Add support for deleting namespaces (users, organizations)

Fixes #102
Fixes #105

data/queue.py

@@ -33,12 +33,14 @@ class BuildMetricQueueReporter(object):
 class WorkQueue(object):
   """ Work queue defines methods for interacting with a queue backed by the database. """
   def __init__(self, queue_name, transaction_factory,
-               canonical_name_match_list=None, reporter=None, metric_queue=None):
+               canonical_name_match_list=None, reporter=None, metric_queue=None,
+               has_namespace=False):
     self._queue_name = queue_name
     self._reporter = reporter
     self._metric_queue = metric_queue
     self._transaction_factory = transaction_factory
     self._currently_processing = False
+    self._has_namespaced_items = has_namespace
 
     if canonical_name_match_list is None:
       self._canonical_name_match_list = []
@@ -130,6 +132,15 @@ class WorkQueue(object):
       except QueueItem.DoesNotExist:
         return False
 
+  def delete_namespaced_items(self, namespace, subpath=None):
+    """ Deletes all items in this queue that exist under the given namespace. """
+    if not self._has_namespaced_items:
+      return False
+
+    subpath_query = '%s/' % subpath if subpath else ''
+    queue_prefix = '%s/%s/%s%%' % (self._queue_name, namespace, subpath_query)
+    QueueItem.delete().where(QueueItem.queue_name ** queue_prefix).execute()
+
   def put(self, canonical_name_list, message, available_after=0, retries_remaining=5):
     """
     Put an item, if it shouldn't be processed for some number of seconds,