Implement solutions that use Azure Event Grid

Azure Event Grid is a powerful service on Microsoft Azure that enables developers to build event-driven solutions. It provides a simple and scalable way to react to events and take actions in real-time. In this article, we will explore how to implement solutions that utilize Azure Event Grid, focusing specifically on the exam topic “Developing Solutions for Microsoft Azure”.

1. Getting started with Azure Event Grid

Azure Event Grid allows you to create publishers that emit events and subscribers that react to those events. Before diving into the implementation details, it is important to understand the basic concepts of Event Grid. The Microsoft documentation provides a comprehensive guide on how to get started with Azure Event Grid. Familiarize yourself with the concepts of topics, publishers, subscribers, and event handlers.

2. Create an Azure Event Grid topic

To implement a solution using Azure Event Grid, you first need to create an Event Grid topic. An Event Grid topic is a logical container for routing events from publishers to subscribers. You can create a topic using the Azure portal, Azure CLI, or Azure PowerShell. Once the topic is created, you will be provided with an endpoint URL. This URL is required to publish events to the topic.

3. Publish events to Azure Event Grid

Once you have created a topic, you can start publishing events to it. Publishers can be any Azure service or custom applications that emit events. The events can be of any type, such as custom events or events specific to Azure services like storage, compute, or even IoT devices.

To publish an event, you need to make an HTTP POST request to the Event Grid topic endpoint URL. The request should include a JSON payload with the event details. The payload typically contains information such as the event type, event source, and event data. You can use any programming language or tool to publish events to Event Grid.

Here’s an example of publishing an event to an Azure Event Grid topic using C#:

using System;
using System.Net.Http;
using System.Threading.Tasks;

var response = await httpClient.SendAsync(request);
response.EnsureSuccessStatusCode();
}
}

Replace the topicEndpointUrl and topicKey with the actual values specific to your Event Grid topic. This code creates a simple custom event and publishes it to the topic.

4. Create an Azure Event Grid subscriber

To react to events published to an Event Grid topic, you need to create a subscriber. A subscriber can be an Azure function, logic app, or any other webhook endpoint that can receive HTTP requests. When an event is published to the topic, Azure Event Grid routes the event to all the subscribers configured for that topic.

To create a subscriber, implement a webhook or an HTTP-triggered function that can handle the events. The subscriber should expose an HTTP endpoint that Event Grid can call to deliver the events. The endpoint should be able to receive the event payload and take appropriate actions based on the event data.

Here’s an example of an Azure function that acts as a subscriber:

#r "Newtonsoft.Json"

// Event not handled
log.LogWarning("Event not recognized");
return new BadRequestResult();
}


This code defines an Azure function that receives the events and logs the event data. It checks if the event type and message match the expected values and takes the appropriate action. Customize the event processing logic based on your requirements.

5. Configure event handlers and subscription

Once you have created a subscriber, you need to configure the event handlers and subscription for your Event Grid topic. An event handler specifies the endpoint URL of the subscriber, and a subscription defines the events to be routed to the handler. You can configure event handlers and subscriptions using the Azure portal, Azure CLI, or Azure PowerShell.

Make sure to specify the event types and filters correctly when configuring the subscription. This ensures that only relevant events are delivered to the subscriber.

6. Test and monitor the solution

After implementing the solution, it’s important to test and monitor the behavior of your Event Grid setup. Publish events to the topic and verify if the subscribers receive the events as expected. Monitor the event delivery, subscriptions, and any error logs to ensure the solution is working correctly.

Azure Event Grid provides diagnostic logs and metrics that you can use to monitor and troubleshoot your solution. Explore the documentation to understand how to enable and utilize these monitoring capabilities effectively.

Conclusion

Azure Event Grid is a powerful service that allows you to build event-driven architectures in Microsoft Azure. By creating publishers, publishing events, and configuring subscribers, you can implement solutions that react to events in real-time. Understanding the concepts, creating topics, publishing events, creating subscribers, and configuring subscriptions are key aspects to successfully implement solutions using Azure Event Grid.