Added a custom auth counter to prometheus metrics (#2690)

* added basic auth and prom client dependencies

* incrementing auth counter

* added custom prometheus metric

* turns out there is no need for basic auth

* updated name

* exact

* exact

backend/middlewares/auth.ts

@@ -5,6 +5,7 @@ import { verifyIdToken } from "../utils/auth";
 import { base64UrlDecode } from "../utils/misc";
 import { NextFunction, Response, Handler } from "express";
 import statuses from "../constants/monkey-status-codes";
+import { incrementAuth } from "../utils/prometheus";
 
 interface RequestAuthenticationOptions {
   isPublic?: boolean;
@@ -38,7 +39,11 @@ function authenticateRequest(authOptions = DEFAULT_OPTIONS): Handler {
           options
         );
       } else if (options.isPublic) {
-        return next();
+        token = {
+          type: "None",
+          uid: "",
+          email: "",
+        };
       } else if (process.env.MODE === "dev") {
         token = authenticateWithBody(req.body);
       } else {
@@ -49,6 +54,8 @@ function authenticateRequest(authOptions = DEFAULT_OPTIONS): Handler {
         );
       }
 
+      incrementAuth(token.type);
+
       req.ctx = {
         ...req.ctx,
         decodedToken: token,

backend/utils/prometheus.ts

@@ -0,0 +1,12 @@
+import "dotenv/config";
+import { Counter } from "prom-client";
+
+const auth = new Counter({
+  name: "api_request_auth_total",
+  help: "Counts authentication events",
+  labelNames: ["type"],
+});
+
+export function incrementAuth(type: "Bearer" | "ApeKey" | "None"): void {
+  auth.inc({ type });
+}