Use taskflow library for building and executing action plans

The aim of this patchset is to integrate taskflow in
the Watcher Applier. Taskflow will help us a lot to make
Action Plan execution easy, consistent, scalable and reliable.

DocImpact

Partially implements: blueprint use-taskflow

Change-Id: I903d6509d74a61ad64e1506b8a7156e6e91abcfb
Closes-Bug: #1535326
Closes-Bug: #1531912

watcher/applier/actions/sleep.py

@@ -0,0 +1,48 @@
+# -*- encoding: utf-8 -*-
+# Copyright (c) 2015 b<>com
+#
+# Authors: Jean-Emile DARTOIS <jean-emile.dartois@b-com.com>
+#
+# 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 time
+
+from oslo_log import log
+
+from watcher.applier.actions import base
+
+
+LOG = log.getLogger(__name__)
+
+
+class Sleep(base.BaseAction):
+
+    @property
+    def duration(self):
+        return int(self.input_parameters.get('duration'))
+
+    def execute(self):
+        LOG.debug("Starting action Sleep duration:%s ", self.duration)
+        time.sleep(self.duration)
+        return True
+
+    def revert(self):
+        LOG.debug("revert action Sleep")
+        return True
+
+    def precondition(self):
+        pass
+
+    def postcondition(self):
+        pass