Golang 通过 管道控制并发数量

package main

import (
    "fmt"
    "math/rand"
    "sync"
    "time"
)

const concurrency = 20

func main() {
    rateChannel := make(chan int, concurrency)
　　// 别忘记 关闭管道
    defer close(rateChannel)
    // channel 控制并发数量
    go func() {
        for {
            rateChannel <- 1
            time.Sleep(time.Duration(1000))
        }
    }()

    var wg sync.WaitGroup
    for{
        <- rateChannel
        wg.Add(1)
        go func(wg *sync.WaitGroup) {
            rand.Seed(1)
            i := rand.Int()
            fmt.Println(i)
        }(&wg)
    }
}