Add simple healthcheck handler

node/http.go

@@ -42,6 +42,12 @@ func newHTTPHandler(n *Node, icecastPort int, domain string) http.Handler {
 		Prefix:    "static",
 	})))
 
+	// Simple healthcheck handler.
+	mux.HandleFunc("/healthcheck", func(w http.ResponseWriter, _ *http.Request) {
+		w.Header().Set("Content-Type", "text/plain")
+		io.WriteString(w, "OK") //nolint
+	})
+
 	// Serve /debug/ pages using the default HTTP handler
 	// (packages will automatically register their debug handlers
 	// there). Using command-line flags it is possible to disable