Event Grid for event routing in Azure - Step-by-Step Execution

Process Flow - Event Grid for event routing

Event Source emits event

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Event Grid receives event

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Event Grid matches event to subscriptions

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Event Grid routes event to subscribers

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Subscribers receive and process event

Events are sent from a source to Event Grid, which then routes them to the right subscribers based on subscriptions.

Execution Sample

Azure

1. Event Source sends event
2. Event Grid receives event
3. Event Grid checks subscriptions
4. Event Grid routes event
5. Subscriber processes event

This sequence shows how an event flows from the source through Event Grid to subscribers.

Process Table

Step	Action	Event Grid State	Routing Decision	Subscriber Action
1	Event Source emits event	Waiting for event	No routing yet	No action
2	Event Grid receives event	Event received	Check subscriptions	No action
3	Event Grid matches event to subscriptions	Event matched	Route to subscriber A and B	No action
4	Event Grid routes event	Routing in progress	Send event to subscriber A and B	No action
5	Subscribers receive event	Event delivered	Routing complete	Subscriber A and B process event
6	End	Idle	No routing	Waiting for next event

💡 Event delivered to all matching subscribers; routing complete.

Status Tracker

Variable	Start	After Step 2	After Step 3	After Step 4	After Step 5	Final
Event Grid State	Waiting for event	Event received	Event matched	Routing in progress	Event delivered	Idle
Routing Decision	None	None	Route to subscriber A and B	Send event to subscribers	Routing complete	None
Subscriber Action	None	None	None	None	Process event	Waiting

Key Moments - 3 Insights

Why does Event Grid check subscriptions after receiving an event?

Event Grid needs to know which subscribers want this event type to route it correctly, as shown in step 3 of the execution_table.

What happens if no subscriptions match the event?

Event Grid will not route the event to any subscriber, so no subscriber action occurs. This is implied by the routing decision in step 3.

When do subscribers actually process the event?

Subscribers process the event only after Event Grid routes and delivers it, as shown in step 5 of the execution_table.

Visual Quiz - 3 Questions

Look at the execution table, what is the Event Grid State at step 3?

A Event received

B Event matched

C Routing in progress

D Waiting for event

💡 Hint

Check the 'Event Grid State' column at step 3 in the execution_table.

At which step do subscribers start processing the event?

A Step 2

B Step 3

C Step 5

D Step 4

💡 Hint

Look at the 'Subscriber Action' column in the execution_table.

If no subscriptions match the event, what would the routing decision be at step 3?

A No routing

B Send event to subscribers

C Route to subscriber A and B

D Event delivered

💡 Hint

Refer to the 'Routing Decision' column at step 3 in the execution_table.

Concept Snapshot

Event Grid routes events from sources to subscribers.
It receives events, matches subscriptions, then routes events.
Subscribers process events only after delivery.
If no subscription matches, event is not routed.
This enables decoupled, scalable event-driven apps.

Full Transcript

Event Grid is a service that routes events from sources to subscribers. When an event source emits an event, Event Grid receives it and checks which subscribers have registered for that event type. It then routes the event to those subscribers. Subscribers process the event only after receiving it from Event Grid. If no subscribers match, the event is not routed. This flow allows applications to react to events in a scalable and decoupled way.