mirror of https://github.com/kubernetes/kops.git
71 lines
1.7 KiB
Go
71 lines
1.7 KiB
Go
/*
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Copyright 2019 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 util
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import (
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"fmt"
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"sync"
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"k8s.io/klog/v2"
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)
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// Stoppable implements the standard stop / shutdown logic
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type Stoppable struct {
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// mutex is used to enforce only a single call to Stop is active.
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// Needed because we allow stopping through an http endpoint and
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// allowing concurrent stoppers leads to stack traces.
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// We also use it for lazy-init
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mutex sync.Mutex
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shutdown bool
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stopChannel chan struct{}
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}
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// StopChannel gets the stopChannel, initializing it if needed
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func (s *Stoppable) StopChannel() <-chan struct{} {
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s.mutex.Lock()
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defer s.mutex.Unlock()
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if s.stopChannel == nil {
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s.stopChannel = make(chan struct{})
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}
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return s.stopChannel
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}
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// Stop stops the controller.
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func (s *Stoppable) Stop() error {
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s.mutex.Lock()
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defer s.mutex.Unlock()
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if s.shutdown {
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return fmt.Errorf("shutdown already in progress")
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}
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// We initialize the channel to avoid a race if we Stop before anyone is watching
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if s.stopChannel == nil {
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s.stopChannel = make(chan struct{})
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}
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close(s.stopChannel)
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klog.Infof("shutting down controller")
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s.shutdown = true
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return nil
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}
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func (s *Stoppable) StopRequested() bool {
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return s.shutdown
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}
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