packer-cn/builder/azure/common/interruptible_task.go

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package common
import (
"time"
)
type InterruptibleTaskResult struct {
Err error
IsCancelled bool
}
type InterruptibleTask struct {
IsCancelled func() bool
Task func(cancelCh <-chan struct{}) error
}
func NewInterruptibleTask(isCancelled func() bool, task func(cancelCh <-chan struct{}) error) *InterruptibleTask {
return &InterruptibleTask{
IsCancelled: isCancelled,
Task: task,
}
}
func StartInterruptibleTask(isCancelled func() bool, task func(cancelCh <-chan struct{}) error) InterruptibleTaskResult {
t := NewInterruptibleTask(isCancelled, task)
return t.Run()
}
func (s *InterruptibleTask) Run() InterruptibleTaskResult {
completeCh := make(chan error)
cancelCh := make(chan struct{})
defer close(cancelCh)
go func() {
err := s.Task(cancelCh)
completeCh <- err
// senders close, receivers check for close
close(completeCh)
}()
for {
if s.IsCancelled() {
return InterruptibleTaskResult{Err: nil, IsCancelled: true}
}
select {
case err := <-completeCh:
return InterruptibleTaskResult{Err: err, IsCancelled: false}
case <-time.After(100 * time.Millisecond):
}
}
}