Merge pull request #218 from pengzhai/master

Fix data race issue in TextFormatter. Fix for https://github.com/Siru…

text_formatter.go

diff --git a/text_formatter.go b/text_formatter.go
index e25f86c..17cc298 100644
--- a/text_formatter.go
+++ b/text_formatter.go
@@ -73,14 +73,15 @@
 	isColorTerminal := isTerminal && (runtime.GOOS != "windows")
 	isColored := (f.ForceColors || isColorTerminal) && !f.DisableColors
 
-	if f.TimestampFormat == "" {
-		f.TimestampFormat = DefaultTimestampFormat
+	timestampFormat := f.TimestampFormat
+	if timestampFormat == "" {
+		timestampFormat = DefaultTimestampFormat
 	}
 	if isColored {
-		f.printColored(b, entry, keys)
+		f.printColored(b, entry, keys, timestampFormat)
 	} else {
 		if !f.DisableTimestamp {
-			f.appendKeyValue(b, "time", entry.Time.Format(f.TimestampFormat))
+			f.appendKeyValue(b, "time", entry.Time.Format(timestampFormat))
 		}
 		f.appendKeyValue(b, "level", entry.Level.String())
 		f.appendKeyValue(b, "msg", entry.Message)
@@ -93,7 +94,7 @@
 	return b.Bytes(), nil
 }
 
-func (f *TextFormatter) printColored(b *bytes.Buffer, entry *Entry, keys []string) {
+func (f *TextFormatter) printColored(b *bytes.Buffer, entry *Entry, keys []string, timestampFormat string) {
 	var levelColor int
 	switch entry.Level {
 	case DebugLevel:
@@ -111,7 +112,7 @@
 	if !f.FullTimestamp {
 		fmt.Fprintf(b, "\x1b[%dm%s\x1b[0m[%04d] %-44s ", levelColor, levelText, miniTS(), entry.Message)
 	} else {
-		fmt.Fprintf(b, "\x1b[%dm%s\x1b[0m[%s] %-44s ", levelColor, levelText, entry.Time.Format(f.TimestampFormat), entry.Message)
+		fmt.Fprintf(b, "\x1b[%dm%s\x1b[0m[%s] %-44s ", levelColor, levelText, entry.Time.Format(timestampFormat), entry.Message)
 	}
 	for _, k := range keys {
 		v := entry.Data[k]