WIP

kvmemcache/cache.go

@@ -37,6 +37,7 @@ type Config struct {
 type Stats struct {
 	Hits    uint64
 	Misses  uint64
+	Expired uint64
 }
 
 func New(conf Config) *Cache {
@@ -55,7 +56,6 @@ func (c *Cache) Get(key string) (interface{}, error) {
 	item := c.getItem(key)
 	if item == nil {
 		item = c.loadItemFromSource(key)
-
 	}
 	return item.value, item.err
 }
@@ -66,7 +66,7 @@ func (c *Cache) Evict(key string) {
 	c.evictKey(key)
 }
 
-func (c Cache) GetStats() Stats {
+func (c Cache) Stats() Stats {
 	c.lock.Lock()
 	defer c.lock.Unlock()
 	return c.stats

kvmemcache/cache_test.go

@@ -8,7 +8,8 @@ import (
 )
 
 func testRunner(c *Cache, t *testing.T, done chan bool) {
-	for i := 0; i < 2000000; i++ {
+	rand.Seed(time.Now().UnixNano())
+	for i := 0; i < 200001; i++ {
 		x := rand.Int31n(50)
 		if rand.Float64() < 0.01 {
 			x = rand.Int31n(9999)
@@ -42,11 +43,12 @@ func testCache(name string, c *Cache, t *testing.T) {
 		<-done
 	}
 
-	stats := c.GetStats()
+	stats := c.Stats()
 
 	fmt.Println(name)
 	fmt.Printf("  Hits:    %d\n", stats.Hits)
 	fmt.Printf("  Misses:  %d\n", stats.Misses)
+	fmt.Printf("  Expired: %d\n", stats.Expired)
 	fmt.Printf("  Hit-rate: %.2f%%\n",
 		100*float64(stats.Hits)/float64(stats.Hits+stats.Misses))
 }
@@ -54,10 +56,43 @@ func testCache(name string, c *Cache, t *testing.T) {
 func TestCache(t *testing.T) {
 	c := New(Config{
 		MaxSize: 2048,
-		TTL:     time.Second,
+		TTL:     100 * time.Millisecond,
 		Src: func(key string) (interface{}, error) {
 			return fmt.Sprintf("value for %s", key), nil
 		},
 	})
 	testCache("LRUTimeout", c, t)
 }
+
+func TestCacheTTL(t *testing.T) {
+	c := New(Config{
+		MaxSize: 2048,
+		TTL:     100 * time.Millisecond,
+		Src: func(key string) (interface{}, error) {
+			return key, nil
+		},
+	})
+
+	c.Get("a")
+	c.Get("b")
+	time.Sleep(50 * time.Millisecond)
+	c.Get("a")
+	c.Get("b")
+	c.Get("c")
+
+	stats := c.Stats()
+	if stats.Expired != 0 {
+		t.Fatal(stats.Expired)
+	}
+
+	time.Sleep(50 * time.Millisecond)
+	c.Get("a")
+	c.Get("b")
+	c.Get("c")
+
+	stats = c.Stats()
+	if stats.Expired != 2 {
+		t.Fatal(stats.Expired)
+	}
+
+}

kvmemcache/internal.go

@@ -1,26 +1,28 @@
 package kvmemcache
 
-import "time"
+import (
+	"time"
+)
 
 func (c *Cache) getItem(key string) *lruItem {
 	c.lock.Lock()
 	defer c.lock.Unlock()
 
-	li, ok := c.cache[key]
+	elem, ok := c.cache[key]
 	if !ok {
 		c.stats.Misses++
 		return nil
 	}
 
-	item := li.Value.(*lruItem)
+	item := elem.Value.(*lruItem)
 	if c.ttl != 0 && time.Since(item.createdAt) > c.ttl {
+		c.stats.Expired++
 		c.evictKey(key)
-		c.stats.Misses++
 		return nil
 	}
 
 	c.stats.Hits++
-	c.ll.MoveToFront(li)
+	c.ll.MoveToFront(elem)
 	return item
 }
 
@@ -55,9 +57,9 @@ func (c *Cache) putItem(key string, item *lruItem) {
 	c.cache[key] = c.ll.PushFront(item)
 
 	if c.maxSize > 0 && len(c.cache) > c.maxSize {
-		li := c.ll.Back()
-		c.ll.Remove(li)
-		delete(c.cache, li.Value.(*lruItem).key)
+		elem := c.ll.Back()
+		c.ll.Remove(elem)
+		delete(c.cache, elem.Value.(*lruItem).key)
 	}
 }