Receive Service Bus messages in Service Fabric

This is one of the proof of concent that I did at work. The idea was to add another Service Bus application to an existing solution, instead of starting a whole new micro-service. It was a lot faster just to add another .net core console application, but setting up Service Fabric cluster always brings some unexpected experiences.

What are my requirements:

  • everything has to be written in .Net Core
  • reading Service Bus messages is placed in a new console application
  • logging has to be configured
  • dependency injection needs to be configured
  • reading Service Bus messages needs to be registered in stateless service

Let’s get to work!

The entry point in console application

Console application are a bit specific. In most cases, we write console applications that are small and doesn’t require dependency injection or logging, apart from that to the console. But here I want to build a professional console application, that is not run once, but is a decent part of a bigger thing that we would need to maintain in the future.

The specific thing about console applications is that they have Main method and this method is run instantly after the execution and everything that you’d like to do, has to be there. That means, that both configuration and execution of an app needs to be in this one method. Let’s see how the code looks like:

Logging

In order to have logging provided by the framework, we need to install nuget packages:

  • Microsoft.Extensions.Logging
  • Microsoft.Extensions.Logging.Abstractions
  • Microsoft.Extensions.Configuration.Json

The all configuration stuff is done in the beginning:

In this example logging is simple, but if you’d like to configure log4net, just add this code when configuring IoC (I’ll show that later):

Appsettings.json file:

Registering a stateless service

In order to register a service we need to run this line:

You might wonder what is CreateService method, it looks like this:

Here is a place where I configure IoC container. It has to be done here, cause only when registering a Service Fabric service, we have an instance of StatelessServiceContext, that we need later.

Configuring IoC container

In order to have container implementation provided by the framework, just install Microsoft.Extensions.DependencyInjection nuget package. ContainerConfig class, in this case, looks like this:

Adding a stateless service

In Program class I registered ServiceBusStatelessService class, that looks like this:

ServiceBusStatelessService inherits from StatelessService and provides an instance of Service Bus listener. It looks like this:

Notice, that all the work is done in OpenAsync method, that is run only once. In here I just register standard message handler, that reads from a Service Bus Subscription.

Configure Service Fabric cluster

All Service Fabric configuration is done in xml files. This can cause a huge headache when trying to debug and find errors, cause the only place you can find fairly useful information is console window.

It starts with adding a reference in SF project to a console application.

Next this is to have right name in console application ServiceManifest.xml

Notice that ServiceTypeName has the same value as provided when registering a service in Program class.

Next place to set-up things is ApplicationManifest.xml in SF project.

There are a few things you need to remember:

  • ServiceManifestName has the same value as ServiceManifest in ServiceManifest.xml in console app
  • ServiceTypeName type is the same as ServiceTypeName in ServiceManifest.xml in console app
  • MichalBialecki.com.SF.ServiceBusExample.MessageProcessor service has to be configured as StatelessService

Here is a proof that it really works:

That’s it, it should work. And remember that when it doesn’t, starting the whole thing again and build every small code change isn’t crazy idea 🙂

 

 All code posted here you can find on my GitHub: https://github.com/mikuam/service-fabric-service-bus-example

 

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