Logging syntax for Play Framework 2 in Scala

Question

This is a really silly question, but how can you do convenient formatting of log strings in Play Framework 2 (and in Scala?).

I've googled but its very difficult to find an example, essentially most links are talking about configuring Logback in the first place which I've done fine.

I'm basically trying to find the best stylistic way to do something like:

if(Logger.isDebugEnabled)
    Logger.debug("Modified: Id = '" + real_session_id + "', Modified = " + modified.toString)

Coming from a C# background (and log4net) I'd assume you could do something like:

if(Logger.isDebugEnabled)
    Logger.debug("Modified: Id = '{0}', Modified = {1}", real_session_id, modified.toString)

But I can't see how this would work with the trait the way it is defined. I've also seen vague references to how you might be able to avoid checking Logger.isDebugEnabled by using a lazy evaluative syntax like:

Logger.debug("Modified: Id = ${real_session_id}, Modified = ${modified.toString}")

That uses Scala macros - but again, that doesn't work and I can find very little information about it.

Am I missing something really blatant here?

Answer 1

1. The framework used for logging is logback. When you type : Logger.debug, the isDebugEnabled is already implicitly checked.

2. For the syntax of logging, use the Scala string interpolation.

   Logger.debug(s"Modified: Id = '$real_session_id', Modified = $modified.toString")