Simple retry mechanism in Go

main.go

package main

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

type Func func() bool
type CallbackFunc func()

func Retry(ctx context.Context, n int, interval time.Duration, done chan<- bool, f Func, onSucceed CallbackFunc, onError CallbackFunc) {
	var i int = 1
	go func(ctx context.Context, i int, n int, interval time.Duration, done chan<- bool, f Func, onSucceed CallbackFunc, onError CallbackFunc) {

		for {
			select {
			case <-ctx.Done():
				fmt.Printf("worker canceled\n")
				done <- true
				return
			default:
			}

			succeed := f()
			if succeed {
				done <- true
				if onSucceed != nil {
					onSucceed()
				}
				return
			}

			if i >= n {
				done <- true
				if onError != nil {
					onError()
				}
				return
			}

			<-time.After(interval)

			i++

		}
	}(ctx, i, n, interval, done, f, onSucceed, onError)
}

func main() {
	f := func() bool {
		resp, err := httpPost("not_ok")
		if err != nil {
			fmt.Println(err)
			return true
		}

		statusOK := resp.httpCode >= 200 && resp.httpCode < 300
		if !statusOK {
			fmt.Println("retry")
			return false
		}

		return true
	}

	done := make(chan bool, 1)

	ctx, cancel := context.WithCancel(context.Background())
	//ctx, cancel := context.WithTimeout(context.Background(), time.Millisecond*500)
	defer func() { cancel() }()

	onSucceed := func() {
		fmt.Println("execution succeed")
	}

	onError := func() {
		fmt.Println("execution error")
	}
	Retry(ctx, 5, 3*time.Second, done, f, onSucceed, onError)

	<-done

	//time.Sleep(time.Second * 15)
}

type response struct {
	httpCode int
}

func httpPost(data string) (*response, error) {
	if data == "fatal" {
		return nil, errors.New("fatal error")
	}

	if data == "not_ok" {
		return &response{httpCode: 400}, nil
	}

	return &response{httpCode: 200}, nil
}