kubectl: Make scaling smarter

pkg/client/unversioned/conditions.go

@@ -54,7 +54,7 @@ func JobHasDesiredParallelism(c ExtensionsInterface, job *extensions.Job) wait.C
 		}
 
 		// desired parallelism can be either the exact number, in which case return immediately
-		if job.Status.Active == *job.Spec.Parallelism {
+		if job.Spec.Parallelism != nil && job.Status.Active == *job.Spec.Parallelism {
 			return true, nil
 		}
 		// otherwise count successful

pkg/kubectl/cmd/scale.go

@@ -146,6 +146,10 @@ func RunScale(f *cmdutil.Factory, out io.Writer, cmd *cobra.Command, args []stri
 	errs := []error{}
 	for _, info := range infos {
 		if err := scaler.Scale(info.Namespace, info.Name, uint(count), precondition, retry, waitForReplicas); err != nil {
+			if scaleErr, ok := err.(kubectl.ScaleError); ok && scaleErr.FailureType == kubectl.AlreadyScaled {
+				cmdutil.PrintSuccess(mapper, shortOutput, out, info.Mapping.Resource, info.Name, "already scaled")
+				continue
+			}
 			errs = append(errs, err)
 			continue
 		}

pkg/kubectl/scale.go

@@ -17,6 +17,7 @@ limitations under the License.
 package kubectl
 
 import (
+	goerrors "errors"
 	"fmt"
 	"strconv"
 	"time"
@@ -79,8 +80,13 @@ const (
 	ScaleGetFailure ScaleErrorType = iota
 	ScaleUpdateFailure
 	ScaleUpdateInvalidFailure
+	// AlreadyScaled is not really an error but we need a way to surface to the client that
+	// the scaling didn't happen because we already have the desired state the user asked for.
+	AlreadyScaled
 )
 
+var alreadyScaledErr = goerrors.New("desired replicas already equals the requested replicas")
+
 // A ScaleError is returned when a scale request passes
 // preconditions but fails to actually scale the controller.
 type ScaleError struct {
@@ -112,12 +118,14 @@ func ScaleCondition(r Scaler, precondition *ScalePrecondition, namespace, name s
 		case nil:
 			return true, nil
 		case ScaleError:
-			// if it's invalid we shouldn't keep waiting
-			if e.FailureType == ScaleUpdateInvalidFailure {
+			switch e.FailureType {
+			case ScaleUpdateInvalidFailure:
+				// if it's invalid we shouldn't keep waiting
 				return false, err
-			}
-			if e.FailureType == ScaleUpdateFailure {
+			case ScaleUpdateFailure:
 				return false, nil
+			case AlreadyScaled:
+				return false, err
 			}
 		}
 		return false, err
@@ -149,8 +157,10 @@ func (scaler *ReplicationControllerScaler) ScaleSimple(namespace, name string, p
 			return err
 		}
 	}
+	if controller.Spec.Replicas == int(newSize) {
+		return ScaleError{AlreadyScaled, controller.ResourceVersion, alreadyScaledErr}
+	}
 	controller.Spec.Replicas = int(newSize)
-	// TODO: do retry on 409 errors here?
 	if _, err := scaler.c.ReplicationControllers(namespace).Update(controller); err != nil {
 		if errors.IsInvalid(err) {
 			return ScaleError{ScaleUpdateInvalidFailure, controller.ResourceVersion, err}
@@ -216,6 +226,9 @@ func (scaler *JobScaler) ScaleSimple(namespace, name string, preconditions *Scal
 		}
 	}
 	parallelism := int(newSize)
+	if job.Spec.Parallelism != nil && *job.Spec.Parallelism == parallelism {
+		return ScaleError{AlreadyScaled, job.ResourceVersion, alreadyScaledErr}
+	}
 	job.Spec.Parallelism = &parallelism
 	if _, err := scaler.c.Jobs(namespace).Update(job); err != nil {
 		if errors.IsInvalid(err) {
@@ -279,6 +292,9 @@ func (scaler *DeploymentScaler) ScaleSimple(namespace, name string, precondition
 		}
 	}
 	scale := extensions.ScaleFromDeployment(deployment)
+	if scale.Spec.Replicas == int(newSize) {
+		return ScaleError{AlreadyScaled, deployment.ResourceVersion, alreadyScaledErr}
+	}
 	scale.Spec.Replicas = int(newSize)
 	if _, err := scaler.c.Scales(namespace).Update("Deployment", scale); err != nil {
 		if errors.IsInvalid(err) {

pkg/kubectl/scale_test.go

@@ -132,6 +132,31 @@ func TestReplicationControllerScaleFailsPreconditions(t *testing.T) {
 	}
 }
 
