rpdb is a wrapper around pdb that re-routes stdin and stdout to a socket handler. By default it opens the debugger on port 4444:
import rpdb; rpdb.set_trace()
But you can change that by simply instantiating Rpdb manually:
import rpdb debugger = rpdb.Rpdb(port=12345) debugger.set_trace()
It is known to work on Jython 2.5 to 2.7, Python 2.5 to 3.1. It was written originally for Jython since this is pretty much the only way to debug it when running it on Tomcat.
Upon reaching set_trace(), your script will "hang" and the only way to get it to continue is to access rpdb using telnet, netcat, etc..:
nc 127.0.0.1 4444
pip install rpdb
For a quick, ad hoc alternative, you can copy the entire rpdb subdirectory (the directory directly containing the __init__.py file) to somewhere on your $PYTHONPATH.
Just copy the rpdb directory (the one with the __init__.py file) in your WEB-INF/lib/Lib folder along with the standard Jython library (required).
set_trace() can be triggered at any time by using the TRAP signal handler. This allows you to debug a running process independantly of a specific failure or breakpoint:
import rpdb rpdb.handle_trap() # As with set_trace, you can optionally specify addr and port rpdb.handle_trap("0.0.0.0", 54321)
Calling handle_trap will overwrite the existing handler for SIGTRAP if one has already been defined in your application.
- The socket is not always closed properly so you will need to ^C in netcat and Esc+q in telnet to exit after a continue or quit.
- There is a bug in Jython 2.5/pdb that causes rpdb to stop on ghost breakpoints after you continue ('c'), this is fixed in 2.7b1.
With contributions from (chronological, latest first):
- Cameron Davidson-Pilon - @CamDavidsonPilon
- Pavel Fux - @fuxpavel
- Ken Manheimer - @kenmanheimer
- Steven Willis - @onlynone
- Jorge Niedbalski R <email@example.com>
- Cyprien Le Pannérer <firstname.lastname@example.org>
- k4ml <email@example.com>
- Sean M. Collins <firstname.lastname@example.org>
- Sean Myers <email@example.com>
This is inspired by: