mk/recipe.go

package main

import (
	"io"
	"log"
	"os"
	"os/exec"
)

// A monolithic function for executing recipes.
func executeRecipe(program string,
	args []string,
	input string,
	echo_out bool,
	echo_err bool,
	capture_out bool) string {
	cmd := exec.Command(program, args...)

	if echo_out {
		cmdout, err := cmd.StdoutPipe()
		if err != nil {
			go io.Copy(os.Stdout, cmdout)
		}
	}

	if echo_err {
		cmderr, err := cmd.StdoutPipe()
		if err != nil {
			go io.Copy(os.Stderr, cmderr)
		}
	}

	if len(input) > 0 {
		cmdin, err := cmd.StdinPipe()
		if err == nil {
			go func() { cmdin.Write([]byte(input)); cmdin.Close() }()
		}
	}

	output := ""
	var err error
	if capture_out {
		var outbytes []byte
		outbytes, err = cmd.Output()
		output = string(outbytes)
		if output[len(output)-1] == '\n' {
			output = output[:len(output)-1]
		}
	} else {
		err = cmd.Run()
	}

	if err != nil {
		// TODO: better error output
		log.Fatal("Recipe failed")
	}

	return output
}