Introduced "withFrontend" and "withBackend" flags in boot

refs https://github.com/TryGhost/Toolbox/issues/135

- These flags are meant to control initialization of sections of the boot sequence depending on the needs - with or without bakend (API)/frontend (public handlebars site)
- Ideally these flags should not be passed deep into the components, and if the are (like in the web/parent/app case) it's a smell that we need to move things up into the boot process!

core/boot.js

@@ -69,8 +69,9 @@ async function initDatabase({config, logging}) {
  * @param {object} options.ghostServer
  * @param {object} options.config
  * @param {object} options.bootLogger
+ * @param {boolean} options.withFrontend
  */
-async function initCore({ghostServer, config, bootLogger}) {
+async function initCore({ghostServer, config, bootLogger, withFrontend}) {
     debug('Begin: initCore');
 
     // URL Utils is a bit slow, put it here so the timing is visible separate from models
@@ -100,7 +101,8 @@ async function initCore({ghostServer, config, bootLogger}) {
     urlService.init({
         onFinished: () => {
             bootLogger.log('URL Service Ready');
-        }
+        },
+        urlCache: !withFrontend // hacky parameter to make the cache initialization kick in as we can't initialize labs before the boot
     });
     debug('End: Url Service');
 
@@ -159,10 +161,13 @@ async function initFrontend() {
  * At the moment we load our express apps all in one go, they require themselves and are co-located
  * What we want is to be able to optionally load various components and mount them
  * So eventually this function should go away
+ * @param {Object} options
+ * @param {Boolean} options.withBackend
+ * @param {Boolean} options.withFrontend
  */
-async function initExpressApps() {
+async function initExpressApps(options) {
     debug('Begin: initExpressApps');
-    const parentApp = require('./server/web/parent/app')();
+    const parentApp = require('./server/web/parent/app')(options);
     debug('End: initExpressApps');
     return parentApp;
 }
@@ -297,7 +302,7 @@ async function initBackgroundServices({config}) {
 
  * @returns {Promise<object>} ghostServer
  */
-async function bootGhost() {
+async function bootGhost({withBackend = true, withFrontend = true} = {}) {
     // Metrics
     const startTime = Date.now();
     debug('Begin Boot');
@@ -346,11 +351,14 @@ async function bootGhost() {
         // Step 2 - Start server with minimal app in global maintenance mode
         debug('Begin: load server + minimal app');
         const rootApp = require('./app');
-        const GhostServer = require('./server/ghost-server');
-        ghostServer = new GhostServer({url: config.getSiteUrl()});
-        await ghostServer.start(rootApp);
-        bootLogger.log('server started');
-        debug('End: load server + minimal app');
+
+        if (withBackend) {
+            const GhostServer = require('./server/ghost-server');
+            ghostServer = new GhostServer({url: config.getSiteUrl()});
+            await ghostServer.start(rootApp);
+            bootLogger.log('server started');
+            debug('End: load server + minimal app');
+        }
 
         // Step 3 - Get the DB ready
         debug('Begin: Get DB ready');
@@ -360,11 +368,18 @@ async function bootGhost() {
 
         // Step 4 - Load Ghost with all its services
         debug('Begin: Load Ghost Services & Apps');
-        await initCore({ghostServer, config, bootLogger});
-        await initServicesForFrontend();
-        await initFrontend();
-        const ghostApp = await initExpressApps();
-        await initDynamicRouting();
+        await initCore({ghostServer, config, bootLogger, withFrontend});
+
+        if (withFrontend) {
+            await initServicesForFrontend();
+            await initFrontend();
+        }
+        const ghostApp = await initExpressApps({withFrontend, withBackend});
+
+        if (withFrontend) {
+            await initDynamicRouting();
+        }
+
         await initServices({config});
         debug('End: Load Ghost Services & Apps');
 

core/server/services/url/UrlService.js

@@ -319,14 +319,15 @@ 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(options = {}) {
-        this.onFinished = options.onFinished;
+    async init({onFinished, urlCache} = {}) {
+        this.onFinished = onFinished;
 
         let persistedUrls;
         let persistedResources;
 
-        if (labs.isSet('urlCache')) {
+        if (labs.isSet('urlCache') || urlCache) {
             persistedUrls = await this.readCacheFile(this.urlsCachePath);
             persistedResources = await this.readCacheFile(this.resourcesCachePath);
         }

core/server/web/parent/app.js

@@ -5,7 +5,13 @@ const compress = require('compression');
 const mw = require('./middleware');
 const vhost = require('@tryghost/vhost-middleware');
 
-module.exports = function setupParentApp(options = {}) {
+/**
+ * @param {Object} options
+ * @param {Boolean} [options.start]
+ * @param {Boolean} options.withBackend
+ * @param {Boolean} options.withFrontend
+ */
+module.exports = function setupParentApp({start, withFrontend, withBackend}) {
     debug('ParentApp setup start');
     const parentApp = express('parent');
 
@@ -26,14 +32,17 @@ module.exports = function setupParentApp(options = {}) {
 
     // Mount the express apps on the parentApp
 
-    // ADMIN + API
-    const backendApp = require('./backend')();
-    parentApp.use(vhost(config.getBackendMountPath(), backendApp));
-
-    // SITE + MEMBERS
-    const frontendApp = require('./frontend')(options);
-    parentApp.use(vhost(config.getFrontendMountPath(), frontendApp));
+    if (withBackend) {
+        debug('Mounting bakcend: ADMIN + API');
+        const backendApp = require('./backend')();
+        parentApp.use(vhost(config.getBackendMountPath(), backendApp));
+    }
 
+    if (withFrontend) {
+        debug('Mounting frontend: SITE + MEMBERS');
+        const frontendApp = require('./frontend')({start});
+        parentApp.use(vhost(config.getFrontendMountPath(), frontendApp));
+    }
     debug('ParentApp setup end');
 
     return parentApp;