feat(otelecho): add HTTP server metrics support for echo instrumentation

CHANGELOG.md

@@ -20,6 +20,7 @@ The next release will require at least [Go 1.24].
 - Add the `WithLoggerProviderOptions`, `WithMeterProviderOptions` and `WithTracerProviderOptions` options to `NewSDK` to allow passing custom options to providers in `go.opentelemetry.io/contrib/otelconf`. (#7552)
 - Added V2 version of AWS EC2 detector `go.opentelemetry.io/contrib/detectors/aws/ec2/v2` due to deprecation of `github.com/aws/aws-sdk-go`. (#6961)
 - Support testing of [Go 1.25]. (#7732)
+- Add support for HTTP server metrics in `go.opentelemetry.io/contrib/instrumentation/github.com/labstack/echo/otelecho`. (#7668)
 
 ### Changed
 

instrumentation/github.com/labstack/echo/otelecho/config.go

@@ -4,18 +4,34 @@
 package otelecho // import "go.opentelemetry.io/contrib/instrumentation/github.com/labstack/echo/otelecho"
 
 import (
+	"net/http"
+
+	"github.com/labstack/echo/v4"
 	"github.com/labstack/echo/v4/middleware"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/metric"
 	"go.opentelemetry.io/otel/propagation"
 	oteltrace "go.opentelemetry.io/otel/trace"
 )
 
 // config is used to configure the mux middleware.
 type config struct {
-	TracerProvider oteltrace.TracerProvider
-	Propagators    propagation.TextMapPropagator
-	Skipper        middleware.Skipper
+	TracerProvider        oteltrace.TracerProvider
+	MeterProvider         metric.MeterProvider
+	Propagators           propagation.TextMapPropagator
+	Skipper               middleware.Skipper
+	MetricAttributeFn     MetricAttributeFn
+	EchoMetricAttributeFn EchoMetricAttributeFn
 }
 
+// MetricAttributeFn is used to extract additional attributes from the http.Request
+// and return them as a slice of attribute.KeyValue.
+type MetricAttributeFn func(*http.Request) []attribute.KeyValue
+
+// EchoMetricAttributeFn is used to extract additional attributes from the echo.Context
+// and return them as a slice of attribute.KeyValue.
+type EchoMetricAttributeFn func(echo.Context) []attribute.KeyValue
+
 // Option specifies instrumentation configuration options.
 type Option interface {
 	apply(*config)
@@ -38,6 +54,16 @@ func WithPropagators(propagators propagation.TextMapPropagator) Option {
 	})
 }
 
+// WithMeterProvider specifies a meter provider to use for creating a meter.
+// If none is specified, the global provider is used.
+func WithMeterProvider(provider metric.MeterProvider) Option {
+	return optionFunc(func(cfg *config) {
+		if provider != nil {
+			cfg.MeterProvider = provider
+		}
+	})
+}
+
 // WithTracerProvider specifies a tracer provider to use for creating a tracer.
 // If none is specified, the global provider is used.
 func WithTracerProvider(provider oteltrace.TracerProvider) Option {
@@ -54,3 +80,23 @@ func WithSkipper(skipper middleware.Skipper) Option {
 		cfg.Skipper = skipper
 	})
 }
+
+// WithMetricAttributeFn specifies a function that extracts additional attributes from the http.Request
+// and returns them as a slice of attribute.KeyValue.
+//
+// If attributes are duplicated between this method and `WithEchoMetricAttributeFn`, the attributes in this method will be overridden.
+func WithMetricAttributeFn(f MetricAttributeFn) Option {
+	return optionFunc(func(cfg *config) {
+		cfg.MetricAttributeFn = f
+	})
+}
+
+// WithEchoMetricAttributeFn specifies a function that extracts additional attributes from the echo.Context
+// and returns them as a slice of attribute.KeyValue.
+//
+// If attributes are duplicated between this method and `WithMetricAttributeFn`, the attributes in this method will be used.
+func WithEchoMetricAttributeFn(f EchoMetricAttributeFn) Option {
+	return optionFunc(func(cfg *config) {
+		cfg.EchoMetricAttributeFn = f
+	})
+}

instrumentation/github.com/labstack/echo/otelecho/echo.go

@@ -7,11 +7,13 @@ import (
 	"net/http"
 	"slices"
 	"strings"
+	"time"
 
 	"github.com/labstack/echo/v4"
 	"github.com/labstack/echo/v4/middleware"
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/metric"
 	"go.opentelemetry.io/otel/propagation"
 	oteltrace "go.opentelemetry.io/otel/trace"
 
@@ -40,15 +42,23 @@ func Middleware(service string, opts ...Option) echo.MiddlewareFunc {
 	if cfg.Propagators == nil {
 		cfg.Propagators = otel.GetTextMapPropagator()
 	}
-
+	if cfg.MeterProvider == nil {
+		cfg.MeterProvider = otel.GetMeterProvider()
+	}
 	if cfg.Skipper == nil {
 		cfg.Skipper = middleware.DefaultSkipper
 	}
 
-	semconvSrv := semconv.NewHTTPServer(nil)
+	meter := cfg.MeterProvider.Meter(
+		ScopeName,
+		metric.WithInstrumentationVersion(Version()),
+	)
+
+	semconvSrv := semconv.NewHTTPServer(meter)
 
 	return func(next echo.HandlerFunc) echo.HandlerFunc {
 		return func(c echo.Context) error {
+			requestStartTime := time.Now()
 			if cfg.Skipper(c) {
 				return next(c)
 			}
@@ -91,8 +101,35 @@ func Middleware(service string, opts ...Option) echo.MiddlewareFunc {
 			span.SetStatus(semconvSrv.Status(status))
 			span.SetAttributes(semconvSrv.ResponseTraceAttrs(semconv.ResponseTelemetry{
 				StatusCode: status,
+				WriteBytes: c.Response().Size,
 			})...)
 
+			// Record the server-side attributes.
+			var additionalAttributes []attribute.KeyValue
+			if path := c.Path(); path != "" {
+				additionalAttributes = append(additionalAttributes, semconvSrv.Route(path))
+			}
+			if cfg.MetricAttributeFn != nil {
+				additionalAttributes = append(additionalAttributes, cfg.MetricAttributeFn(request)...)
+			}
+			if cfg.EchoMetricAttributeFn != nil {
+				additionalAttributes = append(additionalAttributes, cfg.EchoMetricAttributeFn(c)...)
+			}
+
+			semconvSrv.RecordMetrics(ctx, semconv.ServerMetricData{
+				ServerName:   service,
+				ResponseSize: c.Response().Size,
+				MetricAttributes: semconv.MetricAttributes{
+					Req:                  request,
+					StatusCode:           status,
+					AdditionalAttributes: additionalAttributes,
+				},
+				MetricData: semconv.MetricData{
+					RequestSize: request.ContentLength,
+					ElapsedTime: float64(time.Since(requestStartTime)) / float64(time.Millisecond),
+				},
+			})
+
 			return err
 		}
 	}