1 files changed, 44 insertions, 0 deletions
diff --git a/heat/db/filters.py b/heat/db/filters.py
new file mode 100644
index 000000000..6c7b8cf24
--- /dev/null
+++ b/heat/db/filters.py
@@ -0,0 +1,44 @@
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+
+def exact_filter(query, model, filters):
+    """Applies exact match filtering to a query.
+
+    Returns the updated query.  Modifies filters argument to remove
+    filters consumed.
+
+    :param query: query to apply filters to
+    :param model: model object the query applies to, for IN-style
+                  filtering
+    :param filters: dictionary of filters; values that are lists,
+                    tuples, sets, or frozensets cause an 'IN' test to
+                    be performed, while exact matching ('==' operator)
+                    is used for other values
+    """
+
+    filter_dict = {}
+    if filters is None:
+        filters = {}
+
+    for key, value in filters.items():
+        if isinstance(value, (list, tuple, set, frozenset)):
+            column_attr = getattr(model, key)
+            query = query.filter(column_attr.in_(value))
+        else:
+            filter_dict[key] = value
+
+    if filter_dict:
+        query = query.filter_by(**filter_dict)
+
+    return query