Otel tracing MVP

Signed-off-by: gotgelf <gotgelf@gmail.com>

registry/registry.go

@@ -17,6 +17,7 @@ import (
 	gorhandlers "github.com/gorilla/handlers"
 	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
+	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
 	"golang.org/x/crypto/acme"
 	"golang.org/x/crypto/acme/autocert"
 
@@ -25,6 +26,7 @@ import (
 	"github.com/distribution/distribution/v3/internal/dcontext"
 	"github.com/distribution/distribution/v3/registry/handlers"
 	"github.com/distribution/distribution/v3/registry/listener"
+	"github.com/distribution/distribution/v3/tracing"
 	"github.com/distribution/distribution/v3/version"
 )
 
@@ -152,6 +154,12 @@ func NewRegistry(ctx context.Context, config *configuration.Configuration) (*Reg
 		handler = applyHandlerMiddleware(config, handler)
 	}
 
+	err = tracing.InitOpenTelemetry(app.Context)
+	if err != nil {
+		return nil, fmt.Errorf("error during open telemetry initialization: %v", err)
+	}
+	handler = otelHandler(handler)
+
 	server := &http.Server{
 		Handler: handler,
 	}
@@ -163,6 +171,13 @@ func NewRegistry(ctx context.Context, config *configuration.Configuration) (*Reg
 	}, nil
 }
 
+// otelHandler returns an http.Handler that wraps the provided `next` handler with OpenTelemetry instrumentation.
+// This instrumentation tracks each HTTP request, creating spans with names derived from the request method and URL path.
+func otelHandler(next http.Handler) http.Handler {
+	return otelhttp.NewHandler(next, "",
+		otelhttp.WithSpanNameFormatter(func(_ string, r *http.Request) string { return r.Method + " " + r.URL.Path }))
+}
+
 // takes a list of cipher suites and converts it to a list of respective tls constants
 // if an empty list is provided, then the defaults will be used
 func getCipherSuites(names []string) ([]uint16, error) {

tracing/tracing.go

@@ -0,0 +1,49 @@
+package tracing
+
+import (
+	"context"
+
+	"github.com/distribution/distribution/v3/version"
+	"go.opentelemetry.io/contrib/exporters/autoexport"
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/propagation"
+	"go.opentelemetry.io/otel/sdk/resource"
+	sdktrace "go.opentelemetry.io/otel/sdk/trace"
+	semconv "go.opentelemetry.io/otel/semconv/v1.4.0"
+)
+
+const (
+	// ServiceName is trace service name
+	serviceName = "distribution"
+
+	// DefaultSamplingRatio default sample ratio
+	defaultSamplingRatio = 1
+)
+
+// InitOpenTelemetry initializes OpenTelemetry for the application. This function sets up the
+// necessary components for collecting telemetry data, such as traces.
+func InitOpenTelemetry(ctx context.Context) error {
+	res := resource.NewWithAttributes(
+		semconv.SchemaURL,
+		semconv.ServiceNameKey.String(serviceName),
+		semconv.ServiceVersionKey.String(version.Version),
+	)
+
+	exp, err := autoexport.NewSpanExporter(ctx)
+	if err != nil {
+		return err
+	}
+
+	sp := sdktrace.NewBatchSpanProcessor(exp)
+	provider := sdktrace.NewTracerProvider(
+		sdktrace.WithSampler(sdktrace.TraceIDRatioBased(defaultSamplingRatio)),
+		sdktrace.WithResource(res),
+		sdktrace.WithSpanProcessor(sp),
+	)
+	otel.SetTracerProvider(provider)
+
+	pr := propagation.NewCompositeTextMapPropagator(propagation.TraceContext{}, propagation.Baggage{})
+	otel.SetTextMapPropagator(pr)
+
+	return nil
+}