Azure Event Grid is a fully managed event routing service that enables event-driven architectures by connecting event sources to event handlers using a publish-subscribe model. As an Azure Developer, understanding Event Grid implementation is essential for building reactive, scalable applications.
…Azure Event Grid is a fully managed event routing service that enables event-driven architectures by connecting event sources to event handlers using a publish-subscribe model. As an Azure Developer, understanding Event Grid implementation is essential for building reactive, scalable applications.
**Core Concepts:**
Event Grid uses topics to collect events from publishers and subscriptions to route those events to handlers. Events are lightweight notifications containing minimal data, typically under 1MB, following a standardized schema.
**Implementation Steps:**
1. **Create an Event Grid Topic:** Deploy a custom topic through Azure Portal, CLI, or ARM templates. This serves as your event ingestion endpoint.
2. **Configure Event Publishers:** Applications send events to the topic endpoint using HTTP POST requests with proper authentication via SAS keys or Azure AD tokens.
3. **Create Event Subscriptions:** Define where events should be delivered by specifying endpoint types such as Azure Functions, Logic Apps, Storage Queues, Webhooks, or Event Hubs.
4. **Implement Event Handlers:** Build handlers that process incoming events. For webhooks, implement validation handshake to confirm endpoint ownership.
**Key Features:**
- **Filtering:** Apply subject-based or advanced filtering to route specific events to appropriate handlers.
- **Dead-lettering:** Configure storage accounts to capture undelivered events for later analysis.
- **Retry Policies:** Customize retry attempts and time-to-live settings for reliable delivery.
- **Batching:** Optimize throughput by receiving multiple events per request.
**System Topics:**
Leverage built-in system topics to react to Azure service events like Blob Storage changes, Resource Group modifications, or IoT Hub telemetry.
**Security Considerations:**
Implement managed identities for secure authentication, configure private endpoints for network isolation, and use RBAC for access control.
Event Grid charges per operation, making it cost-effective for variable workloads while providing high availability with multi-region deployment capabilities.
Implement Solutions That Use Azure Event Grid
Why Azure Event Grid is Important
Azure Event Grid is a critical component for building modern, event-driven architectures in the cloud. It enables reactive programming patterns that allow applications to respond to events in near real-time. For the AZ-204 exam, understanding Event Grid is essential because it represents Microsoft's recommended approach for building loosely coupled, scalable applications that can react to state changes across Azure services and custom applications.
What is Azure Event Grid?
Azure Event Grid is a fully managed event routing service that uses a publish-subscribe model. It provides uniform event consumption using a push-based delivery mechanism, enabling you to build reactive applications with minimal polling overhead.
Key Components: - Events: The smallest amount of information describing what happened in the system - Event Sources/Publishers: Where events originate (Azure services, custom applications) - Topics: Endpoints where publishers send events (System topics for Azure services, Custom topics for your applications) - Event Subscriptions: Built-in filters that route events to handlers - Event Handlers: The destination where events are sent (Azure Functions, Logic Apps, Webhooks, Event Hubs, Storage Queues)
How Azure Event Grid Works
1. Event Publishing: A source generates an event when a state change occurs and publishes it to a topic 2. Event Routing: Event Grid receives the event and matches it against subscriptions based on filters 3. Event Delivery: Events are pushed to configured handlers with retry logic and dead-lettering support
Event Schema: Events follow the CloudEvents 1.0 schema or the Event Grid schema, containing properties like id, source, type, time, and data.
Retry Policy and Dead-Lettering: - Default retry: 30 attempts over 24 hours with exponential backoff - Dead-letter events can be stored in Azure Blob Storage for later processing - Time-to-live (TTL) can be configured for event expiration
Common Use Cases
- Serverless application architectures with Azure Functions - Automating operations when resources are created or modified - Application integration across services - Reacting to Blob Storage changes (uploads, deletions) - Processing IoT device telemetry
Exam Tips: Answering Questions on Azure Event Grid
Focus Areas for AZ-204:
1. Know the difference between System Topics and Custom Topics: System topics are automatically created for Azure services, while Custom topics are created for your own applications
2. Understand filtering options: Subject filtering (begins with, ends with), Event type filtering, and Advanced filtering with operators (StringContains, NumberGreaterThan, etc.)
3. Remember supported event handlers: Azure Functions, Event Hubs, Service Bus Queues/Topics, Storage Queues, Webhooks, Hybrid Connections, and Logic Apps
4. Security considerations: Know that webhook endpoints require validation (handshake), SAS tokens or Azure AD can secure custom topics, and managed identities can be used for delivery authentication
5. Batching: Events can be delivered in batches up to 1 MB total size or 5,000 events per batch
6. When to choose Event Grid vs other services: - Event Grid: Reactive event-driven architectures, push model - Event Hubs: High-volume telemetry streaming, pull model - Service Bus: Enterprise messaging with queuing, transactions
7. Dead-letter configuration: Requires a Storage Account container to be specified in the subscription
8. Output bindings in Azure Functions: Know how to configure Event Grid output bindings to publish events from functions
Common Exam Scenarios: - When asked about reacting to Blob Storage uploads, Event Grid is typically the answer - Questions about event filtering often test knowledge of subscription filters - Security questions may focus on webhook validation or topic access keys