text: # 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 django.urls import reverse
  from django.utils.translation import ugettext_lazy as _
  
  from horizon import exceptions
  from horizon import forms
  from horizon import messages
  
  from openstack_dashboard import api
  
  
  class EvacuateHostForm(forms.SelfHandlingForm):
  
      current_host = forms.CharField(label=_("Current Host"),
                                     widget=forms.TextInput(
                                         attrs={'readonly': 'readonly'}))
      target_host = forms.ThemableChoiceField(
          label=_("Target Host"),
          required=False,
          help_text=_("Choose a Host to evacuate servers to. If not selected, "
                      "the scheduler will auto select target host."))
  
      on_shared_storage = forms.BooleanField(label=_("Shared Storage"),
                                             initial=False, required=False)
  
      def __init__(self, request, *args, **kwargs):
          super(EvacuateHostForm, self).__init__(request, *args, **kwargs)
          initial = kwargs.get('initial', {})
          self.fields['target_host'].choices = \
              self.populate_host_choices(request, initial)
  
      def populate_host_choices(self, request, initial):
          hosts = initial.get('hosts')
          current_host = initial.get('current_host')
          host_list = sorted([(host, host)
                              for host in hosts
                              if host != current_host])
          if host_list:
              host_list.insert(0, ("", _("Select a target host")))
          else:
              host_list.insert(0, ("", _("No other hosts available.")))
          return host_list
  
      def handle(self, request, data):
          try:
              current_host = data['current_host']
              target_host = data['target_host']
              on_shared_storage = data['on_shared_storage']
              api.nova.evacuate_host(request, current_host,
                                     target_host, on_shared_storage)
  
              msg = _('Starting to evacuate host: %s.') % current_host
              messages.success(request, msg)
              return True
          except Exception:
              redirect = reverse('horizon:admin:hypervisors:index')
              msg = _('Failed to evacuate host: %s.') % data['current_host']
              exceptions.handle(request, message=msg, redirect=redirect)
              return False
  
  
  class DisableServiceForm(forms.SelfHandlingForm):
      host = forms.CharField(label=_("Host"),
                             widget=forms.TextInput(
                             attrs={"readonly": "readonly"}))
      reason = forms.CharField(max_length=255,
                               label=_("Reason"),
                               required=False)
  
      def handle(self, request, data):
          try:
              host = data["host"]
              reason = data["reason"]
              api.nova.service_disable(request, host, "nova-compute",
                                       reason=reason)
              msg = _("Disabled compute service for host: %s.") % host
              messages.success(request, msg)
              return True
          except Exception:
              redirect = reverse('horizon:admin:hypervisors:index')
              msg = _("Failed to disable compute service for host: %s.") % \
                  data["host"]
              exceptions.handle(request, message=msg, redirect=redirect)
              return False
  
  
  class MigrateHostForm(forms.SelfHandlingForm):
      current_host = forms.CharField(
          label=_("Current Host"),
          required=False,
          widget=forms.TextInput(
              attrs={'readonly': 'readonly'})
      )
  
      migrate_type = forms.ChoiceField(
          label=_('Running Instance Migration Type'),
          choices=[
              ('live_migrate', _('Live Migrate')),
              ('cold_migrate', _('Cold Migrate'))
          ],
          widget=forms.ThemableSelectWidget(
              attrs={
                  'class': 'switchable',
                  'data-slug': 'source'
              }
          )
      )
  
      disk_over_commit = forms.BooleanField(
          label=_("Disk Over Commit"),
          initial=False,
          required=False,
          widget=forms.CheckboxInput(
              attrs={
                  'class': 'switched',
                  'data-switch-on': 'source',
                  'data-source-live_migrate': _('Disk Over Commit')
              }
          )
      )
  
      block_migration = forms.BooleanField(
          label=_("Block Migration"),
          initial=False,
          required=False,
          widget=forms.CheckboxInput(
              attrs={
                  'class': 'switched',
                  'data-switch-on': 'source',
                  'data-source-live_migrate': _('Block Migration')
              }
          )
      )
  
      def handle(self, request, data):
          try:
              current_host = data['current_host']
              migrate_type = data['migrate_type']
              disk_over_commit = data['disk_over_commit']
              block_migration = data['block_migration']
              live_migrate = migrate_type == 'live_migrate'
              api.nova.migrate_host(
                  request,
                  current_host,
                  live_migrate=live_migrate,
                  disk_over_commit=disk_over_commit,
                  block_migration=block_migration
              )
              msg = _('Starting to migrate host: %(current)s') % \
                  {'current': current_host}
              messages.success(request, msg)
              return True
          except Exception:
              msg = _('Failed to migrate host "%s".') % data['current_host']
              redirect = reverse('horizon:admin:hypervisors:index')
              exceptions.handle(request, message=msg, redirect=redirect)
              return False
  