cache archived enterproxy proxy responses much longer (github#23456)

* cache archived enterproxy proxy responses much longer

* Update middleware/archived-enterprise-versions.js

Co-authored-by: Rachael Sewell <rachmari@github.com>

Co-authored-by: Rachael Sewell <rachmari@github.com>

.github/actions-scripts/purge-fastly-edge-cache.js

@@ -2,10 +2,4 @@
 
 import purgeEdgeCache from '../../script/deployment/purge-edge-cache.js'
 
-try {
-  await purgeEdgeCache()
-} catch (error) {
-  console.error(`Failed to purge the edge cache: ${error.message}`)
-  console.error(error)
-  throw error
-}
+await purgeEdgeCache()

.github/workflows/prod-build-deploy.yml

@@ -178,7 +178,7 @@ jobs:
         env:
           FASTLY_TOKEN: ${{ secrets.FASTLY_TOKEN }}
           FASTLY_SERVICE_ID: ${{ secrets.FASTLY_SERVICE_ID }}
-          FASTLY_SURROGATE_KEY: 'all-the-things'
+          FASTLY_SURROGATE_KEY: 'every-deployment'
         run: .github/actions-scripts/purge-fastly-edge-cache.js
 
       - name: Send Slack notification if workflow failed

middleware/archived-enterprise-versions.js

@@ -9,6 +9,7 @@ import {
 import patterns from '../lib/patterns.js'
 import versionSatisfiesRange from '../lib/version-satisfies-range.js'
 import isArchivedVersion from '../lib/is-archived-version.js'
+import { setFastlySurrogateKey, SURROGATE_ENUMS } from './set-fastly-surrogate-key.js'
 import got from 'got'
 import { readCompressedJsonFileFallback } from '../lib/read-json-file.js'
 import { cacheControlFactory } from './cache-control.js'
@@ -55,6 +56,25 @@ const archivedFrontmatterFallbacks = readJsonFileLazily(
 
 const cacheControl = cacheControlFactory(60 * 60 * 24 * 365)
 
+// Combine all the things you need to make sure the response is
+// aggresively cached.
+const cacheAggressively = (res) => {
+  cacheControl(res)
+
+  // This sets a custom Fastly surrogate key so that this response
+  // won't get updated in every deployment.
+  // Essentially, this sets a surrogate key such that Fastly
+  // doesn't do soft-purges on these responses on every
+  // automated deployment.
+  setFastlySurrogateKey(res, SURROGATE_ENUMS.MANUAL)
+
+  // Because this middleware has (quite possibly) been executed before
+  // the CSRF middleware, that would have set a cookie. Remove that.
+  // The reason for removing the 'Set-Cookie' header is because
+  // otherwise Fastly won't cache it.
+  res.removeHeader('set-cookie')
+}
+
 // The way `got` does retries:
 //
 //   sleep = 1000 * Math.pow(2, retry - 1) + Math.random() * 100
@@ -119,7 +139,7 @@ export default async function archivedEnterpriseVersions(req, res, next) {
     // and memoized so calling it is cheap.
     const redirect = archivedRedirects()[req.path]
     if (redirect && redirect !== req.path) {
-      cacheControl(res)
+      cacheAggressively(res)
       return res.redirect(redirectCode, redirect)
     }
   }
@@ -138,7 +158,7 @@ export default async function archivedEnterpriseVersions(req, res, next) {
     // make redirects found via redirects.json redirect with a 301
     if (redirectJson[req.path]) {
       res.set('x-robots-tag', 'noindex')
-      cacheControl(res)
+      cacheAggressively(res)
       return res.redirect(redirectCode, redirectJson[req.path])
     }
   }
@@ -160,11 +180,14 @@ export default async function archivedEnterpriseVersions(req, res, next) {
     // make stubbed redirect files (which exist in versions <2.13) redirect with a 301
     const staticRedirect = r.body.match(patterns.staticRedirect)
     if (staticRedirect) {
-      cacheControl(res)
+      cacheAggressively(res)
       return res.redirect(redirectCode, staticRedirect[1])
     }
 
     res.set('content-type', r.headers['content-type'])
+
+    cacheAggressively(res)
+
     return res.send(r.body)
   }
 
@@ -181,7 +204,7 @@ export default async function archivedEnterpriseVersions(req, res, next) {
       `fallback:${fallbackRedirect}`,
     ])()
     if (r.statusCode === 200) {
-      cacheControl(res)
+      cacheAggressively(res)
       return res.redirect(redirectCode, fallbackRedirect)
     }
   }

middleware/index.js

@@ -14,7 +14,7 @@ import csrf from './csrf.js'
 import handleCsrfErrors from './handle-csrf-errors.js'
 import compression from 'compression'
 import disableCachingOnSafari from './disable-caching-on-safari.js'
-import setFastlySurrogateKey from './set-fastly-surrogate-key.js'
+import setDefaultFastlySurrogateKey from './set-fastly-surrogate-key.js'
 import setFastlyCacheHeaders from './set-fastly-cache-headers.js'
 import catchBadAcceptLanguage from './catch-bad-accept-language.js'
 import reqUtils from './req-utils.js'
@@ -84,7 +84,7 @@ export default function (app) {
   // Must appear before static assets and all other requests
   // otherwise we won't be able to benefit from that functionality
   // for static assets as well.
-  app.use(setFastlySurrogateKey)
+  app.use(setDefaultFastlySurrogateKey)
 
