Update processor to adapt for deadlines set change

- Processor dequeues tasks only when it's available to process
- Processor retries a task when its context's Done channel is closed

context.go

@@ -27,28 +27,14 @@ type ctxKey int
 const metadataCtxKey ctxKey = 0
 
 // createContext returns a context and cancel function for a given task message.
-func createContext(msg *base.TaskMessage) (ctx context.Context, cancel context.CancelFunc) {
+func createContext(msg *base.TaskMessage, deadline time.Time) (ctx context.Context, cancel context.CancelFunc) {
 	metadata := taskMetadata{
 		id:         msg.ID.String(),
 		maxRetry:   msg.Retry,
 		retryCount: msg.Retried,
 	}
 	ctx = context.WithValue(context.Background(), metadataCtxKey, metadata)
-	if msg.Timeout == 0 && msg.Deadline == 0 {
-		panic("asynq: internal error: missing both timeout and deadline")
-	}
-	if msg.Timeout != 0 {
-		timeout := time.Duration(msg.Timeout) * time.Second
-		ctx, cancel = context.WithTimeout(ctx, timeout)
-	}
-	if msg.Deadline != 0 {
-		deadline := time.Unix(int64(msg.Deadline), 0)
-		ctx, cancel = context.WithDeadline(ctx, deadline)
-	}
-	if cancel == nil {
-		ctx, cancel = context.WithCancel(ctx)
-	}
-	return ctx, cancel
+	return context.WithDeadline(ctx, deadline)
 }
 
 // GetTaskID extracts a task ID from a context, if any.

context_test.go

@@ -10,46 +10,38 @@ import (
 	"time"
 
 	"github.com/google/go-cmp/cmp"
-	"github.com/google/go-cmp/cmp/cmpopts"
 	"github.com/hibiken/asynq/internal/base"
 	"github.com/rs/xid"
 )
 
-func TestCreateContextWithTimeRestrictions(t *testing.T) {
+func TestCreateContextWithFutureDeadline(t *testing.T) {
 	tests := []struct {
-		desc         string
-		timeout      time.Duration
-		deadline     time.Time
-		wantDeadline time.Time
+		deadline time.Time
 	}{
-		{"only with timeout", 10 * time.Second, noDeadline, time.Now().Add(10 * time.Second)},
-		{"only with deadline", noTimeout, time.Now().Add(time.Hour), time.Now().Add(time.Hour)},
-		{"with timeout and deadline (timeout < deadline)", 10 * time.Second, time.Now().Add(time.Hour), time.Now().Add(10 * time.Second)},
-		{"with timeout and deadline (timeout > deadline)", 10 * time.Minute, time.Now().Add(30 * time.Second), time.Now().Add(30 * time.Second)},
+		{time.Now().Add(time.Hour)},
 	}
 
 	for _, tc := range tests {
 		msg := &base.TaskMessage{
-			Type:     "something",
-			ID:       xid.New(),
-			Timeout:  int(tc.timeout.Seconds()),
-			Deadline: int(tc.deadline.Unix()),
+			Type:    "something",
+			ID:      xid.New(),
+			Payload: nil,
 		}
 
-		ctx, cancel := createContext(msg)
+		ctx, cancel := createContext(msg, tc.deadline)
 
 		select {
 		case x := <-ctx.Done():
-			t.Errorf("%s: <-ctx.Done() == %v, want nothing (it should block)", tc.desc, x)
+			t.Errorf("<-ctx.Done() == %v, want nothing (it should block)", x)
 		default:
 		}
 
 		got, ok := ctx.Deadline()
 		if !ok {
-			t.Errorf("%s: ctx.Deadline() returned false, want deadline to be set", tc.desc)
+			t.Errorf("ctx.Deadline() returned false, want deadline to be set")
 		}
-		if !cmp.Equal(tc.wantDeadline, got, cmpopts.EquateApproxTime(time.Second)) {
-			t.Errorf("%s: ctx.Deadline() returned %v, want %v", tc.desc, got, tc.wantDeadline)
+		if !cmp.Equal(tc.deadline, got) {
+			t.Errorf("ctx.Deadline() returned %v, want %v", got, tc.deadline)
 		}
 
 		cancel()
@@ -62,19 +54,37 @@ func TestCreateContextWithTimeRestrictions(t *testing.T) {
 	}
 }
 
-func TestCreateContextWithoutTimeRestrictions(t *testing.T) {
-	defer func() {
-		if r := recover(); r == nil {
-			t.Error("did not panic, want panic when both timeout and deadline are missing")
-		}
-	}()
-	msg := &base.TaskMessage{
-		Type:     "something",
-		ID:       xid.New(),
-		Timeout:  0, // zero indicates no timeout
-		Deadline: 0, // zero indicates no deadline
+func TestCreateContextWithPastDeadline(t *testing.T) {
+	tests := []struct {
+		deadline time.Time
+	}{
+		{time.Now().Add(-2 * time.Hour)},
+	}
+
+	for _, tc := range tests {
+		msg := &base.TaskMessage{
+			Type:    "something",
+			ID:      xid.New(),
+			Payload: nil,
+		}
+
+		ctx, cancel := createContext(msg, tc.deadline)
+		defer cancel()
+
+		select {
+		case <-ctx.Done():
+		default:
+			t.Errorf("ctx.Done() blocked, want it to be non-blocking")
+		}
+
+		got, ok := ctx.Deadline()
+		if !ok {
+			t.Errorf("ctx.Deadline() returned false, want deadline to be set")
+		}
+		if !cmp.Equal(tc.deadline, got) {
+			t.Errorf("ctx.Deadline() returned %v, want %v", got, tc.deadline)
+		}
 	}
-	createContext(msg)
 }
 
