type Task struct {
    f func() error  // 具體的執(zhí)行邏輯
}

type Pool struct {
    RunningWorkers int64     // 運(yùn)行著的worker數(shù)量
    Capacity       int64     // 協(xié)程池worker容量---goroutine數(shù)量
    JobCh          chan *Task // 用于worker取任務(wù)
    sync.Mutex
}

// p為Pool對(duì)象指針
for task := range p.JobCh {
    do ...      
}

func NewTask(funcArg func() error) *Task

func NewPool(Capacity int, taskNum int) *Pool

func (p *Pool) AddTask(task *Task)

func (p *Pool) Run()

package main

import (
    "fmt"
    "sync"
    "sync/atomic"
    "time"
)

type Task struct {
    f func() error // 具體的任務(wù)邏輯
}

func NewTask(funcArg func() error) *Task {
    return &Task{
       f: funcArg,
    }
}

type Pool struct {
    RunningWorkers int64      // 運(yùn)行著的worker數(shù)量
    Capacity       int64      // 協(xié)程池worker容量
    JobCh          chan *Task // 用于worker取任務(wù)
    sync.Mutex
}

func NewPool(capacity int64, taskNum int) *Pool {
    return &Pool{
       Capacity: capacity,
       JobCh:    make(chan *Task, taskNum),
    }
}

func (p *Pool) GetCap() int64 {
    return p.Capacity
}

func (p *Pool) incRunning() { // runningWorkers + 1
    atomic.AddInt64(&p.RunningWorkers, 1)
}

func (p *Pool) decRunning() { // runningWorkers - 1
    atomic.AddInt64(&p.RunningWorkers, -1)
}

func (p *Pool) GetRunningWorkers() int64 {
    return atomic.LoadInt64(&p.RunningWorkers)
}

func (p *Pool) run() {
    p.incRunning()
    go func() {
       defer func() {
          p.decRunning()
       }()
       for task := range p.JobCh {
          task.f()
       }
    }()
}

// AddTask 往協(xié)程池添加任務(wù)
func (p *Pool) AddTask(task *Task) {
    // 加鎖防止啟動(dòng)多個(gè) worker
    p.Lock()
    defer p.Unlock()

    if p.GetRunningWorkers() < p.GetCap() { // 如果任務(wù)池滿, 則不再創(chuàng)建 worker
       // 創(chuàng)建啟動(dòng)一個(gè) worker
       p.run()
    }

    // 將任務(wù)推入隊(duì)列, 等待消費(fèi)
    p.JobCh <- task
}

func main() {
    // 創(chuàng)建任務(wù)池
    pool := NewPool(3, 10)

    for i := 0; i < 20; i++ {
       // 任務(wù)放入池中
       pool.AddTask(NewTask(func() error {
          fmt.Printf("I am Task\n")
          return nil
       }))
    }

    time.Sleep(1e9) // 等待執(zhí)行
}