Basic performance metrics

src/fetch.ts

@@ -6,6 +6,12 @@ import { isGraphQLTweet } from './utils/graphql';
 const API_ATTEMPTS = 3;
 let wasElongatorDisabled = false;
 
+declare const globalThis: {
+  fetchCompletedTime: number;
+}
+
+globalThis.fetchCompletedTime = 0;
+
 export const twitterFetch = async (
   url: string,
   event: FetchEvent,
@@ -155,6 +161,8 @@ export const twitterFetch = async (
       continue;
     }
 
+    globalThis.fetchCompletedTime = performance.now();
+
     if (
       !wasElongatorDisabled &&
       !useElongator &&

src/server.ts

@@ -1,3 +1,4 @@
+/* eslint-disable no-case-declarations */
 import Toucan from 'toucan-js';
 
 import { IRequest, Router } from 'itty-router';
@@ -9,6 +10,10 @@ import motd from '../motd.json';
 import { sanitizeText } from './helpers/utils';
 import { handleProfile } from './user';
 
+declare const globalThis: {
+  fetchCompletedTime: number;
+}
+
 const router = Router();
 
 /* Handler for status (Tweet) request */
@@ -153,6 +158,7 @@ const statusRequest = async (
       });
     }
   } else {
+    globalThis.fetchCompletedTime = performance.now();
     /* A human has clicked a fxtwitter.com/:screen_name/status/:id link!
        Obviously we just need to redirect to the Tweet directly.*/
     console.log('Matched human UA', userAgent);
@@ -251,6 +257,7 @@ const genericTwitterRedirect = async (request: IRequest) => {
 };
 
 const versionRequest = async (request: IRequest) => {
+  globalThis.fetchCompletedTime = performance.now();
   return new Response(
     Strings.VERSION_HTML.format({
       rtt: request.cf?.clientTcpRtt ? `🏓 ${request.cf.clientTcpRtt} ms RTT` : '',
@@ -305,6 +312,7 @@ router.get('/version', versionRequest);
 
 Yes, I actually made the endpoint /owoembed. Deal with it. */
 router.get('/owoembed', async (request: IRequest) => {
+  globalThis.fetchCompletedTime = performance.now();
   console.log('oembed hit!');
   const { searchParams } = new URL(request.url);
 
@@ -368,6 +376,7 @@ export const cacheWrapper = async (
   request: Request,
   event?: FetchEvent
 ): Promise<Response> => {
+  const startTime = performance.now();
   const userAgent = request.headers.get('User-Agent') || '';
   // https://developers.cloudflare.com/workers/examples/cache-api/
   const cacheUrl = new URL(
@@ -427,8 +436,6 @@ export const cacheWrapper = async (
         console.log('Cache miss');
       }
 
-      /* Literally do not know what the hell eslint is complaining about */
-      // eslint-disable-next-line no-case-declarations
       const response = await router.handle(request, event);
 
       /* Store the fetched response as cacheKey
@@ -440,6 +447,11 @@ export const cacheWrapper = async (
         console.error((error as Error).stack);
       }
 
+      const endTime = performance.now();
+      const timeSinceFetch = endTime - (globalThis.fetchCompletedTime || 0);
+      const timeSinceStart = endTime - startTime;
+      console.log(`Request took ${timeSinceStart}ms, of which ${timeSinceFetch}ms was CPU time after last fetch`);
+
       return response;
     /* Telegram sends this from Webpage Bot, and Cloudflare sends it if we purge cache, and we respect it.
        PURGE is not defined in an RFC, but other servers like Nginx apparently use it. */