stylelog

Lightweight log/slog helper that:

• routes Info/Debug/Warn to a compact handler (no source info)
• routes Error+ to a handler with source locations
• highlights error attributes using tint
• optionally sets the logger as the global default, so other packages can just use slog.*

Install

go get github.com/vietddude/stylelog

Usage

Basic Usage

package main

import (
	"errors"

	"github.com/vietddude/stylelog"
)

func main() {
	// Create and register the default logger using built-in options.
	log := stylelog.InitDefault()

	log.Debug("Debug message", "detail", "something")
	log.Info("User login", "user", "alice", "ip", "127.0.0.1")
	log.Warn("High memory usage", "usage", "85%")

	err := errors.New("connection refused")
	log.Error("Failed to load", "err", err)
}

Any other package can now just use the global slog:

import (
	"errors"
	"log/slog"
)

func doSomething() {
	testErr := errors.New("test error")
	slog.Error("test error", "error", testErr)
}

Customizing Log Level

You can set the minimum log level by passing tint.Options:

package main

import (
	"log/slog"

	"github.com/lmittmann/tint"
	"github.com/vietddude/stylelog"
)

func main() {
	// Only log Warn and above
	log := stylelog.InitDefault(&tint.Options{
		Level: slog.LevelWarn,
	})

	log.Debug("This won't appear")
	log.Info("This won't appear either")
	log.Warn("This will appear", "key", "value")
	log.Error("This will appear with source", "err", "something")
}

Customizing tint.Options

You can pass your own tint.Options to New or InitDefault.
stylelog will:

• always disable AddSource for low-level logs (Info/Debug/Warn)
• always enable AddSource for error logs
• wrap your ReplaceAttr so that "err" / "error" attributes stay highlighted in red

package main

import (
	"log/slog"
	"time"

	"github.com/lmittmann/tint"
	"github.com/vietddude/stylelog"
)

func main() {
	opts := &tint.Options{
		Level:      slog.LevelDebug,
		TimeFormat: time.RFC3339,
		NoColor:    false,
		ReplaceAttr: func(groups []string, a slog.Attr) slog.Attr {
			// Example: rename "user_id" to "userID" in the output.
			if a.Key == "user_id" {
				a.Key = "userID"
			}
			return a
		},
	}

	logger := stylelog.New(opts)
	slog.SetDefault(logger)

	slog.Info("Processing request", "user_id", 123)
	slog.Error("Failed to process request", "user_id", 123, "err", "timeout")
}

Advanced Usage

If you need more control, use New() directly:

package main

import (
	"log/slog"

	"github.com/lmittmann/tint"
	"github.com/vietddude/stylelog"
)

func main() {
	// Create logger without setting it as default
	logger := stylelog.New(&tint.Options{
		Level:   slog.LevelInfo,
		NoColor: true, // Disable colors for production logs
	})

	// Use it directly or set as default later
	logger.Info("Application started")
	
	// Set as default if needed
	slog.SetDefault(logger)
}

Features

• Level-based routing: Low-level logs (Debug/Info/Warn) use a compact format, while errors include source file and line information
• Configurable: Set minimum log level, time format, colors, and custom attribute transformations
• Error highlighting: err and error attributes are automatically highlighted in red for better visibility
• Global default: Easy integration with existing code that uses slog.* functions
• Zero dependencies (except tint and standard library)

License

MIT