Neutron/FlavorFramework

Rationale

The purpose of Flavor Framework is to provide more abstract API that allows user to chose service by it's capabilities rather then by provider/vendor.
User-facing part of Flavor is a group of service parameters. The proposed Flavor notion is similar to what nova has with the difference that Flavor parameters are dynamic (e.g. not fixed or hardcoded)

From implementation point of view, the flavor is an object that is used to dispatch REST API calls after they pass persistence layer.
That role is not completely moving away from providers, e.g. each service instance is still bound to a certain provider.
Binding process is known as scheduling that maps flavor chosen for particular resource to a provider.

Object model

Flavor Framework defines the following objects:

Flavor

Attributes:

* Service Type - string identifier (LOADBALANCER, FWAAS, L3, VPN, etc)
* Name - name of the flavor
* Parameters - list of (key, value) pairs that define capabilities. Value can be range or integer, or string, or json.
* FlavorType - public or internal

The last attribute - FlavorType defines whether the flavor is publicly available or is internal.
Internal flavors are provided by vendor drivers configured for corresponding services.
Internal flavors are similar to 'provider' notion, plus may have additional parameters that describe service capabilities.
Each driver, including the default one of each service should provide at least their default capabilities object.