Why am I only getting Mailgun.js error in Cloud Run? - node.js

Question

I'm trying to send an email using Mailgun's npm client - Mailgun.js.
When sending in development mode, everything works correctly. But when I upload the Node server to Cloud Run, something breaks.
Here is the code in the sendEmail helper file:
import formData from 'form-data';
import Mailgun from 'mailgun.js';
const sendEmail = async ({ to, subject, text, attachment, scheduledDate }) => {
const mailgun = new Mailgun(formData);
const mg = mailgun.client({
username: 'api',
key: process.env.MAILGUN_KEY,
url: 'https://api.eu.mailgun.net'
});
const data = {
from: `<myemail#mydomain.com>`,
to,
subject,
text
};
if (attachment) {
data.attachment = attachment;
}
if (scheduledDate) {
data['o:deliverytime'] = new Date(scheduledDate).toUTCString();
}
try {
const result = await mg.messages.create(process.env.MAILGUN_DOMAIN, data);
if (result.status && result.status !== 200) {
throw ({ code: result.status, message: result.message });
}
return true;
} catch(err) {
console.log(err);
return { error: err };
}
};
export default sendEmail;
And then in another file:
import { Router } from 'express';
import generateInvoicePDF from '../helpers/generateInvoicePDF.js';
import sendEmail from '../helpers/sendEmail.js';
const router = Router();
router.post('/email', async (req, res, next) => {
try {
const file = await generateInvoicePDF(invoice);
if (file?.error) {
throw ({ code: pdf.error.code, message: pdf.error.message });
}
const email = await sendEmail({
to: 'testemail#example.com',
subject: 'Invoice',
text: 'Test',
attachment: { filename: 'Invoice', data: file }
});
if (email?.error) {
throw ({ code: email.error.code, message: email.error.message });
}
res.status(200).json({ success: true });
} catch(err) {
next(err);
}
});
export default router;
The error I get when in production mode in Cloud Run's logs is:
TypeError: fetch failed
at Object.processResponse (node:internal/deps/undici/undici:5575:34)
at node:internal/deps/undici/undici:5901:42
at node:internal/process/task_queues:140:7
at AsyncResource.runInAsyncScope (node:async_hooks:202:9)
at AsyncResource.runMicrotask (node:internal/process/task_queues:137:8) {
cause: TypeError: object2 is not iterable
at action (node:internal/deps/undici/undici:1661:39)
at action.next (<anonymous>)
at Object.pull (node:internal/deps/undici/undici:1709:52)
at ensureIsPromise (node:internal/webstreams/util:172:19)
at readableStreamDefaultControllerCallPullIfNeeded (node:internal/webstreams/readablestream:1884:5)
at node:internal/webstreams/readablestream:1974:7
}
Why the hell does it work in development mode on my local machine, but not when uploaded to Cloud Run?

Answer 1

For anyone struggling with something similar - I eventually figured out the problem.
On my local machine, where everything was working as expected, I'm using Node v16.15.0, whereas in the Dockerfile, I had specified
FROM node:latest
and therefore Cloud Run was using a newer version, which led to the problems...
I've now deployed using version 16.15.0 and everything works fine