Added job status checks to job manager

refs ttps://github.com/TryGhost/Toolbox/issues/358

- One off jobs need a way to check for prior execution and await for their completion (in cases when it is reasonably short).
- Added `hasExecuted` and `awaitCompletion` methods to the job manager allowing to monitor one off job state

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

@@ -1,4 +1,6 @@
 const path = require('path');
+const util = require('util');
+const setTimeoutPromise = util.promisify(setTimeout);
 const fastq = require('fastq');
 const later = require('@breejs/later');
 const Bree = require('bree');
@@ -229,6 +231,40 @@ class JobManager {
         this.addJob({name, job, data, offloaded});
     }
 
+    /**
+     * Checks if the one-off job has ever been successfully executed
+     * @param {String} name one-off job name
+     */
+    async hasExecuted(name) {
+        // TODO: return false if the job has failed?
+        if (this._jobsRepository) {
+            const persistedJob = await this._jobsRepository.read(name);
+            return !!persistedJob;
+        } else {
+            return false;
+        }
+    }
+
+    /**
+     *
+     * @param {String} name one-off job name
+     * @returns
+     */
+    async awaitCompletion(name) {
+        const persistedJob = await this._jobsRepository.read({
+            name
+        });
+
+        if (!persistedJob || !['finished', 'failed'].includes(persistedJob.get('status'))) {
+            // NOTE: can implement exponential backoff here if that's ever needed
+            await setTimeoutPromise(500);
+
+            return this.awaitCompletion(name);
+        }
+
+        return !!persistedJob;
+    }
+
     /**
      * Removes an "offloaded" job from scheduled jobs queue.
      * It's NOT yet possible to remove "inline" jobs (will be possible when scheduling is added https://github.com/breejs/bree/issues/68).

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

@@ -502,6 +502,73 @@ describe('Job Manager', function () {
         });
     });
 
+    describe('Job execution progress', function () {
+        it('checks if job has ever been executed', async function () {
+            const spy = sinon.spy();
+            const JobModel = {
+                findOne: sinon.stub()
+                    .withArgs('solovei')
+                    .onCall(0)
+                    .resolves(null)
+                    .onCall(1)
+                    .resolves(null)
+                    .resolves({id: 'unique', name: 'solovei'}),
+                add: sinon.stub().resolves()
+            };
+
+            const jobManager = new JobManager({JobModel});
+            let executed = await jobManager.hasExecuted('solovei');
+            should.equal(executed, false);
+
+            await jobManager.addOneOffJob({
+                job: spy,
+                name: 'solovei'
+            });
+
+            assert.equal(JobModel.add.called, true);
+            executed = await jobManager.hasExecuted('solovei');
+            should.equal(executed, true);
+        });
+
+        it('can wait for job completion', async function () {
+            const spy = sinon.spy();
+            let status = 'queued';
+            const jobWithDelay = async () => {
+                await delay(80);
+                status = 'finished';
+                spy();
+            };
+            const JobModel = {
+                findOne: sinon.stub()
+                    // first call when adding a job
+                    .withArgs('solovei')
+                    .onCall(0)
+                    // first call when adding a job
+                    .resolves(null)
+                    .onCall(1)
+                    .resolves(null)
+
+                    .resolves({
+                        id: 'unique',
+                        get: () => status
+                    }),
+                add: sinon.stub().resolves()
+            };
+
+            const jobManager = new JobManager({JobModel});
+
+            await jobManager.addOneOffJob({
+                job: jobWithDelay,
+                name: 'solovei',
+                offloaded: false
+            });
+
+            should.equal(spy.called, false);
+            await jobManager.awaitCompletion('solovei');
+            should.equal(spy.called, true);
+        });
+    });
+
     describe('Remove a job', function () {
         it('removes a scheduled job from the queue', async function () {
             const jobManager = new JobManager({});