rotatewriter

rotatewriter is a Go package that provides an io.Writer with simple file rotation support.

Features

• Drop-in io.Writer implementation
• Automatic log rotation when the file reaches a maximum size
• Configurable maximum number of backup files
• Optional automatic directory creation
• Safe handling of symlinks

Installation

go get github.com/monitoring-forge/rotatewriter

Usage

package main

import (
    "log"

    "github.com/monitoring-forge/rotatewriter"
)

func main() {
    w, err := rotatewriter.New(
        rotatewriter.Filename("/var/log/myapp/app.log"),
        rotatewriter.MaxSize(100),      // Rotate when the file reaches 100 MiB
        rotatewriter.MaxBackups(7),     // Keep up to 7 backup files
        rotatewriter.AutoDirCreate(true),
    )
    if err != nil {
        log.Fatal(err)
    }
    defer w.Close()

    logger := log.New(w, "", log.LstdFlags)
    logger.Println("application started")
}

Options

Option	Default	Description
Filename	required	Path to the log file.
MaxSize	100	Maximum size of the active log file in MiB.
MaxBackups	7	Maximum number of rotated backup files to retain.
AutoDirCreate	false	Automatically create the log directory if it does not exist.

Rotation behavior

• When a write would cause the active log file to exceed MaxSize, the current file is closed and renamed to {basename}-{unixnano}{ext}.
• Old backup files are removed to keep at most MaxBackups files.
• A new active log file is created at the original Filename.

License

See LICENSE.