Removed experimental URL cache

fix https://linear.app/ghost/issue/ENG-1803/remove-url-cache-code

- this feature was intended to write a static cache of our URLs from the
  URL service, which should help boot become faster because we don't
  have to fetch them from the DB
- however, we added this a long time ago and never gave it the love to
  get it going correctly, so it's been sitting there unused for years
  and not providing any real benefit
- little bit of spring cleaning, we can clean up the code here and
  potentially revisit it in the future

ghost/core/core/boot.js

@@ -79,9 +79,8 @@ async function initDatabase({config}) {
  * @param {object} options.ghostServer
  * @param {object} options.config
  * @param {object} options.bootLogger
- * @param {boolean} options.frontend
  */
-async function initCore({ghostServer, config, bootLogger, frontend}) {
+async function initCore({ghostServer, config, bootLogger}) {
     debug('Begin: initCore');
 
     // URL Utils is a bit slow, put it here so the timing is visible separate from models
@@ -118,8 +117,7 @@ async function initCore({ghostServer, config, bootLogger, frontend}) {
         onFinished: () => {
             bootLogger.metric('url-service', urlServiceStart);
             bootLogger.log('URL Service Ready');
-        },
-        urlCache: !frontend // hacky parameter to make the cache initialization kick in as we can't initialize labs before the boot
+        }
     });
     debug('End: Url Service');
 
@@ -563,7 +561,7 @@ async function bootGhost({backend = true, frontend = true, server = true} = {})
 
         // Step 4 - Load Ghost with all its services
         debug('Begin: Load Ghost Services & Apps');
-        await initCore({ghostServer, config, bootLogger, frontend});
+        await initCore({ghostServer, config, bootLogger});
 
         // Instrument the knex instance and connection pool if prometheus is enabled
         // Needs to be after initCore because the pool is destroyed and recreated in initCore, which removes the event listeners

ghost/core/core/server/services/url/UrlService.js

@@ -1,7 +1,6 @@
 const debug = require('@tryghost/debug')('services:url:service');
 const _ = require('lodash');
 const errors = require('@tryghost/errors');
-const labs = require('../../../shared/labs');
 const UrlGenerator = require('./UrlGenerator');
 const Queue = require('./Queue');
 const Urls = require('./Urls');
@@ -15,16 +14,8 @@ const resourcesConfig = require('./config');
  * It will tell you if the url generation is in progress or not.
  */
 class UrlService {
-    /**
-     *
-     * @param {Object} [options]
-     * @param {Object} [options.cache] - cache handler instance
-     * @param {Function} [options.cache.read] - read cache by type
-     * @param {Function} [options.cache.write] - write into cache by type
-     */
-    constructor({cache} = {}) {
+    constructor() {
         this.utils = urlUtils;
-        this.cache = cache;
         this.onFinished = null;
         this.finished = false;
         this.urlGenerators = [];
@@ -304,44 +295,21 @@ class UrlService {
      * @description Initializes components needed for the URL Service to function
      * @param {Object} options
      * @param {Function} [options.onFinished] - callback when url generation is finished
-     * @param {Boolean} [options.urlCache] - whether to init using url cache or not
      */
-    async init({onFinished, urlCache} = {}) {
+    async init({onFinished} = {}) {
         this.onFinished = onFinished;
 
-        let persistedUrls;
-        let persistedResources;
-
-        if (this.cache && (labs.isSet('urlCache') || urlCache)) {
-            persistedUrls = await this.cache.read('urls');
-            persistedResources = await this.cache.read('resources');
-        }
-
-        if (persistedUrls && persistedResources) {
-            this.urls.urls = persistedUrls;
-            this.resources.data = persistedResources;
-            this.resources.initEventListeners();
-
-            this._onQueueEnded('init');
-        } else {
-            this.resources.initEventListeners();
-            await this.resources.fetchResources();
-            // CASE: all resources are fetched, start the queue
-            this.queue.start({
-                event: 'init',
-                tolerance: 100,
-                requiredSubscriberCount: 1
-            });
-        }
+        this.resources.initEventListeners();
+        await this.resources.fetchResources();
+        // CASE: all resources are fetched, start the queue
+        this.queue.start({
+            event: 'init',
+            tolerance: 100,
+            requiredSubscriberCount: 1
+        });
     }
 
     async shutdown() {
-        if (!labs.isSet('urlCache')) {
-            return null;
-        }
-
-        await this.cache.write('urls', this.urls.urls);
-        await this.cache.write('resources', this.resources.getAll());
     }
 
     /**

ghost/core/core/server/services/url/index.js

@@ -1,26 +1,6 @@
-const config = require('../../../shared/config');
-const LocalFileCache = require('./LocalFileCache');
 const UrlService = require('./UrlService');
 
