go-logging

Simple logging & log rotation using slog and lumberjack

Usage

Simple to use

package main

import "github.com/bugph0bia/go-logging"

func main() {
    // Create logger with default values
    logger := logging.NewLogger("log.txt")

    // output logs
    logger.Debug("message")
    logger.Info("message", "attr1", 10)
    logger.Warn("message", "attr1", 10, "attr2", 20)
    logger.Error("message")
}

// The log output is follow:
//
// 2024/10/24 11:22:33 DEBUG: message
// 2024/10/24 11:22:33 INFO [attr1=10]: message
// 2024/10/24 11:22:33 WARN [attr1=10, attr2=20]: message
// 2024/10/24 11:22:33 ERROR: message

If you don't want to pass loggers between functions

package main

import (
    "log/slog"

    "github.com/bugph0bia/go-logging"
)

func main() {
    // Create logger and give to slog.
    slog.SetDefault(logging.NewLogger("log.txt"))

    // output logs
    slog.Debug("message")
}

Options

To change an option, first get the handler with Logging.NewHandler, change options, and then call logging.NewLoggerFromHandler to create the logger.
The sample code below is an example of the options that can be changed and their default values.

func main() {
    // Create handler
    handler := logging.NewHandler("log.txt")


    //////// Change log output behavior ////////

    // Output log level
    handler.Option.Level = slog.LevelInfo

    // Flag to output log to stdout
    handler.Option.WithStdout = true

    //////// Change log format ////////

    // Format of log line (Use tag string)
    handler.Format.Line = fmt.Sprintf("${Datetime} ${Level} ${Attrs}: ${Message}")

    // Format of log line (Use const values)
    handler.Format.Line = fmt.Sprintf("%s %s %s: %s", logging.FDatetime, logging.FLevel, logging.FAttrs, logging.FMessage)

    // Format of datetime
    handler.Format.Datetime = "2006/01/02 15:04:05"

    // Character between the key and value of the attribute
    handler.Format.AttrBetween = "="

    // Separator between attributes
    handler.Format.AttrDelimiter = ", "

    // Attribute list prefix
    handler.Format.AttrPrefix = "["

    // Attribute list suffix
    handler.Format.AttrSuffix = "]"

    //////// Change log rotation ////////

    // Max size of a log file (MB)
    // Rotate beyond this size
    handler.RotateLogger.MaxSizeMB = 1

    // Maximum number of backup files
    // If zero, no limit
    handler.RotateLogger.MaxBackups = 10

    // Maximum number of days to keep backup files
    // If zero, no limit
    handler.RotateLogger.MaxAge = 0

    // Flag to set backup file time to local time
    handler.RotateLogger.LocalTime = true

    // Flag to gzip compress backup files
    handler.RotateLogger.Compress = false


    // Create Logger
    logger := logging.NewLoggerFromHandler(handler)
}

Thanks

• lumberjack