Elastic Beanstalk Worker Simple Routing

Package	Release	Pre-release
BeanstalkWorker.SimpleRouting

CI	Status	Platform(s)	Framework(s)	Test Framework(s)
AppVeyor		Windows	nestandard2.0	netcoreapp3.1

Allows to route a SQS message to a specific endpoint on the Worker instead of having a single endpoint handling all the messages.

Relies on the SQS message attributes. This is distributed via a NuGet package but the implementation is so simple that you can just copy the classes into your own solution if that works better for you.

How it works

Web Tier - Set the attribute on the message

// Instantiate your model
StronglyTypedMessage model = new StronglyTypedMessage();

var sendMessageRequest = new SendMessageRequest
{
  // Serialize your model as JSON (you can use Newtonsoft.Json if you prefer)
  MessageBody = System.Text.Json.JsonSerializer.Serialize(model)
  // Set the QueueUrl and other properties as you see fit
};

// AddRoutingAttribute is an extension method in the "BeanstalkWorker.SimpleRouting" namespace
sendMessageRequest.MessageAttributes.AddRoutingAttribute("task-name");

Web sample project

A sample Web app is provided in samples/SampleWeb.

You can send two distinct types of messages by hitting two different endpoints:

• GET http://localhost:5000/send/work
• GET http://localhost:5000/send/nothing

Configuration

Create a iAM user (if you don't have one already) which has access to SQS.

You'll need to configure four settings using user secrets:

• Aws:RegionSystemName - region code, for example ap-southeast-2
• Aws:Queue:WorkerQueueUrl - URL of the SQS queue, for example https://sqs.ap-southeast-2.amazonaws.com/375985941080/dev-gabriel
• Aws:Queue:AccessKeyId - this is the Access key ID of your iAM user
• Aws:Queue:SecretAccessKey - this is the Secret access key of your iAM user

Worker Tier

Add the middleware to the Worker

In the Configure method of your Startup class:

public void Configure(IApplicationBuilder app)
{
    // The simple routing middleware needs to be added **before** configuring endpoint routing
    app.UseHeaderRouting();

    app.UseRouting();

    app.UseEndpoints(endpoint => endpoint.MapControllers());
}

Use a matching route on a Controller Action

// This is important, we do not want a prefix in front of the action's route
[Route("")]
[ApiController]
public class SomeController : ControllerBase
{
  // The route template has to match the argument given to AddRoutingAttribute
  [HttpPost("task-name")]
  public async Task<IActionResult> SomeMethod(StronglyTypedMessage model)
  {
      // Abbreviated for clarity
  }
}

Worker sample project

A sample Worker app is provided in samples/SampleWorker.

If you wish to run the Worker without deploying to AWS Beanstalk you can leverage my Beanstalk Seeder project.

Limitations

• Does not support periodic tasks
  • It could be added fairly easily if required
• netstandard2.0 and above only
  • .NET is a second class citizen on Elastic Beanstalk, for this reason I recommend creating Docker images so that you can take full advantage of the platform.