 func TestGetTaskMetadataFromContext(t *testing.T) {
@@ -87,7 +97,8 @@ func TestGetTaskMetadataFromContext(t *testing.T) {
 	}
 
 	for _, tc := range tests {
-		ctx, _ := createContext(tc.msg)
+		ctx, cancel := createContext(tc.msg, time.Now().Add(30*time.Minute))
+		defer cancel()
 
 		id, ok := GetTaskID(ctx)
 		if !ok {

internal/base/base.go

@@ -267,7 +267,7 @@ func (c *Cancelations) GetAll() []context.CancelFunc {
 type Broker interface {
 	Enqueue(msg *TaskMessage) error
 	EnqueueUnique(msg *TaskMessage, ttl time.Duration) error
-	Dequeue(qnames ...string) (*TaskMessage, int, error)
+	Dequeue(qnames ...string) (*TaskMessage, time.Time, error)
 	Done(msg *TaskMessage) error
 	Requeue(msg *TaskMessage) error
 	Schedule(msg *TaskMessage, processAt time.Time) error

internal/testbroker/testbroker.go

@@ -60,11 +60,11 @@ func (tb *TestBroker) EnqueueUnique(msg *base.TaskMessage, ttl time.Duration) er
 	return tb.real.EnqueueUnique(msg, ttl)
 }
 
-func (tb *TestBroker) Dequeue(qnames ...string) (*base.TaskMessage, int, error) {
+func (tb *TestBroker) Dequeue(qnames ...string) (*base.TaskMessage, time.Time, error) {
 	tb.mu.Lock()
 	defer tb.mu.Unlock()
 	if tb.sleeping {
-		return nil, 0, errRedisDown
+		return nil, time.Time{}, errRedisDown
 	}
 	return tb.real.Dequeue(qnames...)
 }

processor.go

@@ -158,30 +158,30 @@ func (p *processor) start(wg *sync.WaitGroup) {
 // exec pulls a task out of the queue and starts a worker goroutine to
 // process the task.
 func (p *processor) exec() {
-	qnames := p.queues()
-	msg, err := p.broker.Dequeue(qnames...)
-	switch {
-	case err == rdb.ErrNoProcessableTask:
-		p.logger.Debug("All queues are empty")
-		// Queues are empty, this is a normal behavior.
-		// Sleep to avoid slamming redis and let scheduler move tasks into queues.
-		// Note: We are not using blocking pop operation and polling queues instead.
-		// This adds significant load to redis.
-		time.Sleep(time.Second)
-		return
-	case err != nil:
-		if p.errLogLimiter.Allow() {
-			p.logger.Errorf("Dequeue error: %v", err)
-		}
-		return
-	}
-
 	select {
 	case <-p.abort:
-		// shutdown is starting, return immediately after requeuing the message.
-		p.requeue(msg)
 		return
 	case p.sema <- struct{}{}: // acquire token
+		qnames := p.queues()
+		msg, deadline, err := p.broker.Dequeue(qnames...)
+		switch {
+		case err == rdb.ErrNoProcessableTask:
+			p.logger.Debug("All queues are empty")
+			// Queues are empty, this is a normal behavior.
+			// Sleep to avoid slamming redis and let scheduler move tasks into queues.
+			// Note: We are not using blocking pop operation and polling queues instead.
+			// This adds significant load to redis.
+			time.Sleep(time.Second)
+			<-p.sema // release token
+			return
+		case err != nil:
+			if p.errLogLimiter.Allow() {
+				p.logger.Errorf("Dequeue error: %v", err)
+			}
+			<-p.sema // release token
+			return
+		}
+
 		p.starting <- msg
 		go func() {
 			defer func() {
@@ -189,7 +189,7 @@ func (p *processor) exec() {
 				<-p.sema // release token
 			}()
 
-			ctx, cancel := createContext(msg)
+			ctx, cancel := createContext(msg, deadline)
 			p.cancelations.Add(msg.ID.String(), cancel)
 			defer func() {
 				cancel()
@@ -206,6 +206,10 @@ func (p *processor) exec() {
 				p.logger.Warnf("Quitting worker. task id=%s", msg.ID)
 				p.requeue(msg)
 				return
+			case <-ctx.Done():
+				p.logger.Debugf("Retrying task. task id=%s", msg.ID) // TODO: Improve this log message and above
+				p.retryOrKill(msg, ctx.Err())
+				return
 			case resErr := <-resCh:
 				// Note: One of three things should happen.
 				// 1) Done  -> Removes the message from InProgress
@@ -215,11 +219,7 @@ func (p *processor) exec() {
 					if p.errHandler != nil {
 						p.errHandler.HandleError(task, resErr, msg.Retried, msg.Retry)
 					}
-					if msg.Retried >= msg.Retry {
-						p.kill(msg, resErr)
-					} else {
-						p.retry(msg, resErr)
-					}
+					p.retryOrKill(msg, resErr)
 					return
 				}
 				p.markAsDone(msg)
@@ -251,6 +251,14 @@ func (p *processor) markAsDone(msg *base.TaskMessage) {
 	}
 }
 
+func (p *processor) retryOrKill(msg *base.TaskMessage, err error) {
+	if msg.Retried >= msg.Retry {
+		p.kill(msg, err)
+	} else {
+		p.retry(msg, err)
+	}
+}
+
 func (p *processor) retry(msg *base.TaskMessage, e error) {
 	d := p.retryDelayFunc(msg.Retried, e, NewTask(msg.Type, msg.Payload))
 	retryAt := time.Now().Add(d)