fix double close possibility

client/cherami/consumer.go

@@ -169,29 +169,29 @@ func (c *consumerImpl) Open(deliveryCh chan Delivery) (chan Delivery, error) {
 
 func (c *consumerImpl) Close() {
 
-	if !atomic.CompareAndSwapInt32(&c.isClosing, 0, 1) {
-		return
-	}
+	if atomic.CompareAndSwapInt32(&c.isClosing, 0, 1) {
 
-	close(c.closingCh)
+		close(c.closingCh)
 
-	c.lk.Lock()
-	if c.connections != nil {
-		for _, outputHostConn := range c.connections {
-			outputHostConn.close()
+		c.lk.Lock()
+		if c.connections != nil {
+			for _, outputHostConn := range c.connections {
+				outputHostConn.close()
+			}
+			c.reporter.UpdateGauge(metrics.ConsumeNumConnections, nil, 0)
 		}
-		c.reporter.UpdateGauge(metrics.ConsumeNumConnections, nil, 0)
-	}
 
-	if c.ackConnection != nil {
-		c.ackConnection.Close()
-		c.ackConnection = nil
-	}
+		if c.ackConnection != nil {
+			c.ackConnection.Close()
+			c.ackConnection = nil
+		}
 
-	c.opened = false
-	c.lk.Unlock()
+		c.opened = false
+		c.lk.Unlock()
+	}
 
 	c.wg.Wait()
+	return
 }
 
 func (c *consumerImpl) Pause() {