Explicit Hook Priorities

Pecan hooks are executed by priority, with a default priority of 100.
We are getting to the point where ordering the execution of our hooks
is important. This patch adds several priority constants, and sets
them within existing hooks. Tests provided, and added where missing.

Change-Id: I1ad15102ac63fee54ab1bc71b0d82edb30559637

storyboard/common/hook_priorities.py

@@ -0,0 +1,35 @@
+# Copyright (c) 2015 Hewlett-Packard Development Company, L.P.
+#
+# 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.
+
+# This file contains pre-set priorities for our pecan hooks. For more
+# information, please see the pecan documentation at
+# https://github.com/stackforge/pecan/blob/master/pecan/hooks.py
+
+
+# Authentication must occur relatively early in the hook processing,
+# as subsequent logic may depend on ACLs.
+AUTH = 1
+
+# Data validation occurs after we've figured out who is making the request,
+# but before we perform any cleaning on the data. It's there to make sure
+# that we have a sane request.
+VALIDATION = 50
+
+# Post validation is there for any hook that is dependent on sane request data.
+POST_VALIDATION = 51
+
+# The default notification hook priority is 100. This is set in pecan,
+# but we are including it here for the sake of documentation.
+DEFAULT = 100