Add some hooks for managers when service starts

Adds pre_start_hook() and post_start_hook() and fixes a couple of hard
coded binary name checks in service.py

Change-Id: I062790a88ed7f15a6f28961d6ddc1f230e19e0cb

nova/manager.py

@@ -183,10 +183,30 @@ class Manager(base.Base):
                               locals())
 
     def init_host(self):
-        """Handle initialization if this is a standalone service.
+        """Hook to do additional manager initialization when one requests
+        the service be started.  This is called before any service record
+        is created.
 
         Child classes should override this method.
+        """
+        pass
 
+    def pre_start_hook(self):
+        """Hook to provide the manager the ability to do additional
+        start-up work before any RPC queues/consumers are created. This is
+        called after other initialization has succeeded and a service
+        record is created.
+
+        Child classes should override this method.
+        """
+        pass
+
+    def post_start_hook(self):
+        """Hook to provide the manager the ability to do additional
+        start-up work immediately after a service creates RPC consumers
+        and starts 'running'.
+
+        Child classes should override this method.
         """
         pass
 

nova/scheduler/manager.py

@@ -26,6 +26,7 @@ import sys
 from nova.compute import rpcapi as compute_rpcapi
 from nova.compute import utils as compute_utils
 from nova.compute import vm_states
+import nova.context
 from nova import db
 from nova import exception
 from nova import flags
@@ -62,6 +63,13 @@ class SchedulerManager(manager.Manager):
         self.driver = importutils.import_object(scheduler_driver)
         super(SchedulerManager, self).__init__(*args, **kwargs)
 
+    def post_start_hook(self):
+        """After we start up and can receive messages via RPC, tell all
+        compute nodes to send us their capabilities.
+        """
+        ctxt = nova.context.get_admin_context()
+        compute_rpcapi.ComputeAPI().publish_service_capabilities(ctxt)
+
     def update_service_capabilities(self, context, service_name,
                                     host, capabilities):
         """Process a capability update from a service node."""
@@ -259,6 +267,3 @@ class SchedulerManager(manager.Manager):
     @manager.periodic_task
     def _expire_reservations(self, context):
         QUOTAS.expire(context)
-
-    def request_service_capabilities(self, context):
-        compute_rpcapi.ComputeAPI().publish_service_capabilities(context)

nova/service.py

@@ -397,8 +397,7 @@ class Service(object):
         except exception.NotFound:
             self._create_service_ref(ctxt)
 
-        if 'nova-compute' == self.binary:
+        self.manager.pre_start_hook()
-            self.manager.update_available_resource(ctxt)
 
         self.conn = rpc.create_connection(new=True)
         LOG.debug(_("Creating Consumer connection for Service %s") %
@@ -417,8 +416,7 @@ class Service(object):
         # Consume from all consumers in a thread
         self.conn.consume_in_thread()
 
-        if 'nova-scheduler' == self.binary:
+        self.manager.post_start_hook()
-            self.manager.request_service_capabilities(ctxt)
 
         if self.report_interval:
             pulse = utils.LoopingCall(self.report_state)
@@ -612,7 +610,10 @@ class WSGIService(object):
         """
         if self.manager:
             self.manager.init_host()
+            self.manager.pre_start_hook()
         self.server.start()
+        if self.manager:
+            self.manager.post_start_hook()
 
     def stop(self):
         """Stop serving this API.