your path.

analysis_options.yaml

@@ -1 +1,4 @@
 include: package:workiva_analysis_options/v1.recommended.yaml
+analyzer:
+  exclude: 
+    - src/sdk/trace/exporters/opentelemetry

lib/sdk.dart

@@ -1,3 +1,6 @@
+export 'src/sdk/trace/exporters/collector_exporter.dart'
+  show 
+    CollectorExporter;
 export 'src/sdk/trace/exporters/console_exporter.dart'
   show 
     ConsoleExporter;

lib/src/api/trace/id_generator.dart

@@ -1,8 +1,8 @@
 /// Generator capable of creating OTel compliant IDs.
 abstract class IdGenerator {
   /// Generate an ID for a Span.
-  String generateSpanId();
+  List<int> generateSpanId();
 
   /// Generate an ID for a trace.
-  String generateTraceId();
+  List<int> generateTraceId();
 }

lib/src/api/trace/span.dart

@@ -1,6 +1,7 @@
-import 'package:opentelemetry/src/api/trace/span_status.dart';
-
+import 'package:fixnum/fixnum.dart';
 import 'span_context.dart';
+import 'span_status.dart';
+import 'tracer.dart';
 
 /// A representation of a single operation within a trace.
 ///
@@ -17,13 +18,13 @@ abstract class Span {
   SpanContext get spanContext;
 
   /// Get the time when the span was closed, or null if still open.
-  int get endTime;
+  Int64 get endTime;
 
   /// Get the time when the span was started.
-  int get startTime;
+  Int64 get startTime;
 
   /// The parent span id.
-  String get parentSpanId;
+  List<int> get parentSpanId;
 
   /// The name of the span.
   String get name;
@@ -40,6 +41,9 @@ abstract class Span {
   /// Retrieve the status of the [Span].
   SpanStatus get status;
 
+  /// Tracer responsible for creating the [Span].
+  Tracer get tracer;
+
   /// Marks the end of this span's execution.
   void end();
 }

lib/src/api/trace/span_context.dart

@@ -3,10 +3,10 @@ import 'trace_state.dart';
 /// Representation of the context of the context of an individual span.
 abstract class SpanContext {
   /// Get the ID of the span.
-  String get spanId;
+  List<int> get spanId;
 
   /// Get the ID of the trace the span is a part of.
-  String get traceId;
+  List<int> get traceId;
 
   /// Get the state of the entire trace.
   TraceState get traceState;

lib/src/api/trace/tracer.dart

@@ -9,4 +9,7 @@ abstract class Tracer {
   /// Starts a new [Span] without setting it as the current span in this
   /// tracer's context.
   Span startSpan(String name, {Context context});
+
+  /// The Tracer's name.
+  String get name;
 }

