How to write google function with Twilio to send SMS on value change in Realtime database

Question

I am writing my first google cloud function I don't have in depth knowledge of it. I am trying to write a google cloud Function with Twilio. When ever the value of water change in my Realtime Database it will send a SMS to a given number that the water value of this machine has been changed so the message look like "Water value of "Machine ID" has been changed". I have try to do but I did not find any proper documentation or video on YouTube which Full Fill all the requirement. I was doing research on this from last week I and write some code can anyone please check my code and tell what changes I have to made to get what I want. here is what I have write till now.

exports.testing = functions.https.onRequest((request, response) => {
   var db = admin.database();
    var ref = db.ref("/07D0921210004");//This 07D0921210004 is the machineID
    ref.on("value", function (snapshot) {
      var water = snapshot.val().water;
      const accountSid = process.env.TWILIO_ACCOUNT_SID;
      const authToken = process.env.TWILIO_AUTH_TOKEN;
      const client = require('twilio')(accountSid, authToken); 

      client.messages
  .create({
     body: 'This is the ship that made the Kessel Run in fourteen parsecs?',
     from: '+1501***2661',
     to: '+155586***10'
   })
  .then(message => console.log(message.sid));
     
     
    },);
});

This is my database structure

{
07D0921210004 
{
Date:"value"
Water:"value"
}
}

Answer 1

When ever the value of water change in my Realtime Database...

This kind of trigger is called background trigger and for the Realtime Database the Cloud Function looks like:

exports.sendSMS = functions.database.ref('{machineId}')
    .onCreate((snapshot, context) => {
      // Value of the node
      const nodeValue = snapshot.val();

      // ....

     });

The code of the Cloud Function in your question is for an HTTPS Cloud Function which is triggered through an HTTP request (similar to a REST API endpoint). So it will not be triggered when an event occurs in the Realtime Database.

---

So, your should adapt your code along the following lines (untested). Note the use of async/await, in order to take into account the asynchronicity of the create() method and the Cloud Function life cycle management.

exports.sendSMS = functions.database.ref('{machineId}')
    .onCreate(async (snapshot, context) => {
        
      // Value of water
      var water = snapshot.val().water;

      const accountSid = ...
      const authToken = ...
      const client = require('twilio')(accountSid, authToken); 
      
      const message = await client.messages
      .create({
         body: 'This is the ship that made the Kessel Run in fourteen parsecs?',
         from: '+1501***2661',
         to: '+155586***10'
       });
       
       console.log(message.sid)
       return null;

     });