able to pass tests running interpreter detection in rhel8 container

ansible_mitogen/mixins.py

@@ -122,6 +122,7 @@ class ActionModuleMixin(ansible.plugins.action.ActionBase):
         # required for python interpreter discovery
         connection.templar = self._templar
         self._finding_python_interpreter = False
+        self._rediscovered_python = False
         # redeclaring interpreter discovery vars here in case running ansible < 2.8.0
         self._discovered_interpreter_key = None
         self._discovered_interpreter = False
@@ -402,6 +403,10 @@ class ActionModuleMixin(ansible.plugins.action.ActionBase):
             if result.get('ansible_facts') is None:
                 result['ansible_facts'] = {}
 
+            # only cache discovered_interpreter if we're not running a rediscovery
+            # rediscovery happens in places like docker connections that could have different
+            # python interpreters than the main host
+            if not self._rediscovered_python:
                 result['ansible_facts'][self._discovered_interpreter_key] = self._discovered_interpreter
 
         if self._discovery_warnings:
@@ -457,12 +462,47 @@ class ActionModuleMixin(ansible.plugins.action.ActionBase):
         if executable:
             cmd = executable + ' -c ' + shlex_quote(cmd)
 
-        rc, stdout, stderr = self._connection.exec_command(
+        # TODO: HACK: if finding python interpreter then we need to keep
+        # calling exec_command until we run into the right python we'll use
+        # chicken-and-egg issue, mitogen needs a python to run low_level_execute_command
+        # which is required by Ansible's discover_interpreter function
+        if self._finding_python_interpreter:
+            possible_pythons = [
+                '/usr/bin/python',
+                'python3.7',
+                'python3.6',
+                'python3.5',
+                'python2.7',
+                'python2.6',
+                'usr/libexec/platform-python',
+                'usr/bin/python3',
+                'python'
+            ]
+        else:
+            # not used, just adding a filler value
+            possible_pythons = ['python']
+
+        def _run_cmd():
+            return self._connection.exec_command(
                 cmd=cmd,
                 in_data=in_data,
                 sudoable=sudoable,
                 mitogen_chdir=chdir,
             )
+
+        for possible_python in possible_pythons:
+            try:
+                self._possible_python_interpreter = possible_python
+                rc, stdout, stderr = _run_cmd()
+            # TODO: what exception is thrown?
+            except:
+                # we've reached the last python attempted and failed
+                # TODO: could use enumerate(), need to check which version of python first had it though
+                if possible_python == 'python':
+                    raise
+                else:
+                    continue
+
         stdout_text = to_text(stdout, errors=encoding_errors)
 
         return {

ansible_mitogen/transport_config.py

@@ -88,7 +88,10 @@ def run_interpreter_discovery_if_necessary(s, task_vars, action, rediscover_pyth
     For connections like `docker`, we want to rediscover the python interpreter because
     it could be different than what's ran on the host
     """
-    # TODO: avoid infinite recursion via _finding_python_interpreter + low_level_execute_command called from discover_interpreter
+    # keep trying different interpreters until we don't error
+    if action._finding_python_interpreter:
+        return action._possible_python_interpreter
+    
     if s in ['auto', 'auto_legacy', 'auto_silent', 'auto_legacy_silent']:
         # python is the only supported interpreter_name as of Ansible 2.8.8
         interpreter_name = 'python'
@@ -98,6 +101,11 @@ def run_interpreter_discovery_if_necessary(s, task_vars, action, rediscover_pyth
            task_vars['ansible_facts'] = {}
 
         if rediscover_python and task_vars.get('ansible_facts', {}).get(discovered_interpreter_config):
+            # if we're rediscovering python then chances are we're running something like a docker connection
+            # this will handle scenarios like running a playbook that does stuff + then dynamically creates a docker container,
+            # then runs the rest of the playbook inside that container, and then rerunning the playbook again
+            action._rediscovered_python = True
+
             # blow away the discovered_interpreter_config cache and rediscover
             del task_vars['ansible_facts'][discovered_interpreter_config]
 
@@ -110,6 +118,7 @@ def run_interpreter_discovery_if_necessary(s, task_vars, action, rediscover_pyth
                 interpreter_name=interpreter_name,
                 discovery_mode=s,
                 task_vars=task_vars))
+
             # cache discovered interpreter
             task_vars['ansible_facts'][discovered_interpreter_config] = s
             action._connection.has_pipelining = False