OTLP trace gRPC exporter

.github/dependabot.yml

@@ -236,3 +236,23 @@ updates:
     schedule:
       day: sunday
       interval: weekly
+  -
+    package-ecosystem: gomod
+    directory: /exporters/otlp/otlptrace
+    labels:
+      - dependencies
+      - go
+      - "Skip Changelog"
+    schedule:
+      day: sunday
+      interval: weekly
+  -
+    package-ecosystem: gomod
+    directory: /exporters/otlp/otlptrace/otlptracegrpc
+    labels:
+      - dependencies
+      - go
+      - "Skip Changelog"
+    schedule:
+      day: sunday
+      interval: weekly

CHANGELOG.md

@@ -30,6 +30,8 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
   It can be used to decode a `TraceState` from a `tracestate` header string value. (#1937)
 - The `Len` method is added to the `TraceState` type in the `go.opentelemetry.io/otel/trace` package.
   This method returns the number of list-members the `TraceState` holds. (#1937)
+- Creates package `go.opentelemetry.io/otel/exporters/otlp/otlptrace` that defines a trace exporter that uses a `otlptrace.Client` to send data.
+  Creates package `go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc` implementing a gRPC `otlptrace.Client` and offers convenience functions, `NewExportPipeline` and `InstallNewPipeline`, to setup and install a `otlptrace.Exporter` in tracing .(#1922)
 
 ### Changed
 

Makefile

@@ -168,6 +168,7 @@ dependabot-check:
 	); \
 	if [ -n "$$result" ]; then \
 		echo "missing go.mod dependabot check:"; echo "$$result"; \
+		echo "new modules need to be added to the .github/dependabot.yml file"; \
 		exit 1; \
 	fi
 

bridge/opencensus/go.mod

@@ -57,3 +57,7 @@ replace go.opentelemetry.io/otel/sdk/metric => ../../sdk/metric
 replace go.opentelemetry.io/otel/trace => ../../trace
 
 replace go.opentelemetry.io/otel/example/passthrough => ../../example/passthrough
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace => ../../exporters/otlp/otlptrace
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc => ../../exporters/otlp/otlptrace/otlptracegrpc

bridge/opentracing/go.mod

@@ -53,3 +53,7 @@ replace go.opentelemetry.io/otel/sdk/metric => ../../sdk/metric
 replace go.opentelemetry.io/otel/trace => ../../trace
 
 replace go.opentelemetry.io/otel/example/passthrough => ../../example/passthrough
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace => ../../exporters/otlp/otlptrace
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc => ../../exporters/otlp/otlptrace/otlptracegrpc

example/jaeger/go.mod

@@ -53,3 +53,7 @@ replace go.opentelemetry.io/otel/sdk/metric => ../../sdk/metric
 replace go.opentelemetry.io/otel/trace => ../../trace
 
 replace go.opentelemetry.io/otel/example/passthrough => ../passthrough
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace => ../../exporters/otlp/otlptrace
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc => ../../exporters/otlp/otlptrace/otlptracegrpc

example/namedtracer/go.mod

@@ -54,3 +54,7 @@ replace go.opentelemetry.io/otel/sdk/metric => ../../sdk/metric
 replace go.opentelemetry.io/otel/trace => ../../trace
 
 replace go.opentelemetry.io/otel/example/passthrough => ../passthrough
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace => ../../exporters/otlp/otlptrace
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc => ../../exporters/otlp/otlptrace/otlptracegrpc

example/opencensus/go.mod

@@ -55,3 +55,7 @@ replace go.opentelemetry.io/otel/sdk/metric => ../../sdk/metric
 replace go.opentelemetry.io/otel/trace => ../../trace
 
 replace go.opentelemetry.io/otel/example/passthrough => ../passthrough
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace => ../../exporters/otlp/otlptrace
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc => ../../exporters/otlp/otlptrace/otlptracegrpc

example/otel-collector/go.mod

@@ -57,3 +57,7 @@ replace go.opentelemetry.io/otel/sdk/metric => ../../sdk/metric
 replace go.opentelemetry.io/otel/trace => ../../trace
 
 replace go.opentelemetry.io/otel/example/passthrough => ../passthrough
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace => ../../exporters/otlp/otlptrace
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc => ../../exporters/otlp/otlptrace/otlptracegrpc

