signal cancel and timeout on an infinite loop go golang

README.md

golang program to gracefully terminate on SIGTERM signal or timeout in a loop

ctrl + c gracefully terminates the app using the current terminal

terminate app from different terminal

the program output its pid

...
pid: <pid>

executing the ff command will terminate the program

$ kill -15 <pid>

waiting for 25 seconds terminates the app by itself

you can still test your app within its duration

curl localhost:8080
# Hello World! 2022-07-17 ...

main.go

package main

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

func greet(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintf(w, "Hello World! %s", time.Now())
}

func main() {
	// cancel
	c := make(chan os.Signal)
	signal.Notify(c, os.Interrupt, syscall.SIGTERM)
	endSignal := make(chan struct{})
	go func() {
		fmt.Println("pid:", os.Getpid())
		<-c
		fmt.Println("terminating..")
		endSignal <- struct{}{}
	}()

	// timeout
	hr, err := time.ParseDuration("25s")
	if err != nil {
		fmt.Println("err parse duration:", err)
		return
	}
	timeout := time.After(hr)
	pollInt := 5 * time.Second

	// app
	go func() {
		http.HandleFunc("/", greet)
		http.ListenAndServe(":8080", nil)
	}()

	count := time.Duration(0)
	for {
		select {
		case <-endSignal:
			fmt.Println("The end!")
			return
		case <-timeout:
			fmt.Println("Time's up!")
			return
		default:
		}
		time.Sleep(pollInt)
		count += pollInt
		fmt.Println("time remaining:", hr-count)
	}

}