How to enqueue functions in firebase

Question

I am using firebase functions and am trying to enqueue a function from within a RTDB onWrite trigger, so far I either get errors or nothing happens, I also cannot find anything useful online, and even the firebase docs aren't much of a help...

This is my Realtime DB trigger function which is supposed to enqueue the firebase function.

Attempt #1

exports.onUserBasketUpdated = functions
  .region("my-region")
  .database.ref("/path/{uid}")
  .onWrite(async (change, context) => {
    const queue = getFunctions(admin.app, "my-region").taskQueue(
      "expireUserBasket"
    );
    await queue.enqueue(
      {
        id: 1,
      },
      {
        dispatchDeadlineSeconds: 60 * 1, // 1 minute
      }
    );
    return { data: "ok" };
  });

Attempt #1 Results: Error: "ReferenceError: queue is not defined"

Attempt #2:

exports.onUserBasketUpdated = functions
  .region("my-region")
  .database.ref("/path/{uid}")
  .onWrite(async (change, context) => {
    await functions
      .taskQueue(`locations/my-region/functions/expireUserBasket`)
      .enqueue({ message: "hello" });
    return { data: "ok" };
  });

Attempt #2 Result: Error: "TypeError: functions.taskQueue is not a function"

The function which I am trying to enqueue:

exports.expireUserBasket = functions
  .region("my-region")
  .runWith({ timeoutSeconds: 120 })
  .tasks.taskQueue({
    retryConfig: {
      maxAttempts: 5,
      minBackoffSeconds: 60,
    },
    rateLimits: {
      maxConcurrentDispatches: 6,
    },
  })
  .onDispatch(async (data) => {
    console.info("data from the scheduled function", data);
  });

Any help is greatly appreciated:)

Answer 1

The documentation is pretty good on this feature. Example code is provided.

In terms of actually calling a particular function, do that directly in your function's code. That's how you would call it.

I don't believe the Enqueue functions with Cloud Tasks is utilized in your use case.

Answer 2

As you are getting a queue not defined error, you've probably missed this step in the documentation (emphasis mine):

Deploying the task queue function

Deploy task queue function using the Firebase CLI:

 $ firebase deploy --only functions:backupApod

When deploying a task queue function for the first time, the CLI creates a task queue in Cloud Tasks with options (rate limiting and retry) specified in your source code.

So before trying to deploy and test onUserBasketUpdated , deploy only the expireUserBasket function:

$ firebase deploy --only functions:expireUserBasket