How do I attach a remote debugger to a Python process?

A little bit late, but here is a very lightweight remote debugging solution courtesy of
Michael DeHaan • Tips on Using Debuggers With Ansible:

1. pip install epdb on the remote host.
2. Make sure your firewalling setup is not allowing non-local connections to port 8080 on the remote host, since epdb defaults to listening on any address (INADDR_ANY), not 127.0.0.1.
3. Instead of using import pdb; pdb.set_trace() in your program, use import epdb; epdb.serve().
4. Securely log in to the remote host, since epdb.connect() uses telnet.
5. Attach to the program using python -c 'import epdb; epdb.connect()'.

Adjust the security bits to suit your local network setup and security stance, of course.

Well, you can get something quite similar to that using a twisted manhole, which works like this:

from twisted.internet import reactor
from twisted.cred import portal, checkers 
from twisted.conch import manhole, manhole_ssh 

def getManholeFactory(namespace):
    realm = manhole_ssh.TerminalRealm()
    def getManhole(_): 
        return manhole.Manhole(namespace) 
    realm.chainedProtocolFactory.protocolFactory = getManhole
    p = portal.Portal(realm)
    p.registerChecker(
        checkers.InMemoryUsernamePassword DatabaseDontUse(admin='foobar'))
    f = manhole_ssh.ConchFactory(p)
    return f

reactor.listenTCP(2222, getManholeFactory(globals()))
reactor.run() 

Then you just login to the program over ssh;

$ ssh admin@localhost -p 2222
admin@localhost's password: 

Using foobar as the password.

When you login you'll get a normal python prompt where you can just poke at the data. It's not quite the same as getting a traceback sent over to a host.

Now, this might be tricky to integrate to a GUI program, in that case you might need to choose another reactor, for instance for gtk based programs used the gtk2reactor etc.

If you want the actual traceback sent over you need to create a socket channel for both stderr, stdin and stdout which goes over the network instead of printing to your local host. Shouldn't be too hard to accomplish by using twisted.

Two solutions from modern IDEs:

1. PTVS (Python tools for Visual Studio) cross-platform remote debugging

2. PyCharm / PyDev remote debugging

I find pudb useful at emergency

pip install pudb

Project Description https://pypi.org/project/pudb/

Tutorial: https://vimeo.com/5255125

None of the answers here handle the case where the binary was not prepared in advance. For that purpose, a while ago I hacked together pydbattach.

Some solutions:

• pydbattach
• Google pyringe, last update 2014
• pyrasite, last update 2017
• py-spy, sampling only, dump stack traces
• Pyflame, sampling only
• PyStack, dump stack traces including locals