Analyze Google Cloud Storage Data in R via JDBC

Access Google Cloud Storage data with pure R script and standard SQL on any machine where R and Java can be installed. You can use the CData JDBC Driver for Google Cloud Storage and the RJDBC package to work with remote Google Cloud Storage data in R. By using the CData Driver, you are leveraging a driver written for industry-proven standards to access your data in the popular, open-source R language. This article shows how to use the driver to execute SQL queries to Google Cloud Storage and visualize Google Cloud Storage data by calling standard R functions.

Install R

You can match the driver's performance gains from multi-threading and managed code by running the multithreaded Microsoft R Open or by running open R linked with the BLAS/LAPACK libraries. This article uses Microsoft R Open 3.2.3, which is preconfigured to install packages from the Jan. 1, 2016 snapshot of the CRAN repository. This snapshot ensures reproducibility.

Load the RJDBC Package

To use the driver, download the RJDBC package. After installing the RJDBC package, the following line loads the package:

library(RJDBC)

Connect to Google Cloud Storage as a JDBC Data Source

You will need the following information to connect to Google Cloud Storage as a JDBC data source:

• Driver Class: Set this to cdata.jdbc.googlecloudstorage.GoogleCloudStorageDriver
• Classpath: Set this to the location of the driver JAR. By default this is the lib subfolder of the installation folder.

The DBI functions, such as dbConnect and dbSendQuery, provide a unified interface for writing data access code in R. Use the following line to initialize a DBI driver that can make JDBC requests to the CData JDBC Driver for Google Cloud Storage:

driver <- JDBC(driverClass = "cdata.jdbc.googlecloudstorage.GoogleCloudStorageDriver", classPath = "MyInstallationDir\lib\cdata.jdbc.googlecloudstorage.jar", identifier.quote = "'") 

You can now use DBI functions to connect to Google Cloud Storage and execute SQL queries. Initialize the JDBC connection with the dbConnect function.

Authenticate with a User Account

You can connect without setting any connection properties for your user credentials. After setting InitiateOAuth to GETANDREFRESH, you are ready to connect.

When you connect, the Google Cloud Storage OAuth endpoint opens in your default browser. Log in and grant permissions, then the OAuth process completes

Authenticate with a Service Account

Service accounts have silent authentication, without user authentication in the browser. You can also use a service account to delegate enterprise-wide access scopes.

You need to create an OAuth application in this flow. See the Help documentation for more information. After setting the following connection properties, you are ready to connect:

• InitiateOAuth: Set this to GETANDREFRESH.
• OAuthJWTCertType: Set this to "PFXFILE".
• OAuthJWTCert: Set this to the path to the .p12 file you generated.
• OAuthJWTCertPassword: Set this to the password of the .p12 file.
• OAuthJWTCertSubject: Set this to "*" to pick the first certificate in the certificate store.
• OAuthJWTIssuer: In the service accounts section, click Manage Service Accounts and set this field to the email address displayed in the service account Id field.
• OAuthJWTSubject: Set this to your enterprise Id if your subject type is set to "enterprise" or your app user Id if your subject type is set to "user".
• ProjectId: Set this to the Id of the project you want to connect to.

The OAuth flow for a service account then completes.

Built-in Connection String Designer

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

java -jar cdata.jdbc.googlecloudstorage.jar

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

👁 Using the built-in connection string designer to generate a JDBC URL (Salesforce is shown.)

Below is a sample dbConnect call, including a typical JDBC connection string:

conn <- dbConnect(driver,"jdbc:googlecloudstorage:ProjectId='project1';InitiateOAuth=GETANDREFRESH;")

Schema Discovery

The driver models Google Cloud Storage APIs as relational tables, views, and stored procedures. Use the following line to retrieve the list of tables:

dbListTables(conn)

Execute SQL Queries

You can use the dbGetQuery function to execute any SQL query supported by the Google Cloud Storage API:

buckets <- dbGetQuery(conn,"SELECT Name, OwnerId FROM Buckets WHERE Name = 'TestBucket'")

You can view the results in a data viewer window with the following command:

View(buckets)

Plot Google Cloud Storage Data

You can now analyze Google Cloud Storage data with any of the data visualization packages available in the CRAN repository. You can create simple bar plots with the built-in bar plot function:

par(las=2,ps=10,mar=c(5,15,4,2))
barplot(buckets$OwnerId, main="Google Cloud Storage Buckets", names.arg = buckets$Name, horiz=TRUE)

👁 A basic bar plot. (Salesforce is shown.)