Merge "Add an interface specifying the API for storage backends"

storyboard/api/v1/storage/storage.py

@@ -0,0 +1,58 @@
+# Copyright (c) 2019 Adam Coldrick
+#
+# 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.
+
+import abc
+
+from oslo_config import cfg
+
+
+CONF = cfg.CONF
+
+STORAGE_OPTS = [
+    cfg.BoolOpt("enable_attachments",
+                default=False,
+                help="Enable (or disable) the attachments API"),
+    cfg.StrOpt("storage_backend",
+               default="swift",
+               help="Storage backend implementation to use. Currently only"
+                    "`swift` is supported."),
+]
+
+CONF.register_opts(STORAGE_OPTS, 'attachments')
+
+
+class StorageBackend(object):
+    """Interface which must be implemented by attachment storage backends."""
+
+    @abc.abstractmethod
+    def get_upload_url(self):
+        pass
+
+    @abc.abstractmethod
+    def get_auth(self):
+        pass
+
+
+STORAGE_BACKEND = None
+
+
+def get_storage_backend():
+    global STORAGE_BACKEND
+    return STORAGE_BACKEND
+
+
+def set_storage_backend(impl):
+    global STORAGE_BACKEND
+    STORAGE_BACKEND = impl