Add common stack methods

* Creating and removing stacks
* Waiting for resource status to be complete
* Loading Heat template

Change-Id: I3dbafb03d5ca671865335e7320c67f07fa5f9aaa

tobiko/common/stack.py

@@ -0,0 +1,64 @@
+# Copyright 2018 Red Hat
+#
+#    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 os
+import time
+
+from heatclient.common import template_utils
+import yaml
+
+
+class StackManager(object):
+    """Manages Heat stacks."""
+
+    def __init__(self, client_manager, templates_dir):
+        self.client = client_manager.get_heat_client()
+        self.templates_dir = templates_dir
+
+    def load_template(self, template_path):
+        """Loads template from a given file."""
+        _files, template = template_utils.get_template_contents(template_path)
+        return yaml.safe_dump(template)
+
+    def create_stack(self, stack_name, template_name, parameters):
+        """Creates stack based on passed parameters."""
+        template = self.load_template(os.path.join(self.templates_dir,
+                                                   template_name))
+
+        stack = self.client.stacks.create(stack_name=stack_name,
+                                          template=template,
+                                          parameters=parameters)
+
+        print(stack)
+        return stack
+
+    def delete_stack(self, sid):
+        """Deletes stack."""
+        self.client.stacks.delete(sid)
+
+    def get_stack(self, stack_name):
+        """Returns stack ID."""
+        return self.client.stacks.get(stack_name)
+
+    def wait_for_status_complete(self, stack_id, resource_name):
+        """Verifies resource reached complete status.
+
+        If it didn't, the method will wait until resource reaches
+        complete status or when timeout reached.
+        """
+        res = self.client.resources.get(stack_id, resource_name)
+        print(res.resource_status)
+        while (res.resource_status != 'CREATE_COMPLETE'):
+            print(res.resource_status)
+            time.sleep(5)
+            res = self.client.resources.get(stack_id, resource_name)