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