Consume Kafka OData Feeds in SAP Lumira

You can use the CData API Server to create data visualizations based on Kafka data in SAP Lumira. The API Server enables connectivity to live data: dashboards and reports can be refreshed on demand. This article shows how to create a chart that is always up to date.

Set Up the API Server

If you have not already done so, download the CData API Server. Once you have installed the API Server, follow the steps below to begin producing secure Kafka OData services:

Connect to Kafka

To work with Kafka data from SAP Lumira, we start by creating and configuring a Kafka connection. Follow the steps below to configure the API Server to connect to Kafka data:

1. First, navigate to the Connections page.
2. Click Add Connection and then search for and select the Kafka connection. 👁 Selecting a data source (SQLite is shown)
   
3. Enter the necessary authentication properties to connect to Kafka.

   Set BootstrapServers and the Topic properties to specify the address of your Apache Kafka server, as well as the topic you would like to interact with.

   Authorization Mechanisms

   • SASL Plain: The User and Password properties should be specified. AuthScheme should be set to 'Plain'.
   • SASL SSL: The User and Password properties should be specified. AuthScheme should be set to 'Scram'. UseSSL should be set to true.
   • SSL: The SSLCert and SSLCertPassword properties should be specified. UseSSL should be set to true.
   • Kerberos: The User and Password properties should be specified. AuthScheme should be set to 'Kerberos'.

   You may be required to trust the server certificate. In such cases, specify the TrustStorePath and the TrustStorePassword if necessary.

   👁 Connecting to a datasource (SQLite is shown)
   
4. After configuring the connection, click Save & Test to confirm a successful connection.

Configure API Server Users

Next, create a user to access your Kafka data through the API Server. You can add and configure users on the Users page. Follow the steps below to configure and create a user:

1. On the Users page, click Add User to open the Add User dialog.
2. Next, set the Role, Username, and Privileges properties and then click Add User. 👁 Configure a new user
   
3. An Authtoken is then generated for the user. You can find the Authtoken and other information for each user on the Users page: 👁 API Server user settings
   

Creating API Endpoints for Kafka

Having created a user, you are ready to create API endpoints for the Kafka tables:

1. First, navigate to the API page and then click Add Table . 👁 Add tables
   
2. Select the connection you wish to access and click Next. 👁 Select the connection (SQLite is shown)
   
3. With the connection selected, create endpoints by selecting each table and then clicking Confirm. 👁 Adding tables from the connection (SQLite is shown)
   

Gather the OData Url

Having configured a connection to Kafka data, created a user, and added resources to the API Server, you now have an easily accessible REST API based on the OData protocol for those resources. From the API page in API Server, you can view and copy the API Endpoints for the API:

Connect to Kafka from SAP Lumira

Follow the steps below to retrieve Kafka data into SAP Lumira. You can execute an SQL query or use the UI.

1. In SAP Lumira, click File -> New -> Query with SQL. The Add New Dataset dialog is displayed.
2. Expand the Generic section and click the Generic OData 2.0 Connector option.
3. In the Service Root URI box, enter the OData endpoint of the API Server. This URL will resemble the following:

   https://your-server:8080/api.rsc
   

4. In the User Name and Password boxes, enter the username and authtoken of an API user. These credentials will be used in HTTP Basic authentication. 👁 The OData endpoint and HTTP Basic authentication configured for an API user.
   

5. Select entities in the tree or enter an SQL query. This article imports Kafka SampleTable_1 entities.

   👁 Available entities for import. (Salesforce is shown.)
   

6. When you click Connect, SAP Lumira will generate the corresponding OData request and load the results into memory. You can then use any of the data processing tools available in SAP Lumira, such as filters, aggregates, and summary functions.

   👁 Tables of Kafka data to be imported into SAP Lumira. (Salesforce Accounts are shown.)
   

Create Data Visualizations

After you have imported the data, you can create data visualizations in the Visualize room. Follow the steps below to create a basic chart.

1. In the Measures and Dimensions pane, drag measures and dimensions onto the x-axis and y-axis fields in the Visualization Tools pane. SAP Lumira automatically detects dimensions and measures from the metadata service of the API Server.

   By default, the SUM function is applied to all measures. Click the gear icon next to a measure to change the default summary.

2. In the Visualization Tools pane, select the chart type.
3. In the Chart Canvas pane, apply filters, sort by measures, add rankings, and update the chart with the current Kafka data. 👁 A basic line chart. (Salesforce is shown.)