stop go

tony2099 included in Go

2021-05-05 250 words 2 minutes

Contents

linux signal

an important event happen; send by kernel or other process(shell command);

the list of signal

1 up: hang up 2 int (ctrl + c) 3 quit (ctrl + ) 9 kill: can’t be caught and ignreo
15 termination

graceful stop go

how:

stop all open and idle resouce
wait running work to finish

http server:

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package main

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

func main() {

	srv := &http.Server{Addr: ":8090"}

	go func() {
		if err := srv.ListenAndServe(); err != http.ErrServerClosed {
			log.Fatalf("ListenAndServe(): %v", err)
		}
	}()
	// Setting up signal capturing
	stop := make(chan os.Signal, 1)
	signal.Notify(stop, os.Interrupt, os.Kill)
	<-stop

	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
	defer cancel()
	if err := srv.Shutdown(ctx); err != nil {
		log.Fatal("Server Shutdown Failded:", err)
	}
	log.Println("Server exiting gracefully")
}

shutdown:

closing all open listeners
close all idle connections,
wait indefinitely for connections to return to idle and then shut down, so you have to set canceled timeout

1. the conventional way to stop a program in linux

press keyboard crtl +c(interrupt); crtl+(quit)
send a signal kill -15 pid; kil -9 pid

2. how to gracefully stop a program

catch all possible signal, do some clean work before exiting

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    ch := make(chan os.Signal, 1)
 signal.Notify(ch, syscall.SIGINT, syscall.SIGQUIT, syscall.SIGTERM)
 t := <-ch
 log.Println("clean work")
 os.Exit(0)