Add comments as suggested by SonarCloud

pkg/httpserver/config.go

@@ -141,27 +141,29 @@ func (c *config) validate() error {
 
 // validateAddr checks if a http server bind address is valid.
 func validateAddr(addr string) error {
+	addrErr := fmt.Errorf("invalid http server address: %s", addr)
+
 	if !strings.Contains(addr, ":") {
-		return fmt.Errorf("invalid http server address: %s", addr)
+		return addrErr
 	}
 
 	parts := strings.Split(addr, ":")
 	if len(parts) != 2 {
-		return fmt.Errorf("invalid http server address: %s", addr)
+		return addrErr
 	}
 
 	port := parts[1]
 	if port == "" {
-		return fmt.Errorf("invalid http server address: %s", addr)
+		return addrErr
 	}
 
 	portInt, err := strconv.Atoi(port)
 	if err != nil {
-		return fmt.Errorf("invalid http server address: %s", addr)
+		return addrErr
 	}
 
 	if portInt < 1 || portInt > math.MaxUint16 {
-		return fmt.Errorf("invalid http server address: %s", addr)
+		return addrErr
 	}
 
 	return nil

pkg/logging/config.go

@@ -18,6 +18,7 @@ type config struct {
 }
 
 func defaultConfig() *config {
+	// Return default configuration fields.
 	return &config{
 		fields:            make([]zap.Field, 0, 3),
 		format:            JSONFormat,

pkg/metrics/metrics.go

@@ -50,6 +50,7 @@ func (c *Default) InstrumentRoundTripper(next http.RoundTripper) http.RoundTripp
 
 // MetricsHandlerFunc returns an http handler function.
 func (c *Default) MetricsHandlerFunc() http.HandlerFunc {
+	// Returns "OK" by default.
 	return func(w http.ResponseWriter, r *http.Request) { _, _ = w.Write([]byte(`OK`)) }
 }
 
@@ -60,4 +61,7 @@ func (c *Default) IncLogLevelCounter(level string) {}
 func (c *Default) IncErrorCounter(task, operation, code string) {}
 
 // Close method.
-func (c *Default) Close() error { return nil }
+func (c *Default) Close() error {
+	// Do nothing by default.
+	return nil
+}