example/passthrough/go.mod

@@ -1,6 +1,6 @@
 module go.opentelemetry.io/otel/example/passthrough
 
-go 1.16
+go 1.15
 
 require (
 	go.opentelemetry.io/otel v0.20.0
@@ -55,3 +55,7 @@ replace go.opentelemetry.io/otel/sdk/export/metric => ../../sdk/export/metric
 replace go.opentelemetry.io/otel/sdk/metric => ../../sdk/metric
 
 replace go.opentelemetry.io/otel/sdk/trace => ../../sdk/trace
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace => ../../exporters/otlp/otlptrace
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc => ../../exporters/otlp/otlptrace/otlptracegrpc

example/prom-collector/go.mod

@@ -56,3 +56,7 @@ replace go.opentelemetry.io/otel/sdk/metric => ../../sdk/metric
 replace go.opentelemetry.io/otel/trace => ../../trace
 
 replace go.opentelemetry.io/otel/example/passthrough => ../passthrough
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace => ../../exporters/otlp/otlptrace
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc => ../../exporters/otlp/otlptrace/otlptracegrpc

example/prometheus/go.mod

@@ -53,3 +53,7 @@ replace go.opentelemetry.io/otel/sdk/metric => ../../sdk/metric
 replace go.opentelemetry.io/otel/trace => ../../trace
 
 replace go.opentelemetry.io/otel/example/passthrough => ../passthrough
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace => ../../exporters/otlp/otlptrace
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc => ../../exporters/otlp/otlptrace/otlptracegrpc

example/zipkin/go.mod

@@ -54,3 +54,7 @@ replace go.opentelemetry.io/otel/sdk/metric => ../../sdk/metric
 replace go.opentelemetry.io/otel/trace => ../../trace
 
 replace go.opentelemetry.io/otel/example/passthrough => ../passthrough
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace => ../../exporters/otlp/otlptrace
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc => ../../exporters/otlp/otlptrace/otlptracegrpc

exporters/metric/prometheus/go.mod

@@ -58,3 +58,7 @@ replace go.opentelemetry.io/otel/sdk/metric => ../../../sdk/metric
 replace go.opentelemetry.io/otel/trace => ../../../trace
 
 replace go.opentelemetry.io/otel/example/passthrough => ../../../example/passthrough
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace => ../../otlp/otlptrace
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc => ../../otlp/otlptrace/otlptracegrpc

exporters/otlp/go.mod

@@ -64,4 +64,8 @@ replace go.opentelemetry.io/otel/sdk/metric => ../../sdk/metric
 
 replace go.opentelemetry.io/otel/trace => ../../trace
 
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace => ./otlptrace
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc => ./otlptrace/otlptracegrpc
+
 replace go.opentelemetry.io/otel/example/passthrough => ../../example/passthrough

exporters/otlp/otlptrace/clients.go

@@ -0,0 +1,43 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlptrace // import "go.opentelemetry.io/otel/exporters/otlp/otlptrace"
+
+import (
+	"context"
+
+	tracepb "go.opentelemetry.io/proto/otlp/trace/v1"
+)
+
+// Client manages connections to the collector, handles the
+// transformation of data into wire format, and the transmission of that
+// data to the collector.
+type Client interface {
+	// Start should establish connection(s) to endpoint(s). It is
+	// called just once by the exporter, so the implementation
+	// does not need to worry about idempotence and locking.
+	Start(ctx context.Context) error
+	// Stop should close the connections. The function is called
+	// only once by the exporter, so the implementation does not
+	// need to worry about idempotence, but it may be called
+	// concurrently with UploadTraces, so proper
+	// locking is required. The function serves as a
+	// synchronization point - after the function returns, the
+	// process of closing connections is assumed to be finished.
+	Stop(ctx context.Context) error
+	// UploadTraces should transform the passed traces to the wire
+	// format and send it to the collector. May be called
+	// concurrently.
+	UploadTraces(ctx context.Context, protoSpans []*tracepb.ResourceSpans) error
+}

