README.md

slogevent

slogevent is a simplified API for integrating with slog.

Add slogevent as a dependency by running:

go get github.com/vikstrous/slogevent

Writing a handler for Go's standard library log/slog package is hard for good reasons. See the details for how to do that here. However, sometimes there's a need to simply trigger an event when certain logs are written and this should be easy.

This package provides the missing glue to allow you to write log handlers like this:

func EventHandler(ctx context.Context, e slogevent.Event) {
    if e.Level >= slog.LevelError {
        attrs, _ := json.Marshal(e.Attrs)
        SoundTheAlarm(e.Message, string(attrs))
    }
}

To use this custom even handler with slog, pass it into slog as a handler when creating your logger, like this:

slogLogger := slog.New(slogevent.NewHandler(EventHandler, slog.NewTextHandler(os.Stderr, nil)))

There's a more detailed example in the slogexamples repo along with other examples of how to extend slog without writing a handler.

slogevent acts as a wrapper for whatever handler you would normally use and fires your event before the next handler runs. It takes care of the annoying glue code needed to collect attrs and groups when With() and WithGroup() are used and converts all groups into a flag list of slog.Attrs that you can use without much effort.

This package is pre-v1 and the API may change. Please provide feedback about the API in the issues and let me know how I can make your slogging easier 💪