Connection timed out while connecting to AWS DocumentDB outside the VPC - node.js

Question

I'm trying create a very simple node app that can use DocumentDB. I'm not using Cloud9 neither Lambda, I'm coding locally. I was following this link https://docs.aws.amazon.com/documentdb/latest/developerguide/connect-from-outside-a-vpc.html and this link https://docs.aws.amazon.com/documentdb/latest/developerguide/connect-ec2.html
I created a poorly secured EC2 instance with the following inbound rules
port range
protocol
source
security group
22
TCP
0.0.0.0/0
demoEC2
This demoEC2 security group has the following inbound rules
type
protocol
port range
source
SSH
TCP
22
0.0.0.0/0
Then I created a DocumentDB cluster with 1 instance available that belongs to a security group that has the following inbound rules
type
protocol
port range
source
custom tcp
TCP
27017
demoEC2
After that, I open my terminal and created a tunnel:
ssh -i "mykeypair.pem" -L 27017:<CLUSTER ENDPOINT>:27017 ec2-user#<EC2 PUBLIC IPV4 DNS> -N
And, to test if my tunnel is working, I connect using mongoshell:
> mongo "mongodb://<MASTER USERNAME>:<MASTER PASSWORD>#localhost:27017/<DATABASE>" --tls --tlsAllowInvalidHostnames --tlsCAFile rds-combined-ca-bundle.pem
MongoDB shell version v4.2.13
connecting to: mongodb://localhost:27017/<DATABASE>?compressors=disabled&gssapiServiceName=mongodb
2021-07-29T10:10:59.309+0200 W NETWORK [js] The server certificate does not match the host name. Hostname: localhost does not match docdb-2021-07-27-10-32-49.ctuxybn342pe.eu-central-1.docdb.amazonaws.com docdb-2021-07-27-10-32-49.cluster-ctuxybn342pe.eu-central-1.docdb.amazonaws.com docdb-2021-07-27-10-32-49.cluster-ro-ctuxybn342pe.eu-central-1.docdb.amazonaws.com , Subject Name: C=US,ST=Washington,L=Seattle,O=Amazon.com,OU=RDS,CN=docdb-2021-07-27-10-32-49.ctuxybn342pe.eu-central-1.docdb.amazonaws.com
Implicit session: session { "id" : UUID("63340995-54ad-471b-aa8d-85763f3c7281") }
MongoDB server version: 4.0.0
WARNING: shell and server versions do not match
Warning: Non-Genuine MongoDB Detected
This server or service appears to be an emulation of MongoDB rather than an official MongoDB product.
Some documented MongoDB features may work differently, be entirely missing or incomplete, or have unexpected performance characteristics.
To learn more please visit: https://dochub.mongodb.org/core/non-genuine-mongodb-server-warning.
rs0:PRIMARY>
However, when I try to connect in my node app:
const mongoose = require('mongoose');
const fs = require('fs');
const path = require('path');
const username = ...
const password = ...
const database = ...
const connstring = `mongodb://${username}:${password}#localhost:27017/${database}?tls=true&replicaSet=rs0&readPreference=secondaryPreferred`;
const certFile = path.resolve(__dirname, './rds-combined-ca-bundle.pem');
const certFileBuf = fs.readFileSync(certFile); //I tried this one in tlsCAFile option as well
mongoose.connect(connstring,
{
tlsCAFile: certFile,
useNewUrlParser: true,
tlsAllowInvalidHostnames: true,
}
).then(() => console.log('Connection to DB successful'))
.catch((err) => console.error(err, 'Error'));
I get a connection timeout error after a while:
> > node .\index.js
(node:12388) [MONGODB DRIVER] Warning: Current Server Discovery and Monitoring engine is deprecated, and will be removed in a future version. To use the new Server Discover and Monitoring engine, pass option { useUnifiedTopology: true } to the MongoClient constructor.
MongoNetworkError: failed to connect to server [<CLUSTER ENDPOINT WITHOUT HAVING .cluster->:27017] on first connect [MongoNetworkTimeoutError: connection timed out
at connectionFailureError (D:\projects\documentdb-connect\node_modules\mongoose\node_modules\mongodb\lib\core\connection\connect.js:345:14)
at TLSSocket.<anonymous> (D:\projects\documentdb-connect\node_modules\mongoose\node_modules\mongodb\lib\core\connection\connect.js:313:16)
at Object.onceWrapper (events.js:421:28)
at TLSSocket.emit (events.js:315:20)
at TLSSocket.Socket._onTimeout (net.js:481:8)
at listOnTimeout (internal/timers.js:549:17)
at processTimers (internal/timers.js:492:7)]
at Pool.<anonymous> (D:\projects\documentdb-connect\node_modules\mongoose\node_modules\mongodb\lib\core\topologies\server.js:441:11)
at Pool.emit (events.js:315:20)
at D:\projects\documentdb-connect\node_modules\mongoose\node_modules\mongodb\lib\core\connection\pool.js:564:14
at D:\projects\documentdb-connect\node_modules\mongoose\node_modules\mongodb\lib\core\connection\pool.js:1013:9
at D:\projects\documentdb-connect\node_modules\mongoose\node_modules\mongodb\lib\core\connection\connect.js:32:7
at callback (D:\projects\documentdb-connect\node_modules\mongoose\node_modules\mongodb\lib\core\connection\connect.js:283:5)
at TLSSocket.<anonymous> (D:\projects\documentdb-connect\node_modules\mongoose\node_modules\mongodb\lib\core\connection\connect.js:313:7)
at Object.onceWrapper (events.js:421:28)
at TLSSocket.emit (events.js:315:20)
at TLSSocket.Socket._onTimeout (net.js:481:8)
at listOnTimeout (internal/timers.js:549:17)
at processTimers (internal/timers.js:492:7) Error
Since I could connect using mongoshell, I think the tunnel is working and I can even do some inserts on it, but why Mongoose can't connect? I tried also using the MongoClient (const MongoClient = require('mongodb').MongoClient and MongoClient.connect(same everything)) but it didn't worked, I'm still getting the same timeout error.

Answer 1

Turns out all I need to do is to pass the username and password through the options, not in the connection string:
const connstring = `mongodb://localhost:27017/${database}`;
const certFile = path.resolve(__dirname, './rds-combined-ca-bundle.pem');
const certFileBuf = fs.readFileSync(certFile);
mongoose.connect(connstring,
{
tls: true,
tlsCAFile: certFile,
useNewUrlParser: true,
tlsAllowInvalidHostnames: true,
auth: {
username,
password
}
}
)