scala-java-logging

Utilise the Java Logger – with excellent formatting and filtering – in Scala projects.

The primary motivation is to clear up the output from log messages (and in particular, exceptions) so that problems can be very easily identified. This is achieved by:

1. custom formatter which allows configuration file definition of output logs (why this never shipped with Java, we'll never know).
2. stacktrace filter which (by default) hides internal Java / Scala / Akka traces.
3. custom log filter which uses the classname (not the logger name): excellent for use with Akka.
4. LoggedFuture which means that failing fire-and-forget Akka Futures are not ignored.
5. (hacky) support for Specs2, which by default tries to do its own exception handling (copy over the LoggedStackTraceFilter to your project to get this support).

Points 1 - 3 can be enabled by copying the logging.properties file to your project (customising as needed) and passing -Djava.util.logging.config.file=logging.properties to the java binary when running your application.

To get a handle to a Logger, simply mixin the JavaLogging trait (this is actually part of akka-contrib).

Akka developers are advised to use the following Config setup to ensure that the Akka Logger is using the Java Logger backend:

akka {
  event-handlers = ["akka.contrib.jul.JavaLoggingEventHandler"]
  actor.debug.unhandled = true
  loglevel = DEBUG
  stdout-loglevel = WARNING
}

Installation

We haven't built to sonatype yet, so clone this repository and issue an sbt publish-local. Then use the following in your build.sbt:

libraryDependencies += "fommil" % "scala-java-logging" % "1.0"

Java developers can copy the relevant java files to their codebases to get the benefit of the custom formatters and filters.