cl-log is a highly configurable logging library.

It supports logging to several destinations at once, via "messengers", each of which can be tailored on-the-fly to accept some log messages and reject others; very rapid processing of messages which are rejected by all messengers; support for messengers which do or do not care to invoke cl:format. Use cl-log to record random objects instead of plain text, to generate internationalized log messages, or to create specialized binary logs.