How to do non-blocking Read() for io.PipeRaeder in Golang

Question

I have following code. The executable program will send some text to stdout after 5 seconds. So, in.ReadLine() will block until receive data. How can I set a timeout for ReadLine() or do it in a non-blocking way?

package main

import (
    "bufio"
    "fmt"
    "io"
    "os/exec"
)

func main() {
    cmd := exec.Command("/path/to/executable")

    stdoutReader, stdoutWriter := io.Pipe()

    cmd.Stdout = stdoutWriter

    cmd.Start()

    in := bufio.NewReader(stdoutReader)
    b, _, _ := in.ReadLine()

    fmt.Println(string(b))
}

Answer 1

Thanks for the comments. I figure it out.

package main

import (
    "bufio"
    "fmt"
    "io"
    "os/exec"
    "time"
)

func main() {
    ch := make(chan []byte)
    cmd := exec.Command("/path/to/executable")
    stdoutReader, stdoutWriter := io.Pipe()

    cmd.Stdout = stdoutWriter

    if err := cmd.Start(); err != nil {
        return
    }

    in := bufio.NewReader(stdoutReader)

    go func() {
        b, _, _ := in.ReadLine()
        ch <- b
    }()

    complete := false
    for !complete {
        select {
        case s := <-ch:
            fmt.Println(string(s))
            complete = true
        case <-time.After(time.Second * 5):
            fmt.Println("timeout")
            complete = true
        }
    }

}