golang的context基础

package main

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

func main() {
    ctx, cancel := context.WithCancel(context.Background())
    eatNum := chiHanBao(ctx)
    for n := range eatNum {
        if n >= 10 {
            cancel()
            break
        }
    }

    fmt.Println("正在统计结果。。。")
    time.Sleep(1 * time.Second)
}

func chiHanBao(ctx context.Context) <-chan int {
    c := make(chan int)
    // 个数
    n := 0
    // 时间
    t := 0
    go func() {
        for {
            //time.Sleep(time.Second)
            select {
            case <-ctx.Done():
                fmt.Printf("耗时 %d 秒，吃了 %d 个汉堡 \n", t, n)
                return
            case c <- n:
                incr := 1
                n += incr
                if n >= 10 {
                    n = 10
                }
                t++
                fmt.Printf("我吃了 %d 个汉堡\n", n)
            }
        }
    }()

    return c
}