Firebase functions invoke in next 20s

Question

So, I'm making multiplayer mobile game using Xamarin and Firebase. In game there are many moment when I'm letting players decide what to do and send their decision to the server (by putting decision enum in player-specific Firebase database node). Decision is time limited (short time, no longer than 20s).

I set listener to that specific node in my Firebase functions to check if all player decided or player decision comes after time deadline, but I need to deal with case when: some players send their decision in time - sersnmart were will not execute next action, and that one player just will not send his decision (eave game or something) - server won't be poke again to check deadline and invoke functions.

That why I'm looking for something else, I found method for schedule functions using crontab, but the minimal time interval there seems to be minutes, which is way more to long for me.

Second idea includes wait that specific time interval in previous Firebase thread, but it seems too bad way to deal with this.

Which way is best for dynamic invoking short-interval scheduled Firebase functions?

Answer 1

The best way to schedule Cloud Functions to run at a specific time it through the Google Cloud Tasks schedules. See Doug's blog post for a full description of this: How to schedule a Cloud Function to run in the future with Cloud Tasks (to build a Firestore document TTL)

That said, I regularly use setTimeOut in my own Cloud Functions too when I need to delay an operation for a short period of time. Just keep in mind that you pay for the seconds that the function is sleeping, so cost-wise you'll want to trade that time off against what another invocation would cost.

Answer 2

So for now I decided to use setTimeout, free firebase plan seems to limit only functions invoke number, not working plan so this shouldn't be a problem. Depsite this, I'm still waiting for advice from you