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Merge pull request kubernetes#56077 from p0lyn0mial/kubectl_generic_s…
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…caler

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

adds generic scaler to kubectl

**What this PR does / why we need it**:
this PR adds generic scaler to kubectl. The implementation uses a polymorphic scale client capable of operating against scale subresources which can be found here https://github.com/kubernetes/client-go/tree/master/scale

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #

**Release note**:

```release-note
NONE
```
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Kubernetes Submit Queue authored Dec 19, 2017
2 parents 0d42e74 + da05fbe commit 622386e
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Showing 3 changed files with 398 additions and 0 deletions.
8 changes: 8 additions & 0 deletions pkg/kubectl/BUILD
View file
Original file line number Diff line number Diff line change
Expand Up @@ -56,6 +56,7 @@ go_test(
"//pkg/printers:go_default_library",
"//vendor/github.com/spf13/cobra:go_default_library",
"//vendor/k8s.io/api/apps/v1beta1:go_default_library",
"//vendor/k8s.io/api/apps/v1beta2:go_default_library",
"//vendor/k8s.io/api/autoscaling/v1:go_default_library",
"//vendor/k8s.io/api/batch/v1:go_default_library",
"//vendor/k8s.io/api/batch/v1beta1:go_default_library",
Expand All @@ -68,18 +69,24 @@ go_test(
"//vendor/k8s.io/api/scheduling/v1alpha1:go_default_library",
"//vendor/k8s.io/apimachinery/pkg/api/equality:go_default_library",
"//vendor/k8s.io/apimachinery/pkg/api/errors:go_default_library",
"//vendor/k8s.io/apimachinery/pkg/api/meta:go_default_library",
"//vendor/k8s.io/apimachinery/pkg/api/resource:go_default_library",
"//vendor/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
"//vendor/k8s.io/apimachinery/pkg/apis/meta/v1/unstructured:go_default_library",
"//vendor/k8s.io/apimachinery/pkg/runtime:go_default_library",
"//vendor/k8s.io/apimachinery/pkg/runtime/schema:go_default_library",
"//vendor/k8s.io/apimachinery/pkg/runtime/serializer:go_default_library",
"//vendor/k8s.io/apimachinery/pkg/util/intstr:go_default_library",
"//vendor/k8s.io/apimachinery/pkg/util/sets:go_default_library",
"//vendor/k8s.io/apimachinery/pkg/util/uuid:go_default_library",
"//vendor/k8s.io/apimachinery/pkg/watch:go_default_library",
"//vendor/k8s.io/client-go/discovery:go_default_library",
"//vendor/k8s.io/client-go/discovery/fake:go_default_library",
"//vendor/k8s.io/client-go/dynamic:go_default_library",
"//vendor/k8s.io/client-go/kubernetes/fake:go_default_library",
"//vendor/k8s.io/client-go/rest:go_default_library",
"//vendor/k8s.io/client-go/rest/fake:go_default_library",
"//vendor/k8s.io/client-go/scale:go_default_library",
"//vendor/k8s.io/client-go/testing:go_default_library",
"//vendor/k8s.io/client-go/util/testing:go_default_library",
],
Expand Down Expand Up @@ -183,6 +190,7 @@ go_library(
"//vendor/k8s.io/client-go/kubernetes/typed/apps/v1beta1:go_default_library",
"//vendor/k8s.io/client-go/kubernetes/typed/extensions/v1beta1:go_default_library",
"//vendor/k8s.io/client-go/rest:go_default_library",
"//vendor/k8s.io/client-go/scale:go_default_library",
"//vendor/k8s.io/client-go/util/integer:go_default_library",
"//vendor/k8s.io/client-go/util/jsonpath:go_default_library",
"//vendor/k8s.io/client-go/util/retry:go_default_library",
Expand Down
93 changes: 93 additions & 0 deletions pkg/kubectl/scale.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@ import (
"strconv"
"time"

autoscalingapi "k8s.io/api/autoscaling/v1"
"k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/fields"
Expand All @@ -31,6 +32,8 @@ import (
"k8s.io/kubernetes/pkg/apis/batch"
api "k8s.io/kubernetes/pkg/apis/core"
"k8s.io/kubernetes/pkg/apis/extensions"

scaleclient "k8s.io/client-go/scale"
"k8s.io/kubernetes/pkg/client/clientset_generated/internalclientset"
appsclient "k8s.io/kubernetes/pkg/client/clientset_generated/internalclientset/typed/apps/internalversion"
batchclient "k8s.io/kubernetes/pkg/client/clientset_generated/internalclientset/typed/batch/internalversion"
Expand Down Expand Up @@ -516,3 +519,93 @@ func (scaler *DeploymentScaler) Scale(namespace, name string, newSize uint, prec
}
return nil
}

