Add route identifiers for easy metric reporting (#173)

Pre-requisite for https://github.com/matrix-org/matrix-public-archive/issues/162 and https://github.com/matrix-org/matrix-public-archive/issues/148

server/middleware/identify-route-middleware.js

@@ -0,0 +1,11 @@
+'use strict';
+
+// via https://gitlab.com/gitterHQ/env/-/blob/2a184afea5dc5f4db478d651b3597001474ee932/lib/middlewares/identify-route.js
+function identifyRouteMiddleware(routeName) {
+  return function identifyRoute(req, res, next) {
+    req.routeIdentifier = routeName;
+    next();
+  };
+}
+
+module.exports = identifyRouteMiddleware;

server/routes/install-routes.js

@@ -7,10 +7,11 @@ const asyncHandler = require('../lib/express-async-handler');
 
 const { handleTracingMiddleware } = require('../tracing/tracing-middleware');
 const getVersionTags = require('../lib/get-version-tags');
-const preventClickjackingMiddleware = require('./prevent-clickjacking-middleware');
-const contentSecurityPolicyMiddleware = require('./content-security-policy-middleware');
+const preventClickjackingMiddleware = require('../middleware/prevent-clickjacking-middleware');
+const contentSecurityPolicyMiddleware = require('../middleware/content-security-policy-middleware');
+const identifyRoute = require('../middleware/identify-route-middleware');
 const clientSideRoomAliasHashRedirectRoute = require('./client-side-room-alias-hash-redirect-route');
-const redirectToCorrectArchiveUrlIfBadSigil = require('./redirect-to-correct-archive-url-if-bad-sigil-middleware');
+const redirectToCorrectArchiveUrlIfBadSigil = require('../middleware/redirect-to-correct-archive-url-if-bad-sigil-middleware');
 
 function installRoutes(app) {
   app.use(handleTracingMiddleware);
@@ -21,6 +22,7 @@ function installRoutes(app) {
   let healthCheckResponse;
   app.get(
     '/health-check',
+    identifyRoute('health-check'),
     asyncHandler(async function (req, res) {
       if (!healthCheckResponse) {
         const versionTags = await getVersionTags();
@@ -71,11 +73,19 @@ function installRoutes(app) {
   // Since everything after the hash (`#`) won't make it to the server, let's serve a 404
   // page that will potentially redirect them to the correct place if they tried
   // `/r/#room-alias:server/date/2022/10/27` -> `/r/room-alias:server/date/2022/10/27`
-  app.use('/:entityDescriptor(r|roomid)', clientSideRoomAliasHashRedirectRoute);
+  app.get(
+    '/:entityDescriptor(r|roomid)',
+    identifyRoute('client-side-room-alias-hash-redirect'),
+    clientSideRoomAliasHashRedirectRoute
+  );
 
   // Correct any honest mistakes: If someone accidentally put the sigil in the URL, then
   // redirect them to the correct URL without the sigil to the correct path above.
-  app.use('/:roomIdOrAliasDirty', redirectToCorrectArchiveUrlIfBadSigil);
+  app.get(
+    '/:roomIdOrAliasDirty',
+    identifyRoute('redirect-to-correct-archive-url-if-bad-sigil'),
+    redirectToCorrectArchiveUrlIfBadSigil
+  );
 }
 
 module.exports = installRoutes;

server/routes/room-directory-routes.js

@@ -6,6 +6,7 @@ const urlJoin = require('url-join');
 const express = require('express');
 const asyncHandler = require('../lib/express-async-handler');
 
+const identifyRoute = require('../middleware/identify-route-middleware');
 const fetchPublicRooms = require('../lib/matrix-utils/fetch-public-rooms');
 const renderHydrogenVmRenderScriptToPageHtml = require('../hydrogen-render/render-hydrogen-vm-render-script-to-page-html');
 const setHeadersToPreloadAssets = require('../lib/set-headers-to-preload-assets');
@@ -29,6 +30,7 @@ const router = express.Router({
 
 router.get(
   '/',
+  identifyRoute('app-room-directory-index'),
   asyncHandler(async function (req, res) {
     const paginationToken = req.query.page;
     const searchTerm = req.query.search;

server/routes/room-routes.js

@@ -7,8 +7,9 @@ const express = require('express');
 const asyncHandler = require('../lib/express-async-handler');
 const StatusError = require('../lib/status-error');
 
-const timeoutMiddleware = require('./timeout-middleware');
-const redirectToCorrectArchiveUrlIfBadSigil = require('./redirect-to-correct-archive-url-if-bad-sigil-middleware');
+const timeoutMiddleware = require('../middleware/timeout-middleware');
+const redirectToCorrectArchiveUrlIfBadSigil = require('../middleware/redirect-to-correct-archive-url-if-bad-sigil-middleware');
+const identifyRoute = require('../middleware/identify-route-middleware');
 
 const { HTTPResponseError } = require('../lib/fetch-endpoint');
 const parseViaServersFromUserInput = require('../lib/parse-via-servers-from-user-input');
@@ -167,6 +168,7 @@ router.use(redirectToCorrectArchiveUrlIfBadSigil);
 
 router.get(
   '/',
+  identifyRoute('app-archive-room-index'),
   asyncHandler(async function (req, res) {
     const roomIdOrAlias = getRoomIdOrAliasFromReq(req);
 
@@ -208,6 +210,7 @@ router.get(
 
 router.get(
   '/event/:eventId',
+  identifyRoute('app-archive-room-event'),
   asyncHandler(async function (req, res) {
     // TODO: Fetch event to get `origin_server_ts` and redirect to
     // /!roomId/2022/01/01?at=$eventId
@@ -217,6 +220,7 @@ router.get(
 
 router.get(
   '/jump',
+  identifyRoute('app-archive-room-jump'),
   // eslint-disable-next-line max-statements, complexity
   asyncHandler(async function (req, res) {
     const roomIdOrAlias = getRoomIdOrAliasFromReq(req);
@@ -726,6 +730,7 @@ router.get(
   // `path-to-regex` bug where the `?` wasn't attaching to the capture group, see
   // https://github.com/pillarjs/path-to-regexp/issues/287
   '/date/:yyyy(\\d{4})/:mm(\\d{2})/:dd(\\d{2}):time(T\\d\\d?:\\d\\d?((:\\d\\d?)?))?',
+  identifyRoute('app-archive-room-date'),
   timeoutMiddleware,
   // eslint-disable-next-line max-statements, complexity
   asyncHandler(async function (req, res) {