Rotatorr

Go App Log Rotation!

Description

Rotatorr provides a simple io.WriteCloser you can plug into the default log package. This interface handles log rotation while providing many features and overridable interfaces to customize the rotation experience. Inspired by Lumberjack. I wrote this because I wanted integer log files, and I figured why not fix a few of the things reported in the Lumberjack issues and pull requests.

Simple Usage

This example rotates logs once they reach 10mb. The backup log files have a time stamp written to their name.

log.SetOutput(rotatorr.NewMust(&rotatorr.Config{
	Filesize: 1024 * 1024 * 10, // 10 megabytes
	Filepath: "/var/log/service.log",
	Rotatorr: &timerotator.Layout{FileCount: 10},
}))

Advanced Usage

In the example above you can see that the Rotatorr interface is satisfied by *timerotator.Layout. The other built-in option is *introtator.Layout.

As a version 0 package, some of the interfaces are bound to change as we find bugs and make further improvements. Feedback and bug reports are welcomed and encouraged!

The time rotator puts time stamps in the backup log file names. The int rotator uses an integer (like logfile.1.log). Pick one and stick with it for best results. You may also enable compression by adding a callback to either rotator that calls the included compressor library. All the advanced examples are in godoc, or just check out the examples_test.go file in this repo and the example app that's included. Below you'll find the three main data structures you can provide to this package to make log file rotation work just the way you want.

Type: rotatorr.Config

All of the struct members are optional except the Rotatorr interface.

type Config struct {
	Filepath string        // Full path to log file. Set this, the default is lousy.
	FileMode os.FileMode   // POSIX mode for new files.
	DirMode  os.FileMode   // POSIX mode for new folders.
	Every    time.Duration // Maximum log file age. Rotate every hour or day, etc.
	FileSize int64         // Maximum log file size in bytes. Default is unlimited (no rotation).
	Rotatorr Rotatorr      // REQUIRED: Custom log Rotatorr. Use your own or one of the provided interfaces.
}

Type: introtator.Layout

• Rotatorr interface.

type Layout struct {
	ArchiveDir string // Location where rotated backup logs are moved to.
	FileCount  int    // Maximum number of rotated log files.
	FileOrder  Order  // Control the order of the integer-named backup log files.
	PostRotate func(fileName, newFile string)
}

Type: timerotator.Layout

• Rotatorr interface.

type Layout struct {
	ArchiveDir string        // Location where rotated backup logs are moved to.
	FileCount  int           // Maximum number of rotated log files.
	FileAge    time.Duration // Maximum age of rotated files.
	UseUTC     bool          // Sets the time zone to UTC when writing Time Formats (backup files).
	Format     string        // Format for Go Time. Used as the name.
	Joiner     string        // The string betwene the file name prefix and time stamp. Default: -
	PostRotate func(fileName, newFile string)
}