Azure Event Grid Tutorial

Azure Event Grid is a fully managed event routing service that allows you to send and receive events from any source to any destination. It is designed to handle millions of events per second and can be used to build event-driven architectures.

Prerequisites

  • An Azure subscription.
  • Azure CLI installed on your computer.

Create an Azure Event Grid Topic

To get started, we need to create an Event Grid topic. A topic is the endpoint where events are sent to and processed by Event Grid. To create a topic, follow the steps below:

  1. Open the Azure CLI and log in to your Azure account using the following command: az login
  2. Once you are logged in, create a resource group using the following command:
az group create --name myResourceGroup --location eastus

Replace “myResourceGroup” with the name of your resource group and “eastus” with your desired location.

  1. Next, create the Event Grid topic using the following command:
az eventgrid topic create --resource-group myResourceGroup --name myTopicName

Replace “myResourceGroup” with the name of your resource group and “myTopicName” with the name of your topic.

Subscribe to an Azure Event Grid Topic

Now that we have created a topic, we need to subscribe to it. A subscription is the endpoint where events are sent to once they have been processed by Event Grid. To subscribe to a topic, follow the steps below:

  1. Create a webhook endpoint to receive the events using the following command:
az webapp create -g myResourceGroup -p myPlanName -n myAppName --runtime "node|10.14" --deployment-local-git

Replace “myResourceGroup” with the name of your resource group, “myPlanName” with the name of your App Service plan, and “myAppName” with the name of your App Service.

  1. Retrieve the URL of the webhook endpoint using the following command:
az webapp deployment source show -g myResourceGroup -n myAppName --query '[url]' -o tsv
  1. Subscribe to the topic using the following command:
az eventgrid event-subscription create --resource-group myResourceGroup --name mySubscriptionName --topic-name myTopicName --endpoint <Webhook URL>

Replace “myResourceGroup” with the name of your resource group, “mySubscriptionName” with the name of your subscription, “myTopicName” with the name of your topic, and “<Webhook URL>” with the URL of your webhook endpoint.

Publish an Event to an Azure Event Grid Topic

Now that we have created a topic and subscribed to it, we can publish an event to the topic. To publish an event, follow the steps below:

  1. Create a JSON file containing the event data using the following format:
[
  {
    "id": "1",
    "eventType": "myEventType",
    "subject": "mySubject",
    "data": {
      "message": "Hello, world!"
    },
    "dataVersion": "1.0"
  }
]

Replace “1” with a unique ID for the event, “myEventType” with the type of the event, “mySubject” with the subject of the event, and “Hello, world!” with the message you want to send.

  1. Publish the event to the topic using the following command:
az eventgrid event send --resource-id /subscriptions/<subscriptionId>/resourceGroups/myResourceGroup/providers/Microsoft.EventGrid/topics<myTopicName> --data @<path/to/json/file>

Replace “<subscriptionId>” with your Azure subscription ID, “myResourceGroup” with the name of your resource group, “myTopicName” with the name of your topic, and “<path/to/json/file>” with the path to the JSON file you created in step 1.

View Azure Event Grid Events

Now that we have published an event to the topic, we can view the event in the webhook endpoint. To view the event, follow the steps below:

1. Log in to the Azure portal and navigate to your webhook endpoint.

2. Select “Logs” from the left-hand menu.

3. Select “All logs” from the dropdown menu.

4. Look for a log entry with the message “Hello, world!” to confirm that the event was received.

Congratulations, you have now created an Azure Event Grid topic, subscribed to it, published an event to it, and viewed the event in the webhook endpoint using CLI commands! Azure Event Grid is a powerful service that can be used to build event-driven architectures and automate workflows.

Delete an Azure Event Grid Topic and Subscription

Now that we have completed our testing, we can delete the Event Grid topic and subscription to avoid incurring unnecessary charges. To delete the topic and subscription, follow the steps below:

  1. Delete the subscription using the following command:
az eventgrid event-subscription delete --resource-group myResourceGroup --name mySubscriptionName --topic-name myTopicName

Replace “myResourceGroup” with the name of your resource group, “mySubscriptionName” with the name of your subscription, and “myTopicName” with the name of your topic.

  1. Delete the topic using the following command:
az eventgrid topic delete --resource-group myResourceGroup --name myTopicName

Replace “myResourceGroup” with the name of your resource group and “myTopicName” with the name of your topic.

And that’s it! You have successfully created an Azure Event Grid topic, subscribed to it, published an event, and viewed the event using CLI commands. Remember to delete your resources once you are done testing to avoid unnecessary charges.

Limitations and Considerations

When using Azure Event Grid, there are a few limitations and considerations that you should keep in mind:

  1. Azure Event Grid topics and subscriptions are billed based on usage. Be sure to monitor your usage and delete any unused resources to avoid unnecessary charges.
  2. Azure Event Grid events have a size limit of 1 MB. If you need to send larger events, consider breaking them up into smaller events.
  3. Azure Event Grid events have a time-to-live (TTL) of 24 hours. If an event is not delivered within the TTL period, it will be discarded.
  4. Azure Event Grid has limits on the number of events that can be processed per second, per topic, and per subscription. Be sure to monitor your usage and adjust your resources as needed.
  5. When using Azure Event Grid with Azure Functions, be aware that events may be processed out of order if multiple instances of the function are running.
  6. When using Azure Event Grid with Azure Logic Apps, be aware that events may be delayed by up to 5 minutes.

Conclusion

Azure Event Grid is a powerful service that can be used to build event-driven architectures and automate workflows. In this tutorial, we covered the basics of Azure Event Grid and demonstrated how to create a topic, subscribe to it, publish an event, and view the event using CLI commands. We also discussed some limitations and considerations to keep in mind when using Azure Event Grid. With Azure Event Grid, you can build scalable and reliable event-driven applications in the cloud.