   // Must come before `csrf` otherwise you get a Set-Cookie on successful
   // asset requests. And it can come before `rateLimit` because if it's a

middleware/set-fastly-surrogate-key.js

@@ -1,12 +1,29 @@
-export default function setFastlySurrogateKey(req, res, next) {
-  // Fastly provides a Soft Purge feature that allows you to mark content as outdated (stale) instead of permanently
-  // purging and thereby deleting it from Fastly's caches. Objects invalidated with Soft Purge will be treated as
-  // outdated (stale) while Fastly fetches a new version from origin.
-  //
-  // Use of a surrogate key is required for soft purging
-  // https://docs.fastly.com/en/guides/soft-purges
-  // https://docs.fastly.com/en/guides/getting-started-with-surrogate-keys
-  res.set('surrogate-key', 'all-the-things')
+// Fastly provides a Soft Purge feature that allows you to mark content as outdated (stale) instead of permanently
+// purging and thereby deleting it from Fastly's caches. Objects invalidated with Soft Purge will be treated as
+// outdated (stale) while Fastly fetches a new version from origin.
+//
+// Use of a surrogate key is required for soft purging
+// https://docs.fastly.com/en/guides/soft-purges
+// https://docs.fastly.com/en/guides/getting-started-with-surrogate-keys
 
+// What the header needs to be called for Fastly to recognize it.
+const KEY = 'surrogate-key'
+
+export const SURROGATE_ENUMS = {
+  DEFAULT: 'every-deployment',
+  MANUAL: 'manual-purge',
+}
+
+export function setFastlySurrogateKey(res, enumKey) {
+  if (!Object.values(SURROGATE_ENUMS).includes(enumKey)) {
+    throw new Error(
+      `Unrecognizes surrogate enumKey. ${enumKey} is not one of ${Object.values(SURROGATE_ENUMS)}`
+    )
+  }
+  res.set(KEY, enumKey)
+}
+
+export default function setDefaultFastlySurrogateKey(req, res, next) {
+  res.set(KEY, SURROGATE_ENUMS.DEFAULT)
   return next()
 }

tests/rendering/server.js

@@ -5,6 +5,7 @@ import { describeViaActionsOnly } from '../helpers/conditional-runs.js'
 import { loadPages } from '../../lib/page-data.js'
 import CspParse from 'csp-parse'
 import { productMap } from '../../lib/all-products.js'
+import { SURROGATE_ENUMS } from '../../middleware/set-fastly-surrogate-key.js'
 import { jest } from '@jest/globals'
 
 const AZURE_STORAGE_URL = 'githubdocs.azureedge.net'
@@ -137,7 +138,7 @@ describe('server', () => {
     const res = await get('/en')
     expect(res.headers['cache-control']).toBe('private, no-store')
     expect(res.headers['surrogate-control']).toBe('private, no-store')
-    expect(res.headers['surrogate-key']).toBe('all-the-things')
+    expect(res.headers['surrogate-key']).toBe(SURROGATE_ENUMS.DEFAULT)
   })
 
   test('does not render duplicate <html> or <body> tags', async () => {

tests/routing/deprecated-enterprise-versions.js

@@ -1,6 +1,7 @@
 import createApp from '../../lib/app.js'
 import enterpriseServerReleases from '../../lib/enterprise-server-releases.js'
 import { get, getDOM } from '../helpers/supertest.js'
+import { SURROGATE_ENUMS } from '../../middleware/set-fastly-surrogate-key.js'
 import supertest from 'supertest'
 import { jest } from '@jest/globals'
 
@@ -54,10 +55,12 @@ describe('enterprise deprecation', () => {
     expect($('h1').text()).toBe('About branches')
   })
 
-  test('sets the expected x-robots-tag header for deprecated Enterprise pages', async () => {
+  test('sets the expected headers for deprecated Enterprise pages', async () => {
     const res = await get('/en/enterprise/2.13/user/articles/about-branches')
     expect(res.statusCode).toBe(200)
     expect(res.get('x-robots-tag')).toBe('noindex')
+    expect(res.get('surrogate-key')).toBe(SURROGATE_ENUMS.MANUAL)
+    expect(res.get('set-cookie')).toBeUndefined()
   })
 
   test('handles requests for deprecated Enterprise pages ( <2.13 )', async () => {