cloudflared-mirror/cmd/cloudflared/tunnel/signal.go

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package tunnel
import (
"os"
"os/signal"
"syscall"
"time"
)
// waitForSignal notifies all routines to shutdownC immediately by closing the
// shutdownC when one of the routines in main exits, or when this process receives
// SIGTERM/SIGINT
func waitForSignal(errC chan error, shutdownC chan struct{}) error {
signals := make(chan os.Signal, 10)
signal.Notify(signals, syscall.SIGTERM, syscall.SIGINT)
defer signal.Stop(signals)
select {
case err := <-errC:
logger.Infof("terminating due to error: %v", err)
close(shutdownC)
return err
case s := <-signals:
logger.Infof("terminating due to signal %s", s)
close(shutdownC)
case <-shutdownC:
}
return nil
}
// waitForSignalWithGraceShutdown notifies all routines to shutdown immediately
// by closing the shutdownC when one of the routines in main exits.
// When this process recieves SIGTERM/SIGINT, it closes the graceShutdownC to
// notify certain routines to start graceful shutdown. When grace period is over,
// or when some routine exits, it notifies the rest of the routines to shutdown
// immediately by closing shutdownC.
// In the case of handling commands from Windows Service Manager, closing graceShutdownC
// initiate graceful shutdown.
func waitForSignalWithGraceShutdown(errC chan error,
shutdownC, graceShutdownC chan struct{},
gracePeriod time.Duration,
) error {
signals := make(chan os.Signal, 10)
signal.Notify(signals, syscall.SIGTERM, syscall.SIGINT)
defer signal.Stop(signals)
select {
case err := <-errC:
logger.Infof("Initiating graceful shutdown due to %v ...", err)
close(graceShutdownC)
close(shutdownC)
return err
case s := <-signals:
logger.Infof("Initiating graceful shutdown due to signal %s ...", s)
close(graceShutdownC)
waitForGracePeriod(signals, errC, shutdownC, gracePeriod)
case <-graceShutdownC:
waitForGracePeriod(signals, errC, shutdownC, gracePeriod)
case <-shutdownC:
close(graceShutdownC)
}
return nil
}
func waitForGracePeriod(signals chan os.Signal,
errC chan error,
shutdownC chan struct{},
gracePeriod time.Duration,
) {
// Unregister signal handler early, so the client can send a second SIGTERM/SIGINT
// to force shutdown cloudflared
signal.Stop(signals)
graceTimerTick := time.Tick(gracePeriod)
// send close signal via shutdownC when grace period expires or when an
// error is encountered.
select {
case <-graceTimerTick:
case <-errC:
}
close(shutdownC)
}