jobs: add ability to stop async jobs

Depends on #3257

fs/rc/job.go

@@ -23,7 +23,7 @@ type Job struct {
 	Success   bool      `json:"success"`
 	Duration  float64   `json:"duration"`
 	Output    Params    `json:"output"`
-	Context   context.Context `json:"-"`
+	Stop      func()    `json:"-"`
 }
 
 // Jobs describes a collection of running tasks
@@ -117,23 +117,29 @@ func (job *Job) finish(out Params, err error) {
 }
 
 // run the job until completion writing the return status
-func (job *Job) run(fn Func, in Params) {
+func (job *Job) run(ctx context.Context, fn Func, in Params) {
 	defer func() {
 		if r := recover(); r != nil {
 			job.finish(nil, errors.Errorf("panic received: %v", r))
 		}
 	}()
-	job.finish(fn(job.Context, in))
+	job.finish(fn(ctx, in))
 }
 
 // NewJob start a new Job off
 func (jobs *Jobs) NewJob(fn Func, in Params) *Job {
+	ctx, cancel := context.WithCancel(context.Background())
+	stop := func() {
+		cancel()
+		// Wait for cancel to propagate before returning.
+		<-ctx.Done()
+	}
 	job := &Job{
 		ID:        atomic.AddInt64(&jobID, 1),
 		StartTime: time.Now(),
-		Context:   context.Background(),
+		Stop:      stop,
 	}
-	go job.run(fn, in)
+	go job.run(ctx, fn, in)
 	jobs.mu.Lock()
 	jobs.jobs[job.ID] = job
 	jobs.mu.Unlock()
@@ -205,9 +211,37 @@ Results
 	})
 }
 
-// Returns the status of a job
+// Returns list of job ids.
 func rcJobList(ctx context.Context, in Params) (out Params, err error) {
 	out = make(Params)
 	out["jobids"] = running.IDs()
 	return out, nil
 }
+
+func init() {
+	Add(Call{
+		Path:  "job/stop",
+		Fn:    rcJobStop,
+		Title: "Stop the running job",
+		Help: `Parameters
+- jobid - id of the job (integer)
+`,
+	})
+}
+
+// Stops the running job.
+func rcJobStop(ctx context.Context, in Params) (out Params, err error) {
+	jobID, err := in.GetInt64("jobid")
+	if err != nil {
+		return nil, err
+	}
+	job := running.Get(jobID)
+	if job == nil {
+		return nil, errors.New("job not found")
+	}
+	job.mu.Lock()
+	defer job.mu.Unlock()
+	out = make(Params)
+	job.Stop()
+	return out, nil
+}

fs/rc/job_test.go

@@ -82,11 +82,17 @@ func TestJobsGet(t *testing.T) {
 }
 
 var longFn = func(ctx context.Context, in Params) (Params, error) {
-	// TODO get execution time from context?
 	time.Sleep(1 * time.Hour)
 	return nil, nil
 }
 
+var ctxFn = func(ctx context.Context, in Params) (Params, error) {
+	select {
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	}
+}
+
 const (
 	sleepTime      = 100 * time.Millisecond
 	floatSleepTime = float64(sleepTime) / 1E9 / 2
@@ -184,7 +190,7 @@ func TestJobsNewJob(t *testing.T) {
 	job := jobs.NewJob(noopFn, Params{})
 	assert.Equal(t, int64(1), job.ID)
 	assert.Equal(t, job, jobs.Get(1))
-
+	assert.NotEmpty(t, job.Stop)
 }
 
 func TestStartJob(t *testing.T) {
@@ -234,3 +240,39 @@ func TestRcJobList(t *testing.T) {
 	require.NotNil(t, out)
 	assert.Equal(t, Params{"jobids": []int64{1}}, out)
 }
+
+func TestRcJobStop(t *testing.T) {
+	jobID = 0
+	_, err := StartJob(ctxFn, Params{})
+	assert.NoError(t, err)
+
+	call := Calls.Get("job/stop")
+	assert.NotNil(t, call)
+	in := Params{"jobid": 1}
+	out, err := call.Fn(context.Background(), in)
+	require.NoError(t, err)
+	require.Empty(t, out)
+
+	in = Params{"jobid": 123123123}
+	_, err = call.Fn(context.Background(), in)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "job not found")
+
+	in = Params{"jobidx": 123123123}
+	_, err = call.Fn(context.Background(), in)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "Didn't find key")
+
+	time.Sleep(10 * time.Millisecond)
+
+	call = Calls.Get("job/status")
+	assert.NotNil(t, call)
+	in = Params{"jobid": 1}
+	out, err = call.Fn(context.Background(), in)
+	require.NoError(t, err)
+	require.NotNil(t, out)
+	assert.Equal(t, float64(1), out["id"])
+	assert.Equal(t, "context canceled", out["error"])
+	assert.Equal(t, true, out["finished"])
+	assert.Equal(t, false, out["success"])
+}