Merge pull request #234 from klihub/fixes/otel-tracing

instrumentation: allow proper reconfiguration of tracing.

pkg/instrumentation/instrumentation.go

@@ -91,7 +91,13 @@ func Restart() error {
 	defer lock.Unlock()
 
 	stop()
-	return start()
+
+	err := start()
+	if err != nil {
+		log.Error("failed to start tracing: %v", err)
+	}
+
+	return err
 }
 
 // Reconfigure our instrumentation services.

pkg/instrumentation/tracing/exporter.go

@@ -0,0 +1,122 @@
+// Copyright The NRI Plugins Authors. All Rights Reserved.
+//
+// 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 tracing
+
+import (
+	"context"
+	"fmt"
+	"net/url"
+	"sync"
+
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
+	sdktrace "go.opentelemetry.io/otel/sdk/trace"
+)
+
+var (
+	_ sdktrace.SpanExporter = (*spanExporter)(nil)
+)
+
+type spanExporter struct {
+	sync.RWMutex
+	exporter sdktrace.SpanExporter
+}
+
+func (e *spanExporter) ExportSpans(ctx context.Context, spans []sdktrace.ReadOnlySpan) error {
+	e.RLock()
+	defer e.RUnlock()
+
+	if e.exporter == nil {
+		return nil
+	}
+	return e.exporter.ExportSpans(ctx, spans)
+}
+
+func (e *spanExporter) Shutdown(ctx context.Context) error {
+	e.Lock()
+	defer e.Unlock()
+
+	if e.exporter == nil {
+		return nil
+	}
+
+	err := e.exporter.Shutdown(ctx)
+	e.exporter = nil
+
+	return err
+}
+
+func (e *spanExporter) setEndpoint(endpoint string) error {
+	e.shutdown()
+
+	if endpoint == "" {
+		return nil
+	}
+
+	e.Lock()
+	defer e.Unlock()
+
+	var (
+		u   *url.URL
+		exp sdktrace.SpanExporter
+		err error
+	)
+
+	// Notes:
+	//   We allow collector endpoint URLs to be given as a plain scheme-prefix,
+	//   IOW, without a host, port, and path. If only a prefix is given, the
+	//   exporters use defaults defined by the OTLP library. These are:
+	//     - otlp-http, http: localhost:4318
+	//     - otlp-grpc, grpc: localhost:4317
+	//
+
+	switch endpoint {
+	case "otlp-http", "http", "otlp-grpc", "grpc":
+		u = &url.URL{Scheme: endpoint}
+	default:
+		u, err = url.Parse(endpoint)
+		if err != nil {
+			return fmt.Errorf("invalid tracing endpoint %q: %w", endpoint, err)
+		}
+	}
+
+	switch u.Scheme {
+	case "otlp-http", "http":
+		opts := []otlptracehttp.Option{otlptracehttp.WithInsecure()}
+		if u.Host != "" {
+			opts = append(opts, otlptracehttp.WithEndpoint(u.Host))
+		}
+		exp, err = otlptracehttp.New(context.Background(), opts...)
+		e.exporter = exp
+		return err
+	case "otlp-grpc", "grpc":
+		opts := []otlptracegrpc.Option{otlptracegrpc.WithInsecure()}
+		if u.Host != "" {
+			opts = append(opts, otlptracegrpc.WithEndpoint(u.Host))
+		}
+		exp, err = otlptracegrpc.New(context.Background(), opts...)
+		e.exporter = exp
+		return err
+	}
+
+	return fmt.Errorf("unsupported tracing endpoint %q", endpoint)
+}
+
+func (e *spanExporter) shutdown() error {
+	ctx, cancel := context.WithTimeout(context.Background(), shutdownTimeout)
+	defer cancel()
+
+	return e.Shutdown(ctx)
+}

pkg/instrumentation/tracing/sampler.go

@@ -0,0 +1,65 @@
+// Copyright The NRI Plugins Authors. All Rights Reserved.
+//
+// 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 tracing
+
+import (
+	"sync"
+
+	sdktrace "go.opentelemetry.io/otel/sdk/trace"
+	"go.opentelemetry.io/otel/trace"
+)
+
+var (
+	drop = sdktrace.SamplingResult{
+		Decision:   sdktrace.Drop,
+		Tracestate: trace.TraceState{},
+	}
+
+	_ sdktrace.Sampler = (*sampler)(nil)
+)
+
+type sampler struct {
+	sync.RWMutex
+	sampler sdktrace.Sampler
+}
+
+func (s *sampler) ShouldSample(p sdktrace.SamplingParameters) sdktrace.SamplingResult {
+	s.RLock()
+	defer s.RUnlock()
+
+	if s.sampler == nil {
+		return drop
+	}
+
+	return s.sampler.ShouldSample(p)
+}
+
+func (s *sampler) Description() string {
+	s.RLock()
+	defer s.RUnlock()
+
+	if s.sampler == nil {
+		return ""
+	}
+
+	return s.sampler.Description()
+}
+
+func (s *sampler) setSampler(sampler sdktrace.Sampler) {
+	s.Lock()
+	defer s.Unlock()
+
+	s.sampler = sampler
+}