Connect to Databricks Data in JRuby

JRuby is a high-performance, stable, fully threaded Java implementation of the Ruby programming language. The CData JDBC Driver for Databricks makes it easy to integrate connectivity to live Databricks data in JRuby. This article shows how to create a simple JRuby app that connects to Databricks data, executes a query, and displays the results.

Getting Started

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Configure a JDBC Connection to Databricks Data

Before creating the app, note the installation location for the JAR file for the JDBC Driver (typically C:\Program Files\CData\CData JDBC Driver for Databricks\lib).

JRuby natively supports JDBC, so you can easily connect to Databricks and execute SQL queries. Initialize the JDBC connection with the getConnection function of the java.sql.DriverManager class.

To connect to a Databricks cluster, set the properties as described below.

Note: The needed values can be found in your Databricks instance by navigating to Clusters, and selecting the desired cluster, and selecting the JDBC/ODBC tab under Advanced Options.

• Server: Set to the Server Hostname of your Databricks cluster.
• HTTPPath: Set to the HTTP Path of your Databricks cluster.
• Token: Set to your personal access token (this value can be obtained by navigating to the User Settings page of your Databricks instance and selecting the Access Tokens tab).

Built-in Connection String Designer

For assistance in constructing the JDBC URL, use the connection string designer built into the Databricks JDBC Driver. Either double-click the JAR file or execute the jar file from the command-line.

java -jar cdata.jdbc.databricks.jar

Fill in the connection properties and copy the connection string to the clipboard.

Below is a typical JDBC connection string for Databricks:

jdbc:databricks:Server=127.0.0.1;Port=443;TransportMode=HTTP;HTTPPath=MyHTTPPath;UseSSL=True;User=MyUser;Password=MyPassword;

Create a JRuby App with Connectivity to Databricks Data

Create a new Ruby file (for example: DatabricksSelect.rb) and open it in a text editor. Copy the following code into your file:

require 'java'
require 'rubygems'
require 'C:/Program Files/CData/CData JDBC Driver for Databricks 2018/lib/cdata.jdbc.databricks.jar'

url = "jdbc:databricks:Server=127.0.0.1;Port=443;TransportMode=HTTP;HTTPPath=MyHTTPPath;UseSSL=True;User=MyUser;Password=MyPassword;"
conn = java.sql.DriverManager.getConnection(url)
stmt = conn.createStatement
rs = stmt.executeQuery("SELECT City, CompanyName FROM Customers")
while (rs.next) do
 puts rs.getString(1) + ' ' + rs.getString(2)
end

With the file completed, you are ready to display your Databricks data with JRuby. To do so, simply run your file from the command line:

jruby -S DatabricksSelect.rb

Writing SQL-92 queries to Databricks allows you to quickly and easily incorporate Databricks data into your own JRuby applications. Download a free trial today!