rotate

Documentation

Index

• type Logger
  • func NewLogger() *Logger
  • func (l *Logger) Close() error
  • func (l *Logger) Rotate() error
  • func (l *Logger) Write(p []byte) (n int, err error)

Types

type Logger

type Logger struct {
	// Filename is the file to write logs to.  Backup xlog files will be retained
	// in the same directory.  It uses <processname>-rotate.xlog in
	// os.TempDir() if empty.
	Filename string `json:"filename" yaml:"filename"`

	// MaxSize is the maximum size in megabytes of the xlog file before it gets
	// rotated. It defaults to 100 megabytes.
	MaxSize int `json:"maxsize" yaml:"maxsize"`

	// MaxAge is the maximum number of days to retain old xlog files based on the
	// timestamp encoded in their filename.  Note that a day is defined as 24
	// hours and may not exactly correspond to calendar days due to daylight
	// savings, leap seconds, etc. The default is not to remove old xlog files
	// based on age.
	MaxAge int `json:"maxage" yaml:"maxage"`

	// MaxBackups is the maximum number of old xlog files to retain.  The default
	// is to retain all old xlog files (though MaxAge may still cause them to get
	// deleted.)
	MaxBackups int `json:"maxbackups" yaml:"maxbackups"`

	// LocalTime determines if the time used for formatting the timestamps in
	// backup files is the computer's local time.  The default is to use UTC
	// time.
	LocalTime bool `json:"localtime" yaml:"localtime"`

	// Compress determines if the rotated xlog files should be compressed
	// using gzip. The default is not to perform compression.
	Compress bool `json:"compress" yaml:"compress"`

	// Interval determines the duration to rotate xlog files.
	// The default is not to rotate xlog files based on time.
	Interval time.Duration `json:"interval" yaml:"interval"`
	// contains filtered or unexported fields
}

Logger is an io.WriteCloser that writes to the specified filename.

Logger opens or creates the logfile on first Write. If the file exists and is less than MaxSize megabytes, rotate will open and append to that file. If the file exists and its size is >= MaxSize megabytes, the file is renamed by putting the current time in a timestamp in the name immediately before the file's extension (or the end of the filename if there's no extension). A new xlog file is then created using original filename.

Whenever a write would cause the current xlog file exceed MaxSize megabytes, the current file is closed, renamed, and a new xlog file created with the original name. Thus, the filename you give Logger is always the "current" xlog file.

Backups use the xlog file name given to Logger, in the form `name-timestamp.ext` where name is the filename without the extension, timestamp is the time at which the xlog was rotated formatted with the time.Time format of `2006-01-02T15-04-05.000` and the extension is the original extension. For example, if your Logger.Filename is `/var/xlog/foo/server.xlog`, a backup created at 6:30pm on Nov 11 2016 would use the filename `/var/xlog/foo/server-2016-11-04T18-30-00.000.xlog`

Cleaning Up Old Log Files

Whenever a new logfile gets created, old xlog files may be deleted. The most recent files according to the encoded timestamp will be retained, up to a number equal to MaxBackups (or all of them if MaxBackups is 0). Any files with an encoded timestamp older than MaxAge days are deleted, regardless of MaxBackups. Note that the time encoded in the timestamp is the rotation time, which may differ from the last time that file was written to.

If MaxBackups and MaxAge are both 0, no old xlog files will be deleted.

func NewLogger

func NewLogger() *Logger

NewLogger ...

func (*Logger) Close

func (l *Logger) Close() error

Close implements io.Closer, and closes the current logfile.

func (*Logger) Rotate

func (l *Logger) Rotate() error

Rotate causes Logger to close the existing xlog file and immediately create a new one. This is a helper function for applications that want to initiate rotations outside of the normal rotation rules, such as in response to SIGHUP. After rotating, this initiates compression and removal of old xlog files according to the configuration.

func (*Logger) Write

func (l *Logger) Write(p []byte) (n int, err error)

Write implements io.Writer. If a write would cause the xlog file to be larger than MaxSize, the file is closed, renamed to include a timestamp of the current time, and a new xlog file is created using the original xlog file name. If the length of the write is greater than MaxSize, an error is returned.