如何在Firebase Cloud Functions上拆分长时间执行的功能

Question

Let's say I have function A, B, C, D, all of them are not exceed the execution time limit of Firebase Cloud Functions. But if at the end of function A it calls function B, at the end of function B, it calls function C ... and so on, like below:

function A(): Promise {
    doStuffA()
    return httpPostFunctionB()
}

function B(): Promise {
    doStuffB()
    return httpPostFunctionC()
}

function C(): Promise {
    doStuffC()
    return httpPostFunctionD()
}

function D() {
    doStuffD()
}

All together it will exceed the time limit.

Is there any way to make function A no need to wait for function B, but also guarantee function B will be executed completely?

I think it is possible, we can just make function A modify some value in Firestore, and make function B listen to that value change. But I wonder if there is a cleaner way to do this.

Answer 1

You can extend the timeout for Cloud Functions. The default of 1 minute can be extended up to 9 minutes. Please read the documentation about that.

If you need more than 9 minutes, you'll need to consider delegating the work to a service that doesn't have strict restrictions, such as App Engine or Compute Engine. But the 9 minute limit for Cloud Functions can't be changed.