Enable the Google Cloud Storage JDBC Driver in KNIME

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Google Cloud Storage JDBC Driver

Rapidly create and deploy powerful Java applications that integrate with Google Cloud Storage.



Use standard data access components in KNIME to create charts and reports with Google Cloud Storage data.

One of the strengths of the CData JDBC Driver for Google Cloud Storage is its cross-platform support, enabling integration with major BI tools. Follow the procedure below to access Google Cloud Storage data in KNIME and to create a chart from Google Cloud Storage data using the report designer.

Define a New JDBC Connection to Google Cloud Storage Data

  1. Install the Report Designer extension: Click File -> Install KNIME Extensions, and filter on "Report".
  2. In a new workflow, click File -> Preferences and expand the KNIME -> Databases node to add cdata.jdbc.googlecloudstorage.jar. The driver JAR is located in the lib subfolder of the installation directory.
  3. In the Node Repository view, expand the Database -> Read/Write node and drag a Database Reader onto the workflow editor.
  4. Double-click the Database Reader and set the following properties:

    • Database Driver: In the menu, select the driver name, cdata.jdbc.googlecloudstorage.GoogleCloudStorageDriver
    • Database URL: Enter the connection properties. The JDBC URL begins with jdbc:googlecloudstorage: and is followed by a semicolon-separated list of connection properties.

      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.

      When you configure the JDBC URL, you may also want to set the Max Rows connection property. This will limit the number of rows returned, which is especially helpful for improving performance when designing reports and visualizations.

      A typical JDBC URL is below.

      jdbc:googlecloudstorage:ProjectId='project1';InitiateOAuth=GETANDREFRESH
    • User Name: The username used to authenticate.
    • Password: The password used to authenticate.
    • SQL Statement: Enter an SQL query in the SQL Statement box or double-click a table. This article uses the query below to create a chart: SELECT Name, OwnerId FROM Buckets WHERE Name = 'TestBucket'
  5. Test the connection by clicking Fetch Metadata.

  6. Connect the Database Reader to a Data to Report node to supply the dataset to a range of data visualization controls. Click Execute and then click Edit Report at the top of the workflow to open the report designer perspective.
  7. You can now generate reports based on live data. To create a chart, drag the chart control from the palette to the report designer. In the resulting wizard, you can use the filtering and aggregation controls available in KNIME.

Troubleshooting

The following list shows how to resolve common errors:

  • Encountered duplicate row Id "Row1": To resolve this error, add the following to the knime.ini file located in your KNIME installation directory:-Dknime.database.fetchsize=0