add setFields to set multiple fields

nop.go

@@ -7,6 +7,8 @@ var NopLogger = &nop{}
 
 func (n nop) SetField(name string, value interface{}) {}
 
+func (n nop) SetFields(fields F) {}
+
 func (n nop) GetFields() F { return map[string]interface{}{} }
 
 func (n nop) OutputF(level Level, calldepth int, msg string, fields map[string]interface{}, err error) {

xlog.go

@@ -41,6 +41,9 @@ type Logger interface {
 	// SetField sets a field on the logger's context. All future messages on this logger
 	// will have this field set.
 	SetField(name string, value interface{})
+	// SetFields sets a fielsd on the logger's context. All future messages on this logger
+	// will have this fields set.
+	SetFields(fields F)
 	// GetFields returns all the fields set on the logger
 	GetFields() F
 	// Debug logs a debug message. If last parameter is a map[string]string, it's content
@@ -248,6 +251,13 @@ func (l *logger) SetField(name string, value interface{}) {
 	l.fields[name] = value
 }
 
+// SetFields
+func (l *logger) SetFields(fields F) {
+	for name, value := range fields {
+		l.fields[name] = value
+	}
+}
+
 // GetFields implements Logger interface
 func (l *logger) GetFields() F {
 	return l.fields