URI Connection Settings

Optional connection settings are settings not covered by the URI Connection String . The following options are passed in the options parameter when you create a mongo client.

const MongoClient = require('mongodb').MongoClient;
const assert = require('assert');

// Connection URL
const url = 'mongodb://localhost:50000,localhost:50001';
// Database Name
const dbName = 'myproject';

// create a client, passing in additional options
const client = new MongoClient(url, {
  poolSize: 10, ssl: true
});

// Use connect method to connect to the server
client.connect(function(err) {
  assert.equal(null, err);
  console.log("Connected correctly to server");

  client.close();
});

The table below shows all settings and what topology they affect.

Ensure your connection string is valid for Replica Sets

The connection string passed to the driver must use the fully qualified host names for the servers as set in the replicaset config. Given the following configuration settings for your replicaset.

{
	"_id" : "testSet",
	"version" : 1,
	"protocolVersion" : 1,
	"members" : [
		{
			"_id" : 1,
			"host" : "server1:31000",
		},
		{
			"_id" : 2,
			"host" : "server2:31001",
		},
		{
			"_id" : 3,
			"host" : "server3:31002",
		}
	]
}

You must ensure server1, server2 and server3 are resolvable from the driver for the Replicaset discovery and failover to work correctly.