Added optional writing to stdout.

pkg/logging/logger.go

@@ -13,16 +13,19 @@ import (
 
 type Logger struct {
 	file     io.WriteCloser
+	toStdout bool
 	mut      sync.Mutex
 }
 
-func NewLogger(path string) (*Logger, error) {
+// NewLogger creates a Logger instance with given filename and
+// toStdout tells wether to write to Stdout as well or not.
+func NewLogger(path string, toStdout bool) (*Logger, error) {
 	f, err := os.OpenFile(path, os.O_WRONLY|os.O_APPEND|os.O_CREATE, os.ModeAppend)
 	if err != nil {
 		return nil, errors.Wrap(err, "failed to open log file")
 	}
 
-	return &Logger{file: f}, nil
+	return &Logger{file: f, toStdout: toStdout}, nil
 }
 
 func (l *Logger) Println(v ...interface{}) {
@@ -32,6 +35,10 @@ func (l *Logger) Println(v ...interface{}) {
 
 	fmt.Fprintln(l.file, nowStr, v)
 
+	if l.toStdout {
+		fmt.Println(nowStr, v)
+	}
+
 	l.mut.Unlock()
 }
 
@@ -47,6 +54,10 @@ func (l *Logger) Printf(format string, v ...interface{}) {
 
 	fmt.Fprintf(l.file, nowStr+" "+format, v...)
 
+	if l.toStdout {
+		fmt.Printf(nowStr+" "+format, v...)
+	}
+
 	l.mut.Unlock()
 }
 
@@ -57,6 +68,10 @@ func (l *Logger) Fatalln(v ...interface{}) {
 
 	fmt.Fprintln(l.file, nowStr, v)
 
+	if l.toStdout {
+		fmt.Println(nowStr, v)
+	}
+
 	l.file.Close()
 	os.Exit(1)
 }
@@ -73,6 +88,10 @@ func (l *Logger) Fatalf(format string, v ...interface{}) {
 
 	fmt.Fprintf(l.file, nowStr+" "+format, v...)
 
+	if l.toStdout {
+		fmt.Printf(nowStr+" "+format, v...)
+	}
+
 	l.file.Close()
 	os.Exit(1)
 }