Access Google Spanner Data in Mule Applications Using the CData JDBC Driver

The CData JDBC Driver for Google Spanner connects Google Spanner data to Mule applications enabling read , write, update, and delete functionality with familiar SQL queries. The JDBC Driver allows users to easily create Mule applications to backup, transform, report, and analyze Google Spanner data.

This article demonstrates how to use the CData JDBC Driver for Google Spanner inside of a Mule project to create a Web interface for Google Spanner data. The application created allows you to request Google Spanner data using an HTTP request and have the results returned as JSON. The exact same procedure outlined below can be used with any CData JDBC Driver to create a Web interface for the hundreds of available data sources.

1. Create a new Mule Project in Anypoint Studio.
2. Add an HTTP Connector to the Message Flow.
3. Configure the address for the HTTP Connector. 👁 Add and Configure the HTTP Connector
   
4. Add a Database Select Connector to the same flow, after the HTTP Connector.
5. Create a new Connection (or edit an existing one) and configure the properties.
   • Set Connection to "Generic Connection"
   • Select the CData JDBC Driver JAR file in the Required Libraries section (e.g. cdata.jdbc.googlespanner.jar). 👁 Adding the JAR file (Salesforce is shown).
     
   • Set the URL to the connection string for Google Spanner

     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.

   • Set the Driver class name to cdata.jdbc.googlespanner.GoogleSpannerDriver. 👁 A configured Database Connection (Salesforce is shown).
     
   • Click Test Connection.
6. Set the SQL Query Text to a SQL query to request Google Spanner data. For example:

   SELECT Name, TotalDue FROM Customer

   👁 Configure the Select object (Salesforce is Shown)
   
7. Add a Transform Message Component to the flow.
8. Set the Output script to the following to convert the payload to JSON:

   %dw 2.0
   output application/json
   ---
   payload
    

   👁 Add the Transform Message Component to the Flow
   
9. To view your Google Spanner data, navigate to the address you configured for the HTTP Connector (localhost:8081 by default): http://localhost:8081. The Google Spanner data is available as JSON in your Web browser and any other tools capable of consuming JSON endpoints.

At this point, you have a simple Web interface for working with Google Spanner data (as JSON data) in custom apps and a wide variety of BI, reporting, and ETL tools. Download a free, 30 day trial of the JDBC Driver for Google Spanner and see the CData difference in your Mule Applications today.