Add gathering_policy parameter to run_ansible_playbook function

This patch adds a new parameter called 'gathering_policy' (Defaults to
None) to the 'run_ansible_playbook' function. This parameter will
control the default policy of the Ansible fact gathering. Sets to None
by default, it will use the default policy for Ansible (ie. 'implicit').

Change-Id: I0668241a1675dd4e344cc24b6ff2cbb8f93b7a45
Signed-off-by: Gael Chamoulaud <gchamoul@redhat.com>

tripleoclient/utils.py

@@ -84,7 +84,8 @@ def run_ansible_playbook(logger,
                          skip_tags=None,
                          verbosity=1,
                          extra_vars=None,
-                         plan='overcloud'):
+                         plan='overcloud',
+                         gathering_policy=None):
     """Simple wrapper for ansible-playbook
 
     :param logger: logger instance
@@ -147,6 +148,12 @@ def run_ansible_playbook(logger,
     :param extra_vars: set additional variables as a Dict
     or the absolute path of a JSON or YAML file type
     :type extra_vars: Either a Dict or the absolute path of JSON or YAML
+
+    :param gathering_policy: This setting controls the default policy of
+    fact gathering ('smart', 'implicit', 'explicit'). Defaults to None.
+    When not specified, the policy will be the default Ansible one, ie.
+    'implicit'.
+    :type gathering_facts: String
     """
     env = os.environ.copy()
 
@@ -177,6 +184,9 @@ def run_ansible_playbook(logger,
 
     env['ANSIBLE_HOST_KEY_CHECKING'] = 'False'
 
+    if gathering_policy in ['smart', 'explicit', 'implicit']:
+        env['ANSIBLE_GATHERING'] = gathering_policy
+
     if extra_vars is None:
         extra_vars = {}