From a9eabd0f195ebec4f691c0be77114b0f4b438786 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=99=BD=E8=8C=B6=E6=B8=85=E6=AC=A2?=
 <go_developer@163.com>
Date: Tue, 23 Nov 2021 20:02:15 +0800
Subject: [PATCH] =?UTF-8?q?lease=E5=A2=9E=E5=8A=A0=E6=B0=B8=E4=B9=85?=
 =?UTF-8?q?=E7=BB=AD=E6=9C=9F=E6=94=AF=E6=8C=81?=
MIME-Version: 1.0
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Content-Transfer-Encoding: 8bit

---
 middleware/etcd/define.go      |  3 +++
 middleware/etcd/lease.go       | 39 ++++++++++++++++++++++++++++++++++
 middleware/etcd/string_test.go | 20 +++++++++++++++++
 3 files changed, 62 insertions(+)

diff --git a/middleware/etcd/define.go b/middleware/etcd/define.go
index 3b1c3aa..3a65392 100644
--- a/middleware/etcd/define.go
+++ b/middleware/etcd/define.go
@@ -44,3 +44,6 @@ type CancelWatcherHandler func(key string, data interface{})
 
 // TimeoutWatcherHandler 超时之后的回调函数
 type TimeoutWatcherHandler func(key string, timeout time.Duration)
+
+// LeaseKeepALiveHandler 续期成功的处理
+type LeaseKeepALiveHandler func(key string, leaseDetail *clientv3.LeaseKeepAliveResponse)
diff --git a/middleware/etcd/lease.go b/middleware/etcd/lease.go
index 4cc8966..22f4108 100644
--- a/middleware/etcd/lease.go
+++ b/middleware/etcd/lease.go
@@ -41,3 +41,42 @@ func LeaseOnce(ctx context.Context, key string, val string, ttl int64) error {
 	}
 	return nil
 }
+
+// LeaseKeepAliveForever 无限续租一个key
+//
+// Author : go_developer@163.com<白茶清欢>
+//
+// Date : 7:40 下午 2021/11/23
+func LeaseKeepAliveForever(ctx context.Context, key string, val string, ttl int64, keepAliveHandler LeaseKeepALiveHandler) error {
+	if ttl <= 0 {
+		return errors.New("lease time must be more than 0")
+	}
+	if nil == ctx {
+		ctx = context.TODO()
+	}
+	var (
+		resp     *clientv3.LeaseGrantResponse
+		respChan <-chan *clientv3.LeaseKeepAliveResponse
+		err      error
+	)
+	// 创建一个5秒的租约
+	if resp, err = Client.Grant(ctx, ttl); err != nil {
+		return errors.New("lease grant error : " + err.Error())
+	}
+
+	// ttl 秒钟之后,  这个key就会被移除
+	if _, err = Client.Put(context.TODO(), key, val, clientv3.WithLease(resp.ID)); err != nil {
+		return errors.New("lease key put fail : " + err.Error())
+	}
+	// the key will be kept forever
+	if respChan, err = Client.KeepAlive(ctx, resp.ID); nil != err {
+		return errors.New("lease keep alive fail : " + err.Error())
+	}
+	// 监听 chan
+	for ka := range respChan {
+		if nil != keepAliveHandler {
+			keepAliveHandler(key, ka)
+		}
+	}
+	return nil
+}
diff --git a/middleware/etcd/string_test.go b/middleware/etcd/string_test.go
index c7f8c9a..4fb4780 100644
--- a/middleware/etcd/string_test.go
+++ b/middleware/etcd/string_test.go
@@ -173,3 +173,23 @@ func TestLeaseOnce(t *testing.T) {
 		time.Sleep(time.Second)
 	}
 }
+
+// TestLeaseKeepAliveForever ...
+//
+// Author : go_developer@163.com<白茶清欢>
+//
+// Date : 7:54 下午 2021/11/23
+func TestLeaseKeepAliveForever(t *testing.T) {
+	key := "lock"
+	keepAliveHandler := func(key string, data *clientv3.LeaseKeepAliveResponse) {
+		fmt.Println(key, data.ID, data.TTL, data.Size(), data.String())
+	}
+	go func() {
+		fmt.Println(LeaseKeepAliveForever(nil, key, "lock", 10, keepAliveHandler))
+	}()
+	for i := 0; i < 15; i++ {
+		r, e := Get(nil, key, 1)
+		fmt.Println("读取", r, e)
+		time.Sleep(time.Second)
+	}
+}