[KAFKA-3962] ConfigDef support for resource-specific configuration

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: config
• Assignee: Unassigned
• Reporter: Shikhar Bhushan
• Created: 13/Jul/16 22:52
• Updated: 03/Aug/18 18:08

Description

It often comes up with connectors that you want some piece of configuration that should be overridable at the topic-level, table-level, etc.

The ConfigDef API should allow for defining these resource-overridable config properties and we should have getter variants that accept a resource argument, and return the more specific config value (falling back to the default).

There are a couple of possible ways to allow for this:

1. Support for map-style config properties "resource1:v1,resource2:v2". There are escaping considerations to think through here. Also, how should the user override fallback/default values – perhaps * as a special resource?

2. Templatized configs – so you would define $resource.some.property. The default value is more naturally overridable here, by the user setting some.property without the $resource prefix.