Merge pull request #200 from freeformz/no_msg

Don't emit a msg if there is none to emit

text_formatter.go

@@ -84,7 +84,9 @@ func (f *TextFormatter) Format(entry *Entry) ([]byte, error) {
 			f.appendKeyValue(b, "time", entry.Time.Format(timestampFormat))
 		}
 		f.appendKeyValue(b, "level", entry.Level.String())
+		if entry.Message != "" {
 			f.appendKeyValue(b, "msg", entry.Message)
+		}
 		for _, key := range keys {
 			f.appendKeyValue(b, key, entry.Data[key])
 		}