Can HttpClient on an Azure WebRole with only internal endpoints call out to an external URL?

Question

I have an Azure solution containing an MVC application, hosting some Web API controllers that constitute a RESTful API, and a back end WCF service. The MVC app is on a Web Role with a public http endpoint. The WCF application is on another Web Role, with no public endpoints. The MVC app communicates with the WCF service using a ChannelFactory over a discovered internal http endpoint.

I would like to keep this configuration, but I need a component within the WCF service implementation to be able to call a method on the RESTful API, using HttpClient.

My question is: with only an internal endpoint, does my back end web role have the connectivity to allow HttpClient to work like this?

At first glance I would not expect it to, but I note that it does have the capability to use the Azure Storage Client library to obtain resources from Azure Blob and Table storage, and I believe these calls are executed using http to an external URL (unless Azure does something clever to enable these calls under the hood).

Answer 1

Internal endpoints are for inbound traffic. Your WCF service, in turn, can absolutely make outbound calls. As you've already noticed, you're using the storage client library, and storage is a separate endpoint (RESTful, in fact), not a part of your deployed cloud service.