Allow using custom level field format (#136)

globals.go

@@ -13,6 +13,11 @@ var (
 	// LevelFieldName is the field name used for the level field.
 	LevelFieldName = "level"
 
+	// LevelFieldMarshalFunc allows customization of global level field marshaling
+	LevelFieldMarshalFunc = func(l Level) string {
+		return l.String()
+	}
+
 	// MessageFieldName is the field name used for the message field.
 	MessageFieldName = "message"
 
@@ -27,7 +32,7 @@ var (
 
 	// CallerMarshalFunc allows customization of global caller marshaling
 	CallerMarshalFunc = func(file string, line int) string {
-		return file+":"+strconv.Itoa(line)
+		return file + ":" + strconv.Itoa(line)
 	}
 
 	// ErrorStackFieldName is the field name used for error stacks.

log.go

@@ -152,19 +152,19 @@ func (l Level) String() string {
 // returns an error if the input string does not match known values.
 func ParseLevel(levelStr string) (Level, error) {
 	switch levelStr {
-	case DebugLevel.String():
+	case LevelFieldMarshalFunc(DebugLevel):
 		return DebugLevel, nil
-	case InfoLevel.String():
+	case LevelFieldMarshalFunc(InfoLevel):
 		return InfoLevel, nil
-	case WarnLevel.String():
+	case LevelFieldMarshalFunc(WarnLevel):
 		return WarnLevel, nil
-	case ErrorLevel.String():
+	case LevelFieldMarshalFunc(ErrorLevel):
 		return ErrorLevel, nil
-	case FatalLevel.String():
+	case LevelFieldMarshalFunc(FatalLevel):
 		return FatalLevel, nil
-	case PanicLevel.String():
+	case LevelFieldMarshalFunc(PanicLevel):
 		return PanicLevel, nil
-	case NoLevel.String():
+	case LevelFieldMarshalFunc(NoLevel):
 		return NoLevel, nil
 	}
 	return NoLevel, fmt.Errorf("Unknown Level String: '%s', defaulting to NoLevel", levelStr)
@@ -380,7 +380,7 @@ func (l *Logger) newEvent(level Level, done func(string)) *Event {
 	e.done = done
 	e.ch = l.hooks
 	if level != NoLevel {
-		e.Str(LevelFieldName, level.String())
+		e.Str(LevelFieldName, LevelFieldMarshalFunc(level))
 	}
 	if l.context != nil && len(l.context) > 0 {
 		e.buf = enc.AppendObjectData(e.buf, l.context)

log_test.go

@@ -650,9 +650,9 @@ func TestCallerMarshalFunc(t *testing.T) {
 	// test default behaviour this is really brittle due to the line numbers
 	// actually mattering for validation
 	_, file, line, _ := runtime.Caller(0)
-	caller := fmt.Sprintf("%s:%d", file, line + 2)
+	caller := fmt.Sprintf("%s:%d", file, line+2)
 	log.Log().Caller().Msg("msg")
-	if got, want := decodeIfBinaryToString(out.Bytes()), `{"caller":"` + caller + `","message":"msg"}`+"\n"; got != want {
+	if got, want := decodeIfBinaryToString(out.Bytes()), `{"caller":"`+caller+`","message":"msg"}`+"\n"; got != want {
 		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
 	}
 	out.Reset()
@@ -663,19 +663,55 @@ func TestCallerMarshalFunc(t *testing.T) {
 	CallerMarshalFunc = func(file string, line int) string {
 		parts := strings.Split(file, "/")
 		if len(parts) > 1 {
-			return strings.Join(parts[len(parts)-2:], "/")+":"+strconv.Itoa(line)
+			return strings.Join(parts[len(parts)-2:], "/") + ":" + strconv.Itoa(line)
 		} else {
-			return file+":"+strconv.Itoa(line)
+			return file + ":" + strconv.Itoa(line)
 		}
 	}
 	_, file, line, _ = runtime.Caller(0)
 	caller = CallerMarshalFunc(file, line+2)
 	log.Log().Caller().Msg("msg")
-	if got, want := decodeIfBinaryToString(out.Bytes()), `{"caller":"` + caller + `","message":"msg"}`+"\n"; got != want {
+	if got, want := decodeIfBinaryToString(out.Bytes()), `{"caller":"`+caller+`","message":"msg"}`+"\n"; got != want {
 		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
 	}
 }
 
+func TestLevelFieldMarshalFunc(t *testing.T) {
+	origLevelFieldMarshalFunc := LevelFieldMarshalFunc
+	LevelFieldMarshalFunc = func(l Level) string {
+		return strings.ToUpper(l.String())
+	}
+	defer func() {
+		LevelFieldMarshalFunc = origLevelFieldMarshalFunc
+	}()
+	out := &bytes.Buffer{}
+	log := New(out)
+
+	log.Debug().Msg("test")
+	if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"DEBUG","message":"test"}`+"\n"; got != want {
+		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+	}
+	out.Reset()
+
+	log.Info().Msg("test")
+	if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"INFO","message":"test"}`+"\n"; got != want {
+		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+	}
+	out.Reset()
+
+	log.Warn().Msg("test")
+	if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"WARN","message":"test"}`+"\n"; got != want {
+		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+	}
+	out.Reset()
+
+	log.Error().Msg("test")
+	if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"ERROR","message":"test"}`+"\n"; got != want {
+		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+	}
+	out.Reset()
+}
+
 type errWriter struct {
 	error
 }