Connecting an external application

Using connection information

All the information a driver needs to make a connection to your deployment is in the "MongoDB" section of a credential created on the Service credentials page. The table contains a breakdown for reference.

• 0... indicates that there might be one or more of these entries in an array.

Many MongoDB drivers are able to connect to your deployment when given the URI-formatted connection string found in the "composed" field of the connection information. Cloud Databases provides a highly available instance of MongoDB, so make sure to include all members in the connection string. For example:

mongodb://admin:$PASSWORD@d5eeee66-5bc4-498a-b73b-1307848f1eac.8f7bfd8f3faa4218aec56e069eb46187-0.databases.appdomain.cloud:30484,d5eeee66-5bc4-498a-b73b-1307848f1eac.8f7bfd8f3faa4218aec56e069eb46187-1.databases.appdomain.cloud:30484,d5eeee66-5bc4-498a-b73b-1307848f1eac.8f7bfd8f3faa4218aec56e069eb46187-2.databases.appdomain.cloud:30484/<database name>?authSource=admin&replicaSet=replset

The replicaSet query parameter contains the replica set name for your deployment. It is probably replset. Some drivers and applications need it passed in separately.

The following example uses the information from your connection string and the MongoDB Java Driver to connect to your database.

public class MongodbConnect {
    private static Logger log = LoggerFactory.getLogger(LoggerFactory.class);

    public static void main(String[] args) {

        // make sure you append ssl=true to the connection URI
        final String mongoURI = "mongodb://user:password@host:port,host:port/?authSource=admin&replicaSet=replset&ssl=true";

        MongoClient mongoClient = MongoClients.create(mongoURI);
        boolean testDB = false;

        // this loop will continue attempting to connect to the database until the admin database is found
        while (!testDB) {
            try {
                // check if you can connect to the database by checking for
                // the presence of the admin database. If the admin databases isn't found
                // then you're not connected.
                MongoIterable<String> databases = mongoClient.listDatabaseNames();
                for (String name: databases) {
                    if (name.contains("admin")) {
                        System.out.println("admin found...");
                        testDB = true;
                    }
                }
            } catch (Exception e) {
                log.info(e.getMessage());
            }
        }

        // close connection
        mongoClient.close();

    }
}

This next example uses information from your connection string and the Python driver pymongo to connect to your database. This is just a simple connection example, without error handling or retry logic and may not be suitable for production.

import pymongo
from pymongo import MongoClient
from pymongo.errors import ConnectionFailure


client = MongoClient(
    "mongodb://admin:$PASSWORD@host.databases.appdomain.cloud:30484/<database name>?authSource=adminreplicaSet=replset",
)

try:
    db_list = client.list_database_names()
    print("List of databases:")
    print(db_list)

except ConnectionFailure as err:
    print("Unable to connect to database")

This final example uses the MongoDB Node.js driver

const MongoClient = require("mongodb").MongoClient;

let connectionString = "mongodb://<username>:<password>@<host>:<port>,<host>:<port>/<database>?authSource=admin&replicaSet=replset";

let options = {
    useUnifiedTopology: true
};

// connects to a MongoDB database
MongoClient.connect(connectionString, options, function (err, db) {
    if (err) {
        console.log(err);
    } else {
       // lists the databases that exist in the deployment
        db.db('example').admin().listDatabases(function(err, dbs) {
            console.log(dbs.databases);
            db.close();
        });
    }
});

Other Language Drivers

MongoDB has a vast array of language drivers. The table covers a few of the most common. If you're looking for more languages, try the MongoDB.org Driver List.