Query Kafka Data as a SQL Server in Node.js

You can use CData Connect Server to query Kafka data through a SQL Server interface. Follow the procedure below to create a virtual database for Kafka in Connect Server and start querying using Node.js.

CData Connect Server provides a pure SQL Server interface for Kafka, allowing you to easily build reports from live Kafka data in Node.js — without replicating the data to a natively supported database. As you build visualizations, Node.js generates SQL queries to gather data. Using optimized data processing out of the box, CData Connect Server pushes all supported SQL operations (filters, JOINs, etc) directly to Kafka, leveraging server-side processing to quickly return the requested Kafka data.

Create a Virtual SQL Server Database for Kafka Data

CData Connect Server uses a straightforward, point-and-click interface to connect to data sources and generate APIs.

1. Login to Connect Server and click Connections.
2. Select "Kafka" from Available Data Sources.
3. Enter the necessary authentication properties to connect to Kafka.

   Set BootstrapServers and the Topic properties to specify the address of your Apache Kafka server, as well as the topic you would like to interact with.

   Authorization Mechanisms

   • SASL Plain: The User and Password properties should be specified. AuthScheme should be set to 'Plain'.
   • SASL SSL: The User and Password properties should be specified. AuthScheme should be set to 'Scram'. UseSSL should be set to true.
   • SSL: The SSLCert and SSLCertPassword properties should be specified. UseSSL should be set to true.
   • Kerberos: The User and Password properties should be specified. AuthScheme should be set to 'Kerberos'.

   You may be required to trust the server certificate. In such cases, specify the TrustStorePath and the TrustStorePassword if necessary.

4. Click Save Changes
5. Click Privileges -> Add and add the new user (or an existing user) with the appropriate permissions.

With the virtual database created, you are ready to connect to Kafka data from Node.js.

Query Kafka from Node.js

The following example shows how to define a connection and execute queries to Kafka with the SQL Server module. You will need the following information:

• Host name, or address, and port: The address of your Connect Server instance and the port (1433)
• Username and password: The username and password of a user you authorized on Connect Server
• Database name: The database you configured for Kafka (ApacheKafka1)

Connect to Kafka data and start executing queries with the code below:

const sql = require('mssql');

const config = {
    user: 'your_connect_username', 
    password: 'your_connect_password', 
    server: 'connect_server_url', 
    port: 1433, // optional, defaults to 1433
    database: 'ApacheKafka1',
    authentication: {
        type: 'default'
    },
    options: {
        encrypt: true
    }
}

console.log("Starting...");
connectAndQuery();

async function connectAndQuery() {
    try {
        var poolConnection = await sql.connect(config);

        console.log("Reading rows from the table...");
        var resultSet = await poolConnection.request().query(`SELECT * FROM table_name`);

        console.log(`${resultSet.recordset.length} rows returned.`);

        // output column headers
        var columns = "";
        for (var column in resultSet.recordset.columns) {
            columns += column + ", ";
        }
        console.log("%s	", columns.substring(0, columns.length - 2));

        // ouput row contents from default record set
        resultSet.recordset.forEach(row => {
            console.log("%s	%s", row.CategoryName, row.ProductName);
        });

        // close connection only when we're certain application is finished
        poolConnection.close();
    } catch (err) {
        console.error(err.message);
    }
}

SQL Server Access to Kafka Data from Node.js

You have retrieved live Kafka Data using Node.js. Now, you can easily access data sources and more — all without replicating Kafka data.

To get SQL data access to 200+ SaaS, Big Data, and NoSQL sources directly from your applications, try CData Connect Server.