Chain Two Business Events
Use the output of one Business Event as the trigger for publishing a second Business Event. This creates a lightweight event chain where each step signals the next.
When to use this recipe
Use event chaining when a business process has sequential stages and each stage has independent consumers. Chaining keeps each stage loosely coupled — the first publisher does not need to know what happens next.
Architecture
flowchart LR
P1[Publisher\nNotebook] -->|Publishes| E1[Business Event A\nOrder.Processing.Completed]
E1 --> ACT[Activator\nMonitors Event A]
ACT -->|Condition met| P2[Activator publishes]
P2 -->|Publishes| E2[Business Event B\nOrder.Fulfillment.Started]
E2 --> C1[Eventhouse\nFulfillment analytics]
E2 --> C2[Activator\nNotify warehouse]Step 1: Publish the first event
# Notebook publishes Event A when order processing completes
event_data = {
"order_id": "ORD-4421",
"customer_id": "CUST-882",
"total_amount": 340.00,
"completed_at": "2024-11-15T14:32:00Z"
}
notebookutils.businessEvents.publish(
"MyWorkspace",
"OrderProcessing",
"Order.Processing.Completed",
event_data,
dataVersion="v1"
)
Step 2: Configure Activator to publish Event B
- Go to Real-Time Hub → Business events
- Find Order.Processing.Completed and click Set alert
- Configure Monitor: source = Order.Processing.Completed
- Configure Condition: On each event
- Configure Action: Publish a business event
- Select Order.Fulfillment.Started as the target event
- Map fields from Event A to Event B:
| Event A field | Event B field |
|---|---|
order_id |
order_id |
customer_id |
customer_id |
| (static value) | started_at → current timestamp |
Design considerations
Keep chains short. Each hop adds latency and a potential failure point. If you need more than 2-3 steps, consider whether an orchestration tool (Data Pipeline, Power Automate) is a better fit.
Each event should be independently meaningful. If Event B is only ever triggered by Event A and has no other consumers, evaluate whether two separate events are necessary.
Do not create circular chains. Event A triggering Event B triggering Event A will cause an infinite loop. Design chains to always move forward in the process.