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Create controller services

Learn about creating Controller Services in CDF Flow Designer.

Controller Services are extension points that provide information for use by other components (such as processors or other controller services). The idea is that, rather than configure this information in every processor that might need it, the controller service provides it for any processor to use as needed.

You will use the controller services you create now to configure the behavior of several processors you will add to your flow as you are building it.

  1. Go to Flow Options > Services.


  2. Click Add Service.
    The Add Service page opens.


  3. In the text box, filter for JsonTreeReader.
  4. Provide Service Name: JSON_Reader_Recent_Changes.
  5. Click Add.
  6. Configure the JSON_Reader_Recent_Changes service.

    Set the following Properties:

    Starting Field Strategy
    Nested Field
    Starting Field Name
    recentchanges
  7. Click Apply.
  8. Click Add Service to create another service.
  9. In the text box, filter for AvroRecordSetWriter.
  10. Provide Service Name: AvroWriter_Recent_Changes.
  11. Click Add.
    You do not need to configure the AvroWriter_Recent_Changes service. You can leave all properties with their default values.
  12. Click Add Service to create a third service.
  13. In the text box, filter for AvroReader.
  14. Provide Service Name: AvroReader_Recent_Changes.
  15. Click Add.
    You do not need to configure the AvroReader_Recent_Changes service. You can leave all properties with their default values.
  16. Click Back To Flow Designer to return to the flow design Canvas.
After creating the necessary Controller Services, you can start building and configuring your flow.