Add support for mitogen

[wilfriedroset]

Add support for mitogen

Compared to the Vanilla Ansible, Mitogen calls sshwrapper.py
differently. This imply a different parsing to extract the options, host
and command. Moreover, Mitogen does not passes the remote_user
therefore we must set as well BASTION_ANSIBLE_REMOTE_USER env var.

Apart from setting the BASTION_ANSIBLE_REMOTE_USER the wrapper works
for both vanilla and mitogen connection. Users should refer to mitogen
to learn about the installation process.

The following commit has been tested with:

• Test case 1
  • Mitogen 0.3.7
  • Ansible 210.8
  • Python 3.9.2
  • Debian 11.9
• Test case 2
  • Mitogen 0.3.7
  • Ansible 2.16.6
  • Python 3.12
  • MacOS 14.2

This playbook works as expected with and without mitogen enabled

❯ cat test.yaml
---
- name: test
  hosts: test
  gather_facts: false
  tasks:
    - name: Run the equivalent of "apt-get update" as a separate step
      ansible.builtin.apt:
        update_cache: true

    - name: Create files with copy content module
      copy:
        content: |
          test file {{ item }}
        dest: /tmp/file_{{item}}
      with_sequence: start=1 end=10

    - name: demo template
      ansible.builtin.template:
        src: demo.txt.j2
        dest: /tmp/demo.txt
        mode: 0640

Here is the ansible.cfg

[defaults]
interpreter_python = /usr/bin/python3
host_key_checking = False
deprecation_warnings = False
syslog_facility = LOG_USER
bin_ansible_callbacks = True

gathering = explicit
callbacks_enabled = ansible.posix.profile_tasks

strategy_plugins = ./mitogen/ansible_mitogen/plugins/strategy/
strategy = mitogen_linear

[ssh_connection]
scp_if_ssh = False
# Rely on bastion wrapper
pipelining = True
transfer_method = sftp
ssh_executable = ./bastion-ansible-wrapper/sshwrapper.py
sftp_executable = ./bastion-ansible-wrapper/sftpbastion.sh
retries = 1

[wilfriedroset]

Please note that I've found cases where ansible fails due to an error similar to:

An exception occurred during task execution. To see the full traceback, use -vvv. The error was: ImportError: attempted relative import with no known parent package

According to my research, this is more related to an issue with the collection rather than mitogen itself or the wrapper.
See:

• Some amazon.aws modules fail on relative import error mitogen-hq/mitogen#896
• Use absolute instead of relative imports ansible-collections/amazon.aws#809