# Copyright (c) 2014 VMware, Inc.
# 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.
import ceilometer
from ceilometer.compute import plugin
from ceilometer.compute.pollsters import util
from ceilometer.compute.virt import inspector as virt_inspector
from ceilometer.openstack.common.gettextutils import _
from ceilometer.openstack.common import log
from ceilometer import sample

LOG = log.getLogger(__name__)


class MemoryUsagePollster(plugin.ComputePollster):

    def get_samples(self, manager, cache, resources):
        self._inspection_duration = self._record_poll_time()
        for instance in resources:
            LOG.debug(_('Checking memory usage for instance %s'), instance.id)
            try:
                memory_info = manager.inspector.inspect_memory_usage(
                    instance, self._inspection_duration)
                LOG.debug(_("MEMORY USAGE: %(instance)s %(usage)f"),
                          ({'instance': instance.__dict__,
                            'usage': memory_info.usage}))
                yield util.make_sample_from_instance(
                    instance,
                    name='memory.usage',
                    type=sample.TYPE_GAUGE,
                    unit='MB',
                    volume=memory_info.usage,
                )
            except virt_inspector.InstanceNotFoundException as err:
                # Instance was deleted while getting samples. Ignore it.
                LOG.debug(_('Exception while getting samples %s'), err)
            except ceilometer.NotImplementedError:
                # Selected inspector does not implement this pollster.
                LOG.debug(_('Obtaining Memory Usage is not implemented for %s'
                            ), manager.inspector.__class__.__name__)
            except Exception as err:
                LOG.exception(_('Could not get Memory Usage for '
                                '%(id)s: %(e)s'), {'id': instance.id,
                                                   'e': err})