Try with exception logging

Question

Scala's Try is very useful.

I'd like to use that pattern, but log all exceptions.

How can I do this?

Answer 1

Define the following helper:

import scala.util.{Try, Failure}  def LogTry[A](computation: => A): Try[A] = {   Try(computation) recoverWith {     case e: Throwable =>       log(e)       Failure(e)   } } 

Then you can use it as you would use Try, but any exception will be logged through log(e).

Answer 2

Starting Scala 2.13, the chaining operation tap can be used to apply a side effect (in this case some logging) on any value while returning the original value:

import util.chaining._  val x = Try("aa".toInt).tap(_.failed.foreach(println)) // java.lang.NumberFormatException: For input string: "aa" // x: Try[Int] = Failure(java.lang.NumberFormatException: For input string: "aa") 

Or an equivalent pattern matching version:

val x = Try("aa".toInt).tap { case Failure(e) => println(e) case _ => } // java.lang.NumberFormatException: For input string: "aa" // x: Try[Int] = Failure(java.lang.NumberFormatException: For input string: "aa") 

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The tap chaining operation applies a side effect (in this case println or some logging) on a value (in this case a Try) while returning the original unmodified value on which tap is applied (the Try):

def tap[U](f: (A) => U): A