Code examples for connecting to a sharded MongoDB cluster

Written by

Updated at August 29, 2024

Go
Java
Node.js
PHP
Python

Go

Before connecting, install the dependencies:

sudo apt update && sudo apt install --yes golang git && \
go get go.mongodb.org/mongo-driver/mongo

Connecting via SSL

Connecting without SSL

connect.go

package main

import (
      "fmt"
      "strings"
      "context"
      "go.mongodb.org/mongo-driver/mongo"
      "go.mongodb.org/mongo-driver/mongo/options"
)

func main() {

      const DB_NAME = "<DB_name>"
      DB_HOSTS := []string {"<FQDN_of_MONGOINFRA_or_MONGOS_host_1>:27017",
                            ...,
                            "<FQDN_of_MONGOINFRA_or_MONGOS_host_N>:27017"}
      const DB_USER = "<DB_username>"
      const DB_PASS = "<DB_user_password>"

      const CACERT = "/home/<home_directory>/.mongodb/root.crt"

      url := fmt.Sprintf("mongodb://%s:%s@%s/%s?tls=true&tlsCaFile=%s",
              DB_USER,
              DB_PASS,
              strings.Join(DB_HOSTS, ","),
              DB_NAME,
              CACERT)

      conn, err := mongo.Connect(context.Background(), options.Client().ApplyURI(url))
      if err != nil {
              panic(err)
      }

      defer conn.Disconnect(context.Background())

      fmt.Println(conn.Database(DB_NAME).Name())
}

connect.go

package main

import (
      "fmt"
      "strings"
      "context"
      "go.mongodb.org/mongo-driver/mongo"
      "go.mongodb.org/mongo-driver/mongo/options"
)

func main() {

      const DB_NAME = "<DB_name>"
      DB_HOSTS := []string {"<FQDN_of_MONGOINFRA_or_MONGOS_host_1>:27017",
                            ...,
                            "<FQDN_of_MONGOINFRA_or_MONGOS_host_N>:27017"}
      const DB_USER = "<DB_username>"
      const DB_PASS = "<DB_user_password>"

      url := fmt.Sprintf("mongodb://%s:%s@%s/%s?tls=false",
              DB_USER,
              DB_PASS,
              strings.Join(DB_HOSTS, ","),
              DB_NAME)

      conn, err := mongo.Connect(context.Background(), options.Client().ApplyURI(url))
      if err != nil {
              panic(err)
      }

      defer conn.Disconnect(context.Background())

      fmt.Println(conn.Database(DB_NAME).Name())
}

To learn how to get a host FQDN, see this guide.

Connecting:

go run connect.go

Java

Before connecting:

Install the dependencies:

sudo apt update && sudo apt install --yes default-jdk maven

Add the SSL certificate to the Java trusted certificate store (Java Key Store) so that the MongoDB driver can use this certificate for secure connections to the cluster hosts. Make sure to set the password using the -storepass parameter for additional storage protection:
```
cd ~/.mongodb && \
sudo keytool -importcert \
             -alias YandexCA -file root.crt \
             -keystore ssl -storepass <password> \
             --noprompt
```
Where storepass is the certificate store password, at least 6 characters long.

Create a folder for the Maven project:

cd ~/ && \
mkdir --parents project/src/java/com/example && \
cd ~/project

Create a configuration file for Maven:

pom.xml

<?xml version="1.0" encoding="utf-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">

  <modelVersion>4.0.0</modelVersion>
  <groupId>com.example</groupId>
  <artifactId>app</artifactId>
  <packaging>jar</packaging>
  <version>0.1.0</version>
  <properties>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
  </properties>
  <dependencies>
    <dependency>
      <groupId>org.mongodb</groupId>
      <artifactId>mongodb-driver-sync</artifactId>
      <version>4.1.0</version>
    </dependency>
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-simple</artifactId>
      <version>1.7.30</version>
    </dependency>
  </dependencies>
  <build>
    <finalName>${project.artifactId}-${project.version}</finalName>
    <sourceDirectory>src</sourceDirectory>
    <resources>
      <resource>
        <directory>src</directory>
      </resource>
    </resources>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-assembly-plugin</artifactId>
        <executions>
          <execution>
            <goals>
              <goal>attached</goal>
            </goals>
            <phase>package</phase>
            <configuration>
              <descriptorRefs>
                <descriptorRef>
                jar-with-dependencies</descriptorRef>
              </descriptorRefs>
              <archive>
                <manifest>
                  <mainClass>com.example.App</mainClass>
                </manifest>
              </archive>
            </configuration>
          </execution>
        </executions>
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-jar-plugin</artifactId>
        <version>3.1.0</version>
        <configuration>
          <archive>
            <manifest>
              <mainClass>com.example.App</mainClass>
            </manifest>
          </archive>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

