How to debug an Ammonite script?

Question

Normally my scripts are simple and can be debugged by tracing with prints

But can I use a real debugger? Maybe launching the JVM with remote debugging enabled, but I don't know how to do it.

score 1 · Answer 1 · answered Sep 06 '17 at 07:15

1

Use the Script debug REPL a new feature available in Ammonite 1.0.0.

answered Sep 06 '17 at 07:15

david.perez

david.perez · Accepted Answer · 2017-09-05T11:58:00.770

0

Reconvert Ammonite script to a small SBT project, and import it in IDEA. Then it can be debugged.

But we lose the setup simplicity of an Ammonite script, and the ease of modifying the script.

In addition, magic imports like import $ivy or import $file must be rewritten.

edited Sep 05 '17 at 11:58

answered Apr 13 '17 at 10:00

david.perez

david.perez · Answer 3 · 2017-09-05T12:00:59.973

0

Use jstack to know the stack trace, when the script becomes locked somewhere.

This isn't real debugging, but it helps to troubleshot hung scripts.

edited Sep 05 '17 at 12:00

answered Aug 24 '17 at 07:23

david.perez

david.perez · Answer 4 · 2017-09-05T11:59:05.550

Another technique is to enable Java remote debugging:

JAVA_OPTS='-Xdebug -Xrunjdwp:server=y,transport=dt_socket,address=20614,suspend=y' myscript.sc

Then in IDEA, Eclipse or Netbeans, create a remote debugging configuration in the same port. 20614 in my example.

Tried with IDEA, and the debugger attaches to the JVM that runs the script, but no breakpoints are hit. :-(

The IDE doesn't know the link between .class files and its source.

4 Answers4