Go 1.16: Cleanup shutdownListener related code

[atc0005]

Background

Just learned of this new functionality landing in Go 1.16:

os/signal: add NotifyContext to cancel context using system signals

This is going to clean up much startup boilerplate.

ctx, stop := signal.NotifyContext(ctx, syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM)
defer stop()

Changes

It's been a little bit since I touched the code, but this looks to be the relevant portions to get an update once Go 1.16 is available:

brick/cmd/brick/main.go

Lines 114 to 120 in 88889b6

	// Setup "listener" to cancel the parent context when Signal.Notify()
	// indicates that SIGINT has been received
	go shutdownListener(ctx, quit, cancel)
	// Setup "listener" to shutdown the running http server when
	// the parent context has been cancelled
	go gracefulShutdown(ctx, httpServer, config.HTTPServerShutdownTimeout, httpDone)

also:

brick/cmd/brick/server.go

Lines 29 to 48 in 88889b6

	// shutdownListener listens for an os.Signal on the provided quit channel.
	// When this signal is received, the provided parent context cancel() function
	// is used to cancel all child contexts. This is intended to be run as a
	// goroutine.
	func shutdownListener(ctx context.Context, quit <-chan os.Signal, parentContextCancel context.CancelFunc) {
	// FIXME: If we're passing in the parent context's CancelFunc, do we need
	// the `ctx` that we're passing in?
	// monitor for shutdown signal
	osSignal := <-quit
	log.Debugf("shutdownListener: Received shutdown signal: %v", osSignal)
	// Attempt to trigger a cancellation of the parent context
	log.Debug("shutdownListener: Cancelling context ...")
	parentContextCancel()
	log.Debug("shutdownListener: context canceled")
	}

See also func gracefulShutdown in that same file.

References

• https://twitter.com/dgryski/status/1306274821743861761
  • golang/go@b6dbaef