ready to test

.gitignore

@@ -1 +1,2 @@
 /*.exe
+/notify

README.md

@@ -1,2 +1,2 @@
-# inotify-demo
+# fsnotify-demo
 

notify.go

@@ -4,8 +4,12 @@ import (
 	"context"
 	"fmt"
 	"log"
+	"math/rand"
 	"os"
 	"os/signal"
+	"path/filepath"
+	"sync"
+	"time"
 
 	"github.com/fsnotify/fsnotify"
 )
@@ -24,7 +28,9 @@ func main() {
 	if watcher, err = fsnotify.NewWatcher(); err != nil {
 		log.Fatal("Error:", err)
 	}
-	defer watcher.Close()
+	defer func() {
+		_ = watcher.Close()
+	}()
 
 	ctx, cancel := context.WithCancel(context.Background())
 
@@ -34,6 +40,12 @@ func main() {
 		log.Fatal("Error:", err)
 	}
 
+	sm := new(sync.Map)
+	go createEmptyAndDelete(ctx, sm, time.Second, dir2Watch)
+	go createEmptyAndDelete(ctx, sm, time.Second+(time.Millisecond*200), dir2Watch)
+	go createEmptyAndDelete(ctx, sm, time.Second+(time.Millisecond*400), dir2Watch)
+	go createEmptyAndDelete(ctx, sm, time.Second+(time.Millisecond*600), dir2Watch)
+
 	done := make(chan os.Signal, 1)
 	signal.Notify(done, os.Interrupt)
 
@@ -73,5 +85,104 @@ func checkArgs() (string, error) {
 	if len(os.Args) != 2 {
 		return "", fmt.Errorf("invalid arguments")
 	}
-	return "", nil
+
+	fi, err := os.Stat(os.Args[1])
+	if err != nil {
+		return "", err
+	}
+	if !fi.IsDir() {
+		return "", fmt.Errorf("not a directory")
+	}
+
+	return os.Args[1], nil
+}
+
+func genUniqueRandomString(sm *sync.Map, len uint) string {
+	for {
+		rs := genRandomString(len)
+		if _, ok := sm.LoadOrStore(rs, nil); !ok {
+			return rs
+		}
+	}
+}
+
+func genRandomString(len uint) string {
+	if len == 0 {
+		return ""
+	}
+
+	b := make([]byte, len)
+	var i uint
+	for i = 0; i < len; i++ {
+		b[i] = byte(rand.Intn(52))
+		if b[i] >= 26 {
+			b[i] += 97 - 26
+		} else {
+			b[i] += 65
+		}
+	}
+
+	return string(b)
+}
+
+func createEmptyAndDelete(ctx context.Context, sm *sync.Map, initialWait time.Duration, dir string) {
+	if initialWait < 0 {
+		log.Println("initialWait cannot be less than 0")
+		return
+	}
+
+	tick := time.NewTicker(initialWait)
+	defer tick.Stop()
+
+	const (
+		createFile = iota
+		deleteFile
+
+		iterWait time.Duration = time.Second
+	)
+
+	var (
+		next         int = createFile
+		nextFileName string
+		nextFile     string
+		f            *os.File
+		err          error
+	)
+
+	nextFile = genUniqueRandomString(sm, 6)
+	nextFileName = nextFile + ".txt"
+
+	for {
+		select {
+		case <-tick.C:
+			tick.Stop()
+			switch next {
+			case createFile:
+				nextFileName = filepath.Join(dir, nextFileName)
+				if f, err = os.OpenFile(nextFileName, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0666); err != nil {
+					log.Printf("Error creating file %s: %+v", nextFileName, err)
+					return
+				}
+				_ = f.Close()
+				next = deleteFile
+			case deleteFile:
+				if err = os.Remove(nextFileName); err != nil {
+					log.Printf("Error deleting file %s: %+v", nextFileName, err)
+					return
+				}
+				next = createFile
+
+				sm.Delete(nextFile)
+				nextFile = genUniqueRandomString(sm, 6)
+				nextFileName = nextFile + ".txt"
+			}
+			tick.Reset(iterWait)
+		case <-ctx.Done():
+			if next == deleteFile {
+				_ = os.Remove(nextFileName)
+			}
+
+			return
+		}
+	}
 }