tint

Documentation

Overview

Package tint copied from https://github.com/lmittmann/tint/tree/v1.0.4 to adjust the colors

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),
)

Index

• func Err(err error) slog.Attr
• func NewHandler(w io.Writer, opts *Options) slog.Handler
• type Options

Functions

func Err

func Err(err error) slog.Attr

Err returns a tinted (colorized) slog.Attr that will be written in red color by the tint.Handler. When used with any other slog.Handler, it behaves as

slog.Any("err", err)

func NewHandler

func NewHandler(w io.Writer, opts *Options) slog.Handler

NewHandler creates a slog.Handler that writes tinted logs to Writer w, using the default options. If opts is nil, the default options are used.

Types

type Options

type Options struct {
	// Enable source code location (Default: false)
	AddSource bool

	// Minimum level to log (Default: slog.LevelInfo)
	Level slog.Leveler

	// ReplaceAttr is called to rewrite each non-group attribute before it is logged.
	// See https://pkg.go.dev/log/slog#HandlerOptions for details.
	ReplaceAttr func(groups []string, attr slog.Attr) slog.Attr

	// Time format (Default: time.StampMilli)
	TimeFormat string

	// Disable color (Default: false)
	NoColor bool
}

Options for a slog.Handler that writes tinted logs. A zero Options consists entirely of default values.

Options can be used as a drop-in replacement for slog.HandlerOptions.