Resolved lint issues

callback_plugins/0_version_requirement.py

@@ -1,42 +1,56 @@
 #!/usr/bin/python
 
+"""
+This callback plugin verifies the required minimum version of Ansible
+is installed for proper operation of the OpenShift Ansible Installer.
+The plugin is named with leading `aa_` to ensure this plugin is loaded
+first (alphanumerically) by Ansible.
+"""
 import sys
 from ansible import __version__
 
 if __version__ < '2.0':
+    # pylint: disable=import-error,no-name-in-module
+    # Disabled because pylint warns when Ansible v2 is installed
     from ansible.callbacks import display as pre2_display
     CallbackBase = object
 
     def display(*args, **kwargs):
+        """Set up display function for pre Ansible v2"""
         pre2_display(*args, **kwargs)
 else:
     from ansible.plugins.callback import CallbackBase
     from ansible.utils.display import Display
 
     def display(*args, **kwargs):
+        """Set up display function for Ansible v2"""
         display_instance = Display()
         display_instance.display(*args, **kwargs)
 
 
 # Set to minimum required Ansible version
-required_version = '2.2.0.0'
-DESCRIPTION = "Supported versions: %s or newer" % required_version
+REQUIRED_VERSION = '2.2.0.0'
+DESCRIPTION = "Supported versions: %s or newer" % REQUIRED_VERSION
 
 
 def version_requirement(version):
-    return version >= required_version
+    """Test for minimum required version"""
+    return version >= REQUIRED_VERSION
 
 
 class CallbackModule(CallbackBase):
     """
-    This callback module stops playbook execution if the Ansible
-    version is less than required, defined by required_version
+    Ansible callback plugin
     """
 
     CALLBACK_VERSION = 1.0
     CALLBACK_NAME = 'version_requirement'
 
     def __init__(self):
+        """
+        Version verification is performed in __init__ to catch the
+        requirement early in the execution of Ansible and fail gracefully
+        """
         super(CallbackModule, self).__init__()
 
         if not version_requirement(__version__):