fixing an issue where sentry logger would fail to get tags from grains and some other lint fixes for this file

salt/log/handlers/sentry_mod.py

@@ -112,13 +112,16 @@ __virtualname__ = 'sentry'
 
 def __virtual__():
     if HAS_RAVEN is True:
-        __grains__ = salt.loader.grains(__opts__)
-        __salt__ = salt.loader.minion_mods(__opts__)
         return __virtualname__
     return False
 
 
 def setup_handlers():
+    '''
+    sets up the sentry handler
+    '''
+    __grains__ = salt.loader.grains(__opts__)
+    __salt__ = salt.loader.minion_mods(__opts__)
     if 'sentry_handler' not in __opts__:
         log.debug('No \'sentry_handler\' key was found in the configuration')
         return False
@@ -132,7 +135,9 @@ def setup_handlers():
             transport_registry = TransportRegistry(default_transports)
             url = urlparse(dsn)
             if not transport_registry.supported_scheme(url.scheme):
-                raise ValueError('Unsupported Sentry DSN scheme: {0}'.format(url.scheme))
+                raise ValueError(
+                    'Unsupported Sentry DSN scheme: %s', url.scheme
+                )
         except ValueError as exc:
             log.info(
                 'Raven failed to parse the configuration provided DSN: %s', exc
@@ -201,7 +206,11 @@ def setup_handlers():
     context_dict = {}
     if context is not None:
         for tag in context:
-            tag_value = __salt__['grains.get'](tag)
+            try:
+                tag_value = __grains__[tag]
+            except KeyError:
+                log.debug('Sentry tag \'%s\' not found in grains.', tag)
+                continue
             if len(tag_value) > 0:
                 context_dict[tag] = tag_value
         if len(context_dict) > 0:
@@ -215,4 +224,7 @@ def setup_handlers():
 
 
 def get_config_value(name, default=None):
+    '''
+    returns a configuration option for the sentry_handler
+    '''
     return __opts__['sentry_handler'].get(name, default)