Hipchat plugin: ignore import errors until we care about them

playbooks/callback_plugins/hipchat_plugin.py

 import os
-import prettytable
-import hipchat
 import time
-import random
 from ansible import utils
+try:
+    import prettytable
+except ImportError:
+    prettytable = None
+try:
+    import hipchat
+except ImportError:
+    hipchat = None
 
 
 class CallbackModule(object):
@@ -24,8 +29,21 @@ class CallbackModule(object):
     """
 
     def __init__(self):
-
-        if 'HIPCHAT_TOKEN' in os.environ:
+        self.enabled = "HIPCHAT_TOKEN" in os.environ
+        if not self.enabled:
+            return
+
+        # make sure we got our imports
+        if not hipchat:
+            raise ImportError(
+                "The hipchat plugin requires the hipchat Python module, "
+                "which is not installed or was not found."
+            )
+        if not prettytable:
+            raise ImportError(
+                "The hipchat plugin requires the prettytable Python module, "
+                "which is not installed or was not found."
+            )
         self.start_time = time.time()
         self.task_report = []
         self.last_task = None
@@ -45,9 +63,6 @@ class CallbackModule(object):
         self.hipchat_msg_color = os.getenv('HIPCHAT_MSG_COLOR', '')
         self.printed_playbook = False
         self.playbook_name = None
-            self.enabled = True
-        else:
-            self.enabled = False
 
     def _send_hipchat(self, message, room=None, from_name=None, color=None, message_format='text'):