Added admin email for UpdateChecker's alerts

refs https://github.com/TryGhost/Team/issues/726

- When UpdateCheck service sends a notification with "type: 'alert'" an email goes out to admin users with the "message" content of the notification.
- This functionality is aimed to handling critical messages like urgent instance updates
- Next step will be getting as much of the update check code extracted into a "service" and then moved out of Ghost's codebase

core/server/update-check.js

@@ -16,6 +16,7 @@ const _ = require('lodash');
 const url = require('url');
 const debug = require('ghost-ignition').debug('update-check');
 const api = require('./api').v2;
+const GhostMailer = require('./services/mail').GhostMailer;
 const config = require('../shared/config');
 const urlUtils = require('./../shared/url-utils');
 const errors = require('@tryghost/errors');
@@ -23,9 +24,12 @@ const i18n = require('../shared/i18n');
 const logging = require('../shared/logging');
 const request = require('./lib/request');
 const ghostVersion = require('./lib/ghost-version');
+
 const internal = {context: {internal: true}};
 const allowedCheckEnvironments = ['development', 'production'];
 
+const ghostMailer = new GhostMailer();
+
 function nextCheckTimestamp() {
     const now = Math.round(new Date().getTime() / 1000);
     return now + (24 * 3600);
@@ -67,6 +71,17 @@ async function createCustomNotification(notification) {
         return;
     }
 
+    const {users} = await api.users.browse(Object.assign({
+        limit: 'all',
+        include: ['roles']
+    }, internal));
+
+    const adminEmails = users
+        .filter(user => ['Owner', 'Administrator'].includes(user.roles[0].name))
+        .map(user => user.email);
+
+    const siteUrl = config.get('url');
+
     for (const message of notification.messages) {
         const toAdd = {
             // @NOTE: the update check service returns "0" or "1" (https://github.com/TryGhost/UpdateCheck/issues/43)
@@ -80,6 +95,21 @@ async function createCustomNotification(notification) {
             message: message.content
         };
 
+        if (toAdd.type === 'alert') {
+            for (const email of adminEmails) {
+                try {
+                    ghostMailer.send({
+                        to: email,
+                        subject: `Action required: Critical alert from Ghost instance ${siteUrl}`,
+                        html: toAdd.message,
+                        forceTextContent: true
+                    });
+                } catch (err) {
+                    logging.err(err);
+                }
+            }
+        }
+
         debug('Add Custom Notification', toAdd);
         await api.notifications.add({notifications: [toAdd]}, {context: {internal: true}});
     }

test/regression/update-check/update_check_spec.js

@@ -9,6 +9,7 @@ const testUtils = require('../../utils');
 const configUtils = require('../../utils/configUtils');
 const packageInfo = require('../../../package.json');
 const api = require('../../../core/server/api').v2;
+const mailService = require('../../../core/server/services/mail/');
 
 let updateCheck = rewire('../../../core/server/update-check');
 let ghostVersion = rewire('../../../core/server/lib/ghost-version');
@@ -17,6 +18,7 @@ describe('Update Check', function () {
     beforeEach(function () {
         updateCheck = rewire('../../../core/server/update-check');
         ghostVersion = rewire('../../../core/server/lib/ghost-version');
+        sinon.stub(mailService.GhostMailer.prototype, 'send').resolves('Stubed email response');
     });
 
     afterEach(function () {
@@ -322,6 +324,43 @@ describe('Update Check', function () {
                 })
                 .catch(done);
         });
+
+        it('should send an email for critical notification', async function () {
+            const createCustomNotification = updateCheck.__get__('createCustomNotification');
+
+            const notification = {
+                id: 1,
+                custom: 1,
+                messages: [{
+                    id: uuid.v4(),
+                    version: 'custom1',
+                    content: '<p>Critical message. Upgrade your site!</p>',
+                    dismissible: false,
+                    top: true,
+                    type: 'alert'
+                }]
+            };
+
+            await createCustomNotification(notification);
+
+            mailService.GhostMailer.prototype.send.called.should.be.true();
+            mailService.GhostMailer.prototype.send.args[0][0].to.should.equal('jbloggs@example.com');
+            mailService.GhostMailer.prototype.send.args[0][0].subject.should.equal('Action required: Critical alert from Ghost instance http://127.0.0.1:2369');
+            mailService.GhostMailer.prototype.send.args[0][0].html.should.equal('<p>Critical message. Upgrade your site!</p>');
+            mailService.GhostMailer.prototype.send.args[0][0].forceTextContent.should.equal(true);
+
+            const results = await api.notifications.browse(testUtils.context.internal);
+
+            should.exist(results);
+            should.exist(results.notifications);
+            results.notifications.length.should.eql(1);
+
+            const targetNotification = _.find(results.notifications, {id: notification.messages[0].id});
+            should.exist(targetNotification);
+            targetNotification.dismissible.should.eql(notification.messages[0].dismissible);
+            targetNotification.top.should.eql(notification.messages[0].top);
+            targetNotification.type.should.eql(notification.messages[0].type);
+        });
     });
 
     describe('fn: updateCheckResponse', function () {