+func TestReplicationControllerAlreadyScaled(t *testing.T) {
+	fake := testclient.NewSimpleFake(&api.ReplicationController{
+		Spec: api.ReplicationControllerSpec{
+			Replicas: 3,
+		},
+	})
+	scaler := ReplicationControllerScaler{fake}
+	count := uint(3)
+	name := "foo"
+	err := scaler.Scale("default", name, count, nil, nil, nil)
+	if err == nil {
+		t.Fatal("expected AlreadyScaled error, got nil")
+	}
+	if scaleErr, ok := err.(ScaleError); !ok || scaleErr.FailureType != AlreadyScaled {
+		t.Fatalf("expected AlreadyScaled error, got %s", scaleErr.FailureType)
+	}
+	actions := fake.Actions()
+	if len(actions) != 1 {
+		t.Fatalf("unexpected actions: %v, expected 1 action (get)", actions)
+	}
+	if action, ok := actions[0].(testclient.GetAction); !ok || action.GetResource() != "replicationcontrollers" || action.GetName() != name {
+		t.Errorf("unexpected action: %v, expected get-replicationController %s", actions[0], name)
+	}
+}
+
 func TestValidateReplicationController(t *testing.T) {
 	tests := []struct {
 		preconditions ScalePrecondition
@@ -362,6 +387,32 @@ func TestJobScaleFailsPreconditions(t *testing.T) {
 	}
 }
 
+func TestJobAlreadyScaled(t *testing.T) {
+	three := 3
+	fake := testclient.NewSimpleFake(&extensions.Job{
+		Spec: extensions.JobSpec{
+			Parallelism: &three,
+		},
+	})
+	scaler := JobScaler{&testclient.FakeExperimental{fake}}
+	count := uint(3)
+	name := "foo"
+	err := scaler.Scale("default", name, count, nil, nil, nil)
+	if err == nil {
+		t.Fatal("expected AlreadyScaled error, got nil")
+	}
+	if scaleErr, ok := err.(ScaleError); !ok || scaleErr.FailureType != AlreadyScaled {
+		t.Fatalf("expected AlreadyScaled error, got %s", scaleErr.FailureType)
+	}
+	actions := fake.Actions()
+	if len(actions) != 1 {
+		t.Fatalf("unexpected actions: %v, expected 1 action (get)", actions)
+	}
+	if action, ok := actions[0].(testclient.GetAction); !ok || action.GetResource() != "jobs" || action.GetName() != name {
+		t.Errorf("unexpected action: %v, expected get-job %s", actions[0], name)
+	}
+}
+
 func TestValidateJob(t *testing.T) {
 	zero, ten, twenty := 0, 10, 20
 	tests := []struct {
@@ -626,6 +677,31 @@ func TestDeploymentScaleFailsPreconditions(t *testing.T) {
 	}
 }
 
+func TestDeploymentAlreadyScaled(t *testing.T) {
+	fake := testclient.NewSimpleFake(&extensions.Deployment{
+		Spec: extensions.DeploymentSpec{
+			Replicas: 3,
+		},
+	})
+	scaler := DeploymentScaler{&testclient.FakeExperimental{fake}}
+	count := uint(3)
+	name := "foo"
+	err := scaler.Scale("default", name, count, nil, nil, nil)
+	if err == nil {
+		t.Fatal("expected AlreadyScaled error, got nil")
+	}
+	if scaleErr, ok := err.(ScaleError); !ok || scaleErr.FailureType != AlreadyScaled {
+		t.Fatalf("expected AlreadyScaled error, got %s", scaleErr.FailureType)
+	}
+	actions := fake.Actions()
+	if len(actions) != 1 {
+		t.Fatalf("unexpected actions: %v, expected 1 action (get)", actions)
+	}
+	if action, ok := actions[0].(testclient.GetAction); !ok || action.GetResource() != "deployments" || action.GetName() != name {
+		t.Errorf("unexpected action: %v, expected get-deployment %s", actions[0], name)
+	}
+}
+
 func TestValidateDeployment(t *testing.T) {
 	zero, ten, twenty := 0, 10, 20
 	tests := []struct {

pkg/kubectl/stop.go

@@ -23,7 +23,6 @@ import (
 
 	"k8s.io/kubernetes/pkg/api"
 	"k8s.io/kubernetes/pkg/api/errors"
-	"k8s.io/kubernetes/pkg/api/meta"
 	"k8s.io/kubernetes/pkg/api/unversioned"
 	"k8s.io/kubernetes/pkg/apis/extensions"
 	client "k8s.io/kubernetes/pkg/client/unversioned"
@@ -83,30 +82,6 @@ func ReaperForReplicationController(c client.Interface, timeout time.Duration) (
 	return &ReplicationControllerReaper{c, Interval, timeout}, nil
 }
 
