Recently, somebody asked for zstd compression <https://github.com/apache/logging-log4j2/issues/1508>. I indicated that adding zstd would be nice, but ideally we should make the compression extensible [by means of plugins]. As usual, even though I offered PR assistance, the user has individually submitted a PR only solving their problem: adding zstd to the rolling appender. I am not inclined to accept these kinds of "add button X to dialer Y" contributions, where I think Log4j suffers a lot from.
AFAIC, there should be plugins implementing a certain compressor interface, a registry of these, and the use-site (`RollingAppender`, `GelfLayout`, etc.) accessing these compression schemes via registry. This will not only enable users to add their custom compression scheme, but also other components to take advantage of this. As a particular example, more or less the only thing `JsonTemplateLayout` falls short compared to `GelfLayout` is compression support; though this could have perfectly been solved via a [wrapper] `CompressingLayout` I suggested in LOG4J2-3023. I would appreciate some feedback on my thinking process here. When it comes to Log4j, I am really allergic to specialized solutions ignoring the rest of the code base.
