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https://github.com/optim-enterprises-bv/kubernetes.git
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kubectl: Support scaling deployments
This commit adds support for using kubectl scale to scale deployments. Makes use of the deployments/scale endpoint instead of updating deployment.spec.replicas directly.
This commit is contained in:
Michail Kargakis
@@ -28,74 +28,7 @@ import (
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"k8s.io/kubernetes/pkg/util/wait"
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)
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// ScalePrecondition describes a condition that must be true for the scale to take place
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// If CurrentSize == -1, it is ignored.
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// If CurrentResourceVersion is the empty string, it is ignored.
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// Otherwise they must equal the values in the replication controller for it to be valid.
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type ScalePrecondition struct {
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Size int
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ResourceVersion string
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}
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// A PreconditionError is returned when a replication controller fails to match
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// the scale preconditions passed to kubectl.
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type PreconditionError struct {
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Precondition string
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ExpectedValue string
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ActualValue string
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}
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func (pe PreconditionError) Error() string {
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return fmt.Sprintf("Expected %s to be %s, was %s", pe.Precondition, pe.ExpectedValue, pe.ActualValue)
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}
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type ControllerScaleErrorType int
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const (
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ControllerScaleGetFailure ControllerScaleErrorType = iota
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ControllerScaleUpdateFailure
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ControllerScaleUpdateInvalidFailure
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)
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// A ControllerScaleError is returned when a scale request passes
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// preconditions but fails to actually scale the controller.
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type ControllerScaleError struct {
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FailureType ControllerScaleErrorType
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ResourceVersion string
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ActualError error
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}
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func (c ControllerScaleError) Error() string {
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return fmt.Sprintf(
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"Scaling the controller failed with: %s; Current resource version %s",
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c.ActualError, c.ResourceVersion)
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}
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// ValidateReplicationController ensures that the preconditions match. Returns nil if they are valid, an error otherwise
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func (precondition *ScalePrecondition) ValidateReplicationController(controller *api.ReplicationController) error {
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if precondition.Size != -1 && controller.Spec.Replicas != precondition.Size {
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return PreconditionError{"replicas", strconv.Itoa(precondition.Size), strconv.Itoa(controller.Spec.Replicas)}
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}
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if precondition.ResourceVersion != "" && controller.ResourceVersion != precondition.ResourceVersion {
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return PreconditionError{"resource version", precondition.ResourceVersion, controller.ResourceVersion}
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}
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return nil
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}
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// ValidateJob ensures that the preconditions match. Returns nil if they are valid, an error otherwise
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func (precondition *ScalePrecondition) ValidateJob(job *extensions.Job) error {
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if precondition.Size != -1 && job.Spec.Parallelism == nil {
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return PreconditionError{"parallelism", strconv.Itoa(precondition.Size), "nil"}
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}
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if precondition.Size != -1 && *job.Spec.Parallelism != precondition.Size {
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return PreconditionError{"parallelism", strconv.Itoa(precondition.Size), strconv.Itoa(*job.Spec.Parallelism)}
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}
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if precondition.ResourceVersion != "" && job.ResourceVersion != precondition.ResourceVersion {
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return PreconditionError{"resource version", precondition.ResourceVersion, job.ResourceVersion}
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}
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return nil
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}
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// Scaler provides an interface for resources that can be scaled.
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type Scaler interface {
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// Scale scales the named resource after checking preconditions. It optionally
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// retries in the event of resource version mismatch (if retry is not nil),
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@@ -111,16 +44,54 @@ func ScalerFor(kind string, c client.Interface) (Scaler, error) {
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case "ReplicationController":
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return &ReplicationControllerScaler{c}, nil
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case "Job":
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return &JobScaler{c}, nil
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return &JobScaler{c.Extensions()}, nil
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case "Deployment":
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return &DeploymentScaler{c.Extensions()}, nil
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}
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return nil, fmt.Errorf("no scaler has been implemented for %q", kind)
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}
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type ReplicationControllerScaler struct {
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c client.Interface
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// ScalePrecondition describes a condition that must be true for the scale to take place
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// If CurrentSize == -1, it is ignored.
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// If CurrentResourceVersion is the empty string, it is ignored.
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// Otherwise they must equal the values in the resource for it to be valid.
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type ScalePrecondition struct {
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Size int
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ResourceVersion string
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}
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type JobScaler struct {
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c client.Interface
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// A PreconditionError is returned when a resource fails to match
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// the scale preconditions passed to kubectl.
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type PreconditionError struct {
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Precondition string
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ExpectedValue string
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ActualValue string
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}
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func (pe PreconditionError) Error() string {
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return fmt.Sprintf("Expected %s to be %s, was %s", pe.Precondition, pe.ExpectedValue, pe.ActualValue)
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}
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type ScaleErrorType int
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const (
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ScaleGetFailure ScaleErrorType = iota
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ScaleUpdateFailure
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ScaleUpdateInvalidFailure
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)
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// A ScaleError is returned when a scale request passes
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// preconditions but fails to actually scale the controller.
