gracefulshutdown.go

package httpx

import (
	"context"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"
)

// GracefulShutdownServerOnSignal shuts down the passed server
// gracefully after the process was notified with any of the passed signals.
// The server is guaranteed to shut down with the passed timeout after
// a signal. A timeout value of zero disables the timeout.
// If no signals are passed, then SIGHUP, SIGINT, SIGTERM will be used.
// If signalLog is not nil, then the received signal will be logged with it.
// If errorLog is not nil, then any errors from the server shutdown will be logged with it.
func GracefulShutdownServerOnSignal(server *http.Server, signalLog, errorLog Logger, timeout time.Duration, signals ...os.Signal) {
	if len(signals) == 0 {
		signals = []os.Signal{syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM}
	}

	shutdown := make(chan os.Signal, 1)
	signal.Notify(shutdown, signals...)
	go func() {
		sig := <-shutdown
		if signalLog != nil {
			signalLog.Printf("Received signal: %s", sig)
		}

		ctx := context.Background()
		if timeout > 0 {
			var cancel context.CancelFunc
			ctx, cancel = context.WithTimeout(ctx, timeout)
			defer cancel()
		}

		err := server.Shutdown(ctx)
		if err != nil && errorLog != nil {
			errorLog.Printf("http.Server shutdown error: %s", err)
		}
	}()
}