Move the update-check service to a scheduled job

issue https://github.com/TryGhost/Team/issues/729

core/boot.js

@@ -207,6 +207,19 @@ async function initBackgroundServices({config}) {
     const themeService = require('./server/services/themes');
     themeService.loadInactiveThemes();
 
+    const jobsService = require('./server/services/jobs');
+
+    // use a random seconds/minutes/hours value to avoid spikes to the update service API
+    const s = Math.floor(Math.random() * 60); // 0-59
+    const m = Math.floor(Math.random() * 60); // 0-59
+    const h = Math.floor(Math.random() * 24); // 0-23
+
+    jobsService.addJob({
+        at: `${s} ${m} ${h} * * *`, // Every day
+        job: require('path').resolve(__dirname, 'server', 'run-update-check.js'),
+        name: 'update-check'
+    });
+
     debug('End: initBackgroundServices');
 }
 

core/server/run-update-check.js

@@ -0,0 +1,66 @@
+const {parentPort} = require('bthreads');
+
+// Exit early when cancelled to prevent stalling shutdown. No cleanup needed when cancelling as everything is idempotent and will pick up
+// where it left off on next run
+function cancel() {
+    parentPort.postMessage('Update check job cancelled before completion');
+
+    if (parentPort) {
+        parentPort.postMessage('cancelled');
+    } else {
+        setTimeout(() => {
+            process.exit(0);
+        }, 1000);
+    }
+}
+
+if (parentPort) {
+    parentPort.once('message', (message) => {
+        if (message === 'cancel') {
+            return cancel();
+        }
+    });
+}
+
+(async () => {
+    const updateCheck = require('./update-check');
+
+    const logging = {
+        info(message) {
+            parentPort.postMessage(message);
+        },
+        warn(message) {
+            parentPort.postMessage(message);
+        },
+        error(message) {
+            parentPort.postMessage(message);
+        }
+    };
+
+    // INIT required services
+    const models = require('./models');
+    models.init();
+
+    const permissions = require('./services/permissions');
+    await permissions.init();
+
+    const settings = require('./services/settings');
+    await settings.init();
+
+    const i18n = require('../shared/i18n');
+    i18n.init();
+    // Finished INIT
+
+    await updateCheck({logging});
+
+    parentPort.postMessage(`Ran update check`);
+
+    if (parentPort) {
+        parentPort.postMessage('done');
+    } else {
+        // give the logging pipes time finish writing before exit
+        setTimeout(() => {
+            process.exit(0);
+        }, 1000);
+    }
+})();