ansible_mitogen: Respect interpreter_python and ANSIBLE_PYTHON_INTERPRETER

This adapts PR #740 by @extmind (afe0026890),
which augmented the call to `Connection.get_task_var()` with
`C.config.get_config_value('INTERPRETER_PYTHON'` as a default. Instead this
*replaces* the call to `Connection.get_task_var()`. The aim is greater
simplicity by disentangling templating of a configured interpreter path and
discovery of an interpreter when none is configured. I think this also reduces
the number of times `Connection._get_task_vars()` is called, so reducing the
number of times we do the ugly stack frame inspection.

I've also added test cases.

Co-authored-by: Lars Beckers <lars@extmind.de>

ansible_mitogen/transport_config.py

@@ -493,12 +493,24 @@ class PlayContextSpec(Spec):
         return self._connection_option('port')
 
     def python_path(self, rediscover_python=False):
-        s = self._connection.get_task_var('ansible_python_interpreter')
+        # See also
-        # #511, #536: executor/module_common.py::_get_shebang() hard-wires
+        #   - ansible_mitogen.connecton.Connection.get_task_var()
-        # "/usr/bin/python" as the default interpreter path if no other
+        try:
-        # interpreter is specified.
+            delegated_vars = self._task_vars['ansible_delegated_vars']
+            variables = delegated_vars[self._connection.delegate_to_hostname]
+        except KeyError:
+            variables = self._task_vars
+
+        interpreter_python = C.config.get_config_value(
+            'INTERPRETER_PYTHON', variables=variables,
+        )
+
+        if '{{' in interpreter_python or '{%' in interpreter_python:
+            templar = self._connection.templar
+            interpreter_python = templar.template(interpreter_python)
+
         return parse_python_path(
-            s,
+            interpreter_python,
             task_vars=self._task_vars,
             action=self._action,
             rediscover_python=rediscover_python)

docs/changelog.rst

@@ -27,6 +27,8 @@ In progress (unreleased)
   with `meta: reset_connection`
 * :gh:issue:`1083` :mod:`ansible_mitogen`: Templated connection timeout
   (e.g. ``ansible_timeout``).
+* :gh:issue:`740` :mod:`ansible_mitogen`: Respect ``interpreter_python``
+  in ``ansible.cfg`` and ``ANSIBLE_PYTHON_INTERPRETER`` environment variable.
 
 
 v0.3.19 (2024-12-02)

tests/ansible/hosts/default.hosts

@@ -50,6 +50,7 @@ tt-host-key-checking        ansible_host=localhost    ansible_host_key_checking=
 tt-password                 ansible_host=localhost    ansible_password="{{ 'has_sudo_nopw_password' | trim }}"    ansible_user=mitogen__has_sudo_nopw
 tt-port                     ansible_host=localhost    ansible_password=has_sudo_nopw_password    ansible_port="{{ 22 | int }}"    ansible_user=mitogen__has_sudo_nopw
 tt-private-key-file         ansible_host=localhost    ansible_private_key_file="{{ git_basedir }}/tests/data/docker/mitogen__has_sudo_pubkey.key"    ansible_user=mitogen__has_sudo_pubkey
+tt-python-interpreter       ansible_host=localhost    ansible_password=has_sudo_nopw_password    ansible_python_interpreter="{{ ansible_playbook_python | trim }}"    ansible_user=mitogen__has_sudo_nopw
 tt-remote-user              ansible_host=localhost    ansible_password=has_sudo_nopw_password    ansible_user="{{ 'mitogen__has_sudo_nopw' | trim }}"
 tt-ssh-executable           ansible_host=localhost    ansible_password=has_sudo_nopw_password    ansible_ssh_executable="{{ 'ssh' | trim }}"    ansible_user=mitogen__has_sudo_nopw
 tt-timeout                  ansible_host=localhost    ansible_password=has_sudo_nopw_password    ansible_timeout="{{ 5 | int }}"    ansible_user=mitogen__has_sudo_nopw

tests/ansible/templates/test-targets.j2

@@ -84,6 +84,7 @@ tt-host-key-checking        ansible_host={{ tt.hostname }}    ansible_host_key_c
 tt-password                 ansible_host={{ tt.hostname }}    ansible_password="{{ '{{' }} 'has_sudo_nopw_password' | trim {{ '}}' }}"    ansible_port={{ tt.port }}    ansible_python_interpreter={{ tt.python_path }}    ansible_user=mitogen__has_sudo_nopw
 tt-port                     ansible_host={{ tt.hostname }}    ansible_password=has_sudo_nopw_password    ansible_port="{{ '{{' }} {{ tt.port }} | int {{ '}}' }}"    ansible_python_interpreter={{ tt.python_path }}    ansible_user=mitogen__has_sudo_nopw
 tt-private-key-file         ansible_host={{ tt.hostname }}    ansible_port={{ tt.port }}    ansible_private_key_file="{{ '{{' }} git_basedir {{ '}}' }}/tests/data/docker/mitogen__has_sudo_pubkey.key"    ansible_python_interpreter={{ tt.python_path }}    ansible_user=mitogen__has_sudo_pubkey
+tt-python-interpreter       ansible_host={{ tt.hostname }}    ansible_port={{ tt.port }}    ansible_password=has_sudo_nopw_password    ansible_python_interpreter="{{ '{{' }} '{{ tt.python_path }}' | trim {{ '}}' }}"    ansible_user=mitogen__has_sudo_nopw
 tt-remote-user              ansible_host={{ tt.hostname }}    ansible_password=has_sudo_nopw_password    ansible_port={{ tt.port }}    ansible_python_interpreter={{ tt.python_path }}    ansible_user="{{ '{{' }} 'mitogen__has_sudo_nopw' | trim {{ '}}' }}"
 tt-ssh-executable           ansible_host={{ tt.hostname }}    ansible_password=has_sudo_nopw_password    ansible_port={{ tt.port }}    ansible_python_interpreter={{ tt.python_path }}    ansible_ssh_executable="{{ '{{' }} 'ssh' | trim {{ '}}' }}"    ansible_user=mitogen__has_sudo_nopw
 tt-timeout                  ansible_host={{ tt.hostname }}    ansible_password=has_sudo_nopw_password    ansible_port={{ tt.port }}    ansible_python_interpreter={{ tt.python_path }}    ansible_timeout="{{ '{{' }} 5 | int {{ '}}' }}"    ansible_user=mitogen__has_sudo_nopw