Windows Azure project without Web Roles?

Question

just starting to explore Azure and I am still a bit confused regarding the purposes of web roles vs worker roles. In the solution I'm working on mobile apps (iPhone, Android, Windows etc) will be accessing our server product via a REST api. So there is really no public facing web site for our service (as in web pages).

This made me think that I don't need a web role but instead have one or worker roles listening on our http endpoints. I have created a prototype along these lines. When from a mobile device I do I an http post to the endpoint, I get no response back. And I see nothing in the Azure logs that indicate that indeed my worker role was started or is running and responding to it.

Is this an appropriate approach? Is there something I need to do in setup code because I don't have a web role? I read in another thread that web roles run in IIS but worker roles don't.

Thanks for bearing with me. I am still getting to grips with Azure and so have a little difficulty formulating the right question.

Answer 1

You don't need to have a web role in your azure deployment. As you read, a web role has IIS, and your web site is hosted in it. A worker role is basically a plain old W2K8 server without IIS. Honestly, I haven't RDP'd to a worker role instance, so I'm not 100% sure that you don't have IIS or not.

But you don't need a web role in order to expose a WCF service. Here's a nice example (although the background color needs some work) that shows you how to do this.

Good luck! I hope this helps.

Answer 2

Adding to what David Hoerster said: You can host up to 25 externally-facing endpoints (each with its own port number) on any role type, with each endpoint being http, https, or tcp. With a Web Role and IIS, a web application typically grabs an endpoint mapped to port 80. In your case, you'll be creating your own endpoints on your specific ports. You're responsible for creating your ServiceHost (or whatever you're using to host your service) and binding it to one of your endpoints. To do this, you'll need to either map each endpoint explicitly to a specific internally-facing port, or inspect the endpoint's properties to discover which port has been dynamically assigned to it, for you to bind to (might this be the issue you're running into with your prototype code?).

If you're looking for the benefits IIS offers when hosting your endpoint, you're better off with a Web Role, as it's going to be much easier for you to do this since a Web Role enables IIS by default (and it's easy to add WCF services to a Web Role from Visual Studio).

Even if you were to self-host your endpoints, you could still use a Web Role, but now you'd be carrying the extra memory baggage of a running, yet unused, IIS service.