Up-to-date versions of dependencies for Maven:

Connecting via SSL

Connecting without SSL

src/java/com/example/App.java

package com.example;

import java.util.*;
import com.mongodb.*;
import com.mongodb.client.*;

public class App {
  public static void main(String[] args) {

    System.setProperty("javax.net.ssl.trustStore", "/home/<home_directory>/.mongodb/YATrustStore");
    System.setProperty("javax.net.ssl.trustStorePassword", "<certificate_store_password>");

    final Integer DB_PORT = 27017;

    List DB_HOSTS = new ArrayList<ServerAddress>();
    DB_HOSTS.add(new ServerAddress("<FQDN_of_MONGOINFRA_or_MONGOS_host_1>", DB_PORT));
    ...
    DB_HOSTS.add(new ServerAddress("<FQDN_of_MONGOINFRA_or_MONGOS_host_N>", DB_PORT));

    final String DB_NAME = "<DB_name>";
    final String DB_USER = "<DB_username>";
    final String DB_PASS = "<DB_user_password>";

    MongoClient conn = MongoClients.create(
        MongoClientSettings.builder()
              .applyToClusterSettings(builder -> builder.hosts(DB_HOSTS))
              .applyToSslSettings(builder -> builder.enabled(true))
              .credential(MongoCredential.createCredential(DB_USER, DB_NAME, DB_PASS.toCharArray()))
              .build());

    System.out.println(conn.getDatabase(DB_NAME).getName());

    conn.close();
  }
}

src/java/com/example/App.java

package com.example;

import java.util.*;
import com.mongodb.*;
import com.mongodb.client.*;

public class App {
  public static void main(String[] args) {

    final Integer DB_PORT = 27017;

    List DB_HOSTS = new ArrayList<ServerAddress>();
    DB_HOSTS.add(new ServerAddress("<FQDN_of_MONGOINFRA_or_MONGOS_host_1>", DB_PORT));
    ...
    DB_HOSTS.add(new ServerAddress("<FQDN_of_MONGOINFRA_or_MONGOS_host_N>", DB_PORT));

    final String DB_NAME = "<DB_name>";
    final String DB_USER = "<DB_username>";
    final String DB_PASS = "<DB_user_password>";

    MongoClient conn = MongoClients.create(
        MongoClientSettings.builder()
              .applyToClusterSettings(builder -> builder.hosts(DB_HOSTS))
              .credential(MongoCredential.createCredential(DB_USER, DB_NAME, DB_PASS.toCharArray()))
              .build());

    System.out.println(conn.getDatabase(DB_NAME).getName());

    conn.close();
  }
}

To learn how to get a host FQDN, see this guide.

Connecting:

mvn clean package && \
    java -jar target/app-0.1.0-jar-with-dependencies.jar

Node.js

Before connecting, install the dependencies:

sudo apt update && sudo apt install --yes nodejs npm && \
npm install mongodb

Connecting via SSL

Connecting without SSL

app.js

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

const DB_NAME = '<DB_name>'
const DB_HOSTS = ['<FQDN_of_MONGOINFRA_or_MONGOS_host_1>:27017',
                  ...,
                  '<FQDN_of_MONGOINFRA_or_MONGOS_host_N>:27017']
const DB_USER  = '<DB_username>'
const DB_PASS  = '<DB_user_password>'
const CACERT   = '/home/<home_directory>/.mongodb/root.crt'

const url = util.format('mongodb://%s:%s@%s/', DB_USER, DB_PASS, DB_HOSTS.join(','))

const options = {
  useNewUrlParser: true,
  useUnifiedTopology: true,
  tls: true,
  tlsCAFile: CACERT,
  authSource: DB_NAME
}

MongoClient.connect(url, options, function(err, conn) {
  if (conn.isConnected()) {
    const db = conn.db(DB_NAME)
    console.log(db.databaseName)
  }

  conn.close()
})

app.js

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

const DB_NAME = '<DB_name>'
const DB_HOSTS = ['<FQDN_of_MONGOINFRA_or_MONGOS_host_1>:27018',
                  ...,
                  '<FQDN_of_MONGOINFRA_or_MONGOS_host_N>:27018']
const DB_USER  = '<DB_username>'
const DB_PASS  = '<DB_user_password>'

const url = util.format('mongodb://%s:%s@%s/', DB_USER, DB_PASS, DB_HOSTS.join(','))

const options = {
  useNewUrlParser: true,
  useUnifiedTopology: true,
  authSource: DB_NAME
}

MongoClient.connect(url, options, function(err, conn) {
  if (conn.isConnected()) {
    const db = conn.db(DB_NAME)
    console.log(db.databaseName)
  }

  conn.close()
})

To learn how to get a host FQDN, see this guide.

