为什么在for循环中调用ioutil.ReadFile（）后会挂起？

Question

I wrote a function that converts an image to a base64 string:

func getBase64Screenshot() string {
    // Image name
    imageName := "Screenshots/screenshot.png"

    imageFileBytes, err := ioutil.ReadFile(imageName)
    handleError(err)

    // Converts file to base64 string
    encoded := base64.StdEncoding.EncodeToString(imageFileBytes)

    return encoded
}

The above function is called in a for loop, however after some iterations of the for loop, the program just hangs at the line imageFileBytes, err := ioutil.ReadFile(imageName) (it doesn't throw an error, it just stops running and stalls).

I ran some experiments and found that if I used a smaller image, it would make it through ~5 iterations of the for loop before stalling, however if I screenshot my entire screen it would only make it through the first iteration of the for loop before stalling.

My question is this: What is causing the program to hang, and is there anything I can do to prevent it from hanging?

Thanks!

Answer 1

Debug your code.

---

Try this and let me know if this works for you too:
This works like a charm for me on Linux:

package main

import (
    "encoding/base64"
    "fmt"
    "io/ioutil"
    "log"
    "os"
)

func main() {
    for i := 0; i < 10; i++ {
        fmt.Println(getBase64Screenshot()[:10])
    }
}
func getBase64Screenshot() string {
    buf, err := ioutil.ReadFile(os.Args[0])
    if err != nil {
        log.Fatal(err)
    }
    encoded := base64.StdEncoding.EncodeToString(buf)
    return encoded
}

Output:

time go run main.go
f0VMRgIBAQ
f0VMRgIBAQ
f0VMRgIBAQ
f0VMRgIBAQ
f0VMRgIBAQ
f0VMRgIBAQ
f0VMRgIBAQ
f0VMRgIBAQ
f0VMRgIBAQ
f0VMRgIBAQ

real    0m0.340s
user    0m0.369s
sys     0m0.128s