Allow cancel of queued job

prunner.go

@@ -153,6 +153,13 @@ func (j *PipelineJob) deinitScheduler() {
 	j.taskRunner = nil
 }
 
+func (j *PipelineJob) markAsCanceled() {
+	j.Canceled = true
+	for i := range j.Tasks {
+		j.Tasks[i].Canceled = true
+	}
+}
+
 // jobTask is a single task invocation inside the PipelineJob
 type jobTask struct {
 	definition.TaskDef
@@ -937,7 +944,15 @@ func (r *PipelineRunner) cancelJobInternal(id uuid.UUID) error {
 	}
 
 	if job.Start == nil {
-		return errJobNotStarted
+		job.markAsCanceled()
+
+		log.
+			WithField("component", "runner").
+			WithField("pipeline", job.Pipeline).
+			WithField("jobID", job.ID).
+			Debugf("Marked job as canceled, since it was not started")
+
+		return nil
 	}
 
 	log.

prunner_test.go

@@ -270,6 +270,70 @@ func TestPipelineRunner_CancelJob_WithRunningJob(t *testing.T) {
 	}
 }
 
+func TestPipelineRunner_CancelJob_WithQueuedJob(t *testing.T) {
+	var defs = &definition.PipelinesDef{
+		Pipelines: map[string]definition.PipelineDef{
+			"long_running": {
+				// Concurrency of 1 is the default for a single concurrent execution
+				Concurrency: 1,
+				QueueLimit:  nil,
+				Tasks: map[string]definition.TaskDef{
+					"sleep": {
+						Script: []string{"# that takes long"},
+					},
+				},
+				SourcePath: "fixtures",
+			},
+		},
+	}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	var (
+		startedJobsIDs []string
+		wait           = make(chan struct{})
+	)
+
+	pRunner, err := NewPipelineRunner(ctx, defs, func(j *PipelineJob) taskctl.Runner {
+		return &test.MockRunner{
+			OnRun: func(t *task.Task) error {
+				jobID := t.Variables.Get(taskctl.JobIDVariableName)
+				startedJobsIDs = append(startedJobsIDs, jobID.(string))
+
+				// Wait until the job should proceed (wait channel is closed)
+				<-wait
+
+				return nil
+			},
+		}
+	}, nil, test.NewMockOutputStore())
+	require.NoError(t, err)
+
+	job1, err := pRunner.ScheduleAsync("long_running", ScheduleOpts{})
+	require.NoError(t, err)
+
+	job2, err := pRunner.ScheduleAsync("long_running", ScheduleOpts{})
+	require.NoError(t, err)
+
+	waitForStartedJobTask(t, pRunner, job1.ID, "sleep")
+
+	// Make sure the queued job can be canceled
+	err = pRunner.CancelJob(job2.ID)
+	require.NoError(t, err)
+
+	// Close the channel to let the first job proceed
+	close(wait)
+
+	waitForCompletedJob(t, pRunner, job1.ID)
+	waitForCanceledJob(t, pRunner, job2.ID)
+
+	assert.Equal(t, true, job2.Tasks.ByName("sleep").Canceled, "job task was marked as canceled")
+
+	assert.Equal(t, []string{job1.ID.String()}, startedJobsIDs, "only job1 was started")
+
+}
+
 func TestPipelineRunner_CancelJob_WithStoppedJob_ShouldNotThrowFatalError(t *testing.T) {
 	var defs = &definition.PipelinesDef{
 		Pipelines: map[string]definition.PipelineDef{
@@ -456,6 +520,18 @@ func waitForCompletedJob(t *testing.T, pRunner *PipelineRunner, jobID uuid.UUID)
 	}, 1*time.Millisecond, "job completed")
 }
 
+func waitForCanceledJob(t *testing.T, pRunner *PipelineRunner, jobID uuid.UUID) {
+	t.Helper()
+
+	test.WaitForCondition(t, func() bool {
+		var canceled bool
+		_ = pRunner.ReadJob(jobID, func(j *PipelineJob) {
+			canceled = j.Canceled
+		})
+		return canceled
+	}, 1*time.Millisecond, "job canceled")
+}
+
 func TestPipelineRunner_ShouldRemoveOldJobsWhenRetentionPeriodIsConfigured(t *testing.T) {
 	var defs = &definition.PipelinesDef{
 		Pipelines: map[string]definition.PipelineDef{