Revert "Merge pull request #15976 from mesosphere/sur-k8sm-475-error-checking"

The given merge will be rebased manually and appended to the scheduler refactoring.

This reverts commit 8d923afe23, reversing
changes made to d7458ddd4c.

contrib/mesos/pkg/scheduler/plugin.go

@@ -278,18 +278,7 @@ func (k *kubeScheduler) Schedule(pod *api.Pod, unused algorithm.NodeLister) (str
 			log.Infof("aborting Schedule, pod has been deleted %+v", pod)
 			return "", noSuchPodErr
 		}
-
-		task, err := k.api.createPodTask(ctx, pod)
-		if err != nil {
-			return "", err
-		}
-
-		task, err = k.api.tasks().Register(task)
-		if err != nil {
-			return "", err
-		}
-
-		return k.doSchedule(task)
+		return k.doSchedule(k.api.tasks().Register(k.api.createPodTask(ctx, pod)))
 
 	//TODO(jdef) it's possible that the pod state has diverged from what
 	//we knew previously, we should probably update the task.Pod state here
@@ -305,7 +294,7 @@ func (k *kubeScheduler) Schedule(pod *api.Pod, unused algorithm.NodeLister) (str
 			// but we're going to let someone else handle it, probably the mesos task error handler
 			return "", fmt.Errorf("task %s has already been launched, aborting schedule", task.ID)
 		} else {
-			return k.doSchedule(task)
+			return k.doSchedule(task, nil)
 		}
 
 	default:
@@ -313,18 +302,16 @@ func (k *kubeScheduler) Schedule(pod *api.Pod, unused algorithm.NodeLister) (str
 	}
 }
 
-// doSchedule schedules the given task and returns the machine the task is scheduled on
-// or an error if the scheduling failed.
-func (k *kubeScheduler) doSchedule(task *podtask.T) (string, error) {
+// Call ScheduleFunc and subtract some resources, returning the name of the machine the task is scheduled on
+func (k *kubeScheduler) doSchedule(task *podtask.T, err error) (string, error) {
 	var offer offers.Perishable
-	var err error
-
 	if task.HasAcceptedOffer() {
 		// verify that the offer is still on the table
-		var ok bool
-		offer, ok = k.api.offers().Get(task.GetOfferId())
-
-		if !ok || offer.HasExpired() {
+		offerId := task.GetOfferId()
+		if offer, ok := k.api.offers().Get(offerId); ok && !offer.HasExpired() {
+			// skip tasks that have already have assigned offers
+			offer = task.Offer
+		} else {
 			task.Offer.Release()
 			task.Reset()
 			if err = k.api.tasks().Update(task); err != nil {
@@ -332,46 +319,36 @@ func (k *kubeScheduler) doSchedule(task *podtask.T) (string, error) {
 			}
 		}
 	}
-
-	if offer == nil {
+	if err == nil && offer == nil {
 		offer, err = k.api.algorithm().SchedulePod(k.api.offers(), k.api, task)
 	}
-
 	if err != nil {
 		return "", err
 	}
-
 	details := offer.Details()
 	if details == nil {
 		return "", fmt.Errorf("offer already invalid/expired for task %v", task.ID)
 	}
-
 	slaveId := details.GetSlaveId().GetValue()
-	slaveHostName := k.api.slaveHostNameFor(slaveId)
-	if slaveHostName == "" {
+	if slaveHostName := k.api.slaveHostNameFor(slaveId); slaveHostName == "" {
 		// not much sense in Release()ing the offer here since its owner died
 		offer.Release()
 		k.api.offers().Invalidate(details.Id.GetValue())
 		return "", fmt.Errorf("Slave disappeared (%v) while scheduling task %v", slaveId, task.ID)
-	}
+	} else {
+		if task.Offer != nil && task.Offer != offer {
+			return "", fmt.Errorf("task.offer assignment must be idempotent, task %+v: offer %+v", task, offer)
+		}
 
-	if task.Offer != nil && task.Offer != offer {
-		return "", fmt.Errorf("task.offer assignment must be idempotent, task %+v: offer %+v", task, offer)
-	}
+		task.Offer = offer
+		k.api.algorithm().Procurement()(task, details) // TODO(jdef) why is nothing checking the error returned here?
 
