Connect to Elasticsearch Data in JRuby

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

Getting Started

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Configure a JDBC Connection to Elasticsearch 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 Elasticsearch\lib).

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

Set the Server and Port connection properties to connect. To authenticate, set the User and Password properties, PKI (public key infrastructure) properties, or both. To use PKI, set the SSLClientCert, SSLClientCertType, SSLClientCertSubject, and SSLClientCertPassword properties.

The data provider uses X-Pack Security for TLS/SSL and authentication. To connect over TLS/SSL, prefix the Server value with 'https://'. Note: TLS/SSL and client authentication must be enabled on X-Pack to use PKI.

Once the data provider is connected, X-Pack will then perform user authentication and grant role permissions based on the realms you have configured.

Built-in Connection String Designer

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

java -jar cdata.jdbc.elasticsearch.jar

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

Below is a typical JDBC connection string for Elasticsearch:

jdbc:elasticsearch:Server=127.0.0.1;Port=9200;User=admin;Password=123456;

Create a JRuby App with Connectivity to Elasticsearch Data

Create a new Ruby file (for example: ElasticsearchSelect.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 Elasticsearch 2018/lib/cdata.jdbc.elasticsearch.jar'

url = "jdbc:elasticsearch:Server=127.0.0.1;Port=9200;User=admin;Password=123456;"
conn = java.sql.DriverManager.getConnection(url)
stmt = conn.createStatement
rs = stmt.executeQuery("SELECT OrderName, Freight FROM Orders")
while (rs.next) do
 puts rs.getString(1) + ' ' + rs.getString(2)
end

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

jruby -S ElasticsearchSelect.rb

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