add Prometheus support

some basic counters and gauges are now exposed

api/router.go

@@ -9,6 +9,7 @@ import (
 	"github.com/go-chi/chi"
 	"github.com/go-chi/chi/middleware"
 	"github.com/go-chi/render"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
 // GetHTTPRouter returns the configured HTTP handler
@@ -31,6 +32,8 @@ func initializeRouter() {
 		sendAPIResponse(w, r, nil, "Method not allowed", http.StatusMethodNotAllowed)
 	}))
 
+	router.Handle(metricsPath, promhttp.Handler())
+
 	router.Get(versionPath, func(w http.ResponseWriter, r *http.Request) {
 		render.JSON(w, r, utils.GetAppVersion())
 	})