Added loggign and more graceful error handling

no issue

- This is a quick implementation change to prevent from queue stalling and never becoming idle in case there's an error thrown from within the job function/module
- More robust error handling should be designed soon!

ghost/job-manager/lib/job-manager.js

@@ -1,6 +1,7 @@
 const fastq = require('fastq');
 const later = require('@breejs/later');
 const pWaitFor = require('p-wait-for');
+const errors = require('@tryghost/errors');
 const isCronExpression = require('./is-cron-expression');
 
 const worker = async (task, callback) => {
@@ -14,7 +15,8 @@ const worker = async (task, callback) => {
 
 const handler = (error, result) => {
     if (error) {
-        throw error;
+        // TODO: this handler should not be throwing as this blocks the queue
+        // throw error;
     }
     // Can potentially standardise the result here
     return result;
@@ -37,10 +39,24 @@ class JobManager {
         this.logging.info('Adding one off job to the queue');
 
         this.queue.push(async () => {
-            if (typeof job === 'function') {
-                await job(data);
-            } else {
-                await require(job)(data);
+            try {
+                if (typeof job === 'function') {
+                    await job(data);
+                } else {
+                    await require(job)(data);
+                }
+            } catch (err) {
+                // NOTE: each job should be written in a safe way and handle all errors internally
+                //       if the error is caught here jobs implementaton should be changed
+                this.logging.error(new errors.IgnitionError({
+                    level: 'critical',
+                    errorType: 'UnhandledJobError',
+                    message: 'Processed job threw an unhandled error',
+                    context: (typeof job === 'function') ? 'function' : job,
+                    err
+                }));
+
+                throw err;
             }
         }, handler);
     }

ghost/job-manager/test/job-manager.test.js

@@ -5,11 +5,17 @@ const sinon = require('sinon');
 const delay = require('delay');
 
 const JobManager = require('../index');
-const logging = {
-    info: sinon.stub()
-};
 
 describe('Job Manager', function () {
+    let logging;
+
+    beforeEach(() => {
+        logging = {
+            info: sinon.stub(),
+            error: sinon.stub()
+        };
+    });
+
     it('public interface', function () {
         const jobManager = new JobManager(logging);
 
@@ -32,6 +38,22 @@ describe('Job Manager', function () {
             should(spy.called).be.true();
             should(spy.args[0][0]).equal('test data');
         });
+
+        it('handles failed job gracefully', async function () {
+            const spy = sinon.stub().throws();
+            const jobManager = new JobManager(logging);
+
+            jobManager.addJob(spy, 'test data');
+            should(jobManager.queue.idle()).be.false();
+
+            // give time to execute the job
+            await delay(1);
+
+            should(jobManager.queue.idle()).be.true();
+            should(spy.called).be.true();
+            should(spy.args[0][0]).equal('test data');
+            should(logging.error.called).be.true();
+        });
     });
 
     describe('Schedule Job', function () {