How to connect `firebase-admin` to the firebase emulators?

There is a related issue (https://github.com/firebase/firebase-admin-node/issues/575) but it seems that it’s still unresolved.

We would like to connect the admin SDK to firebase emulators when running tests. Our setup code looks like this:

import * as admin from 'firebase-admin'
admin.initializeApp({ credential: ... })
export default admin

Then in every file that needs access to firestore, we use:

import firebase from `./firebase`
firebase.firestore().doSomething()

How can we modify this setup so that is connects to the firebase emulators instead?

This is what we’ve tried so far:

• Have the setup code return the @firebase/testing namespace depending on the node environment. However this library doesn’t setup a default firebase app so calling firebase.firestore() fails.
• Have firebase-admin connect to the emulators directly, by providing an explicit databaseURL and firestore URLs, and overriding credential.getAccessToken() to return owner. Now the issue is that the admin’s implementation of firestore expects a service account and throws on the credentials override: https://github.com/firebase/firebase-admin-node/blob/master/src/firestore/firestore.ts#L95-L100
• Return the firebase app as part of the setup code, so that app.firestore() always works. This requires refactoring the whole codebase to use an app instance instead of a firebase workspace.

Is there a recommended way to connect the admin sdk to emulators?

[fouchekeagan]

The Admin SDKs support the FIRESTORE_EMULATOR_HOST environment variable. You can simply set it to localhost:8080 to connect directly to the emulator.

Let us know if you have any other questions, but for now I hope you are unblocked.

For those in the future, please note this is an environment variable and not a parameter to the admin SDK. To elaborate this, if you are running a NodeJS backend/script:

const useEmulator = true;

if (useEmulator){
    process.env['FIRESTORE_EMULATOR_HOST'] = 'localhost:8080';
}

admin.initializeApp({ ... });

This will set the environment variable from within code (not recommend for production environments), you can read more in this S.O Article for other ways of setting Environment Variables for NodeJS.

Do not try to do it this way:

admin.initializeApp({
    ...
    FIRESTORE_EMULATOR_HOST: 'localhost:8080'
});

It will have no effect locally, only remotely.

[schmidt-sebastian]

The Admin SDKs support the FIRESTORE_EMULATOR_HOST environment variable. You can simply set it to localhost:8080 to connect directly to the emulator.

Let us know if you have any other questions, but for now I hope you are unblocked.