devslog

🧻 devslog - Go slog.Handler for development

devslog is a zero dependency structured logging handler for Go's log/slog package with pretty and colorful output for developers.

Devslog output

Compared to

TextHandler

JSONHandler

Install

go get github.com/golang-cz/devslog@latest

Examples

Logger without options

logger := slog.New(devslog.NewHandler(os.Stdout, nil))

// optional: set global logger
slog.SetDefault(logger)

Logger with custom options

// new logger with options
opts := &devslog.Options{
	MaxSlicePrintSize: 4,
	SortKeys:          true,
	TimeFormat:        "[04:05]",
	NewLineAfterLog:   true,
	DebugColor:        devslog.Magenta,
}

logger := slog.New(devslog.NewHandler(os.Stdout, opts))

// optional: set global logger
slog.SetDefault(logger)

Logger with default slog options

Handler accepts default slog.HandlerOptions

// slog.HandlerOptions
slogOpts := &slog.HandlerOptions{
	AddSource:   true,
	Level:       slog.LevelDebug,
}

// new logger with options
opts := &devslog.Options{
	HandlerOptions:    slogOpts,
	MaxSlicePrintSize: 4,
	SortKeys:          true,
	NewLineAfterLog:   true,
}

logger := slog.New(devslog.NewHandler(os.Stdout, opts))

// optional: set global logger
slog.SetDefault(logger)

Example usage

slogOpts := &slog.HandlerOptions{
	AddSource: true,
	Level:     slog.LevelDebug,
}

var logger *slog.Logger
if production {
	logger = slog.New(slog.NewJSONHandler(os.Stdout, slogOpts))
} else {
	opts := &devslog.Options{
		HandlerOptions:    slogOpts,
		MaxSlicePrintSize: 10,
		SortKeys:          true,
		NewLineAfterLog:   true,
	}

	logger = slog.New(devslog.NewHandler(os.Stdout, opts))
}

// optional: set global logger
slog.SetDefault(logger)

Options