Consolidate apiHost & host for RabbitMQ scaler

closes kedacore#711

Signed-off-by: Tomek Urbaszek <tomasz.urbaszek@polidea.com>

pkg/scalers/rabbitmq_scaler.go

@@ -23,8 +23,12 @@ const (
 	rabbitQueueLengthMetricName = "queueLength"
 	defaultRabbitMQQueueLength  = 20
 	rabbitMetricType            = "External"
-	rabbitIncludeUnacked        = "includeUnacked"
-	defaultIncludeUnacked       = false
+)
+
+const (
+	httpProtocol    = "http"
+	amqpProtocol    = "amqp"
+	defaultProtocol = amqpProtocol
 )
 
 type rabbitMQScaler struct {
@@ -34,11 +38,10 @@ type rabbitMQScaler struct {
 }
 
 type rabbitMQMetadata struct {
-	queueName      string
-	host           string // connection string for AMQP protocol
-	apiHost        string // connection string for management API requests
-	queueLength    int
-	includeUnacked bool // if true uses HTTP API and requires apiHost, if false uses AMQP and requires host
+	queueName   string
+	host        string // connection string for either HTTP or AMQP protocol
+	queueLength int
+	protocol    string // either http or amqp protocol
 }
 
 type queueInfo struct {
@@ -56,7 +59,7 @@ func NewRabbitMQScaler(resolvedEnv, metadata, authParams map[string]string) (Sca
 		return nil, fmt.Errorf("error parsing rabbitmq metadata: %s", err)
 	}
 
-	if meta.includeUnacked {
+	if meta.protocol == httpProtocol {
 		return &rabbitMQScaler{metadata: meta}, nil
 	}
 
@@ -75,47 +78,35 @@ func NewRabbitMQScaler(resolvedEnv, metadata, authParams map[string]string) (Sca
 func parseRabbitMQMetadata(resolvedEnv, metadata, authParams map[string]string) (*rabbitMQMetadata, error) {
 	meta := rabbitMQMetadata{}
 
-	meta.includeUnacked = defaultIncludeUnacked
-	if val, ok := metadata[rabbitIncludeUnacked]; ok {
-		includeUnacked, err := strconv.ParseBool(val)
-		if err != nil {
-			return nil, fmt.Errorf("includeUnacked parsing error %s", err.Error())
+	// Resolve protocol type
+	meta.protocol = defaultProtocol
+	if val, ok := metadata["protocol"]; ok {
+		if val == amqpProtocol || val == httpProtocol {
+			meta.protocol = val
+		} else {
+			return nil, fmt.Errorf("the protocol has to be either `%s` or `%s` but is `%s`", amqpProtocol, httpProtocol, val)
 		}
-		meta.includeUnacked = includeUnacked
 	}
 
-	if meta.includeUnacked {
-		if authParams["apiHost"] != "" {
-			meta.apiHost = authParams["apiHost"]
-		} else if metadata["apiHost"] != "" {
-			meta.apiHost = metadata["apiHost"]
-		} else if metadata["apiHostFromEnv"] != "" {
-			meta.apiHost = resolvedEnv[metadata["apiHostFromEnv"]]
-		}
-
-		if meta.apiHost == "" {
-			return nil, fmt.Errorf("no apiHost setting given")
-		}
+	// Resolve host value
+	if authParams["host"] != "" {
+		meta.host = authParams["host"]
+	} else if metadata["host"] != "" {
+		meta.host = metadata["host"]
+	} else if metadata["hostFromEnv"] != "" {
+		meta.host = resolvedEnv[metadata["hostFromEnv"]]
 	} else {
-		if authParams["host"] != "" {
-			meta.host = authParams["host"]
-		} else if metadata["host"] != "" {
-			meta.host = metadata["host"]
-		} else if metadata["hostFromEnv"] != "" {
-			meta.host = resolvedEnv[metadata["hostFromEnv"]]
-		}
-
-		if meta.host == "" {
-			return nil, fmt.Errorf("no host setting given")
-		}
+		return nil, fmt.Errorf("no host setting given")
 	}
 
+	// Resolve queueName
 	if val, ok := metadata["queueName"]; ok {
 		meta.queueName = val
 	} else {
 		return nil, fmt.Errorf("no queue name given")
 	}
 
+	// Resolve queueLength
 	if val, ok := metadata[rabbitQueueLengthMetricName]; ok {
 		queueLength, err := strconv.Atoi(val)
 		if err != nil {
@@ -167,7 +158,7 @@ func (s *rabbitMQScaler) IsActive(ctx context.Context) (bool, error) {
 }
 
 func (s *rabbitMQScaler) getQueueMessages() (int, error) {
-	if s.metadata.includeUnacked {
+	if s.metadata.protocol == httpProtocol {
 		info, err := s.getQueueInfoViaHTTP()
 		if err != nil {
 			return -1, err
@@ -202,7 +193,7 @@ func getJSON(url string, target interface{}) error {
 }
 
 func (s *rabbitMQScaler) getQueueInfoViaHTTP() (*queueInfo, error) {
-	parsedURL, err := url.Parse(s.metadata.apiHost)
+	parsedURL, err := url.Parse(s.metadata.host)
 
 	if err != nil {
 		return nil, err