Configure usage plans for an API on the `APIProduct`

[marcogschmidt]

Problem

Some users allow developers to only create APIDoc, APIProduct (and possibly Route) resources, while the platform/ops team controls Environments and Portals. In this scenario, developers do not have the ability to define the usage plans for the APIs they manage, as the usage plans are currently defined on the Environment. These users have requested a change to allow choosing the usage plan for an API directly on APIProducts.

Proposed solution

To allow this use case we could let admins define a set of usage plans on Environments; developers can then choose which plan to apply to their APIs by referencing them on their APIProducts. With this solution:

• admins would retain some control over the auth and rate limit policies of an API environment, and
• developers would have the freedom to decide which usage plans should apply to their APIs.

[marcogschmidt]

This feature has been released with Gloo Portal 1.0.0.