Use cache Append() for saving objects in memory, GetObject() caches un-cached entries while reading

pkg/storage/donut/cache.go

@@ -106,14 +106,16 @@ func NewCache(maxSize uint64, expiration time.Duration, donutName string, nodeDi
 // GetObject - GET object from cache buffer
 func (cache Cache) GetObject(w io.Writer, bucket string, object string) (int64, error) {
 	cache.lock.RLock()
-	defer cache.lock.RUnlock()
 	if !IsValidBucket(bucket) {
+		cache.lock.RUnlock()
 		return 0, iodine.New(BucketNameInvalid{Bucket: bucket}, nil)
 	}
 	if !IsValidObjectName(object) {
+		cache.lock.RUnlock()
 		return 0, iodine.New(ObjectNameInvalid{Object: object}, nil)
 	}
 	if _, ok := cache.storedBuckets[bucket]; ok == false {
+		cache.lock.RUnlock()
 		return 0, iodine.New(BucketNotFound{Bucket: bucket}, nil)
 	}
 	objectKey := bucket + "/" + object
@@ -122,20 +124,38 @@ func (cache Cache) GetObject(w io.Writer, bucket string, object string) (int64,
 		if cache.donut != nil {
 			reader, size, err := cache.donut.GetObject(bucket, object)
 			if err != nil {
+				cache.lock.RUnlock()
 				return 0, iodine.New(err, nil)
 			}
-			written, err := io.CopyN(w, reader, size)
+			// new proxy writer to capture data read from disk
+			pw := newProxyWriter(w)
+			written, err := io.CopyN(pw, reader, size)
 			if err != nil {
+				cache.lock.RUnlock()
 				return 0, iodine.New(err, nil)
 			}
+			cache.lock.RUnlock()
+			/// cache object read from disk
+			{
+				cache.lock.Lock()
+				ok := cache.objects.Set(objectKey, pw.writtenBytes)
+				cache.lock.Unlock()
+				pw.writtenBytes = nil
+				go debug.FreeOSMemory()
+				if !ok {
+					return 0, iodine.New(InternalError{}, nil)
+				}
+			}
 			return written, nil
 		}
+		cache.lock.RUnlock()
 		return 0, iodine.New(ObjectNotFound{Object: object}, nil)
 	}
-	written, err := io.Copy(w, bytes.NewBuffer(data))
+	written, err := io.CopyN(w, bytes.NewBuffer(data), int64(cache.objects.Len(objectKey)))
 	if err != nil {
 		return 0, iodine.New(err, nil)
 	}
+	cache.lock.RUnlock()
 	return written, nil
 }
 
@@ -148,14 +168,16 @@ func (cache Cache) GetPartialObject(w io.Writer, bucket, object string, start, l
 		"length": strconv.FormatInt(length, 10),
 	}
 	cache.lock.RLock()
-	defer cache.lock.RUnlock()
 	if !IsValidBucket(bucket) {
+		cache.lock.RUnlock()
 		return 0, iodine.New(BucketNameInvalid{Bucket: bucket}, errParams)
 	}
 	if !IsValidObjectName(object) {
+		cache.lock.RUnlock()
 		return 0, iodine.New(ObjectNameInvalid{Object: object}, errParams)
 	}
 	if start < 0 {
+		cache.lock.RUnlock()
 		return 0, iodine.New(InvalidRange{
 			Start:  start,
 			Length: length,
@@ -167,23 +189,40 @@ func (cache Cache) GetPartialObject(w io.Writer, bucket, object string, start, l
 		if cache.donut != nil {
 			reader, _, err := cache.donut.GetObject(bucket, object)
 			if err != nil {
+				cache.lock.RUnlock()
 				return 0, iodine.New(err, nil)
 			}
 			if _, err := io.CopyN(ioutil.Discard, reader, start); err != nil {
+				cache.lock.RUnlock()
 				return 0, iodine.New(err, nil)
 			}
+			pw := newProxyWriter(w)
 			written, err := io.CopyN(w, reader, length)
 			if err != nil {
+				cache.lock.RUnlock()
 				return 0, iodine.New(err, nil)
 			}
+			cache.lock.RUnlock()
+			{
+				cache.lock.Lock()
+				ok := cache.objects.Set(objectKey, pw.writtenBytes)
+				cache.lock.Unlock()
+				pw.writtenBytes = nil
+				go debug.FreeOSMemory()
+				if !ok {
+					return 0, iodine.New(InternalError{}, nil)
+				}
+			}
 			return written, nil
 		}
+		cache.lock.RUnlock()
 		return 0, iodine.New(ObjectNotFound{Object: object}, nil)
 	}
 	written, err := io.CopyN(w, bytes.NewBuffer(data[start:]), length)
 	if err != nil {
 		return 0, iodine.New(err, nil)
 	}
+	cache.lock.RUnlock()
 	return written, nil
 }
 
