gorouting使用

1.起固定個數的goroutine

package utils

import (
	"sync"
)

type pool struct {
	queue chan int
	wg    *sync.WaitGroup
}

func New(size int) *pool {
	if size <= 0 {
		size = 1
	}
	return &pool{
		queue: make(chan int, size),
		wg:    &sync.WaitGroup{},
	}
}

func (p *pool) Add(delta int) {
	for i := 0; i < delta; i++ {
		p.queue <- 1
	}
	for i := 0; i > delta; i-- {
		<-p.queue
	}
	p.wg.Add(delta)
}

func (p *pool) Done() {
	<-p.queue
	p.wg.Done()
}

func (p *pool) Wait() {
	p.wg.Wait()
}

** // 使用示例**

// 初始化数据，创建10个goroutine
pool := utils.New(10)

for i:=0; i< 100;i++ {
    pool.Add(1)
    go func() {
        DOSomething()
        pool.Done()
    }
}

pool.Wait()

2.重试机制

func Retry(attempts int, sleep time.Duration, f func() error) (err error) {
    for i := 0; ; i++ {
        err = f()
        if err == nil {
            return
        }

        if i >= (attempts - 1) {
            break
        }

        time.Sleep(sleep)

    }
    return fmt.Errorf("after %d attempts, last error: %v", attempts, err)
}