include basedir as 'playbook_dir' variable

closes #4246

lib/ansible/playbook/__init__.py

@@ -138,6 +138,7 @@ class PlayBook(object):
         self.basedir     = os.path.dirname(playbook) or '.'
         utils.plugins.push_basedir(self.basedir)
         vars = extra_vars.copy()
+        vars['playbook_dir'] = self.basedir
         if self.inventory.basedir() is not None:
             vars['inventory_dir'] = self.inventory.basedir()
 

lib/ansible/playbook/play.py

@@ -123,6 +123,7 @@ class Play(object):
         self.max_fail_pct     = int(ds.get('max_fail_percentage', 100))
 
         load_vars = {}
+        load_vars['playbook_dir'] = self.basedir
         if self.playbook.inventory.basedir() is not None:
             load_vars['inventory_dir'] = self.playbook.inventory.basedir()
 

lib/ansible/runner/__init__.py

@@ -415,6 +415,7 @@ class Runner(object):
         inject['vars']        = self.module_vars
         inject['defaults']    = self.default_vars
         inject['environment'] = self.environment
+        inject['playbook_dir'] = self.basedir
 
         if self.inventory.basedir() is not None:
             inject['inventory_dir'] = self.inventory.basedir()