package main

import (
	"errors"
	"fmt"
	"github.com/matryer/try"
	"math/rand"
	"time"
)

func main() {
	var value string

	err := try.Do(func(attempt int) (bool, error) {
		var err error
		value, err = randomFunc()
		if err != nil {
			fmt.Println("run error:", err)
		} else {
			fmt.Println("run ok:", value)
		}

		return attempt < 5, err //设置尝试次数，即尝试5次
	})

	if err != nil {
		fmt.Println("ERROR:", err)
	}
}

func randomFunc() (string, error) {
	rand_seed := rand.New(rand.NewSource(time.Now().UnixNano()))
	if rand_seed.Intn(100) < 50 {
		return "test ok", nil
	} else {
		return "", errors.New("test error")
	}
}

package try

import "errors"

// MaxRetries is the maximum number of retries before bailing.
var MaxRetries = 10

var errMaxRetriesReached = errors.New("exceeded retry limit")

// Func represents functions that can be retried.
type Func func(attempt int) (retry bool, err error)

// Do keeps trying the function until the second argument
// returns false, or no error is returned.
func Do(fn Func) error {
	var err error
	var cont bool
	attempt := 1
	for {
		cont, err = fn(attempt)
		if !cont || err == nil {
			break
		}
		attempt++
		if attempt > MaxRetries {
			return errMaxRetriesReached
		}
	}
	return err
}

// IsMaxRetries checks whether the error is due to hitting the
// maximum number of retries or not.
func IsMaxRetries(err error) bool {
	return err == errMaxRetriesReached
}