mirror of
https://github.com/ceph/ceph-csi.git
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106 lines
3.6 KiB
Go
106 lines
3.6 KiB
Go
/*
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Copyright 2016 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package retry
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import (
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"time"
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"k8s.io/apimachinery/pkg/api/errors"
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"k8s.io/apimachinery/pkg/util/wait"
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)
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// DefaultRetry is the recommended retry for a conflict where multiple clients
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// are making changes to the same resource.
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var DefaultRetry = wait.Backoff{
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Steps: 5,
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Duration: 10 * time.Millisecond,
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Factor: 1.0,
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Jitter: 0.1,
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}
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// DefaultBackoff is the recommended backoff for a conflict where a client
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// may be attempting to make an unrelated modification to a resource under
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// active management by one or more controllers.
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var DefaultBackoff = wait.Backoff{
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Steps: 4,
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Duration: 10 * time.Millisecond,
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Factor: 5.0,
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Jitter: 0.1,
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}
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// OnError allows the caller to retry fn in case the error returned by fn is retriable
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// according to the provided function. backoff defines the maximum retries and the wait
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// interval between two retries.
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func OnError(backoff wait.Backoff, retriable func(error) bool, fn func() error) error {
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var lastErr error
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err := wait.ExponentialBackoff(backoff, func() (bool, error) {
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err := fn()
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switch {
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case err == nil:
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return true, nil
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case retriable(err):
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lastErr = err
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return false, nil
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default:
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return false, err
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}
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})
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if err == wait.ErrWaitTimeout {
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err = lastErr
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}
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return err
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}
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// RetryOnConflict is used to make an update to a resource when you have to worry about
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// conflicts caused by other code making unrelated updates to the resource at the same
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// time. fn should fetch the resource to be modified, make appropriate changes to it, try
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// to update it, and return (unmodified) the error from the update function. On a
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// successful update, RetryOnConflict will return nil. If the update function returns a
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// "Conflict" error, RetryOnConflict will wait some amount of time as described by
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// backoff, and then try again. On a non-"Conflict" error, or if it retries too many times
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// and gives up, RetryOnConflict will return an error to the caller.
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//
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// err := retry.RetryOnConflict(retry.DefaultRetry, func() error {
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// // Fetch the resource here; you need to refetch it on every try, since
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// // if you got a conflict on the last update attempt then you need to get
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// // the current version before making your own changes.
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// pod, err := c.Pods("mynamespace").Get(name, metav1.GetOptions{})
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// if err ! nil {
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// return err
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// }
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//
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// // Make whatever updates to the resource are needed
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// pod.Status.Phase = v1.PodFailed
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//
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// // Try to update
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// _, err = c.Pods("mynamespace").UpdateStatus(pod)
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// // You have to return err itself here (not wrapped inside another error)
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// // so that RetryOnConflict can identify it correctly.
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// return err
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// })
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// if err != nil {
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// // May be conflict if max retries were hit, or may be something unrelated
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// // like permissions or a network error
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// return err
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// }
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// ...
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//
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// TODO: Make Backoff an interface?
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func RetryOnConflict(backoff wait.Backoff, fn func() error) error {
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return OnError(backoff, errors.IsConflict, fn)
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}
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