cloud foundry intra-application communication

Question

I have 3 applications running in a private vcap instance. One acts as a customer facing web-app, while the others are backend systems, one exposing data services over REST which the web-app consumes, and another application which asynchronously writes to database through rabbitmq.

Now, my questions are:

1) Instead of the customer facing webapp call a public URL, how can I communicate directly to the rest urls?

2) How do I bind the webapp and the database writer application to the same rabbit instance. I will opt out of auto reconfiguration, but how do i get the rabbit connection parameters?

Answer 1

I'm going to answer these the other way round! You can bind the application by inspecting the VCAP_SERVICES environment variable, this will have the details of the bound Rabbit instance.

When you deploy an instance of an application, it's started up on a VM (called a DEA). The application instance is assigned a port on the VM. Internally, all DEAs can "see" each other so there is no reason why an application shouldn't be able to talk on a private IP address to another application running on a different DEA.

Obviously you don't know what private IP address or even port an application will live on until is has been pushed, so I would suggest you have each application "register" it's address via Rabbit after it's been pushed so the other applications can find it.