@@ -317,13 +356,24 @@ func (cache Cache) createObject(bucket, key, contentType, expectedMD5Sum string,
 		expectedMD5Sum = hex.EncodeToString(expectedMD5SumBytes)
 	}
 
+	if cache.donut != nil {
+		objMetadata, err := cache.donut.PutObject(bucket, key, expectedMD5Sum, data, map[string]string{"contentType": contentType})
+		if err != nil {
+			return ObjectMetadata{}, iodine.New(err, nil)
+		}
+		cache.lock.Lock()
+		storedBucket.objectMetadata[objectKey] = objMetadata
+		cache.storedBuckets[bucket] = storedBucket
+		cache.lock.Unlock()
+		return objMetadata, nil
+	}
 	// calculate md5
 	hash := md5.New()
-	var readBytes []byte
 
 	var err error
-	var length int
+	var totalLength int
 	for err == nil {
+		var length int
 		byteBuffer := make([]byte, 1024*1024)
 		length, err = data.Read(byteBuffer)
 		// While hash.Write() wouldn't mind a Nil byteBuffer
@@ -332,24 +382,20 @@ func (cache Cache) createObject(bucket, key, contentType, expectedMD5Sum string,
 			break
 		}
 		hash.Write(byteBuffer[0:length])
-		readBytes = append(readBytes, byteBuffer[0:length]...)
+		cache.lock.Lock()
+		ok := cache.objects.Append(objectKey, byteBuffer[0:length])
+		cache.lock.Unlock()
+		if !ok {
+			return ObjectMetadata{}, iodine.New(InternalError{}, nil)
+		}
+		totalLength += length
+		go debug.FreeOSMemory()
 	}
 	if err != io.EOF {
 		return ObjectMetadata{}, iodine.New(err, nil)
 	}
-	md5SumBytes := hash.Sum(nil)
-	totalLength := len(readBytes)
-
-	cache.lock.Lock()
-	ok := cache.objects.Set(objectKey, readBytes)
-	// setting up for de-allocation
-	readBytes = nil
-	go debug.FreeOSMemory()
-	cache.lock.Unlock()
-	if !ok {
-		return ObjectMetadata{}, iodine.New(InternalError{}, nil)
-	}
 
+	md5SumBytes := hash.Sum(nil)
 	md5Sum := hex.EncodeToString(md5SumBytes)
 	// Verify if the written object is equal to what is expected, only if it is requested as such
 	if strings.TrimSpace(expectedMD5Sum) != "" {
@@ -576,14 +622,8 @@ func (cache Cache) expiredObject(a ...interface{}) {
 		cacheStats.Bytes, cacheStats.Items, cacheStats.Expired)
 	key := a[0].(string)
 	// loop through all buckets
-	for bucket, storedBucket := range cache.storedBuckets {
+	for _, storedBucket := range cache.storedBuckets {
 		delete(storedBucket.objectMetadata, key)
-		// remove bucket if no objects found anymore
-		if len(storedBucket.objectMetadata) == 0 {
-			if time.Since(cache.storedBuckets[bucket].bucketMetadata.Created) > cache.expiration {
-				delete(cache.storedBuckets, bucket)
-			}
-		}
 	}
 	debug.FreeOSMemory()
 }

pkg/storage/donut/trove/trove.go

@@ -115,6 +115,17 @@ func (r *Cache) Get(key string) ([]byte, bool) {
 	return value, true
 }
 
+// Len returns length of the value of a given key, returns zero if key doesn't exist
+func (r *Cache) Len(key string) int {
+	r.Lock()
+	defer r.Unlock()
+	_, ok := r.items[key]
+	if !ok {
+		return 0
+	}
+	return len(r.items[key])
+}
+
 // Append will append new data to an existing key,
 // if key doesn't exist it behaves like Set()
 func (r *Cache) Append(key string, value []byte) bool {