AppFog MongoDb Service Terminology

Question

In terms of MongoDb terminology what are

1. Bound Service
2. Service

in AppFog MongoDb service?

Is Bound Service the db name? Or is it the collection name?

Answer 1

A service means a running instance of a software (e.g. MongoDB). Its there and is running, but not related to any client process. You have no idea what endpoint or credentials it needs as your PAAS provider manages it.

Bound service means exposing service's endpoint to your app, with appropriate credentials. For example:

if(process.env.VCAP_SERVICES){
  var env = JSON.parse(process.env.VCAP_SERVICES);
  var mongo = env['mongodb-1.8'][0]['credentials'];
}

Here the App process's environment variable VCAP_SERVICES holds connection data of those services which have been bound to this App's process. Connection data is auto configured for you by PAAS provider, here mongo object has it already, you need not remember URL, Post, username, password etc for that service.

So, a service bound to your App has its connection data readily available to you, through the environment variable.

Refer to Appfog's docs on services here.