Go：所有 goroutine 都睡着了——死锁

Question

我有一段代码来调整图像大小。

我正在使用resize库。

这是片段：

package main

import (

    "fmt"

    "github.com/nfnt/resize"

    "image"

    "image/jpeg"

    "os"

    "runtime"

)

func main() {

    runtime.GOMAXPROCS(4)

    file_names := make([]string, 5)

    for i := 1; i < 6; i++ {

        file_names[i-1] = fmt.Sprintf("%v", i)

    }

    c := make(chan string)

    ce := make(chan error)

    for _, filename := range file_names {

        go func() {

            proccesFileName(filename, c, ce)

        }()

    }

    for {

        select {

        case str := <-c:

            fmt.Println(str)

            break

        case err := <-ce:

            fmt.Println(err)

            break

        }

    }

}

这是我的proccesFileName功能：

func proccesFileName(filename string, c chan string, ce chan error) {

    file, err := os.Open(fmt.Sprintf("in/%v.jpg", filename))

    if err != nil {

        ce <- err

    }

    defer file.Close()

    img, err := jpeg.Decode(file)

    if err != nil {

        ce <- err

    }

    scales := []float32{1.0, 0.8, 0.6, 0.5, 0.25, 0.01}

    thumbs := make([]image.Image, len(scales))

    for i := 0; i < len(scales); i++ {

        thumbs[i] = resize.Resize(uint(float32(img.Bounds().Max.X)*scales[i]),

            uint(float32(img.Bounds().Max.Y)*scales[i]), img, resize.Lanczos3)

        thumb_name := fmt.Sprintf("out/%v_thumb_%v.jpg", filename, i+1)

        out, err := os.Create(thumb_name)

        if err != nil {

            ce <- err

        }

        defer out.Close()

        jpeg.Encode(out, thumbs[i], nil)

        c <- fmt.Sprintf("%v FINISHED", i)

    }

}

我有输出：

0 FINISHED

0 FINISHED

0 FINISHED

0 FINISHED

0 FINISHED

1 FINISHED

1 FINISHED

1 FINISHED

2 FINISHED

1 FINISHED

1 FINISHED

2 FINISHED

3 FINISHED

2 FINISHED

2 FINISHED

2 FINISHED

3 FINISHED

4 FINISHED

4 FINISHED

3 FINISHED

5 FINISHED

3 FINISHED

5 FINISHED

3 FINISHED

4 FINISHED

4 FINISHED

4 FINISHED

5 FINISHED

5 FINISHED

5 FINISHED

问题可能出在哪里？

Answer 1

您无需无限期地等待。您知道消息将如何在频道上播放。for _ = range file_names {&nbsp; &nbsp; select {&nbsp; &nbsp; case str := <-c&nbsp; &nbsp; &nbsp; &nbsp; fmt.Println(str)&nbsp; &nbsp; case err := <-ce&nbsp; &nbsp; &nbsp; &nbsp; fmt.Println(err)&nbsp; &nbsp; }}