Release job on Heroku randomly stops sending Files over FTP - heroku

Question

I have an app release process that has been working fine for a week or two and has now randomly stopped working.
My npm app is built with Heroku and a release job then runs that FTPs the static files to another host. I use the npm ftp library to do this. This has randomly stopped working with a timeout error:
Error: Timeout while connecting to server
at Timeout._onTimeout (/app/node_modules/ftp/lib/connection.js:304:24)
at ontimeout (timers.js:436:11)
at tryOnTimeout (timers.js:300:5)
at listOnTimeout (timers.js:263:5)
at Timer.processTimers (timers.js:223:10)
the release script is as follows:
const DIST_PATH = `dist/cineworld-planner`;
const filesList = readdirSync(join(process.cwd(), DIST_PATH));
const client = new Client();
function pushFiles() {
const putFile = bindNodeCallback(client.put.bind(client));
from(filesList).pipe(
mergeMap(fileName => {
const localPath = join(process.cwd(), DIST_PATH, fileName);
console.log(`Putting path ${localPath} to remote ${fileName}`);
return putFile(localPath, fileName);
}, 1)
).subscribe({
complete: () => client.end()
});
}
client.on('ready', () => {
console.log(`READY`);
pushFiles();
});
client.on('error', (error: any) => {
const code = error.code || 'NO_CODE';
console.log(`ERROR: ${code}`);
console.log(error);
process.exit(1);
});
client.connect({
user: process.env.FTP_USER,
host: process.env.FTP_HOST,
password: process.env.FTP_PASSWORD
});
I have asked my host if there are any issues but all they have said is that the IP address that my script reported it was running on was not blocked.
I have tested the script from my home PC and it also works fine from there.
This will be a major pain if this has stopped working. I really don't know what else to try.
Any help very gratefully received.

Answer 1

It turns out that for me the fix was as simple as increasing the timeout:
const connectOptions: Options = {
user: process.env.FTP_USER,
host: process.env.FTP_HOST,
password: process.env.FTP_PASSWORD,
connTimeout: 60000,
pasvTimeout: 60000,
};
client.connect(connectOptions);