snapshot of https://github.com/ThreeDotsLabs/watermill.git (master, 2026-09-15; blobs > 131072B omitted)

components/metrics/http.go

@@ -0,0 +1,41 @@
+package metrics
+
+import (
+	"errors"
+	"net/http"
+
+	"github.com/go-chi/chi/v5"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+// CreateRegistryAndServeHTTP establishes an HTTP server that exposes the /metrics endpoint for Prometheus at the given address.
+// It returns a new prometheus registry (to register the metrics on) and a canceling function that ends the server.
+func CreateRegistryAndServeHTTP(addr string) (registry *prometheus.Registry, cancel func()) {
+	registry = prometheus.NewRegistry()
+	return registry, ServeHTTP(addr, registry)
+}
+
+// ServeHTTP establishes an HTTP server that exposes the /metrics endpoint for Prometheus at the given address.
+// It takes an existing Prometheus registry and returns a canceling function that ends the server.
+func ServeHTTP(addr string, registry *prometheus.Registry) (cancel func()) {
+	router := chi.NewRouter()
+
+	handler := promhttp.HandlerFor(registry, promhttp.HandlerOpts{})
+	router.Get("/metrics", func(w http.ResponseWriter, r *http.Request) {
+		handler.ServeHTTP(w, r)
+	})
+	server := http.Server{
+		Addr:    addr,
+		Handler: router,
+	}
+
+	go func() {
+		err := server.ListenAndServe()
+		if !errors.Is(err, http.ErrServerClosed) {
+			panic(err)
+		}
+	}()
+
+	return func() { _ = server.Close() }
+}