fsnotifier.go

package main

import (
	"fmt"
	"log"
	"os"
	"path/filepath"

	"github.com/fsnotify/fsnotify"
)

var watcher *fsnotify.Watcher

// main
func main() {
	var err error
	watcher, err = fsnotify.NewWatcher()
	if err != nil {
		log.Fatal(err)
	}
	defer watcher.Close()

	// starting at the root of the project, walk each file/directory searching for
	// directories
	dir := os.Getenv("MYSYNC_DIR")
	fmt.Println("MYSYNC_DIR=", dir)
	if err := filepath.Walk(dir, watchDir); err != nil {
		fmt.Println("ERROR", err)
	}

	go func() {
		for {
			select {
			case event, ok := <-watcher.Events:
                if !ok {
                    return
                }
				log.Println("event:", event)
                if event.Has(fsnotify.Write) {
                    log.Println("modified file:", event.Name)
                }

			case err, ok := <-watcher.Errors:
                if !ok {
                    return
                }
				fmt.Println("ERROR", err)
			}
		}
	}()

	<-make(chan struct{})
}

// watchDir gets run as a walk func, searching for directories to add watchers to
func watchDir(path string, fi os.FileInfo, err error) error {

	// since fsnotify can watch all the files in a directory, watchers only need
	// to be added to each nested directory
	if err != nil {
		log.Fatalln("ERROR", err)
	}
	if fi.Mode().IsDir() {
		return watcher.Add(path)
	}

	return nil
}