auto delete element from kv cache when unlock

.travis.yml

@@ -1,8 +1,9 @@
 language: go
 
 go:
-    - "1.11.x"
-    - "1.12"
+    - "1.13"
+    - "1.14"
+    - "1.15"
 
 before_install:
     - go get github.com/mattn/goveralls

go.mod

@@ -1,5 +1,7 @@
 module github.com/amyangfei/redlock-go
 
+go 1.15
+
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/go-redis/redis v6.14.2+incompatible

redlock/kvcache.go

@@ -28,6 +28,9 @@ type KVCache interface {
 	// Delete removes the LockElem with given key from storage
 	Delete(key string)
 
+	// Size returns element count in kv storage
+	Size() int
+
 	// GC cleans the expired LockElem stored in storage
 	GC()
 }
@@ -77,6 +80,13 @@ func (sc *SimpleCache) Delete(key string) {
 	delete(sc.kvs, key)
 }
 
+// Size implements KVCache.Size
+func (sc *SimpleCache) Size() int {
+	sc.lock.RLock()
+	defer sc.lock.RUnlock()
+	return len(sc.kvs)
+}
+
 // GC implements KVCache.GC
 func (sc *SimpleCache) GC() {
 	sc.lock.Lock()

redlock/redlock.go

@@ -216,6 +216,7 @@ func (r *RedLock) UnLock(resource string) error {
 	if elem == nil {
 		return nil
 	}
+	defer r.cache.Delete(resource)
 	c := make(chan bool, len(r.clients))
 	for _, cli := range r.clients {
 		go unlockInstance(cli, resource, elem.val, c)

redlock/redlock_test.go

@@ -226,3 +226,26 @@ func TestAcquireLockFailed(t *testing.T) {
 
 	wg.Wait()
 }
+
+func TestKVCache(t *testing.T) {
+	lock, err := NewRedLock(redisServers)
+	assert.Nil(t, err)
+
+	var wg sync.WaitGroup
+	for i := 0; i < 4; i++ {
+		wg.Add(1)
+		i := i
+		go func() {
+			defer wg.Done()
+			for j := 0; j < 100; j++ {
+				key := fmt.Sprintf("foo-%d-%d", i, j)
+				_, err = lock.Lock(key, 200)
+				assert.Nil(t, err)
+				err = lock.UnLock(key)
+				assert.Nil(t, err)
+			}
+		}()
+	}
+	wg.Done()
+	assert.Zero(t, lock.cache.Size())
+}