cache changelog feed in CI (#25759)

* cache changelog feed in CI

* unbreak unit tests

* feedbacked

Co-authored-by: Robert Sese <rsese@github.com>

Author: peterbe

.github/workflows/test.yml

@@ -135,4 +135,5 @@ jobs:
       - name: Run tests
         env:
           DIFF_FILE: get_diff_files.txt
+          CHANGELOG_CACHE_FILE_PATH: tests/fixtures/changelog-feed.json
         run: npm test -- tests/${{ matrix.test-group }}/

lib/changelog.js

@@ -4,6 +4,8 @@ import path from 'path'
 
 import Parser from 'rss-parser'
 
+const CHANGELOG_CACHE_FILE_PATH = process.env.CHANGELOG_CACHE_FILE_PATH
+
 async function getRssFeed(url) {
   const parser = new Parser({ timeout: 5000 })
   const feedUrl = `${url}/feed`
@@ -19,9 +21,11 @@ async function getRssFeed(url) {
   return feed
 }
 
-export async function getChangelogItems(prefix, feedUrl) {
-  const fromCache = getChangelogItemsFromCache(prefix, feedUrl)
-  if (fromCache) return fromCache
+export async function getChangelogItems(prefix, feedUrl, ignoreCache = false) {
+  if (!ignoreCache) {
+    const fromCache = getChangelogItemsFromCache(prefix, feedUrl)
+    if (fromCache) return fromCache
+  }
 
   const feed = await getRssFeed(feedUrl)
 
@@ -62,6 +66,9 @@ function getChangelogCacheKey(prefix, feedUrl) {
 function getDiskCachePath(prefix, feedUrl) {
   // When in local development or in tests, use disk caching
   if (process.env.NODE_ENV === 'test' || process.env.NODE_ENV === 'development') {
+    if (CHANGELOG_CACHE_FILE_PATH) {
+      return CHANGELOG_CACHE_FILE_PATH
+    }
     const cacheKey = getChangelogCacheKey(prefix, feedUrl)
     const date = new Date().toISOString().split('T')[0]
     const fileName = `changelogcache-${cacheKey}-${date}.json`

tests/fixtures/changelog-feed.json

@@ -0,0 +1 @@
+[{"title":"Authentication token format updates are generally available","date":"2021-03-31T22:22:03.000Z","href":"https://github.blog/changelog/2021-03-31-authentication-token-format-updates-are-generally-available"},{"title":"Compare REST API now supports pagination","date":"2021-03-23T02:49:54.000Z","href":"https://github.blog/changelog/2021-03-22-compare-rest-api-now-supports-pagination"},{"title":"GitHub Discussions GraphQL API public beta","date":"2021-02-23T18:21:40.000Z","href":"https://github.blog/changelog/2021-02-23-github-discussions-graphql-api-public-beta"}]

tests/unit/get-rss-feeds.js

@@ -18,7 +18,16 @@ describe('getChangelogItems module', () => {
 
     changelog = await getChangelogItems(
       'GitHub Actions:',
-      'https://github.blog/changelog/label/packages'
+      'https://github.blog/changelog/label/packages',
+      // This means: Don't use the cache even if it's present.
+      // The reason we're doing this is because all other tests, the
+      // cache is prepopulated from a file from the test fixtures. But
+      // in this particular file, we really do want to execute that code
+      // that executes on a cache miss. But this particular file special
+      // because it explicitly uses nock() to mock the HTTP socket.
+      // So even if we say "Don't use the cache" here, it still won't
+      // depend on Internet access because we're using `nock` here.
+      true
     )
   })