README.md

This is an example. To run it simply do go build -o slave slave.go && go build -o main main.go && ./main Then you can try typing say for slave process to produce output or exit for slave process to exit. There is an issue when slave exits main process still alive and starts burning through CPU cycles.

But I am lazy to fix that, feel free to do that.

main.go

package main


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

var in chan string  = make(chan string, 20)
var out chan string  = make(chan string, 20)

var cmd *exec.Cmd
var slaveStdin io.WriteCloser
var slaveStdout io.ReadCloser

func main() {
	wg := sync.WaitGroup{}
	wg.Add(1)

	startSlave()
	go localWriter()
	go localReader()

	go slaveWriter()
	go slaveReader()

	wg.Wait()
}

func startSlave() {
	cmd = exec.Command("./slave")
	slaveStdin, _ = cmd.StdinPipe()
	slaveStdout, _ = cmd.StdoutPipe()

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

func localWriter() {
	for {
		text := strings.TrimSpace(<-out)
		if text != "" {
			fmt.Println(text)
		}
	}
}

func localReader() {
	input := bufio.NewReader(os.Stdin)
	for {
		text, err := input.ReadString('\n')
		if err != nil {
			continue
		}
		in <- strings.TrimSpace(text)
	}
}

func slaveWriter() {
	for {
		text := strings.TrimSpace(<-in)
		if text != "" {
			io.WriteString(slaveStdin, text+"\n")
		}
	}
}

func slaveReader() {
	input := bufio.NewReader(slaveStdout)
	for {
		text, err := input.ReadString('\n')
		if err != nil {
			continue
		}
		out <- strings.TrimSpace(text)
	}
}

slave.go

package main


import (
	"bufio"
	"fmt"
	"strings"
	"os"
)

var in chan string  = make(chan string, 20)
var out chan string  = make(chan string, 20)

func main() {
	go writer()
	go reader()
	for {
		command := <-in
		switch command {
			case "exit":
				os.Exit(0)
				break
			case "say":
				out<- "Speaking..."
				break
		}
	}
}

func writer() {
	for {
		text := strings.TrimSpace(<-out)
		if text != "" {
			fmt.Println(text)
		}
	}
}

func reader() {
	input := bufio.NewReader(os.Stdin)
	for {
		text, err := input.ReadString('\n')
		if err != nil {
			continue
		}
		in <- strings.TrimSpace(text)
	}
}