title: How to trigger Cloud Functions from Google cloud firestore
body: <p>How to send the <code>DocumentReference.getId()</code> that is generated every time a new document was added to firestore from Android Studio to cloud function that triggers when there is a write/create operation on Firestore.
  I tried following</p>
  
  <pre><code>'use strict';
  const  https = require( 'firebase-functions');
  const functions = require('firebase-functions');
  const Firestore = require('@google-cloud/firestore');
  const firestore = new Firestore();
  const admin = require('firebase-admin');
  admin.initializeApp(functions.config().firebase);
  exports.helloUser = functions.firestore
      .document('BankInform/Moj2HBrxepX5R7FonvrO')
      .onUpdate(event =&gt;{
      var newValue = event.data.data();
  return event.data.ref.update({
      "status": "Success"
      });
  
      });
  </code></pre>
  
  <p>But I have to give the autoid of document.How to pass document id from android studio to cloud functions</p>