Backup your Firestore db to a Firebase Storage bucket -- to be called from a Firebase Cloud Function (JavaScript/node)

FirestoreBackup.js

const functions = require('firebase-functions');
const firestore = require('@google-cloud/firestore');
const client = new firestore.v1.FirestoreAdminClient();

//
// Add config values with CLI command:
//    firebase functions:config:set my_app_name='{"fsBackupBucket":"gs://my-fs-backup-bucket"}'
//
const config = functions.config();

export const backupToStorage = () => {
  const projectId = process.env.GCP_PROJECT || process.env.GCLOUD_PROJECT;
  const databaseName = client.databasePath(projectId, '(default)');
  const bucketName = config.my_app_name.fsBackupBucket;

  console.log(`firestoreBackup(): projectId is (${projectId})`);
  console.log(`firestoreBackup(): databaseName is (${databaseName})`);
  console.log(`firestoreBackup(): bucketName is (${bucketName})`);

  return client
    .exportDocuments({
      name: databaseName,
      outputUriPrefix: bucketName,
      // Leave collectionIds empty to export all collections
      // or set to a list of collection IDs to export,
      // collectionIds: ['users', 'posts']
      collectionIds: [],
    })
    .then((responses) => {
      const response = responses[0];
      console.log('Operation Name: ' + response['name']);
    })
    .catch((ex) => {
      console.error(`Export operation failed: ${ex.message}\n${ex.stack}`);
      throw new Error(`Export operation failed: ${ex.message}`);
    });
};