This image shows where a custom event enrichment microservice could fit into the Event microservice pipeline. It has the following components:

On the left, the following things outside of Unified Assurance:
- Devices
- An external database
On the right, a container representing Unified Assurance, containing microservices and the Apache Pulsar topics that connect them in the following flow:
1. Devices send events to the collector microservices (Syslog, Trap, and others).
2. The collector microservices publish the events to the collection topic.
3. A custom microservice:
  1. Reads the events from the collection topic.
  2. Makes an API request to the external database.
  3. Enriches the events with the data from the external database.
  4. Publishes the events to a custom topic.
4. The FCOM Processor microservice:
  1. Reads the events from the custom topic.
  2. Processes the events.
  3. Publishes the events to the event sink topic.
5. The Event Sink microservice:
  1. Reads the events from the event sink topic.
  2. Inserts the events into the Event database.

The custom microservice is described in the text that follows the image.

The greater flow and details of the default components are described in Understanding the Event Pipeline in Unified Assurance Concepts.