set up TracerProvider + tracer object

Author: meobilivang

pkg/otel/tracing.go

@@ -0,0 +1,106 @@
+package otel
+
+import (
+	"context"
+	"time"
+
+	"github.com/go-logr/logr"
+	"github.com/pkg/errors"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+	"k8s.io/client-go/pkg/version"
+
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace"
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
+	"go.opentelemetry.io/otel/propagation"
+	"go.opentelemetry.io/otel/sdk/resource"
+	"go.opentelemetry.io/otel/sdk/trace"
+	semconv "go.opentelemetry.io/otel/semconv/v1.4.0"
+)
+
+func RegisterTracing(ctx context.Context, log logr.Logger) error {
+
+	tracerProvider, err := SetUpTracing(ctx)
+	if err != nil {
+		return err
+	}
+
+	// Safely shut down the tracer provider when context terminates
+	go func() {
+		<-ctx.Done()
+
+		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		defer cancel()
+
+		if err := tracerProvider.Shutdown(ctx); err != nil {
+			log.Error(err, "failed to shut down tracer provider")
+		}
+	}()
+
+	return nil
+}
+
+func newExporter(ctx context.Context) (*otlptrace.Exporter, error) {
+
+	conn, err := grpc.DialContext(ctx, "opentelemetry-collector:4317",
+		// Using non-TLS connection for dev environment
+		grpc.WithTransportCredentials(insecure.NewCredentials()),
+		grpc.WithBlock(),
+	)
+
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to create gRPC connection to collector for opentelemetry")
+	}
+
+	// Set up a trace exporter
+	traceExporter, err := otlptracegrpc.New(ctx, otlptracegrpc.WithGRPCConn(conn))
+
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to create trace exporter for opentelemetry")
+	}
+
+	return traceExporter, nil
+}
+
+func SetUpTracing(ctx context.Context) (*trace.TracerProvider, error) {
+
+	traceExporter, err := newExporter(ctx)
+
+	if err != nil {
+		return nil, err
+	}
+
+	// labels/tags/res common to all traces
+	// TODO: consider to add more fields
+	resource, err := resource.New(ctx,
+		resource.WithAttributes(
+			semconv.ServiceNameKey.String("capg"),
+			attribute.String("exporter", "otlpgrpc"),
+			attribute.String("version", version.Get().String()),
+		),
+	)
+
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to create opentelemetry resource")
+	}
+
+	traceProvider := trace.NewTracerProvider(
+		trace.WithBatcher(traceExporter),
+		trace.WithResource(resource),
+		// TODO: dynamic sampling rate?
+		// sampling rate based on parent span = 60%
+		trace.WithSampler(trace.ParentBased(trace.TraceIDRatioBased(0.6))),
+	)
+
+	otel.SetTracerProvider(traceProvider)
+
+	otel.SetTextMapPropagator(
+		propagation.NewCompositeTextMapPropagator(
+			propagation.TraceContext{},
+		),
+	)
+
+	return traceProvider, nil
+}

util/telemetry/oteltracer.go

@@ -0,0 +1,11 @@
+package telemetry
+
+import (
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/trace"
+)
+
+// default Tracer
+func Tracer() trace.Tracer {
+	return otel.Tracer("capg")
+}