Build Impala-Connected Apps in Mendix

Mendix is a high-productivity app platform that allows you to build and maintain both mobile and web applications at-scale. When paired with CData Connect Cloud, Mendix provides instant, cloud-to-cloud access to Impala data for applications. This article demonstrates how to connect to a CData Connect Cloud data source from within Mendix.

CData Connect Cloud provides a pure cloud-to-cloud interface for Impala, allowing you to import data from live Impala data in Mendix — without replicating the data to a natively supported database. As you build web and mobile applications from within Mendix, CData Connect Cloud pushes all supported SQL operations (filters, JOINs, etc.) directly to Impala, leveraging server-side processing to return the requested Impala data quickly.

Configure Impala Connectivity for Mendix

Connectivity to Impala from Mendix is made possible through CData Connect Cloud. To work with Impala data from Mendix, we start by creating and configuring a Impala connection.

1. Log into Connect Cloud, click Connections and click Add Connection
2. Select "Impala" from the Add Connection panel
3. Enter the necessary authentication properties to connect to Impala.

   In order to connect to Apache Impala, set the Server, Port, and ProtocolVersion. You may optionally specify a default Database. To connect using alternative methods, such as NOSASL, LDAP, or Kerberos, refer to the online Help documentation.

4. Click Create & Test
5. Navigate to the Permissions tab in the Add Impala Connection page and update the User-based permissions.

Configure Impala Endpoints for Mendix

After connecting to Impala, create a workspace and virtual dataset for your desired table(s).

1. Navigate to the Virtual Datasets page and click Add to create a new Workspace (or select an existing workspace).
2. Click Add to add new assets to the Workspace.
3. Select the Impala connection (e.g. ApacheImpala1) and click Next.
4. Select the table(s) you wish to work with and click Confirm.
5. Make note of the OData Service URL for your workspace, e.g. https://cloud.cdata.com/api/odata/{workspace_name}

With the connection and Workspace configured, you are ready to connect to Impala data from Mendix.

Build a Impala-Connected App

With the Workspace added to Connect Cloud, you can build an app in Mendix with live access to Impala data.

Downloading the OData Metadata File

When creating a connection in Mendix, the connection flow requires a Data Source Contract File. Follow these steps to download the OData metadata file for CData Connect Cloud using curl, a command line tool:

1. Open a command-line window for your operating system. On Windows, open the start menu, type cmd, and press the Enter key to open a command prompt. On macOS and Linux, open a Terminal window.
2. To check if curl is installed on your system, type curl -help and press the enter key. If it is not installed, install it from the curl website.
3. Issue the following curl command, replacing USER with your CData Connect Cloud username and PAT with the PAT you generated above: curl -u USER:PAT https://cloud.cdata.com/api/odata/{workspace_name}/$metadata -o metadata.xml
4. Locate the metadata.xml file that the curl command created and move it to an accessible location.

Connecting to CData Connect Cloud in Mendix

Follow these steps to establish a connection from Mendix to CData Connect Cloud:

1. Login to Mendix and open the Data Hub page.
2. In the Register a Data Source section, select OData.
3. Upload the metadata.xml file from the steps above and click Next.
4. Enter your desired values for Data Source Name and Data Source Version. In the Data Source Relative Path field, enter /api/odata/{workspace_name} and click Next.
5. On the Application information page, click Register a new application.
6. Enter a name in Application Name and select a technical owner (by default, this is the user who is currently logged in).
7. Click Next. In the Environment Name field, enter a desired name (for example, CData Connect Cloud). In the Environment Location field, enter https://cloud.cdata.com and select the appropriate Environment Type (e.g. Production), depending on what is needed.
8. Click Done! to create your connection.

You can now use your connection in Mendix Studio Pro to easily create applications with access to live Impala data.

Get CData Connect Cloud

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