custom file permission (natefinch#164)

lumberjack.go

@@ -36,9 +36,11 @@ import (
 )
 
 const (
-	backupTimeFormat = "2006-01-02T15-04-05.000"
-	compressSuffix   = ".gz"
-	defaultMaxSize   = 100
+	backupTimeFormat     = "2006-01-02T15-04-05.000"
+	compressSuffix       = ".gz"
+	defaultMaxSize       = 100
+	defaultNewLogFilePem = 0600
+	defaultNewLogDirPem  = 0755
 )
 
 // ensure we always implement io.WriteCloser
@@ -107,6 +109,15 @@ type Logger struct {
 	// using gzip. The default is not to perform compression.
 	Compress bool `json:"compress" yaml:"compress"`
 
+	// NewFilePem determines the permission to create new log file if not exists
+	// log file. Otherwise copy the permission from exist log file to cerate new
+	// log file.
+	NewFilePem uint32 `json:"newfilepem" yaml:"newfilepem"`
+
+	// NewDirPem determines the permission to create log dir if the log dir not
+	// exists.
+	NewDirPem uint32 `json:"newdirpem" yaml:"newdirpem"`
+
 	size int64
 	file *os.File
 	mu   sync.Mutex
@@ -206,13 +217,13 @@ func (l *Logger) rotate() error {
 // openNew opens a new log file for writing, moving any old log file out of the
 // way.  This methods assumes the file has already been closed.
 func (l *Logger) openNew() error {
-	err := os.MkdirAll(l.dir(), 0755)
+	err := os.MkdirAll(l.dir(), l.logDirPem())
 	if err != nil {
 		return fmt.Errorf("can't make directories for new logfile: %s", err)
 	}
 
 	name := l.filename()
-	mode := os.FileMode(0600)
+	mode := l.logFilePem()
 	info, err := osStat(name)
 	if err == nil {
 		// Copy the mode off the old logfile.
@@ -449,6 +460,22 @@ func (l *Logger) max() int64 {
 	return int64(l.MaxSize) * int64(megabyte)
 }
 
+// logFilePem returns the permission of new log file
+func (l *Logger) logFilePem() os.FileMode {
+	if l.NewFilePem == 0 {
+		return os.FileMode(defaultNewLogFilePem)
+	}
+	return os.FileMode(l.NewFilePem)
+}
+
+// logDirPem returns the permission of new log dir
+func (l *Logger) logDirPem() os.FileMode {
+	if l.NewDirPem == 0 {
+		return os.FileMode(defaultNewLogDirPem)
+	}
+	return os.FileMode(l.NewDirPem)
+}
+
 // dir returns the directory for the current filename.
 func (l *Logger) dir() string {
 	return filepath.Dir(l.filename())