Firebase callable functions fail

Question

Many functions have started to fail intermittently with the following error even before the first line of code is executed:

FIREBASE WARNING: {"code":"app/invalid-credential","message":"Credential implementation provided to initializeApp() via the "credential" property failed to fetch a valid Google OAuth2 access token with the following error: "Failed to parse access token response: SyntaxError: Unexpected token p in JSON at position 4"."}

It's been more than 5 five days since i had opened a bug issue with Firebase support and i still don't have any feedback.

Does anyone why this is happening and how it can be fixed?

Libraries used and their versions:

"firebase": "^8.2.9",
"firebase-admin": "^9.5.0",
"firebase-functions": "^3.1.0"

Initializations:

const functions = require('firebase-functions');

const admin = require('firebase-admin');
admin.initializeApp();

var config = {
    apiKey: "...",
    authDomain: "...",
    databaseURL: "..."
};
var firebase = require("firebase");
firebase.initializeApp(config);

Answer 1

In a Cloud Function, if you want to interact with the Firebase services (e.g. Firestore, Auth service, etc), you need to use the Admin SDK.

So, you need to load the firebase-functions and firebase-admin modules, and initialize an admin app instance from which you interact with the services, as follows:

const functions = require('firebase-functions');

const admin = require('firebase-admin');
admin.initializeApp();

const firestoreDB = admin.firestore();
const authService = admin.auth();

// ... 

// Examples:

// In a Cloud Function
return firestoreDB.collection("cities").doc("LA").set({
    name: "Los Angeles",
    state: "CA",
    country: "USA"
});


// In another Cloud Function
return authService.updateUser(uid, {
   email: '[email protected]',
   phoneNumber: '+11234567890',
})
.then((userRecord) => {
  // ...
  // return ...
})

In other words, you don't need to do:

var config = {
    apiKey: "...",
    authDomain: "...",
    databaseURL: "..."
};
var firebase = require("firebase");
firebase.initializeApp(config);

---

Also note this note from the doc:

In many cases, new features and bug fixes are available only with the latest version of the Firebase CLI and the firebase-functions SDK. It's a good practice to frequently update both the Firebase CLI and the SDK with these commands inside the functions folder of your Firebase project:

npm install firebase-functions@latest firebase-admin@latest --save

npm install -g firebase-tools