Move metrics.StartRequest to middleware && Fix Datadog

CHANGELOG.md

@@ -4,6 +4,9 @@
 ### Added
 - (pro) Add `video_meta` to the `/info` response.
 
+### Fix
+- Fix Datadog support.
+
 ## [3.1.3] - 2021-12-17
 ### Fix
 - Fix ETag checking when S3 is used.

metrics/datadog/datadog.go

@@ -34,6 +34,8 @@ func Init() {
 		tracer.WithServiceVersion(version.Version()),
 		tracer.WithLogger(dataDogLogger{}),
 	)
+
+	enabled = true
 }
 
 func Stop() {
@@ -42,6 +44,10 @@ func Stop() {
 	}
 }
 
+func Enabled() bool {
+	return enabled
+}
+
 func StartRootSpan(ctx context.Context, rw http.ResponseWriter, r *http.Request) (context.Context, context.CancelFunc, http.ResponseWriter) {
 	if !enabled {
 		return ctx, func() {}, rw

metrics/metrics.go

@@ -26,6 +26,12 @@ func Stop() {
 	datadog.Stop()
 }
 
+func Enabled() bool {
+	return prometheus.Enabled() ||
+		newrelic.Enabled() ||
+		datadog.Enabled()
+}
+
 func StartRequest(ctx context.Context, rw http.ResponseWriter, r *http.Request) (context.Context, context.CancelFunc, http.ResponseWriter) {
 	promCancel := prometheus.StartRequest()
 	ctx, nrCancel, rw := newrelic.StartTransaction(ctx, rw, r)

metrics/newrelic/newrelic.go

@@ -44,6 +44,10 @@ func Init() error {
 	return nil
 }
 
+func Enabled() bool {
+	return enabled
+}
+
 func StartTransaction(ctx context.Context, rw http.ResponseWriter, r *http.Request) (context.Context, context.CancelFunc, http.ResponseWriter) {
 	if !enabled {
 		return ctx, func() {}, rw

metrics/prometheus/prometheus.go

@@ -95,6 +95,10 @@ func Init() {
 	enabled = true
 }
 
+func Enabled() bool {
+	return enabled
+}
+
 func StartServer(cancel context.CancelFunc) error {
 	if !enabled {
 		return nil

processing_handler.go

@@ -137,8 +137,7 @@ func respondWithNotModified(reqID string, r *http.Request, rw http.ResponseWrite
 }
 
 func handleProcessing(reqID string, rw http.ResponseWriter, r *http.Request) {
-	ctx, metricsCancel, rw := metrics.StartRequest(r.Context(), rw, r)
+	ctx := r.Context()
-	defer metricsCancel()
 
 	path := r.RequestURI
 	if queryStart := strings.IndexByte(path, '?'); queryStart >= 0 {

server.go

@@ -13,6 +13,7 @@ import (
 	"github.com/imgproxy/imgproxy/v3/config"
 	"github.com/imgproxy/imgproxy/v3/errorreport"
 	"github.com/imgproxy/imgproxy/v3/ierrors"
+	"github.com/imgproxy/imgproxy/v3/metrics"
 	"github.com/imgproxy/imgproxy/v3/reuseport"
 	"github.com/imgproxy/imgproxy/v3/router"
 )
@@ -29,7 +30,7 @@ func buildRouter() *router.Router {
 	r.GET("/", handleLanding, true)
 	r.GET("/health", handleHealth, true)
 	r.GET("/favicon.ico", handleFavicon, true)
-	r.GET("/", withCORS(withPanicHandler(withSecret(handleProcessing))), false)
+	r.GET("/", withMetrics(withPanicHandler(withCORS(withSecret(handleProcessing)))), false)
 	r.HEAD("/", withCORS(handleHead), false)
 	r.OPTIONS("/", withCORS(handleHead), false)
 
@@ -75,6 +76,19 @@ func shutdownServer(s *http.Server) {
 	s.Shutdown(ctx)
 }
 
+func withMetrics(h router.RouteHandler) router.RouteHandler {
+	if !metrics.Enabled() {
+		return h
+	}
+
+	return func(reqID string, rw http.ResponseWriter, r *http.Request) {
+		ctx, metricsCancel, rw := metrics.StartRequest(r.Context(), rw, r)
+		defer metricsCancel()
+
+		h(reqID, rw, r.WithContext(ctx))
+	}
+}
+
 func withCORS(h router.RouteHandler) router.RouteHandler {
 	return func(reqID string, rw http.ResponseWriter, r *http.Request) {
 		if len(config.AllowOrigin) > 0 {