Event Grid Topic Azure: A Comprehensive Guide

An event grid topic in Azure is a crucial component that enables event-driven architecture. It's essentially a container that holds events, allowing them to be processed by various subscribers.

To create an event grid topic, you need to specify a name and a provider. The name is used to identify the topic, while the provider determines the type of events it will handle.

Event grid topics can be used to process events from various sources, including Azure services like Azure Storage and Azure Functions. This flexibility makes them a popular choice for building event-driven systems.

The events stored in an event grid topic can be accessed through a subscription, which is essentially a rule that determines how events are processed. This allows for a high degree of customization and control over event processing.

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To get started with Event Grid, you need to understand the basics. First, you'll need to select your Azure subscription. Then, you'll select an existing resource group or create a new one, and enter a name for the resource group.

You'll also need to provide a unique name for the custom topic or domain. This name must be between 3-50 characters and contain only values a-z, A-Z, 0-9, and "-". Don't use the name shown in the image, create your own!

Next, you'll select a location for the Event Grid topic or domain. This is crucial, as it will determine where your events are processed.

Here's a quick rundown of the steps to create a custom topic:

By following these steps, you'll be well on your way to creating a custom topic in Event Grid.

Configuring Event Grid is a crucial step in setting up your Azure event grid topic. Event Grid can be configured to store "dead letters" (messages that couldn't be delivered) in storage.

You can configure Event Grid to save undelivered messages in Azure Storage, allowing you to parse and replay missed messages once your handler is back up and running. This feature is particularly useful for handling temporary issues with your handler.

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Event Grid guarantees delivery within a 24-hour window, ensuring that your messages are delivered on time.

If a handler goes down for any reason, Event Grid will continue to retry until the delivery window expires, giving you peace of mind that your messages will get through.

To configure the delivery time frame, you can follow a specific process, which is demonstrated in a video that shows how to set it up.

You can also configure the retry count, allowing you to control how many attempts Event Grid makes to deliver your messages.

Event Grid will continue to retry until the delivery window expires, giving you a 24-hour window to ensure that your messages are delivered successfully.

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Event Grid offers flexibility in its message schema, allowing you to choose between a proprietary schema and an open standard called CloudEvents.

You can configure Event Grid to use the CloudEvents schema, which is an open standard for cloud messaging created by the Cloud Native Computing Foundation (CNCF).

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This choice is significant because it affects how your messages are formatted and parsed.

To use the CloudEvents schema, you'll need to follow the instructions in the video that shows how to configure Event Grid to use CloudEvents.

This will give you more flexibility and interoperability with other systems that use the CloudEvents standard.

By choosing the CloudEvents schema, you'll be future-proofing your Event Grid setup to work with a wide range of cloud messaging systems.

To publish an event to an Event Grid Topic, you'll need to send a POST request with the required endpoint and access key. This can be done using a tool like Postman, where you'll need to copy the Topic Endpoint value from the Overview tab and a Key from the Access Keys section.

To subscribe to an Event Grid Topic, you'll need to create an event subscription, which is a configuration resource associated with a single topic. This can be done using the Event Subscription feature.

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Here are the allowed formats of events for sending to an Event Grid Basic resource:

To publish an event to an Event Grid Topic, you'll need to use the EventGridPublisherClient. This client provides operations to send event data to a resource specified during client initialization.

You can use the send method to publish events, and it accepts various formats of events, including strongly typed EventGridEvents and CloudEvents.

To send events to an Event Grid Basic resource, you can use a list or a single instance of strongly typed EventGridEvents, or a dict representation of a serialized EventGridEvent object. Alternatively, you can use a list or a single instance of strongly typed CloudEvents, or a dict representation of a serialized CloudEvent object.

For Event Grid Basic resources, you can also send events in a dict representation of any Custom Schema.

If you're publishing events to an Event Grid Namespace resource, you'll need to specify a namespace topic, and you can only send events in a list of single instance of strongly typed CloudEvents or a dict representation of a serialized CloudEvent object.

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Here are the allowed formats of events for Event Grid Basic resources:

To publish an event to the Event Grid Topic, you'll need to send a POST request using an endpoint and an access key of the topic. First, copy the Topic Endpoint value from the Overview tab, and then copy a Key from Access Keys.

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An event subscription is a configuration resource associated with a single topic.

It's a crucial part of the Event Grid system, allowing you to receive notifications when specific events occur.

An event subscription is created when you trigger an Azure Function with an Event Grid trigger, as shown in Example 1, where a subscription is added to Azure Storage.

Event subscriptions can be used to kick off integrations and workflows via Azure Logic Apps, as demonstrated in Example 2.

In Example 3, we see that Event Grid can store "dead letters" (undelivered messages) in storage, and this is made possible by configuring event subscriptions.

Event subscriptions are a powerful tool in the world of Event Grid, enabling you to receive and process events in a variety of ways.

You can secure your Azure Event Grid topic with Azure Active Directory (AAD) for identity-based authentication of requests. Azure AD provides role-based access control (RBAC) to grant access to your Azure Event Grid resources.

To send events to a topic or domain, the authenticated identity should have the "Event Grid Data Sender" role assigned. To receive events from a topic event subscription, the authenticated identity should have the "Event Grid Data Receiver" role assigned. To send and receive events, the authenticated identity should have the "Event Grid Data Contributor" role assigned.

You can use the azure-identity package to seamlessly authorize requests in both development and production environments.

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Azure Active Directory (Azure AD) provides identity-based authentication for Azure Event Grid. You can use role-based access control (RBAC) to grant access to your Azure Event Grid resources.

To send events to a topic or domain, the authenticated identity needs to have the "Event Grid Data Sender" role assigned. This role is required for sending events.

To receive events from a topic event subscription, the authenticated identity should have the "Event Grid Data Receiver" role assigned. This allows the identity to receive events.

The "Event Grid Data Contributor" role is required for both sending and receiving events to/from a topic. This role grants the necessary permissions for both sending and receiving events.

You can use the azure-identity package to authorize requests in both development and production environments. This package makes it easy to authenticate using Azure Active Directory.

Creating a client with credentials is an essential step in using Event Grid. You can create a client with an AzureKeyCredential by passing the access key as a string into an instance of AzureKeyCredential.

The access key can be found in the Azure portal under the "Access Keys" menu of the Event Grid Topic resource. It can also be obtained via the Azure CLI or the Azure-mgmt-eventgrid library.

To publish events to a resource, you'll need to use the EventGridPublisherClient. This client provides operations to send event data to a specified resource.

The EventGridPublisherClient supports sending events in various formats, including strongly typed EventGridEvents, dict representations of serialized EventGridEvent objects, strongly typed CloudEvents, and dict representations of serialized CloudEvent objects. It also supports sending events to an Event Grid Namespace resource when a namespace topic is specified.

Here are the allowed formats for sending events to an Event Grid Basic resource:

For an Event Grid Namespace resource, only the following formats are allowed: