Cloud function not picking up RTDB emulator when using handler namespace from firebase-functions sdk

[russellwheatley]

[REQUIRED] Environment info

firebase CLI 8.14.1

firebase-tools:

macOS Catalina 10.15.4

Platform:

[REQUIRED] Test case

I've created a repository for the bug with the steps in the README.md file to reproduce: https://github.com/russellwheatley/emulator-extension-issue

[REQUIRED] Expected behavior

I expected the cloud function emulator to run with the RTDB emulator when using the handler namespace of the firebase-functions sdk (apologies if this is in the wrong repo, not sure whose responsibility this falls under).

[REQUIRED] Actual behavior

It doesn't recognise the RTDB emulator. Here is a log from the console:

functions[rtdblimit]: function ignored because the unknown emulator does not exist or is not running.

Let me know if you need more information.

[samtstern]

@russellwheatley thanks for filing this, I thought we had this working. @joehan is this a regression with Extensions emulation?

[joehan]

This looks like it may be a regression - investigating today.

[joehan]

Looking into this closer, i'm not certain this is a regression. @russellwheatley which emulator commands are you using - firebase emulators:* or firebase ext:dev:emulators:*? If you are writing an extension using the handler namespace, you'll need to use firebase ext:dev:emulators:* in order to read function triggers from extension.yaml.

To explain a bit further:

A Cloud Function consists of a trigger (what makes the function fire) and a handler (what to do when the function fires). The 'normal' namespace (functions.database.ref.onCreate) defines both a trigger and a handler, whereas the handler namespace (functions.handler.database.ref.onCreate) only defines a handler. You CAN use the normal namespace for extensions - however, the trigger defined by the code will be ignored in favor of the trigger defined in extension.yaml. This is a bit confusing, so we use the handler namespace to avoid defining a trigger in the code that will be ignored.

Because it doesn't define any triggers in the code, the handler namespace won't work with firebase emulators:exec or firebase emulators:start - these commands don't look at extension.yaml, so handler functions won't have a trigger. Instead, for testing extensions, use firebase ext:emulators:exec <path/to/extension.yaml> or firebase ext:emulators:start <path/to/extension.yaml> - this will pick up triggers from extension.yaml.

Even though I don't think this is a regression, its definitely not a very clear experience right now. At the very least, we probably should add some clearer error messages/warnings for when functions defined using the handler namespace are emulated with firebase emulators:*.

[jthegedus]

I am seeing this error with the firebase ext:dev:emulators:exec command but for PubSub triggers:

i  emulators: Starting emulators: functions, pubsub
⚠  functions: The following emulators are not running, calls to these services from the Functions emulator will affect production: auth, firestore, database, hosting
⚠  Your requested "node" version "8" doesn't match your global version "12"
⚠  functions: You are not signed in to the Firebase CLI. If you have authorized this machine using gcloud application-default credentials those may be discovered and used to access production services.
⚠  It appears you are running in a CI environment. You can avoid downloading the Pub/Sub Emulator repeatedly by caching the /home/runner/.cache/firebase/emulators directory.
i  pubsub: downloading pubsub-emulator-0.1.0.zip...

i  pubsub: Pub/Sub Emulator logging to pubsub-debug.log
i  functions: Watching "/home/runner/work/<redacted>" for Cloud Functions...
i  functions[testPubSub]: function ignored because the pubsub emulator does not exist or is not running.
i  Running script: npx mocha --exit tests/test.js
npx: installed 100 in 4.5s
testing...123


  0 passing (1ms)

✔  Script exited successfully (code 0)
i  emulators: Shutting down emulators.
i  functions: Stopping Functions Emulator
i  pubsub: Stopping Pub/Sub Emulator
i  hub: Stopping emulator hub

According to the Emulator shutdown logs the PubSub emulator was running as it was stopped.