diff --git a/Makefile b/Makefile
index 0fabc34..f62e9d8 100644
--- a/Makefile
+++ b/Makefile
@@ -25,6 +25,9 @@ release-x86:
 release-mac:
 	go build -o gor $(MAC_LDFLAGS) && tar -czf gor_$(VERSION)_PRO_mac.tar.gz gor && rm gor
 
+install:
+	go install $(MAC_LDFLAGS)
+
 build:
 	docker build -t $(CONTAINER) .
 
diff --git a/input_kafka.go b/input_kafka.go
index 715d5ee..25e6d72 100644
--- a/input_kafka.go
+++ b/input_kafka.go
@@ -22,7 +22,7 @@ func NewKafkaInput(address string, config *KafkaConfig) *KafkaInput {
 
 	var con sarama.Consumer
 
-	if config.consumer.(*mocks.Consumer) != nil {
+	if mock, ok := config.consumer.(*mocks.Consumer); ok && mock != nil {
 		con = config.consumer
 	} else {
 		var err error
diff --git a/output_file.go b/output_file.go
index f268a7f..4176dce 100644
--- a/output_file.go
+++ b/output_file.go
@@ -74,10 +74,8 @@ func NewFileOutput(pathTemplate string, config *FileOutputConfig) *FileOutput {
 			if o.closed {
 				break
 			}
-			o.mu.Lock()
 			o.updateName()
 			o.flush()
-			o.mu.Unlock()
 		}
 	}()
 
diff --git a/output_kafka.go b/output_kafka.go
index 336800f..ec9855d 100644
--- a/output_kafka.go
+++ b/output_kafka.go
@@ -26,7 +26,7 @@ func NewKafkaOutput(address string, config *KafkaConfig) io.Writer {
 
 	var producer sarama.AsyncProducer
 
-	if config.producer.(*mocks.AsyncProducer) != nil {
+	if mock, ok := config.producer.(*mocks.AsyncProducer); ok && mock != nil {
 		producer = config.producer
 	} else {
 		c.Producer.RequiredAcks = sarama.WaitForLocal