package log import ( "fmt" "os" "path" "time" ) //FileHandler writes log to a file. type FileHandler struct { fd *os.File } func NewFileHandler(fileName string, flag int) (*FileHandler, error) { dir := path.Dir(fileName) os.Mkdir(dir, 0777) f, err := os.OpenFile(fileName, flag, 0) if err != nil { return nil, err } h := new(FileHandler) h.fd = f return h, nil } func (h *FileHandler) Write(b []byte) (n int, err error) { return h.fd.Write(b) } func (h *FileHandler) Close() error { return h.fd.Close() } //RotatingFileHandler writes log a file, if file size exceeds maxBytes, //it will backup current file and open a new one. // //max backup file number is set by backupCount, it will delete oldest if backups too many. type RotatingFileHandler struct { fd *os.File fileName string maxBytes int backupCount int } func NewRotatingFileHandler(fileName string, maxBytes int, backupCount int) (*RotatingFileHandler, error) { dir := path.Dir(fileName) os.Mkdir(dir, 0777) h := new(RotatingFileHandler) if maxBytes <= 0 { return nil, fmt.Errorf("invalid max bytes") } h.fileName = fileName h.maxBytes = maxBytes h.backupCount = backupCount var err error h.fd, err = os.OpenFile(fileName, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666) if err != nil { return nil, err } return h, nil } func (h *RotatingFileHandler) Write(p []byte) (n int, err error) { h.doRollover() return h.fd.Write(p) } func (h *RotatingFileHandler) Close() error { if h.fd != nil { return h.fd.Close() } return nil } func (h *RotatingFileHandler) doRollover() { f, err := h.fd.Stat() if err != nil { return } if h.maxBytes <= 0 { return } else if f.Size() < int64(h.maxBytes) { return } if h.backupCount > 0 { h.fd.Close() for i := h.backupCount - 1; i > 0; i-- { sfn := fmt.Sprintf("%s.%d", h.fileName, i) dfn := fmt.Sprintf("%s.%d", h.fileName, i+1) os.Rename(sfn, dfn) } dfn := fmt.Sprintf("%s.1", h.fileName) os.Rename(h.fileName, dfn) h.fd, _ = os.OpenFile(h.fileName, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666) } } //TimeRotatingFileHandler writes log to a file, //it will backup current and open a new one, with a period time you sepecified. // //refer: http://docs.python.org/2/library/logging.handlers.html. //same like python TimedRotatingFileHandler. type TimeRotatingFileHandler struct { fd *os.File baseName string interval int64 suffix string rolloverAt int64 } const ( WhenSecond = iota WhenMinute WhenHour WhenDay ) func NewTimeRotatingFileHandler(baseName string, when int8, interval int) (*TimeRotatingFileHandler, error) { dir := path.Dir(baseName) os.Mkdir(dir, 0777) h := new(TimeRotatingFileHandler) h.baseName = baseName switch when { case WhenSecond: h.interval = 1 h.suffix = "2006-01-02_15-04-05" case WhenMinute: h.interval = 60 h.suffix = "2006-01-02_15-04" case WhenHour: h.interval = 3600 h.suffix = "2006-01-02_15" case WhenDay: h.interval = 3600 * 24 h.suffix = "2006-01-02" default: return nil, fmt.Errorf("invalid when_rotate: %d", when) } h.interval = h.interval * int64(interval) var err error h.fd, err = os.OpenFile(h.baseName, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666) if err != nil { return nil, err } fInfo, _ := h.fd.Stat() h.rolloverAt = fInfo.ModTime().Unix() + h.interval return h, nil } func (h *TimeRotatingFileHandler) doRollover() { //refer http://hg.python.org/cpython/file/2.7/Lib/logging/handlers.py now := time.Now() if h.rolloverAt <= now.Unix() { fName := h.baseName + now.Format(h.suffix) h.fd.Close() e := os.Rename(h.baseName, fName) if e != nil { panic(e) } h.fd, _ = os.OpenFile(h.baseName, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666) h.rolloverAt = time.Now().Unix() + h.interval } } func (h *TimeRotatingFileHandler) Write(b []byte) (n int, err error) { h.doRollover() return h.fd.Write(b) } func (h *TimeRotatingFileHandler) Close() error { return h.fd.Close() }