Capturing docker stop in a golang application (no need for S6!!)

Dockerfile

from alpine:latest

COPY main /

CMD [ "./main" ]

main.go

package main

import (
	"fmt"
	"os"
	"os/signal"
	"syscall"
	"time"
)

func main() {

	shutdown := make(chan int)

	//create a notification channel to shutdown
	sigChan := make(chan os.Signal, 1)

	go func() {
		for {
			fmt.Println("Working...")
			time.Sleep(3 * time.Second)
		}
	}()

	//register for interupt (Ctrl+C) and SIGTERM (docker)
	signal.Notify(sigChan, os.Interrupt, syscall.SIGTERM)
	go func() {
		<-sigChan
		fmt.Println("Shutting down...")
		shutdown <- 1
	}()

	<-shutdown
}