go协程池实现原理小结

type worker interface {
	task()
}

type worker interface {
	task()
}

type pool struct {
	// 使用无缓冲通道实现协程池
	work chan worker
	// 辅助计数器，用于协程池同步
	wg   sync.waitgroup
}

// new 创建一个工作池
func new(maxgoroutine int) *pool {
	p := pool{
		work: make(chan worker),
	}
	p.wg.add(maxgoroutine)
	for i := 0; i < maxgoroutine; i++ {
		go func() {
			// 一直循环取任务，直到work被关闭为止并且通道中的任务执行完毕为止
			for w := range p.work {
				w.task()
			}
			// 退出时候，减少一个计数器
			p.wg.done()
		}()
	}
	return &p
}

// run 将任务放入工作池
func (p *pool) run(w worker) {
	p.work <- w
}

// shutdown 等待所有goroutine完成工作
func (p *pool) shutdown() {
	// 关闭work所有协程完成任务之后会退出for循环
	close(p.work)
	p.wg.wait()
}

package work

import "sync"

// worker interface 必须满足worker的要求才能使用工作池
type worker interface {
	task()
}

// pool 提供一个goroutine池，这个池可以完成任何已提交的woker任务
type pool struct {
	work chan worker
	wg   sync.waitgroup
}

// new 创建一个工作池
func new(maxgoroutine int) *pool {
	p := pool{
		work: make(chan worker),
	}
	p.wg.add(maxgoroutine)
	for i := 0; i < maxgoroutine; i++ {
		go func() {
			// 一直循环取任务，直到work被关闭为止
			for w := range p.work {
				w.task()
			}
			// 退出时候，减少一个计数器
			p.wg.done()
		}()
	}
	return &p
}

// run 将任务放入工作池
func (p *pool) run(w worker) {
	p.work <- w
}

// shutdown 等待所有goroutine完成工作
func (p *pool) shutdown() {
	// 关闭work所有协程完成任务之后会退出for循环
	close(p.work)
	p.wg.wait()
}

// this sample program demonstrates how to use the work package
// to use a pool of goroutines to get work done.
package main

import (
	"log"
	"sync"
	"time"

	"work"
)

// names provides a set of names to display.
var names = []string{
	"steve",
	"bob",
	"mary",
	"therese",
	"jason",
}

// nameprinter provides special support for printing names.
type nameprinter struct {
	name string
}

// task implements the worker interface.
func (m *nameprinter) task() {
	log.println(m.name)
	time.sleep(time.second)
}

// main is the entry point for all go programs.
func main() {
	// create a work pool with 2 goroutines.
	p := work.new(2)

	var wg sync.waitgroup
	wg.add(100 * len(names))

	for i := 0; i < 100; i++ {
		// iterate over the slice of names.
		for _, name := range names {
			// create a nameprinter and provide the
			// specific name.
			np := nameprinter{
				name: name,
			}

			go func() {
				// submit the task to be worked on. when runtask
				// returns we know it is being handled.
				p.run(&np)
				wg.done()
			}()
		}
	}

	wg.wait()

	// shutdown the work pool and wait for all existing work
	// to be completed.
	p.shutdown()
}