Method Format

json_formatter.go:63–128

Format renders a single log entry

(entry *Entry)

// Format renders a single log entry
func (f *JSONFormatter) Format(entry *Entry) ([]byte, error) {
	data := make(Fields, len(entry.Data)+4)
	for k, v := range entry.Data {
		switch v := v.(type) {
		case error:
			// Otherwise errors are ignored by `encoding/json`
			// https://github.com/sirupsen/logrus/issues/137
			data[k] = v.Error()
		default:
			data[k] = v
		}
	}

	if f.DataKey != "" {
		newData := make(Fields, 4)
		newData[f.DataKey] = data
		data = newData
	}

	prefixFieldClashes(data, f.FieldMap, entry.HasCaller())

	timestampFormat := f.TimestampFormat
	if timestampFormat == "" {
		timestampFormat = defaultTimestampFormat
	}

	if entry.err != "" {
		data[f.FieldMap.resolve(FieldKeyLogrusError)] = entry.err
	}
	if !f.DisableTimestamp {
		data[f.FieldMap.resolve(FieldKeyTime)] = entry.Time.Format(timestampFormat)
	}
	data[f.FieldMap.resolve(FieldKeyMsg)] = entry.Message
	data[f.FieldMap.resolve(FieldKeyLevel)] = entry.Level.String()
	if entry.HasCaller() {
		funcVal := entry.Caller.Function
		fileVal := fmt.Sprintf("%s:%d", entry.Caller.File, entry.Caller.Line)
		if f.CallerPrettyfier != nil {
			funcVal, fileVal = f.CallerPrettyfier(entry.Caller)
		}
		if funcVal != "" {
			data[f.FieldMap.resolve(FieldKeyFunc)] = funcVal
		}
		if fileVal != "" {
			data[f.FieldMap.resolve(FieldKeyFile)] = fileVal
		}
	}

	var b *bytes.Buffer
	if entry.Buffer != nil {
		b = entry.Buffer
	} else {
		b = &bytes.Buffer{}
	}

	encoder := json.NewEncoder(b)
	encoder.SetEscapeHTML(!f.DisableHTMLEscape)
	if f.PrettyPrint {