Trace discovery API requests and enrich request logs

Co-Authored-By: Claude <noreply@anthropic.com>

docs/plans-executions/2026-08-24-1025-otel-tracing.md

@@ -7,7 +7,7 @@ Plan: `docs/plans/2026-08-24-1025-otel-tracing.md`
 - [x] Step 3 — `provider.WithTracing` decorator
 - [x] Step 4 — `cmd/main.go` wiring
 - [x] Step 5 — Reconciler spans
-- [ ] Step 6 — Discovery server
+- [x] Step 6 — Discovery server
 - [ ] Step 7 — GC + health
 - [ ] Step 8 — GCP wire-log enrichment
 - [ ] Step 9 — Manifests + docs
@@ -118,3 +118,18 @@ span's content — a real PATCH shows up as its k8s HTTP child). Tests that
 call `r.Reconcile` directly bypass the wrapper; with no global tracer set
 they see no-op spans, so the existing fake-client and envtest suites run
 unchanged.
+
+## Step 6 — Discovery server
+
+Middleware chain is now recover → tracing (server span + request logger) →
+request-log → body cap → auth; the request-log middleware and the three
+handler error sites log via `logf.FromContext(r.Context())` — which is
+`s.log` enriched with the request's traceID/spanID by the tracing
+middleware, not a different logger (logr sinks can't read ctx at log time,
+so per-request values must ride on the logger instance in the ctx; user
+asked, answered in-session).
+
+Deviation from the plan's letter: `recoverMiddleware` keeps `s.log`. It sits
+*outside* the tracing layer, so its request ctx never has the enriched
+logger — switching it to `FromContext` would silently drop the `"discovery"`
+name and gain nothing.

internal/discovery/handlers.go

@@ -11,6 +11,7 @@ import (
 
 	apimeta "k8s.io/apimachinery/pkg/api/meta"
 	"sigs.k8s.io/controller-runtime/pkg/client"
+	logf "sigs.k8s.io/controller-runtime/pkg/log"
 
 	crawlv1alpha1 "gitea.home.hrajfrisbee.cz/kacerr/egress-proxies-operator/api/v1alpha1"
 	"gitea.home.hrajfrisbee.cz/kacerr/egress-proxies-operator/internal/lease"
@@ -82,7 +83,10 @@ func (s *Server) handleListProxies(w http.ResponseWriter, r *http.Request) {
 
 	var list crawlv1alpha1.ProxyList
 	if err := s.Reader.List(r.Context(), &list); err != nil {
-		s.log.Error(err, "listing proxies")
+		// The ctx logger is s.log enriched with this request's
+		// traceID/spanID by the tracing middleware (logr sinks can't read
+		// ctx at log time, so per-request values ride on the logger).
+		logf.FromContext(r.Context()).Error(err, "listing proxies")
 		writeError(w, http.StatusInternalServerError, "internal", "listing proxies failed")
 		return
 	}
@@ -138,7 +142,7 @@ func (s *Server) handleAcquireLease(w http.ResponseWriter, r *http.Request) {
 
 	var list crawlv1alpha1.ProxyList
 	if err := s.Reader.List(r.Context(), &list); err != nil {
-		s.log.Error(err, "listing proxies for lease")
+		logf.FromContext(r.Context()).Error(err, "listing proxies for lease")
 		writeError(w, http.StatusInternalServerError, "internal", "listing proxies failed")
 		return
 	}
@@ -231,7 +235,7 @@ func (s *Server) handleReportLease(w http.ResponseWriter, r *http.Request) {
 			writeError(w, http.StatusNotFound, "unknown_lease", "no such lease")
 			return
 		}
-		s.log.Error(err, "reporting lease", "leaseID", r.PathValue("id"))
+		logf.FromContext(r.Context()).Error(err, "reporting lease", "leaseID", r.PathValue("id"))
 		writeError(w, http.StatusInternalServerError, "internal", "report failed")
 		return
 	}

internal/discovery/server.go

@@ -20,6 +20,7 @@ import (
 	logf "sigs.k8s.io/controller-runtime/pkg/log"
 
 	"gitea.home.hrajfrisbee.cz/kacerr/egress-proxies-operator/internal/lease"
+	"gitea.home.hrajfrisbee.cz/kacerr/egress-proxies-operator/internal/tracing"
 )
 
 // LeaseStore is what the handlers need from a lease backend. Defined here,
@@ -136,7 +137,9 @@ func (s *Server) Start(ctx context.Context) error {
 }
 
 // handler assembles the mux and the middleware chain, outermost first:
-// recover → request-log → body-size cap → bearer auth.
+// recover → tracing (server span + request logger) → request-log →
+// body-size cap → bearer auth. Everything inside the tracing layer logs via
+// logf.FromContext(r.Context()) and so carries traceID/spanID.
 func (s *Server) handler() http.Handler {
 	mux := http.NewServeMux()
 	mux.HandleFunc("GET /healthz", func(w http.ResponseWriter, _ *http.Request) {
@@ -152,6 +155,7 @@ func (s *Server) handler() http.Handler {
 	h = s.authMiddleware(h)
 	h = maxBytesMiddleware(h)
 	h = s.logMiddleware(h)
+	h = tracing.HTTPMiddleware("discovery", s.log)(h)
 	h = s.recoverMiddleware(h)
 	return h
 }
@@ -188,7 +192,7 @@ func (s *Server) logMiddleware(next http.Handler) http.Handler {
 		rec := &statusRecorder{ResponseWriter: w, status: http.StatusOK}
 		start := time.Now()
 		next.ServeHTTP(rec, r)
-		s.log.Info("request",
+		logf.FromContext(r.Context()).Info("request",
 			"method", r.Method, "path", r.URL.Path,
 			"status", rec.status, "duration", time.Since(start).String())
 	})