ansible_playbook_python (#18530)

* ansible_playbook_python

fixes #18471

* fix tests

* removed dupe

CHANGELOG.md

@@ -13,6 +13,7 @@ Ansible Changes By Release
   any user can add back via config options if they don't use those package managers or othewise avoid the errors.
 * Blocks can now have a `name` field, to aid in playbook readability.
 * default strategy is now configurable via ansible.cfg or environment variable.
+* Added 'ansible_playbook_python' which contains 'current python executable', it can be blank in some cases in which Ansible is not invoked via the standard CLI (sys.executable limitation).
 
 ###Deprecations:
 * Specifying --tags (or --skip-tags) multiple times on the command line

docsite/rst/playbooks_variables.rst

@@ -681,6 +681,8 @@ period, without the rest of the domain.
 .. versionadded:: 2.2
 ``ansible_play_batch`` is available as a list of hostnames that are in scope for the current 'batch' of the play. The batch size is defined by ``serial``, when not set it is equivalent to the whole play (making it the same as ``ansible_play_hosts``).
 
+.. versionadded:: 2.3
+``ansible_playbook_python`` is the path to the python executable used to invoke the Ansible command line tool.
 
 These vars may be useful for filling out templates with multiple hostnames or for injecting the list into the rules for a load balancer.
 

lib/ansible/plugins/action/__init__.py

@@ -694,7 +694,7 @@ class ActionBase(with_metaclass(ABCMeta, object)):
                         pass
 
                 # remove some KNOWN keys
-                for hard in ['ansible_rsync_path']:
+                for hard in ['ansible_rsync_path', 'ansible_playbook_python']:
                     if hard in fact_keys:
                         remove_keys.add(hard)
 

lib/ansible/vars/__init__.py

@@ -20,6 +20,7 @@ from __future__ import (absolute_import, division, print_function)
 __metaclass__ = type
 
 import os
+import sys
 
 from collections import defaultdict, MutableMapping
 
@@ -392,6 +393,7 @@ class VariableManager:
 
         variables = dict()
         variables['playbook_dir'] = loader.get_basedir()
+        variables['ansible_playbook_python'] = sys.executable
 
         if host:
             variables['group_names'] = sorted([group.name for group in host.get_groups() if group.name != 'all'])

test/units/vars/test_variable_manager.py

@@ -47,14 +47,11 @@ class TestVariableManager(unittest.TestCase):
 
         v = VariableManager()
         vars = v.get_vars(loader=fake_loader, use_cache=False)
-        if 'omit' in vars:
-            del vars['omit']
-        if 'vars' in vars:
-            del vars['vars']
-        if 'ansible_version' in vars:
-            del vars['ansible_version']
-        if 'ansible_check_mode' in vars:
-            del vars['ansible_check_mode']
+
+        #FIXME: not sure why we remove all and only test playbook_dir
+        for remove in ['omit', 'vars', 'ansible_version', 'ansible_check_mode', 'ansible_playbook_python']:
+            if remove in vars:
+                del vars[remove]
 
         self.assertEqual(vars, dict(playbook_dir='.'))