mirror of https://github.com/k3s-io/k3s
105 lines
3.2 KiB
Go
105 lines
3.2 KiB
Go
/*
|
|
Copyright 2016 The Kubernetes Authors.
|
|
|
|
Licensed under the Apache License, Version 2.0 (the "License");
|
|
you may not use this file except in compliance with the License.
|
|
You may obtain a copy of the License at
|
|
|
|
http://www.apache.org/licenses/LICENSE-2.0
|
|
|
|
Unless required by applicable law or agreed to in writing, software
|
|
distributed under the License is distributed on an "AS IS" BASIS,
|
|
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
See the License for the specific language governing permissions and
|
|
limitations under the License.
|
|
*/
|
|
|
|
package interrupt
|
|
|
|
import (
|
|
"os"
|
|
"os/signal"
|
|
"sync"
|
|
"syscall"
|
|
)
|
|
|
|
// terminationSignals are signals that cause the program to exit in the
|
|
// supported platforms (linux, darwin, windows).
|
|
var terminationSignals = []os.Signal{syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM, syscall.SIGQUIT}
|
|
|
|
// Handler guarantees execution of notifications after a critical section (the function passed
|
|
// to a Run method), even in the presence of process termination. It guarantees exactly once
|
|
// invocation of the provided notify functions.
|
|
type Handler struct {
|
|
notify []func()
|
|
final func(os.Signal)
|
|
once sync.Once
|
|
}
|
|
|
|
// Chain creates a new handler that invokes all notify functions when the critical section exits
|
|
// and then invokes the optional handler's notifications. This allows critical sections to be
|
|
// nested without losing exactly once invocations. Notify functions can invoke any cleanup needed
|
|
// but should not exit (which is the responsibility of the parent handler).
|
|
func Chain(handler *Handler, notify ...func()) *Handler {
|
|
if handler == nil {
|
|
return New(nil, notify...)
|
|
}
|
|
return New(handler.Signal, append(notify, handler.Close)...)
|
|
}
|
|
|
|
// New creates a new handler that guarantees all notify functions are run after the critical
|
|
// section exits (or is interrupted by the OS), then invokes the final handler. If no final
|
|
// handler is specified, the default final is `os.Exit(1)`. A handler can only be used for
|
|
// one critical section.
|
|
func New(final func(os.Signal), notify ...func()) *Handler {
|
|
return &Handler{
|
|
final: final,
|
|
notify: notify,
|
|
}
|
|
}
|
|
|
|
// Close executes all the notification handlers if they have not yet been executed.
|
|
func (h *Handler) Close() {
|
|
h.once.Do(func() {
|
|
for _, fn := range h.notify {
|
|
fn()
|
|
}
|
|
})
|
|
}
|
|
|
|
// Signal is called when an os.Signal is received, and guarantees that all notifications
|
|
// are executed, then the final handler is executed. This function should only be called once
|
|
// per Handler instance.
|
|
func (h *Handler) Signal(s os.Signal) {
|
|
h.once.Do(func() {
|
|
for _, fn := range h.notify {
|
|
fn()
|
|
}
|
|
if h.final == nil {
|
|
os.Exit(1)
|
|
}
|
|
h.final(s)
|
|
})
|
|
}
|
|
|
|
// Run ensures that any notifications are invoked after the provided fn exits (even if the
|
|
// process is interrupted by an OS termination signal). Notifications are only invoked once
|
|
// per Handler instance, so calling Run more than once will not behave as the user expects.
|
|
func (h *Handler) Run(fn func() error) error {
|
|
ch := make(chan os.Signal, 1)
|
|
signal.Notify(ch, terminationSignals...)
|
|
defer func() {
|
|
signal.Stop(ch)
|
|
close(ch)
|
|
}()
|
|
go func() {
|
|
sig, ok := <-ch
|
|
if !ok {
|
|
return
|
|
}
|
|
h.Signal(sig)
|
|
}()
|
|
defer h.Close()
|
|
return fn()
|
|
}
|