Paramiko hanging during authentication, when runned by dint of unittest runner

Question

Good day.

I have a strange problem with paramiko ssh client. Connect paramiko method hangs when it's called outside unittest2 classes/functions and code was run by unittest runner.

There is a piece of code, where problem appears:

import paramiko
import unittest2

ssh = paramiko.SSHClient()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
ssh.connect('172.18.67.10',
            username='root',
            password='secrete')
_, stdout, _ = ssh.exec_command('date')


class TestTest(unittest2.TestCase):
    def setUp(self):
        pass

If I move ssh.connect into TestTest class or setUpModule function, connection will be successful. Also everything is OK when code is run by original Python interpreter.

When I try to debug paramiko, I figure out this problem inside while True loop in paramiko/auth_handler.py:AuthHandler.wait_for_response method.

Any suggestions?

Answer 1

According to this SO answer, it seems to be a thread-related bug in paramiko and can be avoided by not calling connect() during import.