text: # vim: tabstop=4 shiftwidth=4 softtabstop=4
  
  # Copyright 2012 IBM Corp.
  #
  #    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.
  
  from oslo.config import cfg
  import webob.exc
  
  from nova.api.openstack import extensions
  from nova.api.openstack import wsgi
  from nova.api.openstack import xmlutil
  from nova import compute
  from nova import exception
  from nova.openstack.common import timeutils
  from nova import utils
  
  authorize = extensions.extension_authorizer('compute', 'services')
  CONF = cfg.CONF
  CONF.import_opt('service_down_time', 'nova.service')
  
  
  class ServicesIndexTemplate(xmlutil.TemplateBuilder):
      def construct(self):
          root = xmlutil.TemplateElement('services')
          elem = xmlutil.SubTemplateElement(root, 'service', selector='services')
          elem.set('binary')
          elem.set('host')
          elem.set('zone')
          elem.set('status')
          elem.set('state')
          elem.set('updated_at')
  
          return xmlutil.MasterTemplate(root, 1)
  
  
  class ServiceUpdateTemplate(xmlutil.TemplateBuilder):
      def construct(self):
          root = xmlutil.TemplateElement('service', selector='service')
          root.set('host')
          root.set('binary')
          root.set('status')
  
          return xmlutil.MasterTemplate(root, 1)
  
  
  class ServiceUpdateDeserializer(wsgi.XMLDeserializer):
      def default(self, string):
          node = xmlutil.safe_minidom_parse_string(string)
          service = {}
          service_node = self.find_first_child_named(node, 'service')
          if service_node is None:
              return service
          service['host'] = service_node.getAttribute('host')
          service['binary'] = service_node.getAttribute('binary')
  
          return dict(body=service)
  
  
  class ServiceController(object):
  
      def __init__(self):
          self.host_api = compute.HostAPI()
  
      @wsgi.serializers(xml=ServicesIndexTemplate)
      def index(self, req):
          """
          Return a list of all running services. Filter by host & service name.
          """
          context = req.environ['nova.context']
          authorize(context)
          now = timeutils.utcnow()
          services = self.host_api.service_get_all(
              context, set_zones=True)
  
          host = ''
          if 'host' in req.GET:
              host = req.GET['host']
          binary = ''
          if 'binary' in req.GET:
              binary = req.GET['binary']
          if host:
              services = [s for s in services if s['host'] == host]
          if binary:
              services = [s for s in services if s['binary'] == binary]
  
          svcs = []
          for svc in services:
              delta = now - (svc['updated_at'] or svc['created_at'])
              alive = abs(utils.total_seconds(delta)) <= CONF.service_down_time
              art = (alive and "up") or "down"
              active = 'enabled'
              if svc['disabled']:
                  active = 'disabled'
              svcs.append({"binary": svc['binary'], 'host': svc['host'],
                           'zone': svc['availability_zone'],
                           'status': active, 'state': art,
                           'updated_at': svc['updated_at']})
          return {'services': svcs}
  
      @wsgi.deserializers(xml=ServiceUpdateDeserializer)
      @wsgi.serializers(xml=ServiceUpdateTemplate)
      def update(self, req, id, body):
          """Enable/Disable scheduling for a service."""
          context = req.environ['nova.context']
          authorize(context)
  
          if id == "enable":
              disabled = False
          elif id == "disable":
              disabled = True
          else:
              raise webob.exc.HTTPNotFound(_("Unknown action"))
  
          status = id + 'd'
  
          try:
              host = body['host']
              binary = body['binary']
          except (TypeError, KeyError):
              raise webob.exc.HTTPUnprocessableEntity()
  
          try:
              svc = self.host_api.service_update(context, host, binary,
                                                 {'disabled': disabled})
          except exception.ServiceNotFound as exc:
              raise webob.exc.HTTPNotFound(_("Unknown service"))
  
          return {'service': {'host': host, 'binary': binary, 'status': status}}
  
  
  class Services(extensions.ExtensionDescriptor):
      """Services support."""
  
      name = "Services"
      alias = "os-services"
      namespace = "http://docs.openstack.org/compute/ext/services/api/v2"
      updated = "2012-10-28T00:00:00-00:00"
  
      def get_resources(self):
          resources = []
          resource = extensions.ResourceExtension('os-services',
                                                  ServiceController())
          resources.append(resource)
          return resources
  