Gist for medium article https://medium.com/evenbit/63b847fbcb1f

cloudfunction.ts

export const cronEndpoint = functions.https.onRequest((request, response) => {
    if (functions.config().cron.apikey !== request.body.key) {
        response.status(401).send("I'm sorry Dave, I'm afraid I can't do that");
        return;
    }

    response.status(200).send("The time is now.");
});