text: # Copyright 2010 United States Government as represented by the
  # Administrator of the National Aeronautics and Space Administration.
  # Copyright 2011 Justin Santa Barbara
  # 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.
  
  """Generic Node base class for all workers that run on hosts."""
  
  import os
  import random
  import sys
  
  from oslo_concurrency import processutils
  from oslo_log import log as logging
  import oslo_messaging as messaging
  from oslo_service import service
  from oslo_utils import importutils
  
  from nova import baserpc
  from nova import conductor
  import nova.conf
  from nova import context
  from nova import debugger
  from nova import exception
  from nova.i18n import _, _LE, _LI, _LW
  from nova import objects
  from nova.objects import base as objects_base
  from nova.objects import service as service_obj
  from nova import rpc
  from nova import servicegroup
  from nova import utils
  from nova import version
  from nova import wsgi
  
  LOG = logging.getLogger(__name__)
  
  CONF = nova.conf.CONF
  
  SERVICE_MANAGERS = {
      'nova-compute': 'nova.compute.manager.ComputeManager',
      'nova-console': 'nova.console.manager.ConsoleProxyManager',
      'nova-consoleauth': 'nova.consoleauth.manager.ConsoleAuthManager',
      'nova-cert': 'nova.cert.manager.CertManager',
      'nova-conductor': 'nova.conductor.manager.ConductorManager',
      'nova-metadata': 'nova.api.manager.MetadataManager',
      'nova-scheduler': 'nova.scheduler.manager.SchedulerManager',
      'nova-cells': 'nova.cells.manager.CellsManager',
  }
  
  
  def _create_service_ref(this_service, context):
      service = objects.Service(context)
      service.host = this_service.host
      service.binary = this_service.binary
      service.topic = this_service.topic
      service.report_count = 0
      service.create()
      return service
  
  
  def _update_service_ref(service):
      if service.version != service_obj.SERVICE_VERSION:
          LOG.info(_LI('Updating service version for %(binary)s on '
                       '%(host)s from %(old)i to %(new)i'),
                   {'binary': service.binary,
                    'host': service.host,
                    'old': service.version,
                    'new': service_obj.SERVICE_VERSION})
          service.version = service_obj.SERVICE_VERSION
          service.save()
  
  
  class Service(service.Service):
      """Service object for binaries running on hosts.
  
      A service takes a manager and enables rpc by listening to queues based
      on topic. It also periodically runs tasks on the manager and reports
      its state to the database services table.
      """
  
      def __init__(self, host, binary, topic, manager, report_interval=None,
                   periodic_enable=None, periodic_fuzzy_delay=None,
                   periodic_interval_max=None, *args, **kwargs):
          super(Service, self).__init__()
          self.host = host
          self.binary = binary
          self.topic = topic
          self.manager_class_name = manager
          self.servicegroup_api = servicegroup.API()
          manager_class = importutils.import_class(self.manager_class_name)
          self.manager = manager_class(host=self.host, *args, **kwargs)
          self.rpcserver = None
          self.report_interval = report_interval
          self.periodic_enable = periodic_enable
          self.periodic_fuzzy_delay = periodic_fuzzy_delay
          self.periodic_interval_max = periodic_interval_max
          self.saved_args, self.saved_kwargs = args, kwargs
          self.backdoor_port = None
          if objects_base.NovaObject.indirection_api:
              conductor_api = conductor.API()
              conductor_api.wait_until_ready(context.get_admin_context())
  
      def __repr__(self):
          return "<%(cls_name)s: host=%(host)s, binary=%(binary)s, " \
                 "manager_class_name=%(manager)s>" % {
                   'cls_name': self.__class__.__name__,
                   'host': self.host,
                   'binary': self.binary,
                   'manager': self.manager_class_name
                  }
  
      def start(self):
          verstr = version.version_string_with_package()
          LOG.info(_LI('Starting %(topic)s node (version %(version)s)'),
                    {'topic': self.topic, 'version': verstr})
          self.basic_config_check()
          self.manager.init_host()
          self.model_disconnected = False
          ctxt = context.get_admin_context()
          self.service_ref = objects.Service.get_by_host_and_binary(
              ctxt, self.host, self.binary)
          if self.service_ref:
              _update_service_ref(self.service_ref)
  
          else:
              try:
                  self.service_ref = _create_service_ref(self, ctxt)
              except (exception.ServiceTopicExists,
                      exception.ServiceBinaryExists):
                  # NOTE(danms): If we race to create a record with a sibling
                  # worker, don't fail here.
                  self.service_ref = objects.Service.get_by_host_and_binary(
                      ctxt, self.host, self.binary)
  
          self.manager.pre_start_hook()
  
          if self.backdoor_port is not None:
              self.manager.backdoor_port = self.backdoor_port
  
          LOG.debug("Creating RPC server for service %s", self.topic)
  
          target = messaging.Target(topic=self.topic, server=self.host)
  
          endpoints = [
              self.manager,
              baserpc.BaseRPCAPI(self.manager.service_name, self.backdoor_port)
          ]
          endpoints.extend(self.manager.additional_endpoints)
  
          serializer = objects_base.NovaObjectSerializer()
  
          self.rpcserver = rpc.get_server(target, endpoints, serializer)
          self.rpcserver.start()
  
          self.manager.post_start_hook()
  
          LOG.debug("Join ServiceGroup membership for this service %s",
                    self.topic)
          # Add service to the ServiceGroup membership group.
          self.servicegroup_api.join(self.host, self.topic, self)
  
          if self.periodic_enable:
              if self.periodic_fuzzy_delay:
                  initial_delay = random.randint(0, self.periodic_fuzzy_delay)
              else:
                  initial_delay = None
  
              self.tg.add_dynamic_timer(self.periodic_tasks,
                                       initial_delay=initial_delay,
                                       periodic_interval_max=
                                          self.periodic_interval_max)
  
      def __getattr__(self, key):
          manager = self.__dict__.get('manager', None)
          return getattr(manager, key)
  
      @classmethod
      def create(cls, host=None, binary=None, topic=None, manager=None,
                 report_interval=None, periodic_enable=None,
                 periodic_fuzzy_delay=None, periodic_interval_max=None):
          """Instantiates class and passes back application object.
  
          :param host: defaults to CONF.host
          :param binary: defaults to basename of executable
          :param topic: defaults to bin_name - 'nova-' part
          :param manager: defaults to CONF.<topic>_manager
          :param report_interval: defaults to CONF.report_interval
          :param periodic_enable: defaults to CONF.periodic_enable
          :param periodic_fuzzy_delay: defaults to CONF.periodic_fuzzy_delay
          :param periodic_interval_max: if set, the max time to wait between runs
  
          """
          if not host:
              host = CONF.host
          if not binary:
              binary = os.path.basename(sys.argv[0])
          if not topic:
              topic = binary.rpartition('nova-')[2]
          if not manager:
              manager = SERVICE_MANAGERS.get(binary)
          if report_interval is None:
              report_interval = CONF.report_interval
          if periodic_enable is None:
              periodic_enable = CONF.periodic_enable
          if periodic_fuzzy_delay is None:
              periodic_fuzzy_delay = CONF.periodic_fuzzy_delay
  
          debugger.init()
  
          service_obj = cls(host, binary, topic, manager,
                            report_interval=report_interval,
                            periodic_enable=periodic_enable,
                            periodic_fuzzy_delay=periodic_fuzzy_delay,
                            periodic_interval_max=periodic_interval_max)
  
          return service_obj
  
      def kill(self):
          """Destroy the service object in the datastore.
  
          NOTE: Although this method is not used anywhere else than tests, it is
          convenient to have it here, so the tests might easily and in clean way
          stop and remove the service_ref.
  
          """
          self.stop()
          try:
              self.service_ref.destroy()
          except exception.NotFound:
              LOG.warning(_LW('Service killed that has no database entry'))
  
      def stop(self):
          try:
              self.rpcserver.stop()
              self.rpcserver.wait()
          except Exception:
              pass
  
          try:
              self.manager.cleanup_host()
          except Exception:
              LOG.exception(_LE('Service error occurred during cleanup_host'))
              pass
  
          super(Service, self).stop()
  
      def periodic_tasks(self, raise_on_error=False):
          """Tasks to be run at a periodic interval."""
          ctxt = context.get_admin_context()
          return self.manager.periodic_tasks(ctxt, raise_on_error=raise_on_error)
  
      def basic_config_check(self):
          """Perform basic config checks before starting processing."""
          # Make sure the tempdir exists and is writable
          try:
              with utils.tempdir():
                  pass
          except Exception as e:
              LOG.error(_LE('Temporary directory is invalid: %s'), e)
              sys.exit(1)
  
      def reset(self):
          self.manager.reset()
  
  
  class WSGIService(service.Service):
      """Provides ability to launch API from a 'paste' configuration."""
  
      def __init__(self, name, loader=None, use_ssl=False, max_url_len=None):
          """Initialize, but do not start the WSGI server.
  
          :param name: The name of the WSGI server given to the loader.
          :param loader: Loads the WSGI application using the given name.
          :returns: None
  
          """
          self.name = name
          # NOTE(danms): Name can be metadata, os_compute, or ec2, per
          # nova.service's enabled_apis
          self.binary = 'nova-%s' % name
          self.topic = None
          self.manager = self._get_manager()
          self.loader = loader or wsgi.Loader()
          self.app = self.loader.load_app(name)
          # inherit all compute_api worker counts from osapi_compute
          if name.startswith('openstack_compute_api'):
              wname = 'osapi_compute'
          else:
              wname = name
          self.host = getattr(CONF, '%s_listen' % name, "0.0.0.0")
          self.port = getattr(CONF, '%s_listen_port' % name, 0)
          self.workers = (getattr(CONF, '%s_workers' % wname, None) or
                          processutils.get_worker_count())
          if self.workers and self.workers < 1:
              worker_name = '%s_workers' % name
              msg = (_("%(worker_name)s value of %(workers)s is invalid, "
                       "must be greater than 0") %
                     {'worker_name': worker_name,
                      'workers': str(self.workers)})
              raise exception.InvalidInput(msg)
          self.use_ssl = use_ssl
          self.server = wsgi.Server(name,
                                    self.app,
                                    host=self.host,
                                    port=self.port,
                                    use_ssl=self.use_ssl,
                                    max_url_len=max_url_len)
          # Pull back actual port used
          self.port = self.server.port
          self.backdoor_port = None
  
      def reset(self):
          """Reset server greenpool size to default and service version cache.
  
          :returns: None
  
          """
          self.server.reset()
          service_obj.Service.clear_min_version_cache()
  
      def _get_manager(self):
          """Initialize a Manager object appropriate for this service.
  
          Use the service name to look up a Manager subclass from the
          configuration and initialize an instance. If no class name
          is configured, just return None.
  
          :returns: a Manager instance, or None.
  
          """
          manager = SERVICE_MANAGERS.get(self.binary)
          if manager is None:
              return None
  
          manager_class = importutils.import_class(manager)
          return manager_class()
  
      def start(self):
          """Start serving this service using loaded configuration.
  
          Also, retrieve updated port number in case '0' was passed in, which
          indicates a random port should be used.
  
          :returns: None
  
          """
          ctxt = context.get_admin_context()
          service_ref = objects.Service.get_by_host_and_binary(ctxt, self.host,
                                                               self.binary)
          if service_ref:
              _update_service_ref(service_ref)
          else:
              try:
                  service_ref = _create_service_ref(self, ctxt)
              except (exception.ServiceTopicExists,
                      exception.ServiceBinaryExists):
                  # NOTE(danms): If we race to create a record wth a sibling,
                  # don't fail here.
                  service_ref = objects.Service.get_by_host_and_binary(
                      ctxt, self.host, self.binary)
  
          if self.manager:
              self.manager.init_host()
              self.manager.pre_start_hook()
              if self.backdoor_port is not None:
                  self.manager.backdoor_port = self.backdoor_port
          self.server.start()
          if self.manager:
              self.manager.post_start_hook()
  
      def stop(self):
          """Stop serving this API.
  
          :returns: None
  
          """
          self.server.stop()
  
      def wait(self):
          """Wait for the service to stop serving this API.
  
          :returns: None
  
          """
          self.server.wait()
  
  
  def process_launcher():
      return service.ProcessLauncher(CONF, restart_method='mutate')
  
  
  # NOTE(vish): the global launcher is to maintain the existing
  #             functionality of calling service.serve +
  #             service.wait
  _launcher = None
  
  
  def serve(server, workers=None):
      global _launcher
      if _launcher:
          raise RuntimeError(_('serve() can only be called once'))
  
      _launcher = service.launch(CONF, server, workers=workers)
  
  
  def wait():
      _launcher.wait()
  