slackline | tiny bridge for customising Prometheus AlertManager alerts | Monitoring library

The "right" solution is option 2 that you suggest: since you're doing an asynchronous call, you need to handle this correctly when working with the dialogflow-fulfillment library.

Basically, if your handler makes an asynchronous call, it needs to be asynchronous as well. To indicate to the handleRequest() method that your handler is async, you need to return a Promise object.

Firebase's once() method returns a Promise if you don't pass it a callback function. You can take advantage of this, return that Promise, and also handle what you want it to do as part of a .then() clause. It might look something like this: