Azure Event Grid is now GA and along with it comes a nice collection of SDKs. This blog post will demonstrate the .NET SDK for publishing events.
The code for this post can be found in the following GitHub repository: https://github.com/dbarkol/azure-event-grid-samples.
Getting Started
We’ll need to provision a few things in Azure before using the SDK. For this, I’ll use the Azure CLI rather than go through the portal.
(1) Create a resource group:
az group create --name sdkdemo --location westus2
(2) Create a custom topic:
az eventgrid topic create --name <topic-name> --resource-group sdkdemo --location westus2
(3) Retrieve the list of keys associated with the custom topic:
az eventgrid topic key list --name <topic-name> --resource-group sdkdemo
Make a copy of one of the keys as well as the custom topic endpoint – we’ll need them for the event subscription.
(4) Create a RequestBin or Hookbin URL. Keep in mind that these are great sites for demos and basic testing. Do not expect these sites to display and capture each event, especially if you are sending a large collection of events within a short period of time.
Note: RequestBin no longer offers a hosted solution. You can try Hookbin or host your own with this alternative:
- Azure Event Grid Viewer (write up)
- Deploy to Azure (repo and ARM template)
(5) Create an event subscription using one of the URLs from the previous step:
az eventgrid event-subscription create --topic-name <topic-name> --name testsub --endpoint <subscription-url> --resource-group sdkdemo
Using the SDK from Visual Studio
For this example, we’ll use a simple console application that targets the .NET Framework. Using the Package Manager Console, we can add a reference to the NuGet package with the following command:
Install-Package Microsoft.Azure.EventGrid -Version 1.1.0-preview
Note that at the time of this post, the latest version of the package is set to 1.1.0-preview. To keep track of version history, see: https://www.nuget.org/packages/Microsoft.Azure.EventGrid.
Publishing an Event
Now, let’s get to the code! We’ll start with a basic class that has a few properties. This will be the payload we want to pass along with the event in the data property. For more details about the schema, please review: https://docs.microsoft.com/en-us/azure/event-grid/event-schema.
namespace PublishEvents.Data
{
public class Musician
{
public string Name { get; set; }
public string Instruments { get; set; }
}
}
And now, the code that publishes the event:
using System; using System.Collections.Generic; using System.Threading.Tasks; using Microsoft.Rest; using Microsoft.Azure.EventGrid; using Microsoft.Azure.EventGrid.Models; using PublishEvents.Data; namespace PublishEvents { internal class Program { // The custom topic host name // Example: {topicname}.westus2-1.eventgrid.azure.net private const string TopicHostName = "{topic-host-name}"; // Custom topic access key private const string TopicKey = "{custom-topic-access-key}"; private static async Task Main(string[] args) { await PublishEvents(); } private static async Task PublishEvents() { // Create service credential with the topic credential // class and custom topic access key ServiceClientCredentials credentials = new TopicCredentials(TopicKey); // Create an instance of the event grid client class var client = new EventGridClient(credentials); // Retrieve a collection of events var events = GetEvents(); // Publish the events await client.PublishEventsAsync( TopicHostName, events); } private static IList GetEvents() { // Return a list of events var events = new List { new EventGridEvent() { Id = Guid.NewGuid().ToString(), Data = new Musician() { Name = "Eddie Van Halen", Instruments = "Guitar, Keyboards" }, EventTime = DateTime.Now, EventType = "EventGrid.Sample.MusicianAdded", Subject = "Musicians", DataVersion = "1.0" }, new EventGridEvent() { Id = Guid.NewGuid().ToString(), Data = new Musician() { Name = "Slash", Instruments = "Guitar" }, EventTime = DateTime.Now, EventType = "EventGrid.Sample.MusicianAdded", Subject = "Musicians", DataVersion = "1.0" } }; return events; } } }Reviewing the Events
Note: If you are looking for an alternative to Request Bin, use this ASP.NET Core site to view incoming messages: https://madeofstrings.com/2018/03/14/azure-event-grid-viewer-with-asp-net-core-and-signalr/
An event sent to a Request Bin subscription looks like:
A Hookbin subscription:
Resources
- Event Grid Overview: https://docs.microsoft.com/en-us/azure/event-grid/overview
- NuGet Package: https://www.nuget.org/packages/Microsoft.Azure.EventGrid/
- Azure SDK for .NET: https://github.com/Azure/azure-sdk-for-net
- Sample: https://github.com/dbarkol/azure-event-grid-samples
Made of Strings 