Slog: Strict

slogstrict defines a stricter interface for slog.

Why?

Slog is a great logging library, but the *slog.Logger contains a lot of methods. This makes it easy to use, but also easy to misuse. The slogstrict.Logger in this package does this:

1. Always require a context for log messages. This is very useful if you want to include things like requestID, traceID or spanID in our log messages.
2. Always log with slog.Attr. This prevents any mistakes when using ...any in the slog.Logger methods.

type Logger interface {
	With(attrs ...slog.Attr) Logger
	WithGroup(name string) Logger

	Debug(ctx context.Context, msg string, attrs ...slog.Attr)
	Info(ctx context.Context, msg string, attrs ...slog.Attr)
	Warn(ctx context.Context, msg string, attrs ...slog.Attr)
	Error(ctx context.Context, msg string, err error, attrs ...slog.Attr)

	// For custom levels
	Log(ctx context.Context, level slog.Level, msg string, attrs ...slog.Attr)

	// To retrieve a *slog.Logger
	ToSlog() *slog.Logger
}

The package includes a slogstrict.New() function that creates a new logger from a slog.Handler, similar to slog.New().

// Create a new [Logger] from a [slog.Handler]
func New(h slog.Handler) Logger {
	return impl{slog.New(h)}
}

The package also includes a slogstrict.FromSlog() function that creates a new logger from a *slog.Logger.

// Create a new [Logger] from a [*slog.Logger]
func FromSlog(l *slog.Logger) Logger {
	return logger{l}
}