Communication with other Go process

Question

I have a program that reads a filename from the console and executes go run filename.go.

// main.go
package main

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

func main() {
    console := bufio.NewReader(os.Stdin)
    fmt.Print("Enter a filename: ")

    input, err := console.ReadString('\n')
    if err != nil {
        log.Fatalln(err)
    }

    input = input[:len(input)-1]

    gorun := exec.Command("go", "run", input)
    result, err := gorun.Output()
    if err != nil {
        log.Println(err)
    }

    fmt.Println("---", input, "Result ---")
    fmt.Println(string(result))
}

In the same directory, I have another file like this.

// hello.go
package main

import "fmt"

func main() {
    fmt.Println("Hello, World!")
}

When I input "hello.go" in the console, that file is run, and its output gets returned to the parent Go process. However, I have another program like this.

// count.go
package main

import (
    "fmt"
    "time"
)

func main() {
    i := 0
    for {
        time.Sleep(time.Second)
        i++
        fmt.Println(i)
    }
}

Except, because this program never returns, my parent process is left hanging forever. Is there a way to communicate with different Go processes? I'm thinking something like channels for goroutines, but for processes. I need to be able to receive live stdout from the child process.

The problem I'm trying to solve is dynamically executing Go programs from a directory. Go files will be added, removed, and modified daily. I'm kind of trying to make something like Go Playgrounds. The main process is a webserver serving webpages, so I can't shut it down all the time to modify code.

Answer 1

Don't use go run, you need to do what go run is doing yourself to have the go program be a direct child of your server process.

Using go build -o path_to/binary source_file.go will give you more control. Then you can can directly execute and communicate with the resulting binary.