Slog Pretty Logger

A colorful, readable logging handler for Go's standard slog package. Makes logs easier to read during development with color-coded levels and clean formatting. Inspired by zerolog's console output.

Features

• 🎨 Color-coded levels: DEBUG, INFO, WARN, ERROR
• 🔍 Bold messages: Highlights log messages and errors
• 🧩 Field formatting: Formats fields based on type
• ⏱ Custom time: Override the default time.Kitchen format
• 🚫 No-color mode: Disable ANSI colors
• 🖌️ Custom colors: Set your own colors per log level

Installation

go get github.com/nentgroup/slog-prettylogger

Usage

package main

import (
	"log/slog"
	"os"
	"time"

	"github.com/nentgroup/slog-prettylogger"
)

func main() {
	// Create a new pretty logger
	logger := slog.New(prettylogger.NewHandler(os.Stdout, prettylogger.HandlerOptions{
		SlogOpts: slog.HandlerOptions{
			AddSource: true, // Include caller information
			Level:     slog.LevelDebug,
		},
		TimeFormat: time.TimeOnly, // Customize time format, default is time.Kitchen
	}))

	// Set as default logger
	slog.SetDefault(logger)

	// Basic logging
	slog.Info("application started", "version", "1.0.0")
	slog.Debug("debug information", "cache_hits", 42)
	slog.Warn("resource usage high", "cpu", 85.5, "memory", "3.2GB")
	slog.Error("failed to connect to database",
		"error", "connection refused",
		"retry_count", 3,
		"db_host", "localhost:5432")

	// With structured data
	logger.Info("user logged in",
		"user_id", 123,
		"metadata", map[string]interface{}{
			"browser":  "Chrome",
			"version":  "98.0.4758.102",
			"platform": "macOS",
		})
}

Output Example

When using pretty logger, your console output will look similar to:

Configuration Options

Use the HandlerOptions struct to customize the logger:

type HandlerOptions struct {
    SlogOpts    slog.HandlerOptions        // Standard slog handler options (level, AddSource, etc.)
    TimeFormat  string                     // Optional: custom time format (default is time.Kitchen)
    NoColor     bool                       // Optional: disable ANSI colors
    LevelColors map[slog.Level]string      // Optional: override colors per log level (DEBUG, INFO, WARN, ERROR)
}

Example with custom colors

logger := slog.New(prettylogger.NewHandler(os.Stdout, prettylogger.HandlerOptions{
	SlogOpts: slog.HandlerOptions{
		AddSource: true,
		Level:     slog.LevelDebug,
	},
	TimeFormat:  time.RFC3339,
	LevelColors: map[slog.Level]string{slog.LevelError: prettylogger.BoldRed}, // or use any ANSI color code
}))

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Acknowledgements

Developed and maintained by Viaplay Group.