User an interface

logger.go

@@ -43,7 +43,7 @@ type Logger struct {
 	// Writer specifies the writer of output. It uses os.Stderr in if empty.
 	Writer io.Writer
 
-	MultiWriters *MultiWriter
+	leveledWriterRouter LeveledWriterRouter
 }
 
 const (
@@ -285,8 +285,8 @@ func (l *Logger) header(level Level) *Event {
 		e.exit = false
 		e.panic = true
 	}
-	if l.MultiWriters != nil {
-		e.w = l.MultiWriters.GetWriterByLevel(level)
+	if l.leveledWriterRouter != nil {
+		e.w = l.leveledWriterRouter.GetWriterByLevel(level)
 	} else if l.Writer != nil {
 		e.w = l.Writer
 	} else {

multi.go

@@ -5,6 +5,10 @@ import (
 	"io"
 )
 
+type LeveledWriterRouter interface {
+	GetWriterByLevel(level Level) io.Writer
+}
+
 type CombinedWriter []io.Writer
 
 func (cw CombinedWriter) Write(p []byte) (n int, firstErr error) {
@@ -82,7 +86,7 @@ func (w *MultiWriter) GetWriterByLevel(level Level) io.Writer {
 	return CombinedWriter(w.levelWriters[:int(level)+1])
 }
 
-// Close implements io.Closer, and closes the underlying MultiWriters.
+// Close implements io.Closer, and closes the underlying leveledWriterRouter.
 func (w *MultiWriter) Close() (err error) {
 	for _, writer := range []io.Writer{
 		w.InfoWriter,

multi_test.go

@@ -24,9 +24,9 @@ func TestNewMultiWriters(t *testing.T) {
 		},
 	}
 	logger := Logger{
-		Level:        InfoLevel,
-		Caller:       1,
-		MultiWriters: w,
+		Level:               InfoLevel,
+		Caller:              1,
+		leveledWriterRouter: w,
 	}
 	assertNLogs := func(want int) {
 		matches, _ := filepath.Glob("file-*.*.log")
@@ -229,9 +229,9 @@ func BenchmarkNewMultiWriter(b *testing.B) {
 		},
 	}
 	logger := Logger{
-		Level:        InfoLevel,
-		Caller:       1,
-		MultiWriters: w,
+		Level:               InfoLevel,
+		Caller:              1,
+		leveledWriterRouter: w,
 	}
 	b.ReportAllocs()
 	b.ResetTimer()