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).
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.