dougal-software/lib/www/server/events/index.js

const { listen } = require('../lib/db/notify');
const channels = require('../lib/db/channels');
const handlers = require('./handlers').init();
const { ERROR, INFO, DEBUG } = require('DOUGAL_ROOT/debug')(__filename);

function start () {
	listen(channels, async function (data) {
		DEBUG("Incoming data", data);
		for (const handler of handlers) {
			// NOTE: We are intentionally passing the same instance
			// of the data to every handler. This means that earlier
			// handlers could, in principle, modify the data to be
			// consumed by latter ones, provided that they are
			// synchronous (as otherwise, the completion order is
			// undefined).
			await handler.run(data);
		}
	});

	INFO("Events manager started.", handlers.length, "active handlers");
}

module.exports = { start }

if (require.main === module) {
	start();
}