124929e373
- tasks subpackage responsible for managing system process lifecycle - minion propagates SIGTERM to child procs - child procs will be SIGKILL'd upon parent process death
99 lines
2.7 KiB
Go
99 lines
2.7 KiB
Go
/*
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Copyright 2015 The Kubernetes Authors All rights reserved.
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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 tasks
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type Events interface {
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// Close stops delivery of events in the completion and errors channels; callers must close this when they intend to no longer read from completion() or errors()
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Close() Events
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// Completion reports Completion events as they happen
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Completion() <-chan *Completion
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// Done returns a signal chan that closes when all tasks have completed and there are no more events to deliver
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Done() <-chan struct{}
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}
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type eventsImpl struct {
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tc chan *Completion
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stopForwarding chan struct{}
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done <-chan struct{}
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}
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func newEventsImpl(tcin <-chan *Completion, done <-chan struct{}) *eventsImpl {
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ei := &eventsImpl{
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tc: make(chan *Completion),
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stopForwarding: make(chan struct{}),
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done: done,
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}
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go func() {
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defer close(ei.tc)
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forwardCompletionUntil(tcin, ei.tc, ei.stopForwarding, done, nil)
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}()
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return ei
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}
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func (e *eventsImpl) Close() Events { close(e.stopForwarding); return e }
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func (e *eventsImpl) Completion() <-chan *Completion { return e.tc }
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func (e *eventsImpl) Done() <-chan struct{} { return e.done }
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// forwardCompletionUntil is a generic pipe that forwards objects between channels.
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// if discard is closed, objects are silently dropped.
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// if tap != nil then it's invoked for each object as it's read from tin, but before it's written to tch.
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// returns when either reading from tin completes (no more objects, and is closed), or else
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// abort is closed, which ever happens first.
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func forwardCompletionUntil(tin <-chan *Completion, tch chan<- *Completion, discard <-chan struct{}, abort <-chan struct{}, tap func(*Completion, bool)) {
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var tc *Completion
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var ok bool
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forwardLoop:
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for {
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select {
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case tc, ok = <-tin:
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if !ok {
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return
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}
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if tap != nil {
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tap(tc, false)
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}
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select {
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case <-abort:
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break forwardLoop
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case <-discard:
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case tch <- tc:
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}
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case <-abort:
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// best effort
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select {
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case tc, ok = <-tin:
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if ok {
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if tap != nil {
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tap(tc, true)
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}
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break forwardLoop
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}
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default:
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}
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return
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}
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}
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// best effort
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select {
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case tch <- tc:
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case <-discard:
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default:
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}
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}
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