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type ScaleError struct {
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FailureType ScaleErrorType
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ResourceVersion string
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ActualError error
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}
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func (c ScaleError) Error() string {
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return fmt.Sprintf(
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"Scaling the resource failed with: %v; Current resource version %s",
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c.ActualError, c.ResourceVersion)
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}
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// RetryParams encapsulates the retry parameters used by kubectl's scaler.
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@@ -136,15 +107,15 @@ func NewRetryParams(interval, timeout time.Duration) *RetryParams {
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func ScaleCondition(r Scaler, precondition *ScalePrecondition, namespace, name string, count uint) wait.ConditionFunc {
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return func() (bool, error) {
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err := r.ScaleSimple(namespace, name, precondition, count)
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switch e, _ := err.(ControllerScaleError); err.(type) {
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switch e, _ := err.(ScaleError); err.(type) {
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case nil:
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return true, nil
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case ControllerScaleError:
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case ScaleError:
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// if it's invalid we shouldn't keep waiting
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if e.FailureType == ControllerScaleUpdateInvalidFailure {
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if e.FailureType == ScaleUpdateInvalidFailure {
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return false, err
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}
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if e.FailureType == ControllerScaleUpdateFailure {
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if e.FailureType == ScaleUpdateFailure {
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return false, nil
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}
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}
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@@ -152,10 +123,25 @@ func ScaleCondition(r Scaler, precondition *ScalePrecondition, namespace, name s
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}
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}
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// ValidateReplicationController ensures that the preconditions match. Returns nil if they are valid, an error otherwise
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func (precondition *ScalePrecondition) ValidateReplicationController(controller *api.ReplicationController) error {
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if precondition.Size != -1 && controller.Spec.Replicas != precondition.Size {
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return PreconditionError{"replicas", strconv.Itoa(precondition.Size), strconv.Itoa(controller.Spec.Replicas)}
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}
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if len(precondition.ResourceVersion) != 0 && controller.ResourceVersion != precondition.ResourceVersion {
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return PreconditionError{"resource version", precondition.ResourceVersion, controller.ResourceVersion}
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}
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return nil
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}
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type ReplicationControllerScaler struct {
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c client.Interface
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}
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func (scaler *ReplicationControllerScaler) ScaleSimple(namespace, name string, preconditions *ScalePrecondition, newSize uint) error {
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controller, err := scaler.c.ReplicationControllers(namespace).Get(name)
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if err != nil {
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return ControllerScaleError{ControllerScaleGetFailure, "Unknown", err}
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return ScaleError{ScaleGetFailure, "Unknown", err}
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}
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if preconditions != nil {
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if err := preconditions.ValidateReplicationController(controller); err != nil {
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@@ -166,11 +152,10 @@ func (scaler *ReplicationControllerScaler) ScaleSimple(namespace, name string, p
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// TODO: do retry on 409 errors here?
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if _, err := scaler.c.ReplicationControllers(namespace).Update(controller); err != nil {
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if errors.IsInvalid(err) {
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return ControllerScaleError{ControllerScaleUpdateInvalidFailure, controller.ResourceVersion, err}
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return ScaleError{ScaleUpdateInvalidFailure, controller.ResourceVersion, err}
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}
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return ControllerScaleError{ControllerScaleUpdateFailure, controller.ResourceVersion, err}
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return ScaleError{ScaleUpdateFailure, controller.ResourceVersion, err}
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}
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// TODO: do a better job of printing objects here.
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return nil
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}
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@@ -200,11 +185,29 @@ func (scaler *ReplicationControllerScaler) Scale(namespace, name string, newSize
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return nil
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}
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// ValidateJob ensures that the preconditions match. Returns nil if they are valid, an error otherwise.
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func (precondition *ScalePrecondition) ValidateJob(job *extensions.Job) error {
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if precondition.Size != -1 && job.Spec.Parallelism == nil {
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return PreconditionError{"parallelism", strconv.Itoa(precondition.Size), "nil"}
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}
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if precondition.Size != -1 && *job.Spec.Parallelism != precondition.Size {
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return PreconditionError{"parallelism", strconv.Itoa(precondition.Size), strconv.Itoa(*job.Spec.Parallelism)}
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}
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if len(precondition.ResourceVersion) != 0 && job.ResourceVersion != precondition.ResourceVersion {
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return PreconditionError{"resource version", precondition.ResourceVersion, job.ResourceVersion}
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}
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return nil
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}
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type JobScaler struct {
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c client.ExtensionsInterface
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}
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// ScaleSimple is responsible for updating job's parallelism.
