1/* 2Copyright 2016 The Kubernetes Authors. 3 4Licensed under the Apache License, Version 2.0 (the "License"); 5you may not use this file except in compliance with the License. 6You may obtain a copy of the License at 7 8 http://www.apache.org/licenses/LICENSE-2.0 9 10Unless required by applicable law or agreed to in writing, software 11distributed under the License is distributed on an "AS IS" BASIS, 12WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13See the License for the specific language governing permissions and 14limitations under the License. 15*/ 16 17package retry 18 19import ( 20 "time" 21 22 "k8s.io/apimachinery/pkg/api/errors" 23 "k8s.io/apimachinery/pkg/util/wait" 24) 25 26// DefaultRetry is the recommended retry for a conflict where multiple clients 27// are making changes to the same resource. 28var DefaultRetry = wait.Backoff{ 29 Steps: 5, 30 Duration: 10 * time.Millisecond, 31 Factor: 1.0, 32 Jitter: 0.1, 33} 34 35// DefaultBackoff is the recommended backoff for a conflict where a client 36// may be attempting to make an unrelated modification to a resource under 37// active management by one or more controllers. 38var DefaultBackoff = wait.Backoff{ 39 Steps: 4, 40 Duration: 10 * time.Millisecond, 41 Factor: 5.0, 42 Jitter: 0.1, 43} 44 45// RetryConflict executes the provided function repeatedly, retrying if the server returns a conflicting 46// write. Callers should preserve previous executions if they wish to retry changes. It performs an 47// exponential backoff. 48// 49// var pod *api.Pod 50// err := RetryOnConflict(DefaultBackoff, func() (err error) { 51// pod, err = c.Pods("mynamespace").UpdateStatus(podStatus) 52// return 53// }) 54// if err != nil { 55// // may be conflict if max retries were hit 56// return err 57// } 58// ... 59// 60// TODO: Make Backoff an interface? 61func RetryOnConflict(backoff wait.Backoff, fn func() error) error { 62 var lastConflictErr error 63 err := wait.ExponentialBackoff(backoff, func() (bool, error) { 64 err := fn() 65 switch { 66 case err == nil: 67 return true, nil 68 case errors.IsConflict(err): 69 lastConflictErr = err 70 return false, nil 71 default: 72 return false, err 73 } 74 }) 75 if err == wait.ErrWaitTimeout { 76 err = lastConflictErr 77 } 78 return err 79} 80