81 lines
2.2 KiB
Go
81 lines
2.2 KiB
Go
|
package main
|
||
|
|
|
||
|
|
// Heavily inspired by https://github.com/btcsuite/btcd/blob/master/signal.go
|
||
|
|
|
||
|
|
import (
|
||
|
|
"os"
|
||
|
|
"os/signal"
|
||
|
|
)
|
||
|
|
|
||
|
|
// interruptChannel is used to receive SIGINT (Ctrl+C) signals.
|
||
|
|
var interruptChannel chan os.Signal
|
||
|
|
|
||
|
|
// addHandlerChannel is used to add an interrupt handler to the list of handlers
|
||
|
|
// to be invoked on SIGINT (Ctrl+C) signals.
|
||
|
|
var addHandlerChannel = make(chan func())
|
||
|
|
|
||
|
|
// mainInterruptHandler listens for SIGINT (Ctrl+C) signals on the
|
||
|
|
// interruptChannel and invokes the registered interruptCallbacks accordingly.
|
||
|
|
// It also listens for callback registration. It must be run as a goroutine.
|
||
|
|
func mainInterruptHandler() {
|
||
|
|
// interruptCallbacks is a list of callbacks to invoke when a
|
||
|
|
// SIGINT (Ctrl+C) is received.
|
||
|
|
var interruptCallbacks []func()
|
||
|
|
|
||
|
|
// isShutdown is a flag which is used to indicate whether or not
|
||
|
|
// the shutdown signal has already been received and hence any future
|
||
|
|
// attempts to add a new interrupt handler should invoke them
|
||
|
|
// immediately.
|
||
|
|
var isShutdown bool
|
||
|
|
|
||
|
|
for {
|
||
|
|
select {
|
||
|
|
case <-interruptChannel:
|
||
|
|
// Ignore more than one shutdown signal.
|
||
|
|
if isShutdown {
|
||
|
|
ltndLog.Infof("Received SIGINT (Ctrl+C). " +
|
||
|
|
"Already shutting down...")
|
||
|
|
continue
|
||
|
|
}
|
||
|
|
|
||
|
|
isShutdown = true
|
||
|
|
ltndLog.Infof("Received SIGINT (Ctrl+C). Shutting down...")
|
||
|
|
|
||
|
|
// Run handlers in LIFO order.
|
||
|
|
for i := range interruptCallbacks {
|
||
|
|
idx := len(interruptCallbacks) - 1 - i
|
||
|
|
callback := interruptCallbacks[idx]
|
||
|
|
callback()
|
||
|
|
}
|
||
|
|
|
||
|
|
// Signal the main goroutine to shutdown.
|
||
|
|
go func() {
|
||
|
|
shutdownChannel <- struct{}{}
|
||
|
|
}()
|
||
|
|
|
||
|
|
case handler := <-addHandlerChannel:
|
||
|
|
// The shutdown signal has already been received, so
|
||
|
|
// just invoke and new handlers immediately.
|
||
|
|
if isShutdown {
|
||
|
|
handler()
|
||
|
|
}
|
||
|
|
|
||
|
|
interruptCallbacks = append(interruptCallbacks, handler)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// addInterruptHandler adds a handler to call when a SIGINT (Ctrl+C) is
|
||
|
|
// received.
|
||
|
|
func addInterruptHandler(handler func()) {
|
||
|
|
// Create the channel and start the main interrupt handler which invokes
|
||
|
|
// all other callbacks and exits if not already done.
|
||
|
|
if interruptChannel == nil {
|
||
|
|
interruptChannel = make(chan os.Signal, 1)
|
||
|
|
signal.Notify(interruptChannel, os.Interrupt)
|
||
|
|
go mainInterruptHandler()
|
||
|
|
}
|
||
|
|
|
||
|
|
addHandlerChannel <- handler
|
||
|
|
}
|