How to update two databases reference with a single trigger function in firebase RTDB? - firebase

Question

Let's say we have firebase project in which we have to use RTDB.
In RTDB we have created multiple databases.
I created a cloud trigger function i.e .onCreate so that my both databases get updated whenever I update any of two. When I am creating anything in default database it is working completely fine but when I am trying to update through other database (other than default one) it doesn't update default one. So could you please help me on this?
/* eslint-disable */
import * as functions from "firebase-functions";
import * as admin from "firebase-admin";
admin.initializeApp();
//this method is updating on creating data on database mentioned in instance id
export const newTest1=functions.database.instance('flysample-75b81-227ae').ref('/msg')
.onCreate((snapshot, context) => {
let app = admin.app();
app.database('https://flysample-75b81.firebaseio.com/').ref('/db1').set({Name:"Database1"})
app.database('https://flysample-75b81-227ae.firebaseio.com/').ref('/db1').set({Name:"Database1"})
return "done";
});
//this method is updating only by creating data on default database
export const newTest2=functions.database.ref('/msg')
.onCreate((snapshot, context) => {
let app = admin.app();
app.database('https://flysample-75b81.firebaseio.com/').ref('/db1').set({Name:"Database1"})
app.database('https://flysample-75b81-227ae.firebaseio.com/').ref('/db1').set({Name:"Database1"})
return "done";
});
//below 2 method works fine but i want to do this by single function
export const myFunTest1 = functions.database.instance('flysample-75b81').ref('/name')
.onCreate((snapshot, context) => {
let app = admin.app();
app.database('https://flysample-75b81.firebaseio.com/').ref('/db1').set({Name:"Database1"})
app.database('https://flysample-75b81-227ae.firebaseio.com/').ref('/db1').set({Name:"Database1"})
return "done";
});
export const myFunTest2 = functions.database.instance('flysample-75b81-227ae').ref('/name')
.onCreate((snapshot, context) => {
let app = admin.app();
app.database('https://flysample-75b81.firebaseio.com/').ref('/db1').set({Name:"Database1"})
app.database('https://flysample-75b81-227ae.firebaseio.com/').ref('/db1').set({Name:"Database1"})
return "done";
});

Answer 1

Your code is completely ignoring the asynchronous nature of writing to the database, which means there is no guarantee that any of the database writes completes before the instance gets terminated.
To ensure the writes don't get interrupted, wait for them to complete before returning a result with something like this:
export const newTest2=functions.database.ref('/msg')
.onCreate((snapshot, context) => {
let app = admin.app();
return Promise.all([
app.database('https://flysample-75b81.firebaseio.com/').ref('/db1').set({Name:"Database1"})
app.database('https://flysample-75b81-227ae.firebaseio.com/').ref('/db1').set({Name:"Database1"})
]).then(() => {
return "done";
});
});