From 2e8c58365fe64592eedc12f0ad9ae11b8e66ce36 Mon Sep 17 00:00:00 2001
From: Miodec <jack@monkeytype.com>
Date: Tue, 25 Jul 2023 15:46:46 +0200
Subject: [PATCH] sending client version in headers logging which client
 versions are getting errors closes #4475

---
 backend/src/middlewares/error.ts              |  5 +++++
 backend/src/utils/prometheus.ts               | 10 ++++++++++
 frontend/src/ts/ape/adapters/axios-adapter.ts |  2 ++
 3 files changed, 17 insertions(+)

diff --git a/backend/src/middlewares/error.ts b/backend/src/middlewares/error.ts
index 85cef8165..5b93d7c97 100644
--- a/backend/src/middlewares/error.ts
+++ b/backend/src/middlewares/error.ts
@@ -5,6 +5,7 @@ import MonkeyError from "../utils/error";
 import { incrementBadAuth } from "./rate-limit";
 import { NextFunction, Response } from "express";
 import { MonkeyResponse, handleMonkeyResponse } from "../utils/monkey-response";
+import { recordClientErrorByVersion } from "../utils/prometheus";
 
 async function errorHandlingMiddleware(
   error: Error,
@@ -37,6 +38,10 @@ async function errorHandlingMiddleware(
 
     await incrementBadAuth(req, res, monkeyResponse.status);
 
+    if (monkeyResponse.status >= 400 && monkeyResponse.status < 500) {
+      recordClientErrorByVersion(req.headers["x-client-version"] as string);
+    }
+
     if (process.env.MODE !== "dev" && monkeyResponse.status >= 500) {
       const { uid, errorId } = monkeyResponse.data;
 
diff --git a/backend/src/utils/prometheus.ts b/backend/src/utils/prometheus.ts
index a2f516855..afee67b2d 100644
--- a/backend/src/utils/prometheus.ts
+++ b/backend/src/utils/prometheus.ts
@@ -179,6 +179,16 @@ export function recordServerVersion(serverVersion: string): void {
   serverVersionCounter.inc({ version: serverVersion });
 }
 
+const clientErrorByVersion = new Counter({
+  name: "api_client_error_by_version",
+  help: "Client versions which are experiencing 400 errors",
+  labelNames: ["version"],
+});
+
+export function recordClientErrorByVersion(version: string): void {
+  clientErrorByVersion.inc({ version });
+}
+
 const authTime = new Histogram({
   name: "api_request_auth_time",
   help: "Time spent authenticating",
diff --git a/frontend/src/ts/ape/adapters/axios-adapter.ts b/frontend/src/ts/ape/adapters/axios-adapter.ts
index c5837013b..8f2e7ed5d 100644
--- a/frontend/src/ts/ape/adapters/axios-adapter.ts
+++ b/frontend/src/ts/ape/adapters/axios-adapter.ts
@@ -1,6 +1,7 @@
 import { Auth } from "../../firebase";
 import { getIdToken } from "firebase/auth";
 import axios, { AxiosRequestConfig, AxiosResponse } from "axios";
+import { CLIENT_VERSION } from "../../version";
 
 type AxiosClientMethod = (
   endpoint: string,
@@ -27,6 +28,7 @@ async function adaptRequestOptions(
       Accept: "application/json",
       "Content-Type": "application/json",
       ...(idToken && { Authorization: `Bearer ${idToken}` }),
+      "X-Client-Version": CLIENT_VERSION,
     },
   };
 }