-	task.Offer = offer
-	if err := k.api.algorithm().Procurement()(task, details); err != nil {
-		offer.Release()
-		task.Reset()
-		return "", err
+		if err := k.api.tasks().Update(task); err != nil {
+			offer.Release()
+			return "", err
+		}
+		return slaveHostName, nil
 	}
-
-	if err := k.api.tasks().Update(task); err != nil {
-		offer.Release()
-		return "", err
-	}
-
-	return slaveHostName, nil
 }
 
 type queuer struct {

contrib/mesos/pkg/scheduler/plugin_test.go

@@ -880,17 +880,11 @@ func TestDeleteOne_PendingPod(t *testing.T) {
 			UID:       "foo0",
 			Namespace: api.NamespaceDefault,
 		}}}
-
-	task, err := podtask.New(api.NewDefaultContext(), "bar", *pod.Pod, &mesos.ExecutorInfo{})
+	_, err := reg.Register(podtask.New(api.NewDefaultContext(), "bar", *pod.Pod, &mesos.ExecutorInfo{}))
 	if err != nil {
 		t.Fatalf("failed to create task: %v", err)
 	}
 
-	_, err = reg.Register(task)
-	if err != nil {
-		t.Fatalf("failed to register task: %v", err)
-	}
-
 	// preconditions
 	qr := newQueuer(nil)
 	qr.podQueue.Add(pod, queue.ReplaceExisting)
@@ -923,13 +917,7 @@ func TestDeleteOne_Running(t *testing.T) {
 			UID:       "foo0",
 			Namespace: api.NamespaceDefault,
 		}}}
-
-	task, err := podtask.New(api.NewDefaultContext(), "bar", *pod.Pod, &mesos.ExecutorInfo{})
-	if err != nil {
-		t.Fatalf("unexpected error: %v", err)
-	}
-
-	task, err = reg.Register(task)
+	task, err := reg.Register(podtask.New(api.NewDefaultContext(), "bar", *pod.Pod, &mesos.ExecutorInfo{}))
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
 	}

contrib/mesos/pkg/scheduler/podtask/registry.go

@@ -41,7 +41,7 @@ const (
 type Registry interface {
 	// register the specified task with this registry, as long as the current error
 	// condition is nil. if no errors occur then return a copy of the registered task.
-	Register(*T) (*T, error)
+	Register(*T, error) (*T, error)
 
 	// unregister the specified task from this registry
 	Unregister(*T)
@@ -103,19 +103,20 @@ func (k *inMemoryRegistry) ForPod(podID string) (task *T, currentState StateType
 }
 
 // registers a pod task unless the spec'd error is not nil
-func (k *inMemoryRegistry) Register(task *T) (*T, error) {
-	k.rw.Lock()
-	defer k.rw.Unlock()
-	if _, found := k.podToTask[task.podKey]; found {
-		return nil, fmt.Errorf("task already registered for pod key %q", task.podKey)
+func (k *inMemoryRegistry) Register(task *T, err error) (*T, error) {
+	if err == nil {
+		k.rw.Lock()
+		defer k.rw.Unlock()
+		if _, found := k.podToTask[task.podKey]; found {
+			return nil, fmt.Errorf("task already registered for pod key %q", task.podKey)
+		}
+		if _, found := k.taskRegistry[task.ID]; found {
+			return nil, fmt.Errorf("task already registered for id %q", task.ID)
+		}
+		k.podToTask[task.podKey] = task.ID
+		k.taskRegistry[task.ID] = task
 	}
-	if _, found := k.taskRegistry[task.ID]; found {
-		return nil, fmt.Errorf("task already registered for id %q", task.ID)
-	}
-	k.podToTask[task.podKey] = task.ID
-	k.taskRegistry[task.ID] = task
-
-	return task.Clone(), nil
+	return task.Clone(), err
 }
 