lib/src/sdk/trace/exporters/collector_exporter.dart

@@ -0,0 +1,82 @@
+import 'package:http/http.dart' as http;
+
+import '../../../api/trace/span.dart';
+import '../../../api/trace/span_status.dart';
+
+import 'opentelemetry/proto/collector/trace/v1/trace_service.pb.dart';
+import 'opentelemetry/proto/common/v1/common.pb.dart';
+import 'opentelemetry/proto/resource/v1/resource.pb.dart';
+import 'opentelemetry/proto/trace/v1/trace.pb.dart' as pb;
+import 'span_exporter.dart';
+
+class CollectorExporter implements SpanExporter {
+  Uri uri;
+  http.Client client;
+  var _isShutdown = false;
+
+  CollectorExporter(this.uri, {http.Client httpClient}) {
+    client = httpClient ?? http.Client();
+  }
+
+  @override
+  void export(List<Span> spans) {
+    if (_isShutdown) {
+      return;
+    }
+
+    if (spans.isEmpty) {
+      return;
+    }
+
+    final pbSpans = <pb.Span>[];
+    for (var i = 0; i < spans.length; i++) {
+      pbSpans.add(_spanToProtobuf(spans[i]));
+    }
+
+    final body = ExportTraceServiceRequest(resourceSpans: [
+      pb.ResourceSpans(
+          resource: Resource(attributes: [
+            KeyValue(
+                key: 'service.name',
+                value: AnyValue(stringValue: spans[0].tracer.name))
+          ]),
+          instrumentationLibrarySpans: [
+            pb.InstrumentationLibrarySpans(spans: pbSpans)
+          ])
+    ]);
+
+    client.post(uri,
+        body: body.writeToBuffer(),
+        headers: {'Content-Type': 'application/x-protobuf'});
+  }
+
+  pb.Span _spanToProtobuf(Span span) {
+    pb.Status_StatusCode statusCode;
+
+    switch (span.status.code) {
+      case StatusCode.UNSET:
+        statusCode = pb.Status_StatusCode.STATUS_CODE_UNSET;
+        break;
+      case StatusCode.ERROR:
+        statusCode = pb.Status_StatusCode.STATUS_CODE_ERROR;
+        break;
+      case StatusCode.OK:
+        statusCode = pb.Status_StatusCode.STATUS_CODE_OK;
+        break;
+    }
+
+    return pb.Span(
+        traceId: span.spanContext.traceId,
+        spanId: span.spanContext.spanId,
+        parentSpanId: span.parentSpanId,
+        name: span.name,
+        startTimeUnixNano: span.startTime * 1000,
+        endTimeUnixNano: span.endTime * 1000,
+        status: pb.Status(code: statusCode, message: span.status.description));
+  }
+
+  @override
+  void shutdown() {
+    _isShutdown = true;
+  }
+}

lib/src/sdk/trace/exporters/console_exporter.dart

@@ -9,10 +9,16 @@ class ConsoleExporter implements SpanExporter {
     for (var i=0; i < spans.length; i++) {
       final span = spans[i];
       print({
-        'traceId': span.spanContext.traceId,
-        'parentId': span.parentSpanId,
+        'traceId': span.spanContext.traceId
+            .map((x) => x.toRadixString(16).padLeft(2, '0'))
+            .join(),
+        'parentId': span.parentSpanId
+            .map((x) => x.toRadixString(16).padLeft(2, '0'))
+            .join(),
         'name': span.name,
-        'id': span.spanContext.spanId,
+        'id': span.spanContext.spanId
+            .map((x) => x.toRadixString(16).padLeft(2, '0'))
+            .join(),
         'timestamp': span.startTime,
         'duration': span.endTime - span.startTime,
         'status': span.status.code

lib/src/sdk/trace/id_generator.dart

@@ -6,17 +6,17 @@ import '../../../src/api/trace/id_generator.dart' as api;
 class IdGenerator implements api.IdGenerator {
   static final Random _random = Random.secure();
 
-  static String _generateId(int byteLength) {
-    final buffer = StringBuffer();
+  static List<int> _generateId(int byteLength) {
+    final buffer = [];
     for (var i = 0; i < byteLength; i++) {
-      buffer.write(_random.nextInt(256).toRadixString(16).padLeft(2, '0'));
+      buffer.add(_random.nextInt(256));
     }
-    return buffer.toString();
+    return buffer.cast<int>();
   }
 
   @override
-  String generateSpanId() => _generateId(8);
+  List<int> generateSpanId() => _generateId(8);
 
   @override
-  String generateTraceId() => _generateId(16);
+  List<int> generateTraceId() => _generateId(16);
 }

lib/src/sdk/trace/span.dart

@@ -1,28 +1,28 @@
+import 'package:fixnum/fixnum.dart';
+
 import '../../api/trace/span.dart' as span_api;
 import '../../api/trace/span_context.dart';
 import '../../api/trace/span_status.dart';
+import '../../api/trace/tracer.dart';
 import 'span_processors/span_processor.dart';
 
 /// A representation of a single operation within a trace.
 class Span implements span_api.Span {
-  int _startTime;
-  int _endTime;
-  final String _parentSpanId;
+  Int64 _startTime;
+  Int64 _endTime;
+  final List<int> _parentSpanId;
   final SpanContext _spanContext;
   final SpanStatus _status = SpanStatus();
   final List<SpanProcessor> _processors;
+  final Tracer _tracer;
 
