diff --git a/SUMMARY.md b/SUMMARY.md
index 0ea6776..7ca581c 100644
--- a/SUMMARY.md
+++ b/SUMMARY.md
@@ -60,7 +60,7 @@
    * [6.5. 分布式缓存(TODO)](ch6-cloud/ch6-05-cache.md)
    * [6.6. etcd(TODO)](ch6-cloud/ch6-06-etcd.md)
    * [6.7. 分布式 id 生成器](ch6-cloud/ch6-07-dist-id.md)
-   * [6.8. 分布式锁(TODO)](ch6-cloud/ch6-08-lock.md)
+   * [6.8. 分布式锁(Doing)](ch6-cloud/ch6-08-lock.md)
    * [6.9. 分布式任务调度系统(TODO)](ch6-cloud/ch6-09-sched.md)
    * [6.10. 延时任务系统](ch6-cloud/ch6-10-delay-job.md)
    * [6.12. 补充说明(TODO)](ch6-cloud/ch6-11-faq.md)
diff --git a/ch6-cloud/ch6-08-lock.md b/ch6-cloud/ch6-08-lock.md
index a8b35e1..831aae5 100644
--- a/ch6-cloud/ch6-08-lock.md
+++ b/ch6-cloud/ch6-08-lock.md
@@ -74,64 +74,64 @@ println(counter)
 package main
 
 import (
-	"sync"
+    "sync"
 )
 
 // Lock try lock
 type Lock struct {
-	c chan struct{}
+    c chan struct{}
 }
 
 // NewLock generate a try lock
 func NewLock() Lock {
-	var l Lock
-	l.c = make(chan struct{}, 1)
-	l.c <- struct{}{}
-	return l
+    var l Lock
+    l.c = make(chan struct{}, 1)
+    l.c <- struct{}{}
+    return l
 }
 
 // Lock try lock, return lock result
 func (l Lock) Lock() bool {
-	lockResult := false
-	select {
-	case <-l.c:
-		lockResult = true
-	default:
-	}
-	return lockResult
+    lockResult := false
+    select {
+    case <-l.c:
+        lockResult = true
+    default:
+    }
+    return lockResult
 }
 
 // Unlock , Unlock the try lock
 func (l Lock) Unlock() bool {
-	unlockResult := false
-	select {
-	case l.c <- struct{}{}:
-		unlockResult = true
-	default:
-	}
-	return unlockResult
+    unlockResult := false
+    select {
+    case l.c <- struct{}{}:
+        unlockResult = true
+    default:
+    }
+    return unlockResult
 }
 
 var counter int
 
 func main() {
-	var l = NewLock()
-	var wg sync.WaitGroup
-	for i := 0; i < 10; i++ {
-		wg.Add(1)
-		go func() {
-			defer wg.Done()
-			if !l.Lock() {
-				// log error
-				println("lock failed")
-				return
-			}
-			counter++
-			println("current counter", counter)
-			l.Unlock()
-		}()
-	}
-	wg.Wait()
+    var l = NewLock()
+    var wg sync.WaitGroup
+    for i := 0; i < 10; i++ {
+        wg.Add(1)
+        go func() {
+            defer wg.Done()
+            if !l.Lock() {
+                // log error
+                println("lock failed")
+                return
+            }
+            counter++
+            println("current counter", counter)
+            l.Unlock()
+        }()
+    }
+    wg.Wait()
 }
 
 ```