Watcher to automate some tasks (modify as you wish)

watcher-example.go

// temp solution to run browserify with watch
package main

import (
	"flag"
	"log"
	"os"
	"os/exec"
	"strings"
	"time"

	"gopkg.in/fsnotify.v1"
)

var (
	dir = flag.String("d", "", "dir to watch")
	com = flag.String("c", "", "comand to exec")
)

func init() {
	flag.Parse()
	//flag.Usage()
}

func main() {
	d := "C:/www/scala/simple-blog/src/main/webapp/WEB-INF/templates/js"
	dae := "browserify"
	excludeFile := "bundle.js"
	c := dae + " " + d + "/app.js" + " -o " + d + "/" + excludeFile

	w, err := fsnotify.NewWatcher()
	if err != nil {
		log.Fatal(err)
	}
	defer w.Close()

	// prepare slice
	args := strings.Split(c, " ")

	done := make(chan bool)
	go func() {
		for {
			select {
			case e := <-w.Events:
				if e.Op&fsnotify.Write == fsnotify.Write {
					// ignore exclude file
					if strings.HasSuffix(e.Name, excludeFile) || !strings.HasSuffix(e.Name, ".js") {
						continue
					}
					log.Println("File modified:", e.Name)
					// execute command
					cmd := exec.Command(args[0])
					cmd.Stdout = os.Stdout
					cmd.Stderr = os.Stderr
					cmd.Args = args
					cmd.Env = os.Environ()
					cmd.Run()
					// wait
					time.Sleep(2 * time.Second)
				}
			case err := <-w.Errors:
				log.Println("Error:", err)
			}
		}
	}()

	err = w.Add(d)
	if err != nil {
		log.Fatalln(err)
	}

	<-done

}