wslog

Overview ¶

Package tint implements a zero-dependency slog.Handler that writes tinted (colorized) logs. The output format is inspired by the zerolog.ConsoleWriter and slog.TextHandler.

The output format can be customized using Options, which is a drop-in replacement for slog.HandlerOptions.

Customize Attributes ¶

Options.ReplaceAttr can be used to alter or drop attributes. If set, it is called on each non-group attribute before it is logged. See slog.HandlerOptions for details.

w := os.Stderr
logger := slog.New(
	tint.NewHandler(w, &tint.Options{
		ReplaceAttr: func(groups []string, a slog.Attr) slog.Attr {
			if a.Key == slog.TimeKey && len(groups) == 0 {
				return slog.Attr{}
			}
			return a
		},
	}),
)

Automatically Enable Colors ¶

Colors are enabled by default and can be disabled using the Options.NoColor attribute. To automatically enable colors based on the terminal capabilities, use e.g. the go-isatty package.

w := os.Stderr
logger := slog.New(
	tint.NewHandler(w, &tint.Options{
		NoColor: !isatty.IsTerminal(w.Fd()),
	}),
)

Windows Support ¶

Color support on Windows can be added by using e.g. the go-colorable package.

w := os.Stderr
logger := slog.New(
	tint.NewHandler(colorable.NewColorable(w), nil),
)

package main

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

	"github.com/oke11o/wslog"
)

func main() {
	slog.SetDefault(slog.New(wslog.NewHandler(os.Stderr, &wslog.Options{
		Level:      slog.LevelDebug,
		TimeFormat: time.Kitchen,
	})))

	slog.Info("Starting server", "addr", ":8080", "env", "production")
	slog.Debug("Connected to DB", "db", "myapp", "host", "localhost:5432")
	slog.Warn("Slow request", "method", "GET", "path", "/users", "duration", 497*time.Millisecond)
	slog.Error("DB connection lost", wslog.Err(errors.New("connection reset")), "db", "myapp")
}