How to work with Gmail Data in Apache Spark using SQL

Apache Spark is a fast and general engine for large-scale data processing. When paired with the CData JDBC Driver for Gmail, Spark can work with live Gmail data. This article describes how to connect to and query Gmail data from a Spark shell.

The CData JDBC Driver offers unmatched performance for interacting with live Gmail data due to optimized data processing built into the driver. When you issue complex SQL queries to Gmail, the driver pushes supported SQL operations, like filters and aggregations, directly to Gmail and utilizes the embedded SQL engine to process unsupported operations (often SQL functions and JOIN operations) client-side. With built-in dynamic metadata querying, you can work with and analyze Gmail data using native data types.

Install the CData JDBC Driver for Gmail

Download the CData JDBC Driver for Gmail installer, unzip the package, and run the JAR file to install the driver.

Start a Spark Shell and Connect to Gmail Data

1. Open a terminal and start the Spark shell with the CData JDBC Driver for Gmail JAR file as the jars parameter: $ spark-shell --jars /CData/CData JDBC Driver for Gmail/lib/cdata.jdbc.gmail.jar
2. With the shell running, you can connect to Gmail with a JDBC URL and use the SQL Context load() function to read a table.

   There are two ways to authenticate to Gmail. Before selecting one, first ensure that you have enabled IMAP access in your Gmail account settings. See the "Connecting to Gmail" section under "Getting Started" in the installed documentation for a guide.

   The User and Password properties, under the Authentication section, can be set to valid Gmail user credentials.

   Alternatively, instead of providing the Password, you can use the OAuth authentication standard. To access Google APIs on behalf on individual users, you can use the embedded credentials or you can register your own OAuth app.

   OAuth also enables you to use a service account to connect on behalf of users in a Google Apps domain. To authenticate with a service account, you will need to register an application to obtain the OAuth JWT values.

   In addition to the OAuth values, you will need to provide the User. See the "Getting Started" chapter in the help documentation for a guide to using OAuth.

   Built-in Connection String Designer

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

   java -jar cdata.jdbc.gmail.jar

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

   Configure the connection to Gmail, using the connection string generated above.

   scala> val gmail_df = spark.sqlContext.read.format("jdbc").option("url", "jdbc:gmail:User=username;Password=password;").option("dbtable","Inbox").option("driver","cdata.jdbc.gmail.GmailDriver").load()
3. Once you connect and the data is loaded you will see the table schema displayed.

4. Register the Gmail data as a temporary table:

   scala> gmail_df.registerTable("inbox")

5. Perform custom SQL queries against the Data using commands like the one below:

   scala> gmail_df.sqlContext.sql("SELECT Subject, Size FROM Inbox WHERE From = test@test.com").collect.foreach(println)

   You will see the results displayed in the console, similar to the following:

Using the CData JDBC Driver for Gmail in Apache Spark, you are able to perform fast and complex analytics on Gmail data, combining the power and utility of Spark with your data. Download a free, 30 day trial of any of the 200+ CData JDBC Drivers and get started today.