Merge pull request #396 from onetwopunch/customzable-json-keys
Added customizable keys to JSON formatter
diff --git a/json_formatter.go b/json_formatter.go
index 2ad6dc5..f3729bf 100644
--- a/json_formatter.go
+++ b/json_formatter.go
@@ -5,9 +5,37 @@
"fmt"
)
+type fieldKey string
+type FieldMap map[fieldKey]string
+
+const (
+ FieldKeyMsg = "msg"
+ FieldKeyLevel = "level"
+ FieldKeyTime = "time"
+)
+
+func (f FieldMap) resolve(key fieldKey) string {
+ if k, ok := f[key]; ok {
+ return k
+ }
+
+ return string(key)
+}
+
type JSONFormatter struct {
// TimestampFormat sets the format used for marshaling timestamps.
TimestampFormat string
+
+ // FieldMap allows users to customize the names of keys for various fields.
+ // As an example:
+ // formatter := &JSONFormatter{
+ // FieldMap: FieldMap{
+ // FieldKeyTime: "@timestamp",
+ // FieldKeyLevel: "@level",
+ // FieldKeyLevel: "@message",
+ // },
+ // }
+ FieldMap FieldMap
}
func (f *JSONFormatter) Format(entry *Entry) ([]byte, error) {
@@ -29,9 +57,9 @@
timestampFormat = DefaultTimestampFormat
}
- data["time"] = entry.Time.Format(timestampFormat)
- data["msg"] = entry.Message
- data["level"] = entry.Level.String()
+ data[f.FieldMap.resolve(FieldKeyTime)] = entry.Time.Format(timestampFormat)
+ data[f.FieldMap.resolve(FieldKeyMsg)] = entry.Message
+ data[f.FieldMap.resolve(FieldKeyLevel)] = entry.Level.String()
serialized, err := json.Marshal(data)
if err != nil {
diff --git a/json_formatter_test.go b/json_formatter_test.go
index 1d70873..5baa93e 100644
--- a/json_formatter_test.go
+++ b/json_formatter_test.go
@@ -3,7 +3,7 @@
import (
"encoding/json"
"errors"
-
+ "strings"
"testing"
)
@@ -118,3 +118,54 @@
t.Fatal("Expected JSON log entry to end with a newline")
}
}
+
+func TestJSONMessageKey(t *testing.T) {
+ formatter := &JSONFormatter{
+ FieldMap: FieldMap{
+ FieldKeyMsg: "message",
+ },
+ }
+
+ b, err := formatter.Format(&Entry{Message: "oh hai"})
+ if err != nil {
+ t.Fatal("Unable to format entry: ", err)
+ }
+ s := string(b)
+ if !(strings.Contains(s, "message") && strings.Contains(s, "oh hai")) {
+ t.Fatal("Expected JSON to format message key")
+ }
+}
+
+func TestJSONLevelKey(t *testing.T) {
+ formatter := &JSONFormatter{
+ FieldMap: FieldMap{
+ FieldKeyLevel: "somelevel",
+ },
+ }
+
+ b, err := formatter.Format(WithField("level", "something"))
+ if err != nil {
+ t.Fatal("Unable to format entry: ", err)
+ }
+ s := string(b)
+ if !strings.Contains(s, "somelevel") {
+ t.Fatal("Expected JSON to format level key")
+ }
+}
+
+func TestJSONTimeKey(t *testing.T) {
+ formatter := &JSONFormatter{
+ FieldMap: FieldMap{
+ FieldKeyTime: "timeywimey",
+ },
+ }
+
+ b, err := formatter.Format(WithField("level", "something"))
+ if err != nil {
+ t.Fatal("Unable to format entry: ", err)
+ }
+ s := string(b)
+ if !strings.Contains(s, "timeywimey") {
+ t.Fatal("Expected JSON to format time key")
+ }
+}
