Go by Example: Signals

Sometimes we’d like our Go programs to intelligently handle Unix signals. For example, we might want a server to gracefully shutdown when it receives a SIGTERM, or a command-line tool to stop processing input if it receives a SIGINT. Here’s a modern way to handle signals using contexts.

 
package main
 
import (
    "context"
    "fmt"
    "os/signal"
    "syscall"
)

signal.NotifyContext returns a context that’s canceled when one of the listed signals arrives.

 
func main() {
 
    ctx, stop := signal.NotifyContext(
        context.Background(), syscall.SIGINT, syscall.SIGTERM)
    defer stop()

The program will wait here until one of the configured signals is received.

 
    fmt.Println("awaiting signal")
    <-ctx.Done()

context.Cause reports why the context was canceled. For a signal-triggered cancellation, this includes the signal value.

 
    fmt.Println()
    fmt.Println(context.Cause(ctx))
    fmt.Println("exiting")
}

When we run this program it will block waiting for a signal. By typing ctrl-C (which the terminal shows as ^C) we can send a SIGINT signal, causing the program to print the cancellation cause and then exit.

 
$ go run signals.go
awaiting signal
^C
interrupt signal received
exiting

Next example: .

by Mark McGranaghan and Eli Bendersky | source | license