 // updates internal task state. updates are limited to Spec, Flags, and Offer for

contrib/mesos/pkg/scheduler/podtask/registry_test.go

@@ -38,14 +38,14 @@ func TestInMemoryRegistry_RegisterGetUnregister(t *testing.T) {
 
 	// add a task
 	a, _ := fakePodTask("a")
-	a_clone, err := registry.Register(a)
+	a_clone, err := registry.Register(a, nil)
 	assert.NoError(err)
 	assert.Equal(a_clone.ID, a.ID)
 	assert.Equal(a_clone.podKey, a.podKey)
 
 	// add another task
 	b, _ := fakePodTask("b")
-	b_clone, err := registry.Register(b)
+	b_clone, err := registry.Register(b, nil)
 	assert.NoError(err)
 	assert.Equal(b_clone.ID, b.ID)
 	assert.Equal(b_clone.podKey, b.podKey)
@@ -79,21 +79,21 @@ func TestInMemoryRegistry_RegisterGetUnregister(t *testing.T) {
 	assert.Nil(task)
 
 	// re-add a task
-	a_clone, err = registry.Register(a)
+	a_clone, err = registry.Register(a, nil)
 	assert.Error(err)
 	assert.Nil(a_clone)
 
 	// re-add a task with another podKey, but same task id
 	another_a := a.Clone()
 	another_a.podKey = "another-pod"
-	another_a_clone, err := registry.Register(another_a)
+	another_a_clone, err := registry.Register(another_a, nil)
 	assert.Error(err)
 	assert.Nil(another_a_clone)
 
 	// re-add a task with another task ID, but same podKey
 	another_b := b.Clone()
 	another_b.ID = "another-task-id"
-	another_b_clone, err := registry.Register(another_b)
+	another_b_clone, err := registry.Register(another_b, nil)
 	assert.Error(err)
 	assert.Nil(another_b_clone)
 
@@ -124,7 +124,7 @@ func TestInMemoryRegistry_State(t *testing.T) {
 
 	// add a task
 	a, _ := fakePodTask("a")
-	a_clone, err := registry.Register(a)
+	a_clone, err := registry.Register(a, nil)
 	assert.NoError(err)
 	assert.Equal(a.State, a_clone.State)
 
@@ -167,7 +167,7 @@ func TestInMemoryRegistry_Update(t *testing.T) {
 	// create registry
 	registry := NewInMemoryRegistry()
 	a, _ := fakePodTask("a")
-	registry.Register(a.Clone()) // here clone a because we change it below
+	registry.Register(a.Clone(), nil) // here clone a because we change it below
 
 	// state changes are ignored
 	a.State = StateRunning
@@ -256,7 +256,7 @@ func testStateTrace(t *testing.T, transitions []transition) *Registry {
 
 	registry := NewInMemoryRegistry()
 	a, _ := fakePodTask("a")
-	a, _ = registry.Register(a)
+	a, _ = registry.Register(a, nil)
 
 	// initial pending state
 	assert.Equal(a.State, StatePending)

contrib/mesos/pkg/scheduler/scheduler.go

@@ -502,7 +502,7 @@ func (k *KubernetesScheduler) reconcileNonTerminalTask(driver bindings.Scheduler
 	} else if pod, err := k.client.Pods(namespace).Get(name); err == nil {
 		if t, ok, err := podtask.RecoverFrom(*pod); ok {
 			log.Infof("recovered task %v from metadata in pod %v/%v", taskId, namespace, name)
-			_, err := k.taskRegistry.Register(t)
+			_, err := k.taskRegistry.Register(t, nil)
 			if err != nil {
 				// someone beat us to it?!
 				log.Warningf("failed to register recovered task: %v", err)
@@ -912,7 +912,7 @@ func (ks *KubernetesScheduler) recoverTasks() error {
 				log.Errorf("failed to delete pod '%v/%v': %v", pod.Namespace, pod.Name, err)
 			}
 		} else if ok {
-			ks.taskRegistry.Register(t)
+			ks.taskRegistry.Register(t, nil)
 			recoverSlave(t)
 			log.Infof("recovered task %v from pod %v/%v", t.ID, pod.Namespace, pod.Name)
 		}