[LOG4J2-3343] Add ability to use exclusion pattern filter on Map Resolver keys

• Type: New Feature
• Status: Resolved
• Priority: Major
• Resolution: Won't Fix
• Component/s: JsonTemplateLayout
• Assignee: Matt Sicker
• Reporter: Matt Sicker
• Created: 15/Jan/22 22:53
• Updated: 22/Jan/22 02:17
• Resolved: 22/Jan/22 02:17

Description

Map Resolver currently supports specifying a pattern to filter for allowed keys in the map being resolved. I'd like a complementary feature to specify a pattern to filter for excluded keys from the map being resolved. It may also be beneficial to provide a similar option for excluded keys as full string matches rather than always using a pattern.

For an example use case, suppose I copy request HTTP header names and values into the ThreadContext for every request. In Spinnaker microservices, this includes custom headers like X-Spinnaker-Groups which contains a list of groups the authenticated user belongs to which are filled in by the Fiat microservice (used for integrating authentication and authorization with various providers and providing a facade over Spring Security). If I want to exclude this header from being logged, I can currently set a negative lookahead pattern like (?i(?!x-spinnaker-groups)) which works effectively the same, but how many developers like reading regex incantations like these?