Merge pull request sirupsen#347 from Sirupsen/level-writer

Add WriterLevel() function to the logger

writer.go

@@ -7,18 +7,40 @@ import (
 )
 
 func (logger *Logger) Writer() *io.PipeWriter {
+	return logger.WriterLevel(InfoLevel)
+}
+
+func (logger *Logger) WriterLevel(level Level) *io.PipeWriter {
 	reader, writer := io.Pipe()
 
-	go logger.writerScanner(reader)
+	var printFunc func(args ...interface{})
+	switch level {
+	case DebugLevel:
+		printFunc = logger.Debug
+	case InfoLevel:
+		printFunc = logger.Info
+	case WarnLevel:
+		printFunc = logger.Warn
+	case ErrorLevel:
+		printFunc = logger.Error
+	case FatalLevel:
+		printFunc = logger.Fatal
+	case PanicLevel:
+		printFunc = logger.Panic
+	default:
+		printFunc = logger.Print
+	}
+
+	go logger.writerScanner(reader, printFunc)
 	runtime.SetFinalizer(writer, writerFinalizer)
 
 	return writer
 }
 
-func (logger *Logger) writerScanner(reader *io.PipeReader) {
+func (logger *Logger) writerScanner(reader *io.PipeReader, printFunc func(args ...interface{})) {
 	scanner := bufio.NewScanner(reader)
 	for scanner.Scan() {
-		logger.Print(scanner.Text())
+		printFunc(scanner.Text())
 	}
 	if err := scanner.Err(); err != nil {
 		logger.Errorf("Error while reading from Writer: %s", err)