do with timeout in go

do_with_timeout.go

package main

import (
	"errors"
	"fmt"
	"time"
)

var timeoutErr = errors.New("timeout")

func main() {
	ret, err, f := genFunc()
	if err := DoTimeout(f, 2*time.Second); err == timeoutErr {
		fmt.Println("timeout")
		return
	}
	fmt.Println("result", *ret, err)
}

// TODO change to time wheel
func DoTimeout(f func(), timeout time.Duration) error {
	timer := time.NewTimer(timeout)
	finish := make(chan struct{})
	go func() {
		f()
		close(finish)
	}()
	select {
	case <-finish:
		timer.Stop()
		return nil
	case <-timer.C:
		return timeoutErr
	}
}

func query(t time.Duration) (int, error) {
	time.Sleep(t)
	return 11, errors.New("xx")
}

func genFunc() (*int, error, func()) {
	var ret int
	var err error
	f := func() {
		ret, err = query(time.Second)
	}
	return &ret, err, f
}