BUGFIX: handle errors in worker by not spinning

If there was an error when fetching a job, we previously just keep trying super fast, which burns CPU and prevents wp.Stop() from working. This can happen if Redis is down. Instead of doing that, chill out and sleep for 10 milliseconds. This addresses #7.

worker.go

@@ -108,6 +108,8 @@ func (w *worker) loop() {
 				job, err := w.fetchJob()
 				if err != nil {
 					logError("worker.fetch", err)
+					gotJob = false
+					timer.Reset(10 * time.Millisecond)
 				} else if job != nil {
 					w.processJob(job)
 					consequtiveNoJobs = 0

worker_test.go

@@ -234,6 +234,23 @@ func TestWorkerDead(t *testing.T) {
 	assert.True(t, (nowEpochSeconds()-job.FailedAt) <= 2)
 }
 
+// Test that in the case of an unavailable Redis server,
+// the worker loop exits in the case of a WorkerPool.Stop
+func TestStop(t *testing.T) {
+	redisPool := &redis.Pool{
+		Dial: func() (redis.Conn, error) {
+			c, err := redis.Dial("tcp", "notworking:6379")
+			if err != nil {
+				return nil, err
+			}
+			return c, nil
+		},
+	}
+	wp := NewWorkerPool(TestContext{}, 10, "work", redisPool)
+	wp.Start()
+	wp.Stop()
+}
+
 func BenchmarkJobProcessing(b *testing.B) {
 	pool := newTestPool(":6379")
 	ns := "work"