   @override
   String name;
 
   /// Construct a [Span].
-  Span(
-    this.name, 
-    this._spanContext, 
-    this._parentSpanId,
-    this._processors
-  ) {
-    _startTime = DateTime.now().toUtc().microsecondsSinceEpoch;
+  Span(this.name, this._spanContext, this._parentSpanId, this._processors,
+      this._tracer) {
+    _startTime = Int64(DateTime.now().toUtc().microsecondsSinceEpoch);
     for (var i = 0; i < _processors.length; i++) {
       _processors[i].onStart();
     }
@@ -32,17 +32,17 @@ class Span implements span_api.Span {
   SpanContext get spanContext => _spanContext;
 
   @override
-  int get endTime => _endTime;
+  Int64 get endTime => _endTime;
 
   @override
-  int get startTime => _startTime;
+  Int64 get startTime => _startTime;
 
   @override
-  String get parentSpanId => _parentSpanId;
+  List<int> get parentSpanId => _parentSpanId;
 
   @override
   void end() {
-    _endTime ??= DateTime.now().toUtc().microsecondsSinceEpoch;
+    _endTime ??= Int64(DateTime.now().toUtc().microsecondsSinceEpoch);
     for (var i = 0; i < _processors.length; i++) {
       _processors[i].onEnd(this);
     }
@@ -66,4 +66,7 @@ class Span implements span_api.Span {
 
   @override
   SpanStatus get status => _status;
+
+  @override
+  Tracer get tracer => _tracer;
 }

lib/src/sdk/trace/span_context.dart

@@ -3,15 +3,15 @@ import '../../../src/api/trace/trace_state.dart';
 
 /// Representation of the context of the context of an individual span.
 class SpanContext implements span_context_api.SpanContext {
-  final String _spanId;
-  final String _traceId;
+  final List<int> _spanId;
+  final List<int> _traceId;
   final TraceState _traceState;
 
   @override
-  String get spanId => _spanId;
+  List<int> get spanId => _spanId;
 
   @override
-  String get traceId => _traceId;
+  List<int> get traceId => _traceId;
 
   @override
   TraceState get traceState => _traceState;

lib/src/sdk/trace/span_processors/batch_processor.dart

@@ -15,13 +15,13 @@ class BatchSpanProcessor implements SpanProcessor {
   final List<Span> _spanBuffer = [];
   Timer _timer; 
 
-  int _maxExportBatchSize = 512;
+  int _maxExportBatchSize;
   final int _maxQueueSize = 2048;
-  int _scheduledDelay = 5000;
+  int _scheduledDelay;
 
   BatchSpanProcessor(this._exporter, {int maxExportBatchSize, int scheduledDelay}) {
-    _maxExportBatchSize = maxExportBatchSize;
-    _scheduledDelay = scheduledDelay;
+    _maxExportBatchSize = maxExportBatchSize ?? 512;
+    _scheduledDelay = scheduledDelay ?? 5000;
   }
 
   @override

lib/src/sdk/trace/tracer.dart

@@ -9,17 +9,21 @@ import 'span_processors/span_processor.dart';
 
 /// An interface for creating [Span]s and propagating context in-process.
 class Tracer implements tracer_api.Tracer {
+  final String _name;
   final IdGenerator _idGenerator = IdGenerator();
   final List<SpanProcessor> _processors;
 
-  Tracer(this._processors);
+  Tracer(this._name, this._processors);
+
+  @override
+  String get name => _name;
 
   @override
   Span startSpan(String name, {Context context}) {
     context ??= Context.current;
 
-    String parentSpanId;
-    String traceId;
+    List<int> parentSpanId;
+    List<int> traceId;
     TraceState traceState;
 
     final spanId = _idGenerator.generateSpanId();
@@ -36,6 +40,6 @@ class Tracer implements tracer_api.Tracer {
 
     final spanContext = SpanContext(traceId, spanId, traceState);
 
-    return Span(name, spanContext, parentSpanId, _processors);
+    return Span(name, spanContext, parentSpanId, _processors, this);
   }
 }