在 GCP 数据存储中初始化 Firestore object

Question

I've a google cloud project A, with firestore running in datastore mode. I have a script (written in javascript running on top of nodejs in google cloud) which when run, need to get the data from firestore running in native mode in another GC project B.

I've deployed the script in project A's workspace and it is able to get records from datastore easily but it is unable to get the data from firestore in project B.

I've the following code in the script (note: I've uploaded the creds.json into the cloud workspace folder in which the script also resides):

const Fs = require("firebase-admin");
const { Datastore } = require("@google-cloud/datastore");

const datastore = new Datastore({});
const servAcc = require(`./creds.json`);

Fs.initializeApp({
  credential: Fs.credential.cert(servAcc),
});
const someFunc = async () => {
      const db = Fs.firestore();
      const dataColl = await db.collection("dataB").get();

I'm able to see that servAcc is indeed populated and valid but the dataColl is empty. I've got "initializeApp is re-initialized again error", so I initialized Fs twice..first with no arguments and the second time with creds and some random appname like so:

Fs.initializeApp({
  credential: Fs.credential.cert(servAcc),
}, "randomAppName");

I'm still unable to see any data from the firestore supposedly coming from project B and yes, firestore in project B has data.

Let me know why google gods have frowned on me.

Answer 1

You'll need to initialize the Firestore object with a project id (projectB). For the GCP node.js SDK you can find an example of creating a Firestore object with a non-default project id at https://cloud.google.com/nodejs/docs/reference/firestore/latest/firestore/firestore#examples . Eg

var firestore = new Firestore({ projectId:
'projectB', keyFilename: '/path/to/keyfile.json'
});

For the Firebase admin SDK, you can see an example at https://github.com/firebase/snippets-node/blob/94a076cf3db7f2954b1d8e332a89b72b7966c034/firestore/main/index.js#L12 . Eg

const serviceAccount = require('./path/to/serviceAccountKey.json');
initializeApp({
  // The `projectId` parameter is optional and represents which project the
  // client will act on behalf of. If not supplied, it falls back to the default
  // project inferred from the environment.
  projectId: 'projectB',
  credential: cert(serviceAccount)
});

Answer 2

I was trying to initialize two firestore clients in the same node project and the other answers didn't work for me, hence posting this answer.

https://firebase.google.com/docs/projects/multiprojects#use_multiple_projects_in_your_application

primary Instance

const {getFirestore} = require('firebase-admin/firestore');
const { initializeApp, cert } = require('firebase-admin/app');

initializeApp({projectId: 'my-project'});
const db = getFirestore();

secondary Instance:

const secondaryServiceAccount = require('./tests-local-sa.json');
const secondaryAppConfig = {
    credential: cert(secondaryServiceAccount),
};
const secondary = initializeApp(secondaryAppConfig, 'secondary');
const cache_db = getFirestore(secondary);