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func (scaler *JobScaler) ScaleSimple(namespace, name string, preconditions *ScalePrecondition, newSize uint) error {
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job, err := scaler.c.Extensions().Jobs(namespace).Get(name)
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job, err := scaler.c.Jobs(namespace).Get(name)
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if err != nil {
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return ControllerScaleError{ControllerScaleGetFailure, "Unknown", err}
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return ScaleError{ScaleGetFailure, "Unknown", err}
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}
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if preconditions != nil {
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if err := preconditions.ValidateJob(job); err != nil {
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@@ -213,12 +216,11 @@ func (scaler *JobScaler) ScaleSimple(namespace, name string, preconditions *Scal
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}
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parallelism := int(newSize)
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job.Spec.Parallelism = ¶llelism
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if _, err := scaler.c.Extensions().Jobs(namespace).Update(job); err != nil {
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if _, err := scaler.c.Jobs(namespace).Update(job); err != nil {
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if errors.IsInvalid(err) {
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return ControllerScaleError{ControllerScaleUpdateInvalidFailure, job.ResourceVersion, err}
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return ScaleError{ScaleUpdateInvalidFailure, job.ResourceVersion, err}
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}
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return ControllerScaleError{ControllerScaleUpdateFailure, job.ResourceVersion, err}
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return ScaleError{ScaleUpdateFailure, job.ResourceVersion, err}
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}
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return nil
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}
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@@ -239,7 +241,7 @@ func (scaler *JobScaler) Scale(namespace, name string, newSize uint, preconditio
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return err
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}
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if waitForReplicas != nil {
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job, err := scaler.c.Extensions().Jobs(namespace).Get(name)
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job, err := scaler.c.Jobs(namespace).Get(name)
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if err != nil {
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return err
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}
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@@ -248,3 +250,65 @@ func (scaler *JobScaler) Scale(namespace, name string, newSize uint, preconditio
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}
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return nil
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}
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// ValidateDeployment ensures that the preconditions match. Returns nil if they are valid, an error otherwise.
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func (precondition *ScalePrecondition) ValidateDeployment(deployment *extensions.Deployment) error {
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if precondition.Size != -1 && deployment.Spec.Replicas != precondition.Size {
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return PreconditionError{"replicas", strconv.Itoa(precondition.Size), strconv.Itoa(deployment.Spec.Replicas)}
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}
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if len(precondition.ResourceVersion) != 0 && deployment.ResourceVersion != precondition.ResourceVersion {
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return PreconditionError{"resource version", precondition.ResourceVersion, deployment.ResourceVersion}
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}
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return nil
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}
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type DeploymentScaler struct {
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c client.ExtensionsInterface
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}
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// ScaleSimple is responsible for updating a deployment's desired replicas count.
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func (scaler *DeploymentScaler) ScaleSimple(namespace, name string, preconditions *ScalePrecondition, newSize uint) error {
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deployment, err := scaler.c.Deployments(namespace).Get(name)
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if err != nil {
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return ScaleError{ScaleGetFailure, "Unknown", err}
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}
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if preconditions != nil {
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if err := preconditions.ValidateDeployment(deployment); err != nil {
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return err
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}
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}
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scale := extensions.ScaleFromDeployment(deployment)
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scale.Spec.Replicas = int(newSize)
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if _, err := scaler.c.Scales(namespace).Update("Deployment", scale); err != nil {
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if errors.IsInvalid(err) {
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return ScaleError{ScaleUpdateInvalidFailure, deployment.ResourceVersion, err}
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}
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return ScaleError{ScaleUpdateFailure, deployment.ResourceVersion, err}
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}
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return nil
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}
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// Scale updates a deployment to a new size, with optional precondition check (if preconditions is not nil),
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// optional retries (if retry is not nil), and then optionally waits for the status to reach desired count.
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func (scaler *DeploymentScaler) Scale(namespace, name string, newSize uint, preconditions *ScalePrecondition, retry, waitForReplicas *RetryParams) error {
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if preconditions == nil {
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preconditions = &ScalePrecondition{-1, ""}
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}
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if retry == nil {
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// Make it try only once, immediately
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retry = &RetryParams{Interval: time.Millisecond, Timeout: time.Millisecond}
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}
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cond := ScaleCondition(scaler, preconditions, namespace, name, newSize)
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if err := wait.Poll(retry.Interval, retry.Timeout, cond); err != nil {
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return err
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}
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if waitForReplicas != nil {
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deployment, err := scaler.c.Deployments(namespace).Get(name)
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if err != nil {
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return err
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}
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return wait.Poll(waitForReplicas.Interval, waitForReplicas.Timeout,
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client.DeploymentHasDesiredReplicas(scaler.c, deployment))
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}
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return nil
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}
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