More HostAPI() cleanup for cells.

This patch contains further changes needed to support HostAPI() with
cells.  This moves the formatting of hosts API extension responses back
to the extension itself.  Methods for getting service entries have been
added to HostAPI() that can be overriden in a subclass for cells.

Also contains a performance improvement for 'show' in hosts extension.

Change-Id: Ifd8b68ff8d7495f537dff5e01bd3df75c6c5930a

1 files changed, 73 insertions, 5 deletions

diff --git a/nova/api/openstack/compute/contrib/hosts.py b/nova/api/openstack/compute/contrib/hosts.py
index 52487c305..d1b39d6db 100644
--- a/nova/api/openstack/compute/contrib/hosts.py
+++ b/nova/api/openstack/compute/contrib/hosts.py
@@ -124,10 +124,17 @@ class HostController(object):
         """
         context = req.environ['nova.context']
         authorize(context)
+        filters = {}
         zone = req.GET.get('zone', None)
-        data = self.api.list_hosts(context, zone)
-
-        return {'hosts': data}
+        if zone:
+            filters['availability_zone'] = zone
+        services = self.api.service_get_all(context, filters=filters)
+        hosts = []
+        for service in services:
+            hosts.append({'host_name': service['host'],
+                          'service': service['topic'],
+                          'zone': service['availability_zone']})
+        return {'hosts': hosts}
 
     @wsgi.serializers(xml=HostUpdateTemplate)
     @wsgi.deserializers(xml=HostUpdateDeserializer)
@@ -243,6 +250,55 @@ class HostController(object):
     def reboot(self, req, id):
         return self._host_power_action(req, host_name=id, action="reboot")
 
+    @staticmethod
+    def _get_total_resources(host_name, compute_node):
+        return {'resource': {'host': host_name,
+                             'project': '(total)',
+                             'cpu': compute_node['vcpus'],
+                             'memory_mb': compute_node['memory_mb'],
+                             'disk_gb': compute_node['local_gb']}}
+
+    @staticmethod
+    def _get_used_now_resources(host_name, compute_node):
+        return {'resource': {'host': host_name,
+                             'project': '(used_now)',
+                             'cpu': compute_node['vcpus_used'],
+                             'memory_mb': compute_node['memory_mb_used'],
+                             'disk_gb': compute_node['local_gb_used']}}
+
+    @staticmethod
+    def _get_resource_totals_from_instances(host_name, instances):
+        cpu_sum = 0
+        mem_sum = 0
+        hdd_sum = 0
+        for instance in instances:
+            cpu_sum += instance['vcpus']
+            mem_sum += instance['memory_mb']
+            hdd_sum += instance['root_gb'] + instance['ephemeral_gb']
+
+        return {'resource': {'host': host_name,
+                             'project': '(used_max)',
+                             'cpu': cpu_sum,
+                             'memory_mb': mem_sum,
+                             'disk_gb': hdd_sum}}
+
+    @staticmethod
+    def _get_resources_by_project(host_name, instances):
+        # Getting usage resource per project
+        project_map = {}
+        for instance in instances:
+            resource = project_map.setdefault(instance['project_id'],
+                    {'host': host_name,
+                     'project': instance['project_id'],
+                     'cpu': 0,
+                     'memory_mb': 0,
+                     'disk_gb': 0})
+            resource['cpu'] += instance['vcpus']
+            resource['memory_mb'] += instance['memory_mb']
+            resource['disk_gb'] += (instance['root_gb'] +
+                                    instance['ephemeral_gb'])
+        return project_map
+
     @wsgi.serializers(xml=HostShowTemplate)
     def show(self, req, id):
         """Shows the physical/usage resource given by hosts.
@@ -256,14 +312,26 @@ class HostController(object):
                     'cpu': 1, 'memory_mb': 2048, 'disk_gb': 30}
         """
         context = req.environ['nova.context']
+        host_name = id
         try:
-            data = self.api.describe_host(context, id)
+            service = self.api.service_get_by_compute_host(context, host_name)
         except exception.NotFound as e:
             raise webob.exc.HTTPNotFound(explanation=e.message)
         except exception.AdminRequired:
             msg = _("Describe-resource is admin only functionality")
             raise webob.exc.HTTPForbidden(explanation=msg)
-        return {'host': data}
+        compute_node = service['compute_node'][0]
+        instances = self.api.instance_get_all_by_host(context, host_name)
+        resources = [self._get_total_resources(host_name, compute_node)]
+        resources.append(self._get_used_now_resources(host_name,
+                                                      compute_node))
+        resources.append(self._get_resource_totals_from_instances(host_name,
+                                                                  instances))
+        by_proj_resources = self._get_resources_by_project(host_name,
+                                                           instances)
+        for resource in by_proj_resources.itervalues():
+            resources.append({'resource': resource})
+        return {'host': resources}
 
 
 class Hosts(extensions.ExtensionDescriptor):