go-subprocess-and-channel.go

package main

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

func runThing(c1 chan string, wg *sync.WaitGroup) {
	defer wg.Done()
	cmd := exec.Command("./subprocess.sh")
	cmd.Stderr = os.Stderr
	stdout, err := cmd.StdoutPipe()
	if nil != err {
		log.Fatalf("Error obtaining stdout: %s", err.Error())
	}
	reader := bufio.NewReader(stdout)

	go func(reader io.Reader) {
		scanner := bufio.NewScanner(reader)
		for scanner.Scan() {
			log.Printf("running subprocess: %s", scanner.Text())
			c1 <- scanner.Text()
		}
	}(reader)
	if err := cmd.Start(); nil != err {
		log.Fatalf("Error starting program: %s, %s", cmd.Path, err.Error())
	}
	fmt.Println("we are near the end")
	cmd.Wait()
	fmt.Println("we are done")
}

func channelListener(c1 <- chan string) {
	for {
		select {
			case msg := <-c1: {
				fmt.Println("message:", msg)
			}
			default: {
				time.Sleep(time.Millisecond*100)
			}
		}
	}
}

func main() {
	var wg sync.WaitGroup
	wg.Add(2)
	c1 := make(chan string)
	go runThing(c1, &wg)
	go runThing(c1, &wg)
	go channelListener(c1)
	wg.Wait()
}

subprocess.sh

#!/bin/bash
echo "blah blah blah"
sleep 10
echo "sub done"