Merge current v3.1 into master

pkg/config/static/static_config.go

@@ -212,6 +212,9 @@ type Tracing struct {
 func (t *Tracing) SetDefaults() {
 	t.ServiceName = "traefik"
 	t.SampleRate = 1.0
+
+	t.OTLP = &opentelemetry.Config{}
+	t.OTLP.SetDefaults()
 }
 
 // Providers contains providers configuration.

pkg/middlewares/capture/capture.go

@@ -43,9 +43,21 @@ const capturedData key = "capturedData"
 // It satisfies the alice.Constructor type.
 func Wrap(next http.Handler) (http.Handler, error) {
 	return http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
-		c := &Capture{}
-		newRW, newReq := c.renew(rw, req)
-		next.ServeHTTP(newRW, newReq)
+		capt, err := FromContext(req.Context())
+		if err != nil {
+			c := &Capture{}
+			newRW, newReq := c.renew(rw, req)
+			next.ServeHTTP(newRW, newReq)
+			return
+		}
+
+		if capt.NeedsReset(rw) {
+			newRW, newReq := capt.renew(rw, req)
+			next.ServeHTTP(newRW, newReq)
+			return
+		}
+
+		next.ServeHTTP(rw, req)
 	}), nil
 }
 

pkg/server/service/service.go

@@ -22,6 +22,7 @@ import (
 	"github.com/traefik/traefik/v3/pkg/healthcheck"
 	"github.com/traefik/traefik/v3/pkg/logs"
 	"github.com/traefik/traefik/v3/pkg/middlewares/accesslog"
+	"github.com/traefik/traefik/v3/pkg/middlewares/capture"
 	metricsMiddle "github.com/traefik/traefik/v3/pkg/middlewares/metrics"
 	"github.com/traefik/traefik/v3/pkg/middlewares/observability"
 	"github.com/traefik/traefik/v3/pkg/safe"
@@ -372,6 +373,17 @@ func (m *Manager) getLoadBalancerServiceHandler(ctx context.Context, serviceName
 			proxy = observability.NewService(ctx, serviceName, proxy)
 		}
 
+		if m.observabilityMgr.ShouldAddAccessLogs(qualifiedSvcName) || m.observabilityMgr.ShouldAddMetrics(qualifiedSvcName) {
+			// Some piece of middleware, like the ErrorPage, are relying on this serviceBuilder to get the handler for a given service,
+			// to re-target the request to it.
+			// Those pieces of middleware can be configured on routes that expose a Traefik internal service.
+			// In such a case, observability for internals being optional, the capture probe could be absent from context (no wrap via the entrypoint).
+			// But if the service targeted by this piece of middleware is not an internal one,
+			// and requires observability, we still want the capture probe to be present in the request context.
+			// Makes sure a capture probe is in the request context.
+			proxy, _ = capture.Wrap(proxy)
+		}
+
 		lb.Add(proxyName, proxy, server.Weight)
 
 		// servers are considered UP by default.