wait_for_connection gives errors

I’m using ansible + mitogen for automated server updates on Ubuntu. I’m using these tasks to check if a reboot is necessary after the apt upgrade task:

  - name: Check if reboot is required
    stat:
      path: /var/run/reboot-required
    register: reboot_required

  - name: Reboot server
    shell: sleep 2 && shutdown -r now "Ansible updates triggered"
    async: 1
    poll: 0
    when: reboot_required.stat.exists == True

  - name: Wait 300 seconds for server to become available
    wait_for_connection:
      delay: 30
      timeout: 300
    when: reboot_required.stat.exists == True

This can be manually reproduced by just creating a /var/run/reboot-required file.

I recently updated to the latest ansible (2.8.5) and mitogen (master branch). Previously the wait_for_connection would trigger a warning ([WARNING]: Reset is not implemented for this connection), but now the following error is shown every second, from the moment the reboot is complete:

ERROR! [mux  23628] 12:00:35.305036 E mitogen.service: Pool(1c50, size=32, th='mitogen.Pool.1c50.24'): while invoking u'reset' of u'ansible_mitogen.services.ContextService'
Traceback (most recent call last):
  File "/home/epartment/epaflex/mitogen-master/mitogen/service.py", line 621, in _on_service_call
    return invoker.invoke(method_name, kwargs, msg)
  File "/home/epartment/epaflex/mitogen-master/mitogen/service.py", line 307, in invoke
    response = self._invoke(method_name, kwargs, msg)
  File "/home/epartment/epaflex/mitogen-master/mitogen/service.py", line 293, in _invoke
    ret = method(**kwargs)
  File "/home/epartment/epaflex/mitogen-master/ansible_mitogen/services.py", line 186, in reset
    mitogen.core.listen(context, 'disconnect', l.put)
  File "/home/epartment/epaflex/mitogen-master/mitogen/core.py", line 431, in listen
    _signals(obj, name).append(func)
  File "/home/epartment/epaflex/mitogen-master/mitogen/core.py", line 421, in _signals
    obj.__dict__
AttributeError: 'NoneType' object has no attribute '__dict__'

When disabling mitogen, the playbook runs fine.

[davidklaftenegger]

I can reproduce the issue with any use of wait_for_connection

As a workaround you can specify strategy: linear in plays that use this particular module, but to still benefit from mitogen it might be necessary to split this one task out into a separate play within the playbook.

[s1113950]

I integrated the test scenario mentioned in the ticket description into #710 (had to use docker though because testing shutdown is a bit hard on a localhost machine 😅 ). Once all tests pass/PR is approved I’ll merge and this issue should be fixed 👍