HEP: Consumer management support

[CH3CHO]

Why do you need it?

The "consumer" here represents a consumer - or a user - of a Service. User may have the need of configuring governance features/plugins for different consumers or service-consumer combinations. Currently, user needs to configure consumers separately in each plugin, which may take a lot of effort. A global consumer management feature will provide a better user experience and ensure configuration consistency.

How could it be?

We can take Kong as a reference here, since it has a complete support of consumer and plugin management. Consumer itself is just a simple resource entity. Implementing simple CRUD operations would be good enough. However, the key here is set plugin configurations at consumer or service-consumer combination level.

Example 1

Auth plugins, such as basic-auth, key-auth need different credential configurations for each consumer.
Example 2

A route requires different rate-limiting thresholds for each consumer.

The configuration model of Wasm plugin needs to be updated to satisify the requirement above.

Other related information

https://docs.konghq.com/gateway/latest/admin-api/#consumer-object
https://docs.konghq.com/gateway/latest/admin-api/consumer-groups/reference/