[FR] Connect to Firebase Emulator (Auth) using custom hostname and port

[alinturbut]

Is your feature request related to a problem? Please describe.
I am trying to setup a testing phase that would run tests on the Emulator by connecting to it. The Emulator is prepared using TestContainers which don't open specific ports, but rather random. Because of this I cannot use the environment variable specified as that blocks me into selecting a hostname and port.

Describe the solution you'd like
Make the hostname and port dynamic when initialising FirebaseAuth / FirebaseApp.

Describe alternatives you've considered

Additional context

Expected usage

FirebaseAuth.getInstance(firebaseApp()).useEmulator('localhost', '9099')

For example, Firestore has this enabled using FirestoreOptions.newBuilder().setEmulatorHost()

[google-oss-bot]

I couldn't figure out how to label this issue, so I've labeled it for a human to triage. Hang tight.

[lahirumaramba]

Hi @alinturbut, This is interesting... for Node.js I would suggest setting the env variable at runtime with process.env, but I am realizing that it is not that straightforward in Java. I can't promise you a timeline on this, but I think this is a reasonable feature to add to the SDK. In the meantime, how are you getting the port currently? Are you able to set an environment variable in your workspace after you start your emulator instance?

[alinturbut]

@lahirumaramba After Java 17, it's not possible to set environment variables at runtime, unfortunately. For this reason, I haven't yet found a way to start using testcontainers a Firebase Auth Emulator.

[alinturbut]

@lahirumaramba if I get the time this weekend, I might submit a PR (would add a variable in FirebaseOptions that would add in FirebaseProcessEnvironment.localCache the needed values. I think this would do the job). I've signed the CLA for contributions. How do I get branch push rights?

[lahirumaramba]

I am not familiar with Testcontainers, could you explain how you would set the emulator host and port in your code if you don't know the port on Testcontainers ahead of time?

[alinturbut]

Testcontainers are initialised statically (or during early start of the spring boot app), therefore, when we initialize FirebaseOptions, we would already know the host and port of the testcontainers by setting up an application property (spring)

[lahirumaramba]

Thank you for the clarification! An API to set the emulator host sounds like a reasonable approach then. Happy to review any PRs if you would like to contribute to the codebase. :) You have to fork the repo and create a PR against the main branch of firebase/firebase-admin-java. Please note that any changes to the public API requires an internal API review. This can take a while, but I will initiate the process internally once we have a PR. Thanks!

[alinturbut]

please let me know if you think this is enough: https://github.com/firebase/firebase-admin-java/pull/781/files

[lahirumaramba]

Thank you @alinturbut for submitting the PR! We will review the changes and initiate the API review process internally. Please note that this can take some time.

In the meantime, are you able to use a docker-compose file to inject environment variables to spawned containers used by Testcontainers? See: https://stackoverflow.com/a/69767792/1526201

# docker-compose.yml
services:
  my-service:
    environment:
      FIREBASE_AUTH_EMULATOR_HOST: ${FIREBASE_AUTH_EMULATOR_HOST}

new DockerComposeContainer<>(new File("../docker-compose.yml"))
    .withEnv(Map.of("FIREBASE_AUTH_EMULATOR_HOST", "localhost:9092"))
    .withLocalCompose(true)
    .start();