Connect to Google Spanner Data in JRuby

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

Configure a JDBC Connection to Google Spanner 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 Google Spanner\lib).

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

Google Spanner uses the OAuth authentication standard. To authenticate using OAuth, you can use the embedded credentials or register an app with Google.

See the Getting Started guide in the CData driver documentation for more information.

Built-in Connection String Designer

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

java -jar cdata.jdbc.googlespanner.jar

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

Below is a typical JDBC connection string for Google Spanner:

jdbc:googlespanner:ProjectId='project1';InstanceId='instance1';Database='db1';InitiateOAuth=GETANDREFRESH;

Create a JRuby App with Connectivity to Google Spanner Data

Create a new Ruby file (for example: GoogleSpannerSelect.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 Google Spanner 2018/lib/cdata.jdbc.googlespanner.jar'

url = "jdbc:googlespanner:ProjectId='project1';InstanceId='instance1';Database='db1';InitiateOAuth=GETANDREFRESH;"
conn = java.sql.DriverManager.getConnection(url)
stmt = conn.createStatement
rs = stmt.executeQuery("SELECT Name, TotalDue FROM Customer")
while (rs.next) do
 puts rs.getString(1) + ' ' + rs.getString(2)
end

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

jruby -S GoogleSpannerSelect.rb

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