-type ReplicationControllerReaper struct {
-	client.Interface
-	pollInterval, timeout time.Duration
-}
-type DaemonSetReaper struct {
-	client.Interface
-	pollInterval, timeout time.Duration
-}
-type JobReaper struct {
-	client.Interface
-	pollInterval, timeout time.Duration
-}
-type PodReaper struct {
-	client.Interface
-}
-type ServiceReaper struct {
-	client.Interface
-}
-
-type objInterface interface {
-	Delete(name string) error
-	Get(name string) (meta.Object, error)
-}
-
 // getOverlappingControllers finds rcs that this controller overlaps, as well as rcs overlapping this controller.
 func getOverlappingControllers(c client.ReplicationControllerInterface, rc *api.ReplicationController) ([]api.ReplicationController, error) {
 	rcs, err := c.List(api.ListOptions{})
@@ -124,6 +99,11 @@ func getOverlappingControllers(c client.ReplicationControllerInterface, rc *api.
 	return matchingRCs, nil
 }
 
+type ReplicationControllerReaper struct {
+	client.Interface
+	pollInterval, timeout time.Duration
+}
+
 func (reaper *ReplicationControllerReaper) Stop(namespace, name string, timeout time.Duration, gracePeriod *api.DeleteOptions) error {
 	rc := reaper.ReplicationControllers(namespace)
 	scaler, err := ScalerFor(api.Kind("ReplicationController"), *reaper)
@@ -181,7 +161,9 @@ func (reaper *ReplicationControllerReaper) Stop(namespace, name string, timeout
 		retry := NewRetryParams(reaper.pollInterval, reaper.timeout)
 		waitForReplicas := NewRetryParams(reaper.pollInterval, timeout)
 		if err = scaler.Scale(namespace, name, 0, nil, retry, waitForReplicas); err != nil {
-			return err
+			if scaleErr, ok := err.(ScaleError); !ok || scaleErr.FailureType != AlreadyScaled {
+				return err
+			}
 		}
 	}
 	if err := rc.Delete(name); err != nil {
@@ -190,6 +172,11 @@ func (reaper *ReplicationControllerReaper) Stop(namespace, name string, timeout
 	return nil
 }
 
+type DaemonSetReaper struct {
+	client.Interface
+	pollInterval, timeout time.Duration
+}
+
 func (reaper *DaemonSetReaper) Stop(namespace, name string, timeout time.Duration, gracePeriod *api.DeleteOptions) error {
 	ds, err := reaper.Extensions().DaemonSets(namespace).Get(name)
 	if err != nil {
@@ -227,6 +214,11 @@ func (reaper *DaemonSetReaper) Stop(namespace, name string, timeout time.Duratio
 	return nil
 }
 
+type JobReaper struct {
+	client.Interface
+	pollInterval, timeout time.Duration
+}
+
 func (reaper *JobReaper) Stop(namespace, name string, timeout time.Duration, gracePeriod *api.DeleteOptions) error {
 	jobs := reaper.Extensions().Jobs(namespace)
 	pods := reaper.Pods(namespace)
@@ -248,7 +240,9 @@ func (reaper *JobReaper) Stop(namespace, name string, timeout time.Duration, gra
 	retry := NewRetryParams(reaper.pollInterval, reaper.timeout)
 	waitForJobs := NewRetryParams(reaper.pollInterval, timeout)
 	if err = scaler.Scale(namespace, name, 0, nil, retry, waitForJobs); err != nil {
-		return err
+		if scaleErr, ok := err.(ScaleError); !ok || scaleErr.FailureType != AlreadyScaled {
+			return err
+		}
 	}
 	// at this point only dead pods are left, that should be removed
 	selector, _ := extensions.LabelSelectorAsSelector(job.Spec.Selector)
@@ -276,6 +270,10 @@ func (reaper *JobReaper) Stop(namespace, name string, timeout time.Duration, gra
 	return nil
 }
 
+type PodReaper struct {
+	client.Interface
+}
+
 func (reaper *PodReaper) Stop(namespace, name string, timeout time.Duration, gracePeriod *api.DeleteOptions) error {
 	pods := reaper.Pods(namespace)
 	_, err := pods.Get(name)
@@ -289,6 +287,10 @@ func (reaper *PodReaper) Stop(namespace, name string, timeout time.Duration, gra
 	return nil
 }
 
+type ServiceReaper struct {
+	client.Interface
+}
+
 func (reaper *ServiceReaper) Stop(namespace, name string, timeout time.Duration, gracePeriod *api.DeleteOptions) error {
 	services := reaper.Services(namespace)
 	_, err := services.Get(name)