-// NOTE: instead of a path we could give UrlService a "data-resolver" of some sort
-//       so it doesn't have to contain the logic to read data at all. This would be
-//       a possible improvement in the future
-let writeDisabled = false;
-let storagePath = config.getContentPath('data');
-
-// TODO: remove this hack in favor of loading from the content path when it's possible to do so
-//       by mocking content folders in pre-boot phase
-if (process.env.NODE_ENV.startsWith('test')){
-    storagePath = config.get('paths').urlCache;
-
-    // NOTE: prevents test suites from overwriting cache fixtures.
-    //       A better solution would be injecting a different implementation of the
-    //       cache based on the environment, this approach should do the trick for now
-    writeDisabled = true;
-}
-
-const cache = new LocalFileCache({storagePath, writeDisabled});
-const urlService = new UrlService({cache});
+const urlService = new UrlService();
 
 // Singleton
 module.exports = urlService;

ghost/core/core/shared/config/env/config.testing-browser.json

@@ -79,8 +79,7 @@
     "useMinFiles": false,
     "paths": {
         "fixtures": "test/utils/fixtures/fixtures",
-        "defaultSettings": "test/utils/fixtures/default-settings-browser.json",
-        "urlCache": "test/utils/fixtures/urls"
+        "defaultSettings": "test/utils/fixtures/default-settings-browser.json"
     },
     "enableDeveloperExperiments": true
 }

ghost/core/core/shared/config/env/config.testing-mysql.json

@@ -80,7 +80,6 @@
     "useMinFiles": false,
     "paths": {
         "fixtures": "test/utils/fixtures/fixtures",
-        "defaultSettings": "test/utils/fixtures/default-settings.json",
-        "urlCache": "test/utils/fixtures/urls"
+        "defaultSettings": "test/utils/fixtures/default-settings.json"
     }
 }

ghost/core/core/shared/config/env/config.testing.json

@@ -76,7 +76,6 @@
     "useMinFiles": false,
     "paths": {
         "fixtures": "test/utils/fixtures/fixtures",
-        "defaultSettings": "test/utils/fixtures/default-settings.json",
-        "urlCache": "test/utils/fixtures/urls"
+        "defaultSettings": "test/utils/fixtures/default-settings.json"
     }
 }

ghost/core/core/shared/labs.js

@@ -44,7 +44,6 @@ const BETA_FEATURES = [
 
 const ALPHA_FEATURES = [
     'NestPlayground',
-    'urlCache',
     'emailCustomization',
     'mailEvents',
     'collectionsCard',

ghost/core/test/e2e-api/admin/__snapshots__/config.test.js.snap

@@ -31,7 +31,6 @@ Object {
       "postsX": true,
       "stripeAutomaticTax": true,
       "themeErrorsNotification": true,
-      "urlCache": true,
       "webmentions": true,
     },
     "mail": "",

ghost/core/test/unit/shared/config/loader.test.js

@@ -98,7 +98,6 @@ describe('Config Loader', function () {
                 'fixtures',
                 'defaultSettings',
                 'assetSrc',
-                'urlCache',
                 'appRoot',
                 'corePath',
                 'adminAssets',

ghost/core/test/unit/shared/labs.test.js

@@ -33,26 +33,26 @@ describe('Labs Service', function () {
         sinon.stub(process.env, 'NODE_ENV').value('production');
         sinon.stub(settingsCache, 'get');
         settingsCache.get.withArgs('labs').returns({
-            urlCache: true
+            NestPlayground: true
         });
 
         // NOTE: this test should be rewritten to test the alpha flag independently of the internal ALPHA_FEATURES list
         //       otherwise we end up in the endless maintenance loop and need to update it every time a feature graduates from alpha
         assert.deepEqual(labs.getAll(), expectedLabsObject({
-            urlCache: true,
+            NestPlayground: true,
             members: true
         }));
 
         assert.equal(labs.isSet('members'), true);
-        assert.equal(labs.isSet('urlCache'), true);
+        assert.equal(labs.isSet('NestPlayground'), true);
     });
 
     it('returns a falsy alpha flag when dev experiments in NOT toggled', function () {
         configUtils.set('enableDeveloperExperiments', false);
         sinon.stub(process.env, 'NODE_ENV').value('production');
         sinon.stub(settingsCache, 'get');
         settingsCache.get.withArgs('labs').returns({
-            urlCache: true
+            NestPlayground: true
         });
 
         // NOTE: this test should be rewritten to test the alpha flag independently of the internal ALPHA_FEATURES list
@@ -62,7 +62,7 @@ describe('Labs Service', function () {
         }));
 
         assert.equal(labs.isSet('members'), true);
-        assert.equal(labs.isSet('urlCache'), false);
+        assert.equal(labs.isSet('NestPlayground'), false);
     });
 
     it('respects the value in config over settings', function () {