Logger for Go

A simple, customizable logger for Go with both synchronous and asynchronous logging modes, colored output, and various log levels.

Features

• Supports JSON formatted output with metadata (device_id, app_version, service), trace_id, and arbitrary structured data
• Supports sync and async logging
• ANSI color formatting for log levels (text mode)
• Supports Info, Debug, Warn, Error, Panic, Fatal messages
• Buffered channel for async logging with Flush() support
• Configurable log styles
• Tagged log messages

Installation

go get github.com/ABA-Developer/go-logger

Usage

JSON Logger

package main

import (
	"github.com/ABA-Developer/go-logger"
)

func main() {
	config := logger.JSONConfig{
		DeviceID:    "gantry-bersih-01",
		AppVersion:  "v1.4.2",
		Service:     "rfid-hardware",
		LogLevel:    logger.LevelDebug, // LevelDebug (0), LevelInfo (1), LevelWarn (2), LevelError (3), LevelFatal (4)

		PrettyPrint: false,             // set true for formatted JSON
	}

	log := logger.NewSyncJSON(config)

	log.Warn("RFID reader high antenna temperature detected").
		TraceID("TRX-1785752204719").
		Data(map[string]any{"antenna_id": 2, "temperature_celsius": 68.5})
}

Output:

{
    "timestamp": "2026-08-05T13:28:03.123+07:00",
    "level": "WARN",
    "device_id": "gantry-bersih-01",
    "app_version": "v1.4.2",
    "trace_id": "TRX-1785752204719",
    "service": "rfid-hardware",
    "msg": "RFID reader high antenna temperature detected",
    "data": {
        "antenna_id": 2,
        "temperature_celsius": 68.5,
        "threshold_celsius": 65.0
    }
}

Synchronous Logger

package main

import (
	"github.com/ABA-Developer/go-logger"
)

func main() {
	SyncImplementation()
}

func SyncImplementation() {
	logger := logger.NewSync("TEST", true) // Tag: "TEST", Debug mode enabled
	logger.SetDefaultStyle()
	logger.Debug("Sync logger started")

	for i := 1; i <= 10; i++ {
		if i%3 == 0 {
			logger.Error(i)
		} else if i%5 == 0 {
			logger.Warn(i)
		} else {
			logger.Info(i)
		}
	}
}

Asynchronous Logger

package main

import (
	"github.com/ABA-Developer/go-logger"
)

func main() {
	AsyncImplementation()
}

func AsyncImplementation() {
	logger := logger.NewAsync("TEST", 10, true) // Tag: "TEST", Buffer size: 10, Debug mode enabled
	logger.SetDefaultStyle()
	logger.Debug("Async logger started")

	for i := 1; i <= 10; i++ {
		if i%3 == 0 {
			logger.Error(i)
		} else if i%5 == 0 {
			logger.Warn(i)
		} else {
			logger.Info(i)
		}
	}

	logger.Flush() // Ensure all logs are printed before exit
}

API Reference

Logger Creation

• NewSync(tag string, debugMode bool) *LoggerSync
• NewAsync(tag string, bufferSize int, debugMode bool) *LoggerAsync
• NewSyncJSON(config JSONConfig) *LoggerSyncJSON (or NewJSON(config))

Logging Methods

• logger.Info(a ...any)
• logger.Infof(format string, a ...any)
• logger.Debug(a ...any)
• logger.Debugf(format string, a ...any)
• logger.Warn(a ...any)
• logger.Warnf(format string, a ...any)
• logger.Error(a ...any)
• logger.Errorf(format string, a ...any)
• logger.Panic(a ...any)
• logger.Panicf(format string, a ...any)
• logger.Fatal(a ...any)
• logger.Fatalf(format string, a ...any)

JSON Context Methods

• logger.WithTraceID(traceID string)
• logger.WithData(data any)
• logger.With(traceID string, data any)
• logger.WarnWith(msg string, traceID string, data any)
• logger.InfoWith(msg string, traceID string, data any)
• logger.ErrorWith(msg string, traceID string, data any)
• logger.DebugWith(msg string, traceID string, data any)

Additional Methods

• logger.Flush() (async logger)
• logger.SetInfoStyle(styles ...int8)
• logger.SetWarnStyle(styles ...int8)
• logger.SetErrorStyle(styles ...int8)
• logger.SetDebugStyle(styles ...int8)
• logger.SetPanicStyle(styles ...int8)
• logger.SetFatalStyle(styles ...int8)
• logger.SetDefaultStyle()

Log Output Format

Standard text mode:

[INFO ] [YYYY-MM-DD HH:MM:SS.mmm] [TAG]: message
[WARN ] [YYYY-MM-DD HH:MM:SS.mmm] [TAG]: message
[ERROR] [YYYY-MM-DD HH:MM:SS.mmm] [TAG]: message
[DEBUG] [YYYY-MM-DD HH:MM:SS.mmm] [TAG]: message

JSON mode:

{
  "timestamp": "2026-08-05T13:28:03.123+07:00",
  "level": "WARN",
  "device_id": "gantry-bersih-01",
  "app_version": "v1.4.2",
  "trace_id": "TRX-1785752204719",
  "service": "rfid-hardware",
  "msg": "RFID reader high antenna temperature detected",
  "data": {
    "antenna_id": 2,
    "temperature_celsius": 68.5,
    "threshold_celsius": 65
  }
}

License

MIT