exporters/otlp/otlptrace/exporter.go

@@ -0,0 +1,131 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlptrace // import "go.opentelemetry.io/otel/exporters/otlp/otlptrace"
+
+import (
+	"context"
+	"errors"
+	"sync"
+
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/internal/tracetransform"
+
+	"go.opentelemetry.io/otel"
+	tracesdk "go.opentelemetry.io/otel/sdk/trace"
+)
+
+var (
+	errAlreadyStarted = errors.New("already started")
+)
+
+// Exporter exports trace data in the OTLP wire format.
+type Exporter struct {
+	client Client
+
+	mu      sync.RWMutex
+	started bool
+
+	startOnce sync.Once
+	stopOnce  sync.Once
+}
+
+// ExportSpans exports a batch of spans.
+func (e *Exporter) ExportSpans(ctx context.Context, ss []tracesdk.ReadOnlySpan) error {
+	protoSpans := tracetransform.Spans(ss)
+	if len(protoSpans) == 0 {
+		return nil
+	}
+
+	return e.client.UploadTraces(ctx, protoSpans)
+}
+
+// Start establishes a connection to the receiving endpoint.
+func (e *Exporter) Start(ctx context.Context) error {
+	var err = errAlreadyStarted
+	e.startOnce.Do(func() {
+		e.mu.Lock()
+		e.started = true
+		e.mu.Unlock()
+		err = e.client.Start(ctx)
+	})
+
+	return err
+}
+
+// Shutdown flushes all exports and closes all connections to the receiving endpoint.
+func (e *Exporter) Shutdown(ctx context.Context) error {
+	e.mu.RLock()
+	started := e.started
+	e.mu.RUnlock()
+
+	if !started {
+		return nil
+	}
+
+	var err error
+
+	e.stopOnce.Do(func() {
+		err = e.client.Stop(ctx)
+		e.mu.Lock()
+		e.started = false
+		e.mu.Unlock()
+	})
+
+	return err
+}
+
+var _ tracesdk.SpanExporter = (*Exporter)(nil)
+
+// NewExporter constructs a new Exporter and starts it.
+func NewExporter(ctx context.Context, client Client) (*Exporter, error) {
+	exp := NewUnstartedExporter(client)
+	if err := exp.Start(ctx); err != nil {
+		return nil, err
+	}
+	return exp, nil
+}
+
+// NewUnstartedExporter constructs a new Exporter and does not start it.
+func NewUnstartedExporter(client Client) *Exporter {
+	return &Exporter{
+		client: client,
+	}
+}
+
+// NewExportPipeline sets up a complete export pipeline
+// with the recommended TracerProvider setup.
+func NewExportPipeline(ctx context.Context, client Client) (*Exporter, *tracesdk.TracerProvider, error) {
+	exp, err := NewExporter(ctx, client)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	tracerProvider := tracesdk.NewTracerProvider(
+		tracesdk.WithBatcher(exp),
+	)
+
+	return exp, tracerProvider, nil
+}
+
+// InstallNewPipeline instantiates a NewExportPipeline with the
+// recommended configuration and registers it globally.
+func InstallNewPipeline(ctx context.Context, client Client) (*Exporter, *tracesdk.TracerProvider, error) {
+	exp, tp, err := NewExportPipeline(ctx, client)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	otel.SetTracerProvider(tp)
+	return exp, tp, err
+}

exporters/otlp/otlptrace/exporter_test.go

@@ -0,0 +1,66 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlptrace_test
+
+import (
+	"context"
+	"testing"
+
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace"
+
+	"github.com/stretchr/testify/assert"
+
+	"go.opentelemetry.io/otel"
+	tracesdk "go.opentelemetry.io/otel/sdk/trace"
+	tracepb "go.opentelemetry.io/proto/otlp/trace/v1"
+)
+
+type noopClient struct {
+}
+
+var _ otlptrace.Client = (*noopClient)(nil)
+
+func (m *noopClient) Start(_ context.Context) error {
+	return nil
+}
+
+func (m *noopClient) Stop(ctx context.Context) error {
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	default:
+	}
+	return nil
+}
+
+func (m *noopClient) UploadTraces(_ context.Context, _ []*tracepb.ResourceSpans) error {
+	return nil
+}
+
+func (m *noopClient) Reset() {
+}
+
+func TestInstallNewPipeline(t *testing.T) {
+	ctx := context.Background()
+	_, _, err := otlptrace.InstallNewPipeline(ctx, &noopClient{})
+	assert.NoError(t, err)
+	assert.IsType(t, &tracesdk.TracerProvider{}, otel.GetTracerProvider())
+}
+
+func TestNewExportPipeline(t *testing.T) {
+	_, tp, err := otlptrace.NewExportPipeline(context.Background(), &noopClient{})
+	assert.NoError(t, err)
+	assert.NotEqual(t, tp, otel.GetTracerProvider())
+}