Event Hubs

Getting Started

First begin by creating an empty Azure Functions v2 project and then install the core nuget packages for Function Monkey:

Install-Package FunctionMonkey
Install-Package FunctionMonkey.Compiler

You will also need to add the Service Bus trigger bindings:

Install-Package Microsoft.Azure.WebJobs.Extensions.EventHubs

Now create a folder in the solution called commands and create a class called Analytic:

public class Analytic : ICommand
{
    public string Fqn { get; set; }

    public int Value { get; set; }
}

Next create a folder in the solution called Handlers and create a class called AnalyticHandler:

internal class AnalyticHandler : ICommandHandler<Analytic>
{
    public Task ExecuteAsync(Analytic analytic)
    {
        // We won't really send an email from this sample
        return Task.CompletedTask;
    }
}

And now we'll create our function app configuration in the root of the project that registers the command handler and registers the command with a service bus queue:

public class FunctionAppConfiguration : IFunctionAppConfiguration
{
    private const string EventHubName = "analyticHub";

    public void Build(IFunctionHostBuilder builder)
    {
        builder
            .Setup((serviceCollection, commandRegistry) =>
                commandRegistry.Register<Analytic>()
            )
            .Functions(functions => functions
                .EventHub(eventHub => eventHub
                    .EventHubFunction<Analytic>(EventHubName)
                )
            );
    }
}

Finally we need to create an entry in local.settings.json for the Service Bus connection string:

{
  "IsEncrypted": false,
  "Values": {
    "AzureWebJobsStorage": "UseDevelopmentStorage=true",
    "AzureWebJobsDashboard": "UseDevelopmentStorage=true",
    "eventHubConnectionString": "<connection string>" 
  }
}

And that's it! If you run this project having created a queue called sendEmailQueue and use a real connection string you'll find that the AnalyticHandler_ is invoked for each item you place on the event hub.

Note that it is possible to omit the connection setting name - see default connection settings for more details.

Validation

If you want to validate the queue messages as you recieve them then validation is supported and is documented here.