address code review comments re. style/structure

plugins/inputs/http_listener/http_listener.go

@@ -61,13 +61,19 @@ func (t *HttpListener) Start(acc telegraf.Accumulator) error {
 	t.acc = acc
 
 	var rawListener, err = net.Listen("tcp", t.ServiceAddress)
+	if err != nil {
+		return err
+	}
 	t.listener, err = stoppableListener.New(rawListener)
+	if err != nil {
+		return err
+	}
 
 	go t.httpListen()
 
 	log.Printf("Started HTTP listener service on %s\n", t.ServiceAddress)
 
-	return err
+	return nil
 }
 
 // Stop cleans up all resources
@@ -85,7 +91,13 @@ func (t *HttpListener) Stop() {
 func (t *HttpListener) httpListen() error {
 
 	readTimeout, err := strconv.ParseInt(t.ReadTimeout, 10, 32)
+	if err != nil {
+		return err
+	}
 	writeTimeout, err := strconv.ParseInt(t.WriteTimeout, 10, 32)
+	if err != nil {
+		return err
+	}
 
 	var server = http.Server{
 		Handler:      t,
@@ -93,15 +105,18 @@ func (t *HttpListener) httpListen() error {
 		WriteTimeout: time.Duration(writeTimeout) * time.Second,
 	}
 
-	err = server.Serve(t.listener)
-
-	return err
+	return server.Serve(t.listener)
 }
 
 func (t *HttpListener) ServeHTTP(res http.ResponseWriter, req *http.Request) {
 	body, err := ioutil.ReadAll(req.Body)
 
-	if err == nil {
+	if err != nil {
+		log.Printf("Problem reading request: [%s], Error: %s\n", string(body), err)
+		res.WriteHeader(http.StatusInternalServerError)
+		res.Write([]byte("ERROR reading request"))
+	}
+
 	var path = req.URL.Path[1:]
 
 	if path == "write" {
@@ -127,11 +142,6 @@ func (t *HttpListener) ServeHTTP(res http.ResponseWriter, req *http.Request) {
 		res.WriteHeader(http.StatusNotFound)
 		res.Write([]byte("Not Found"))
 	}
-	} else {
-		log.Printf("Problem reading request: [%s], Error: %s\n", string(body), err)
-		res.WriteHeader(http.StatusInternalServerError)
-		res.Write([]byte("ERROR reading request"))
-	}
 }
 
 func (t *HttpListener) storeMetrics(metrics []telegraf.Metric) error {