Firestore local http with real db: The Cloud Firestore emulator is not running so database operations will fail with a 'default credentials' error

Question

I want to run a firebase http cloud function locally accessing a real remote firestore database.

To do it, I'm running my functions locally using:

FIREBASE_CONFIG="/path-to-credential.json" GOOGLE_APPLICATION_CREDENTIALS="/path-to-credential.json" firebase emulators:start --only functions

As written here https://firebase.google.com/docs/admin/setup, this should permit the initialization of the admin sdk without any parameter. My functions index.js is as following

import * as admin from 'firebase-admin';
import * as fromHttpFunc from './http/func'; 

admin.initializeApp(); 

export const httpFunc = fromHttpFunc.httpFunc;

When I then call the function in the browser, this is what I get in logs

[warn] ⚠  The Cloud Firestore emulator is not running so database operations will fail with a 'default credentials' error.
[debug] [2019-07-20T13:16:28.656Z] [runtime-status] Ephemeral server survived. {}
[info] >  (node:41939) UnhandledPromiseRejectionWarning: Error: The incoming JSON object does not contain a client_email field
[info] >      at JWT.fromJSON (/Users/michele/dev/clubup/backoffice/firebase/functions/node_modules/google-auth-library/build/src/auth/jwtclient.js:165:19)
[info] >      at GoogleAuth.fromJSON (/Users/michele/dev/clubup/backoffice/firebase/functions/node_modules/google-auth-library/build/src/auth/googleauth.js:294:16)
[info] >      at GoogleAuth.getClient (/Users/michele/dev/clubup/backoffice/firebase/functions/node_modules/google-auth-library/build/src/auth/googleauth.js:476:52)
[info] >      at GrpcClient._getCredentials (/Users/michele/dev/clubup/backoffice/firebase/functions/node_modules/google-gax/build/src/grpc.js:107:40)
[info] >      at GrpcClient.createStub (/Users/michele/dev/clubup/backoffice/firebase/functions/node_modules/google-gax/build/src/grpc.js:223:34)
[info] >      at new FirestoreClient (/Users/michele/dev/clubup/backoffice/firebase/functions/node_modules/@google-cloud/firestore/build/src/v1/firestore_client.js:128:39)
[info] >      at ClientPool.Firestore._clientPool.pool_1.ClientPool [as clientFactory] (/Users/michele/dev/clubup/backoffice/firebase/functions/node_modules/@google-cloud/firestore/build/src/index.js:315:26)
[info] >      at ClientPool.acquire (/Users/michele/dev/clubup/backoffice/firebase/functions/node_modules/@google-cloud/firestore/build/src/pool.js:61:35)
[info] >      at ClientPool.run (/Users/michele/dev/clubup/backoffice/firebase/functions/node_modules/@google-cloud/firestore/build/src/pool.js:114:29)
[info] >      at Firestore.readStream (/Users/michele/dev/clubup/backoffice/firebase/functions/node_modules/@google-cloud/firestore/build/src/index.js:995:26)
[info] >  (node:41939) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 3)
[info] >  (node:41939) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
[warn] ⚠  Your function timed out after ~60s. To configure this timeout, see
      https://firebase.google.com/docs/functions/manage-functions#set_timeout_and_memory_allocation.
[warn] ⚠  Your function timed out after ~60s. To configure this timeout, see
      https://firebase.google.com/docs/functions/manage-functions#set_timeout_and_memory_allocation.

I don't get what's wrong, I also checked if the path to the credential is ok by doing cat /path-to-credential.json and I have a json with the client_email field.

Answer 1

Managed to have the local cloud functions working with the real remote DB by making sure of the following:

• run firebase login and login into the project you want to use

• follow this comment https://github.com/firebase/firebase-functions/issues/121#issuecomment-337065268 to make sure the file is not there (I had a invalid_grant error)

• run export GOOGLE_APPLICATION_CREDENTIALS="SERVICE_ACCOUNT_PATH.json" in the terminal session you want to use (replace SERVICE_ACCOUNT_PATH)

• serve your http functions NOT by using firebase emulators:start --only functions but using firebase serve --only functions. Currently, this is an undocumented behaviour: https://github.com/firebase/firebase-tools/issues/1412#issuecomment-504561828.

• initialize the app as following (update YOUR_APP_ID):

  admin.initializeApp({ credential: admin.credential.applicationDefault() });