HTTP POST request inside scheduled Cloud Function is not working

Below is my scheduler where I am reading data from firebase database and updating data by calling receiptValidationRequest(key, receiptData, date) . Inside this function , I try to retrieve validation data from the response of HTTP call to apple, but its not working properly. Sometimes it works and a few data got updated. I am not sure why is this happening and what i am missing there.

exports.updateDatabaseScheduler = functions.pubsub.schedule('0 0 */3 * *').onRun(async context => {
console.log('scheduler started');
await ref.on('value', function(snapshot) {
snapshot.forEach(function(childSnapshot) {
var childData = childSnapshot.val();
console.log(i++ + " : " +childSnapshot.key);
receiptValidationRequest(childSnapshot.key, childData['ReceiptData'], myDate);
});
});
console.log('scheduler finished');
});
async function receiptValidationRequest(userID, receiptData, myDate){
let password = 'my password';
try{
const data = JSON.stringify({
'receipt-data': receiptData,
'password' : password,
'exclude-old-transactions': false
});
const options = {
resolveWithFullResponse: true,
// hostname: 'sandbox.itunes.apple.com',
hostname: 'buy.itunes.apple.com',
port: 443,
path: '/verifyReceipt',
method: 'POST',
json: true,
headers: {
'Content-Type': 'application/json',
// 'Content-Length': data.length
}
};
const req =  await https.request(options,res => {
myStatusCode[0] = res.statusCode;
let expireDate = [];
let transactionId = [];
var trialPeriod = [];
var body = '';
console.log(`statusCode: ${res.statusCode}`);
res.on('data', d => {
body = body + d;
// console.log("body : "+body);
});
res.on("end", () => {
body = JSON.parse(body);
let array = Object.keys(body);
console.log("body : "+body);
//parsing data here
insertIntoDB(userID, expireDate, transactionId, trialPeriod, myDate);
});
});
req.write(data);
req.end();
}catch(e){
req.on('error', (error) => {
console.error(error)
});
}   
}

You need to return a promise that resolves when all of the asynchronous work is complete. Without that, Cloud Functions doesn't know when it's safe to shut down the function. What you have right now is a race condition - sometimes the work compeltes before Cloud Functions shuts down, but not always.

I suggest looking into another HTTP library that makes it easier to deal with promises, such as "request-promise".

receiptValidationRequest is an async functioN. You are not awaiting while calling in forEach. Also, use for..of or promise.all instead of forEach as forEach doesn't work with promises in loop.