Scala: print stack trace in Scalatra application

Question

It seems like a pretty straight forward problem, but I would like to write a stack trace when the top-level error handler in Scalatra starts. I intentionally throw an exception in one of my methods, doing something as trivial as:

throw new IllegalArgumentException 

In the error handler, the code is as follows:

  error { case e => { val logger = LoggerFactory.getLogger(getClass) logger.info("an exception occurred: " + e.getStackTrace()) logger.info("the request body is: " + request) NotFound("An error occurred, please contact support") } } 

The error handler itself is specific to Scalatra, but I'm sure that the answer I'm looking for can be solved using any Scala vanilla technique. Is there something I can do at this point to grab the stack? I'm not sure if the request is in the same thread as the error handler, otherwise there might be some kind of answer. e.getStackTrace() gives me [Ljava.lang.StackTraceElement;@1f6b6954

What is the best way to get the stack trace printed here so I can log and view it to fix errors in my horrible code?

Answer 1

I think you want printStackTrace (), not getStackTrace. If you are outputting a log file, getMessage () may be useful. Or you can try passing the entire exception object to the logger.

Answer 2

Use ExceptionUtils from Apache Commons Lang:

 import org.apache.commons.lang3.exception.ExceptionUtils (...) logger.info("an exception occurred: " + ExceptionUtils.getStackTrace(e)) 

Answer 3

This question has several ways to convert an exception stack trace to a string. printStackTrace outputs to System.err if you do not provide an author.

Answer 4

If you use the standard logger: com.typesafe.scalalogging.Logger, the logger prints a stack trace for you.

You can simply use it as follows:

 import com.typesafe.scalalogging.Logger import org.slf4j.LoggerFactory try { throw new Exception("test message") } catch { case e:Exception => logger.error("Exception " , e) } 

There is already an overload that takes 2 parameters, String and Throwable.