Evaluate what will need to be done to support incremental config

[lahabana]

Is there an existing issue for this?

• I have searched the existing issues

Does this enhancement require public documentation?

• I have added an Acceptance Criteria item for adding and/or adjusting public documentation (if applicable)

Problem Statement

There's a version of Gateway that has incremental config and an internal control plane which has an implementation of it.

Now is probably a good time to look at this new feature and get an idea of how it will work for KIC.

Proposed Solution

No response

Additional information

No response

Acceptance Criteria

• Familiarity with Incremental config
• Understand if some code may be shared between us and the internal go-control-plane which uses it
• High level design which explains how we could start using incremental config

[randmonkey]

The specification of the interface between CP and DP is defined here: https://github.com/Kong/openrpc_specfiles/tree/main/kong_sync/v2.
The basic architecture of the incremental sync:
(0) CP connect to DP by websocket
(1) CP notifies to DPs that the configuration updated and the latest version number
(2) DP sends request of diffs of configurations between the version of itself and the latest version
(3) CP sends diffs in incremental/full manner in result of (2).

The availability level of incremental sync is still alpha in the latest version (3.8) and under rapid development. They expect to make the feature GA in Kong 3.9.