Split scheduler out of engine service

Change-Id: Ib57f295b0362e4fc17a3ff5bfb539830f6ac1875

mogan/scheduler/manager.py

@@ -0,0 +1,58 @@
+# Copyright 2017 Huawei Technologies Co.,LTD.
+# All Rights Reserved.
+#
+#    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 eventlet
+import oslo_messaging as messaging
+from oslo_service import periodic_task
+from oslo_utils import importutils
+
+from mogan.common import exception
+from mogan.conf import CONF
+
+
+class SchedulerManager(periodic_task.PeriodicTasks):
+    """Mogan Scheduler manager main class."""
+
+    RPC_API_VERSION = '1.0'
+
+    target = messaging.Target(version=RPC_API_VERSION)
+
+    def __init__(self, topic, host=None):
+        super(SchedulerManager, self).__init__(CONF)
+        self.host = host or CONF.host
+        self.topic = topic
+        scheduler_driver = CONF.scheduler.scheduler_driver
+        self.driver = importutils.import_object(scheduler_driver)
+        self._startup_delay = True
+
+    def init_host(self):
+        self._startup_delay = False
+
+    def _wait_for_scheduler(self):
+        while self._startup_delay and not self.driver.is_ready():
+            eventlet.sleep(1)
+
+    @messaging.expected_exceptions(exception.NoValidNode)
+    def select_destinations(self, ctxt, request_spec, filter_properties):
+        self._wait_for_scheduler()
+        dests = self.driver.schedule(
+            ctxt, request_spec, filter_properties)
+        return dests
+
+    def del_host(self):
+        pass
+
+    def periodic_tasks(self, context, raise_on_error=False):
+        return self.run_periodic_tasks(context, raise_on_error=raise_on_error)