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Fireemu

Connect your app

Fireemu serves the same protocols and default ports as the Local Emulator Suite, so you connect to it the same way.

Server code and the Admin SDK

Section titled “Server code and the Admin SDK”

The Firebase Admin SDK and the Google Cloud client libraries read the emulator environment variables. fireemu exec sets them for the command it runs:

Terminal window
npx fireemu exec -- node ./scripts/seed.mjs
Variable Value
FIRESTORE_EMULATOR_HOST, FIREBASE_FIRESTORE_EMULATOR_ADDRESS Firestore host:port
FIREBASE_AUTH_EMULATOR_HOST Authentication host:port
FIREBASE_STORAGE_EMULATOR_HOST Storage host:port
STORAGE_EMULATOR_HOST Storage URL (http://host:port) for the Cloud Storage client libraries; with Storage App Check enforced and appCheck.storageServerRequests set to "capability" it also carries a per-run Admin capability (see App Check)
PUBSUB_EMULATOR_HOST Pub/Sub host:port, when Pub/Sub runs
CLOUD_EVENTARC_EMULATOR_HOST Eventarc URL, when Functions run
CLOUD_TASKS_EMULATOR_HOST Cloud Tasks host:port, when Functions run
FIREEMU_FUNCTIONS_HOST Functions host:port, when Functions run
FIREEMU_APP_CHECK_EMULATOR_HOST, FIREEMU_APP_CHECK_JWKS_URL App Check exchange host and JWKS URL, when appCheck.enabled
FIREBASE_EMULATOR_HUB Emulator Hub host:port, when the Hub is running
FIREBASE_LOGGING_EMULATOR_HOST Logging emulator host:port
GCLOUD_PROJECT, GOOGLE_CLOUD_PROJECT The project ID
FIREBASE_CONFIG Set from the project ID unless your environment already has it
FIREEMU_CONTROL_URL, FIREEMU_CONTROL_TOKEN Fireemu’s control API, used by fireemu/testing

Variables for emulators that are not selected are left as your environment had them.

import { initializeApp } from 'firebase-admin/app';
import { getFirestore } from 'firebase-admin/firestore';


// Under `fireemu exec`, the Admin SDK finds the emulators from the environment.
initializeApp({ projectId: process.env.GCLOUD_PROJECT });
await getFirestore().doc('notes/n1').set({ text: 'hello' });

Client SDKs

Section titled “Client SDKs”

Client SDKs are connected in code, as with the Local Emulator Suite. Use the project ID Fireemu runs with: the .firebaserc default, else daemon.authProject in fireemu.toml, else demo-app.

import { initializeApp } from 'firebase/app';
import { getAuth, connectAuthEmulator } from 'firebase/auth';
import { getFirestore, connectFirestoreEmulator } from 'firebase/firestore';
import { getStorage, connectStorageEmulator } from 'firebase/storage';
import { getFunctions, connectFunctionsEmulator } from 'firebase/functions';


const app = initializeApp({
  projectId: 'demo-app',
  apiKey: 'fake-api-key',
  storageBucket: 'demo-app.appspot.com',
});


connectAuthEmulator(getAuth(app), 'http://127.0.0.1:9099');
connectFirestoreEmulator(getFirestore(app), '127.0.0.1', 8080);
connectStorageEmulator(getStorage(app), '127.0.0.1', 9199);
connectFunctionsEmulator(getFunctions(app), '127.0.0.1', 5001);

Security Rules unit tests

Section titled “Security Rules unit tests”

@firebase/rules-unit-testing works with Fireemu. Its unsigned mock ID tokens (authenticatedContext()) are accepted by default, also under the strict profile, and the routes it calls to load Firestore and Storage rules and to clear Firestore (testEnv.clearFirestore()) are served. See Security Rules.

The project ID

Section titled “The project ID”

Fireemu takes the project ID from, in order:

  1. --project (-P) on the command line, as an ID or a .firebaserc alias;
  2. the default project of the .firebaserc next to the loaded firebase.json;
  3. daemon.authProject in fireemu.toml;
  4. demo-app.