golang关闭exec的进程

// Start a process:
cmd := exec.Command("sleep", "5")
if err := cmd.Start(); err != nil {
    log.Fatal(err)
}

// Kill it:
if err := cmd.Process.Kill(); err != nil {
    log.Fatal("failed to kill process: ", err)
}

ctx, cancel := context.WithTimeout(context.Background(), 3 * time.Second)
defer cancel()

if err := exec.CommandContext(ctx, "sleep", "5").Run(); err != nil {
    // This will fail after 3 seconds. The 5 second sleep
    // will be interrupted.
}

package main

import (
	"context"
	"os"
	"os/exec"
	"time"
)

func main() {
	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
	defer cancel()

	cmd := exec.CommandContext(ctx, "sleep", "5")
	cmd.Stdout = os.Stdout
	cmd.Dir = "/root"
	err := cmd.Run()
	if err != nil {
		panic(err)
	}
}

panic: signal: killed

goroutine 1 [running]:
main.main()
	test/main.go:19 +0x157
exit status 2

// Start a process:
cmd := exec.Command("sleep", "5")
if err := cmd.Start(); err != nil {
    log.Fatal(err)
}

// Wait for the process to finish or kill it after a timeout (whichever happens first):
done := make(chan error, 1)
go func() {
    done <- cmd.Wait()
}()
select {
case <-time.After(3 * time.Second):
    if err := cmd.Process.Kill(); err != nil {
        log.Fatal("failed to kill process: ", err)
    }
    log.Println("process killed as timeout reached")
case err := <-done:
    if err != nil {
        log.Fatalf("process finished with error = %v", err)
    }
    log.Print("process finished successfully")
}