connection of deno to mongodb fails - mongodb

Question

I'm trying to connect my deno application to mongodb but I get error.
import {MongoClient} from "https://deno.land/x/mongo#v0.21.2/mod.ts";
const client = await new MongoClient();
await client.connect("mongodb+srv://deno:i4vY8AtCEhr6ReqB#sample.7jp1l.mongodb.net/deno?retryWrites=true&w=majority");
const db = client.database("notes");
export default db;
everything seem to be fine but when I run the app, I get this error.
error: Uncaught (in promise) Error: MongoError: "Connection failed: failed to lookup address information: nodename nor servname provided, or not known"
throw new MongoError(`Connection failed: ${e.message || e}`);
^
at MongoClient.connect (client.ts:93:15)
at async mongodb.ts:4:1

Answer 1

2 problems that I see:
The code snippet above only works with Mongo installed in local machine.
The connection string use DNS Seed List, but the current library couldn't resolve to a list of hosts
To make it works with Mongo Atlas, you need to call a connect method with difference parameters and find a correct (static) host instead a (dynamic) DNS Seed List:
const client = new MongoClient();
const db = await client.connect({
db: '<your db or collection with work with>',
tls: true,
servers: [
{
host: '<correct host - the way to get the host - see bellow>',
port: 27017,
},
],
credential: {
username: '<your username>',
password: '<your password>',
mechanism: 'SCRAM-SHA-1',
},
});
How to get the correct host:
Open your Cluster in Mongo Atlas
Select Connect button
Select Connect to application option
Select Driver: Node.js and Version: 2.2.12 or later
Here you will see a list of host follow # character

Answer 2

Thank you #nthung.vlvn for the clue. Indeed the host needs to be a primary shard. It fixed the lookup address information, but I had another error, that my credentials are incorrect. I had to add db "admin" to credential:
credential: {
username: '<your username>',
password: '<your password>',
db: "admin",
mechanism: 'SCRAM-SHA-1',
}
That is weird, because I do not have admin db in my Atlas. Anyway it started to work.