Google Cloud Functions, resolveMX is not working with a list of domain

Question

I have the following function. I have a list of domains (very big list, more than 100000), I'm trying to put them in a foreach and resolveMx all of them and save the mx records in another database.

Edit, this is the complete function:

const dns = require('dns');
const {BigQuery} = require('@google-cloud/bigquery');
const bigquery = new BigQuery(project="smartiodomains");
const functions = require('firebase-functions');

exports.getMxRecords = functions.https.onRequest( async (req, res) => {
    const query = "SELECT string_field_0 FROM smartiodomains.Domains.sk_domains_table";
    
    const options = {
        query: query,
        location: 'US',
      };

    const [job] = await bigquery.createQueryJob(options);

    const [rows] = await job.getQueryResults();

    const datasetId = 'Domains';
    const tableId = 'smartio_records';
    var index = 0;
    rows.forEach((row) => {
        dns.resolveMx(row.string_field_0, function(error,addresses){
            if(error){
                const rows = [
                {domain:row.string_field_0, mx_records: 'No data found.', priority: 'No data found.'}
                ];

                // Insert data into a table
                bigquery
                .dataset(datasetId)
                .table(tableId)
                .insert(rows);
                res.write("Something");
            }else{
                res.write("Something else");
                addresses.forEach( address => {
                    const rows = [
                    {domain:row.string_field_0, mx_records: address.exchange, priority: address.priority}
                    ];

                    // Insert data into a table
                    bigquery
                    .dataset(datasetId)
                    .table(tableId)
                    .insert(rows).then((foundErrors) => {
                        if (foundErrors && foundErrors.insertErrors != undefined) {
                            console.log('Error: ', err);
                        }
                    })
                    .catch((err) => {
                        console.error('ERROR:', err);
                    }); 
                });
            }
        });
    });
});

As @Doug Stevenson suggested i add a response (res.write("Something")). Now i have one error and a warning:

1.- Memory Limit exceeded
2.- TeenyStatisticsWarning: Possible excessive concurrent requests detected. 5000 requests in-flight, which exceeds the configured threshold of 5000. Use the TEENY_REQUEST_WARN_CONCURRENT_REQUESTS environment variable or the concurrentRequests option of teeny-request to increase or disable (0) this warning.

Old error:

With this implementation i got this error in the logs of GCF:

getMxRecordsp5ter5a8u17q { Error: queryMx ETIMEOUT marketingweb.sk

Sorry for my bad english. And thanks for any help.

Answer 1

An HTTP function requires that you send a response to the client after all of the asynchronous work is complete. The function terminates immediately after you send that response. Right now, you're not sending any response, so the function never terminates, and it will always time out. You should send a response after all the calls to dns.resolveMx are fully complete.