Connecting:

node app.js

PHP

Before connecting, install the dependencies:

sudo apt update && sudo apt install --yes php php-mongodb

Connecting via SSL

Connecting without SSL

connect.php

<?php
  $DB_NAME  = '<DB_name>';
  $DB_HOSTS = '<FQDN_of_MONGOINFRA_or_MONGOS_host_1>:27017,...,<FQDN_of_MONGOINFRA_or_MONGOS_host_N>:27017';
  $DB_USER  = '<DB_username>';
  $DB_PASS  = '<DB_user_password>';
  $CACERT   = '/home/<home_directory>/.mongodb/root.crt';

  $uri = sprintf(
      'mongodb://%s:%s@%s/%s',
      $DB_USER,
      $DB_PASS,
      $DB_HOSTS,
      $DB_NAME
  );

  $conn = new \MongoDB\Driver\Manager($uri, ["tls" => "true", "tlsCAFile" => $CACERT], []);
  $command = new MongoDB\Driver\Command(array("ping" => 1));

  try {
      $cursor = $conn->executeCommand($DB_NAME, $command);
        $response = $cursor->toArray()[0];
  } catch(MongoDB\Driver\Exception $ex) {
      echo "$ex->getMessage()";
      exit;
  }

  var_dump($response);
?>

connect.php

<?php
  $DB_NAME  = '<DB_name>';
  $DB_HOSTS = '<FQDN_of_MONGOINFRA_or_MONGOS_host_1>:27017,...,<FQDN_of_MONGOINFRA_or_MONGOS_host_N>:27017';
  $DB_USER  = '<DB_username>';
  $DB_PASS  = '<DB_user_password>';

  $uri = sprintf(
      'mongodb://%s:%s@%s/%s',
      $DB_USER,
      $DB_PASS,
      $DB_HOSTS,
      $DB_NAME
  );

  $conn = new \MongoDB\Driver\Manager($uri);
  $command = new MongoDB\Driver\Command(array("ping" => 1));

  try {
      $cursor = $conn->executeCommand($DB_NAME, $command);
      $response = $cursor->toArray()[0];
  } catch(MongoDB\Driver\Exception $ex) {
      echo "$ex->getMessage()";
      exit;
  }

  var_dump($response);
?>

To learn how to get a host FQDN, see this guide.

Connecting:

php connect.php

Python

Before connecting, install the dependencies:

sudo apt update && sudo apt install --yes python3 python3-pip && \
pip3 install pyMongo

Connecting via SSL

Connecting without SSL

connect.py

import ssl
import pymongo
from urllib.parse import quote_plus as quote

CACERT = '/home/<home_directory>/.mongodb/root.crt'
DB_NAME = '<DB_name>'
DB_HOSTS =','.join([
      '<FQDN_of_MONGOINFRA_or_MONGOS_host_1>:27017',
      ...,
      '<FQDN_of_MONGOINFRA_or_MONGOS_host_N>:27017'
    ])
DB_USER = '<DB_username>'
DB_PASS = '<DB_user_password>'

url = 'mongodb://{user}:{pw}@{hosts}/?authSource={auth_src}'.format(
          user=quote(DB_USER),
          pw=quote(DB_PASS),
          hosts=DB_HOSTS,
          auth_src=DB_NAME)

conn = pymongo.MongoClient(
    url,
    tls=True,
    tlsCAFile=CACERT)

db = conn[DB_NAME]
print(db.name)

conn.close()

connect.py

import ssl
import pymongo
from urllib.parse import quote_plus as quote

DB_NAME = '<DB_name>'
DB_HOSTS =','.join([
      '<FQDN_of_MONGOINFRA_or_MONGOS_host_1>:27017',
      ...,
      '<FQDN_of_MONGOINFRA_or_MONGOS_host_N>:27017'
    ])
DB_USER = '<DB_username>'
DB_PASS = '<DB_user_password>'

url = 'mongodb://{user}:{pw}@{hosts}/?authSource={auth_src}'.format(
          user=quote(DB_USER),
          pw=quote(DB_PASS),
          hosts=DB_HOSTS,
          auth_src=DB_NAME)

conn = pymongo.MongoClient(url)

db = conn[DB_NAME]
print(db.name)

conn.close()

To learn how to get a host FQDN, see this guide.

Connecting:

python3 connect.py

Code examples for connecting to a sharded MongoDB cluster

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