🐛 Fixed settings cache being out of sync after migrations (#11987)

refs https://github.com/TryGhost/Ghost/issues/10318

- re-initialize settings cache after migrations by shutting down to clean up event listeners then and calling `init` again
- important to ensure `db.ready` event is not emitted until settings have finished re-initializing to avoid problems with background processes using the db connection which is disconnected/re-connected or being kicked off with out-of-date settings

core/server/index.js

@@ -130,8 +130,10 @@ const minimalRequiredSetupToStartGhost = (dbState) => {
 
                 migrator.migrate()
                     .then(() => {
-                        events.emit('db.ready');
-                        return initialiseServices();
+                        return settings.reinit().then(() => {
+                            events.emit('db.ready');
+                            return initialiseServices();
+                        });
                     })
                     .then(() => {
                         config.set('maintenance:enabled', false);

core/server/services/settings/index.js

@@ -14,5 +14,10 @@ module.exports = {
                 // This will bind to events for further updates
                 SettingsCache.init(settingsCollection);
             });
+    },
+
+    reinit: function reinit() {
+        SettingsCache.shutdown();
+        return this.init();
     }
 };

test/unit/services/settings/cache_spec.js

@@ -1,6 +1,8 @@
 const rewire = require('rewire');
 const should = require('should');
+const sinon = require('sinon');
 const _ = require('lodash');
+const {events} = require('../../../../core/server/lib/common');
 const publicSettings = require('../../../../core/server/services/settings/public');
 let cache = rewire('../../../../core/server/services/settings/cache');
 
@@ -11,6 +13,10 @@ describe('UNIT: settings cache', function () {
         cache = rewire('../../../../core/server/services/settings/cache');
     });
 
+    afterEach(function () {
+        sinon.restore();
+    });
+
     it('does not auto convert string into number', function () {
         cache.set('key1', {value: '1'});
         (typeof cache.get('key1')).should.eql('string');
@@ -53,4 +59,41 @@ describe('UNIT: settings cache', function () {
 
         cache.getPublic().should.eql(values);
     });
+
+    it('can shutdown and init without double handling of events', function () {
+        const setSpy = sinon.spy(cache, 'set');
+
+        const settingsCollection = {
+            models: [{
+                get: () => 'key1',
+                toJSON: () => ({value: 'init value'})
+            }]
+        };
+
+        cache.init(settingsCollection);
+        cache.get('key1').should.equal('init value');
+
+        // check handler only called once on settings.edit
+        setSpy.callCount.should.equal(1);
+        events.emit('settings.edited', {
+            get: () => 'key1',
+            toJSON: () => ({value: 'first edit'})
+        });
+        setSpy.callCount.should.equal(2);
+        cache.get('key1').should.equal('first edit');
+
+        // shutdown + init
+        cache.shutdown();
+        cache.init(settingsCollection);
+        setSpy.callCount.should.equal(3);
+        cache.get('key1').should.equal('init value');
+
+        // edit again, check event only fired once
+        events.emit('settings.edited', {
+            get: () => 'key1',
+            toJSON: () => ({value: 'second edit'})
+        });
+        setSpy.callCount.should.equal(4);
+        cache.get('key1').should.equal('second edit');
+    });
 });