tracing: wip / test

tracing/tracing.go

@@ -0,0 +1,102 @@
+package tracing
+
+import (
+	"context"
+	"os"
+
+	"go.ntppool.org/common/logger"
+	"go.ntppool.org/common/version"
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace"
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
+	"go.opentelemetry.io/otel/propagation"
+	"go.opentelemetry.io/otel/sdk/resource"
+	otelsdktrace "go.opentelemetry.io/otel/sdk/trace"
+	semconv "go.opentelemetry.io/otel/semconv/v1.21.0"
+	"go.opentelemetry.io/otel/trace"
+)
+
+//
+//  https://github.com/open-telemetry/opentelemetry-go-contrib/blob/main/instrumentation/github.com/labstack/echo/otelecho/example/server.go
+// https://github.com/open-telemetry/opentelemetry-go/blob/main/exporters/otlp/otlptrace/otlptracehttp/example_test.go
+
+func NewTracer(name string) trace.Tracer {
+	traceProvider := otel.GetTracerProvider()
+	return traceProvider.Tracer(name)
+}
+
+type TracerConfig struct {
+	ServiceName string
+	Environment string
+}
+
+func InitTracer(ctx context.Context, cfg *TracerConfig) error {
+
+	log := logger.Setup()
+
+	// exporter, err := srv.newStdoutExporter(os.Stdout)
+
+	var err error
+	var exporter otelsdktrace.SpanExporter
+
+	if otlp := os.Getenv("OTEL_EXPORTER_OTLP_ENDPOINT"); len(otlp) > 0 {
+		exporter, err = newOLTPExporter(ctx)
+	}
+
+	if err != nil {
+		return err
+	}
+
+	if exporter != nil {
+		tp := otelsdktrace.NewTracerProvider(
+			otelsdktrace.WithSampler(otelsdktrace.AlwaysSample()),
+			otelsdktrace.WithBatcher(exporter),
+			otelsdktrace.WithResource(newResource(cfg)),
+		)
+
+		otel.SetTracerProvider(tp)
+		otel.SetTextMapPropagator(propagation.NewCompositeTextMapPropagator(propagation.TraceContext{}, propagation.Baggage{}))
+	} else {
+		log.Warn("tracing not configured")
+	}
+
+	return nil
+}
+
+func newOLTPExporter(ctx context.Context) (otelsdktrace.SpanExporter, error) {
+	client := otlptracehttp.NewClient()
+	exporter, err := otlptrace.New(ctx, client)
+	if err != nil {
+		logger.Setup().Error("creating OTLP trace exporter", "err", err)
+	}
+	return exporter, err
+}
+
+// func (srv *Server) newStdoutExporter(w io.Writer) (sdktrace.SpanExporter, error) {
+// 	return stdouttrace.New(
+// 		stdouttrace.WithWriter(w),
+// 		// Use human-readable output.
+// 		stdouttrace.WithPrettyPrint(),
+// 		// Do not print timestamps for the demo.
+// 		stdouttrace.WithoutTimestamps(),
+// 	)
+// }
+
+// newResource returns a resource describing this application.
+func newResource(cfg *TracerConfig) *resource.Resource {
+	r, err := resource.Merge(
+		resource.Default(),
+		resource.NewWithAttributes(
+			semconv.SchemaURL,
+			semconv.ServiceNameKey.String(cfg.ServiceName),
+			semconv.ServiceVersionKey.String(version.Version()),
+			attribute.String("environment", cfg.Environment),
+		),
+	)
+	if err != nil {
+		panic(err)
+	}
+
+	return r
+}