// validateGeneric ensures that the preconditions match. Returns nil if they are valid, otherwise an error
// TODO(p0lyn0mial): when the work on GenericScaler is done, rename validateGeneric to validate
func (precondition *ScalePrecondition) validateGeneric(scale *autoscalingapi.Scale) error {
if precondition.Size != -1 && int(scale.Spec.Replicas) != precondition.Size {
return PreconditionError{"replicas", strconv.Itoa(precondition.Size), strconv.Itoa(int(scale.Spec.Replicas))}
}
if len(precondition.ResourceVersion) > 0 && scale.ResourceVersion != precondition.ResourceVersion {
return PreconditionError{"resource version", precondition.ResourceVersion, scale.ResourceVersion}
}
return nil
}

// GenericScaler can update scales for resources in a particular namespace
// TODO(o0lyn0mial): when the work on GenericScaler is done, don't
// export the GenericScaler. Instead use ScalerFor method for getting the Scaler
// also update the UTs
type GenericScaler struct {
scaleNamespacer scaleclient.ScalesGetter
targetGR schema.GroupResource
}

var _ Scaler = &GenericScaler{}

// ScaleSimple updates a scale of a given resource. It returns the resourceVersion of the scale if the update was successful.
func (s *GenericScaler) ScaleSimple(namespace, name string, preconditions *ScalePrecondition, newSize uint) (updatedResourceVersion string, err error) {
scale, err := s.scaleNamespacer.Scales(namespace).Get(s.targetGR, name)
if err != nil {
return "", ScaleError{ScaleGetFailure, "", err}
}
if preconditions != nil {
if err := preconditions.validateGeneric(scale); err != nil {
return "", err
}
}

scale.Spec.Replicas = int32(newSize)
updatedScale, err := s.scaleNamespacer.Scales(namespace).Update(s.targetGR, scale)
if err != nil {
if errors.IsConflict(err) {
return "", ScaleError{ScaleUpdateConflictFailure, scale.ResourceVersion, err}
}
return "", ScaleError{ScaleUpdateFailure, scale.ResourceVersion, err}
}
return updatedScale.ResourceVersion, nil
}

// Scale updates a scale of a given resource to a new size, with optional precondition check (if preconditions is not nil),
// optional retries (if retry is not nil), and then optionally waits for the status to reach desired count.
func (s *GenericScaler) Scale(namespace, resourceName string, newSize uint, preconditions *ScalePrecondition, retry, waitForReplicas *RetryParams) error {
if preconditions == nil {
preconditions = &ScalePrecondition{-1, ""}
}
if retry == nil {
// make it try only once, immediately
retry = &RetryParams{Interval: time.Millisecond, Timeout: time.Millisecond}
}
cond := ScaleCondition(s, preconditions, namespace, resourceName, newSize, nil)
if err := wait.PollImmediate(retry.Interval, retry.Timeout, cond); err != nil {
return err
}
if waitForReplicas != nil {
err := wait.PollImmediate(
waitForReplicas.Interval,
waitForReplicas.Timeout,
scaleHasDesiredReplicas(s.scaleNamespacer, s.targetGR, resourceName, namespace, int32(newSize)))
if err == wait.ErrWaitTimeout {
return fmt.Errorf("timed out waiting for %q to be synced", resourceName)
}
return err
}
return nil
}

// scaleHasDesiredReplicas returns a condition that will be true if and only if the desired replica
// count for a scale (Spec) equals its updated replicas count (Status)
func scaleHasDesiredReplicas(sClient scaleclient.ScalesGetter, gr schema.GroupResource, resourceName string, namespace string, desiredReplicas int32) wait.ConditionFunc {
return func() (bool, error) {
actualScale, err := sClient.Scales(namespace).Get(gr, resourceName)
if err != nil {
return false, err
}
// this means the desired scale target has been reset by something else
if actualScale.Spec.Replicas != desiredReplicas {
return true, nil
}
return actualScale.Spec.Replicas == actualScale.Status.Replicas &&
desiredReplicas == actualScale.Status.Replicas, nil
}
}
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