I do this in Scala, via https://www.scala-lang.org/api/2.12.13/scala/util/DynamicVariable.html https://www.scala-lang.org/api/2.12.13/scala/util/DynamicVar...

I do this in Scala, via https://www.scala-lang.org/api/2.12.13/scala/util/DynamicVariable.html https://www.scala-lang.org/api/2.12.13/scala/util/DynamicVar... It's not perfect, since it uses JVM's thread-local storage under the hood; this can break when e.g. evaluating Futures in a ThreadPool. For variables which are rarely-overridden, like loggers, I do so with a wrapper that also switches the ExecutionContext to a new ThreadPool (urgh, multithreading...) PS: I do the same for env vars too ;) http://www.chriswarbo.net/blog/2021-04-08-env_vars.html http://www.chriswarbo.net/blog/2021-04-08-env_vars.html