# Copyright (c) 2014 NetApp, Inc.
# Copyright (c) 2015 Mirantis, 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.

"""Module for managing nova instances for share drivers."""

import abc
import os
import socket
import time

import netaddr
from oslo_config import cfg
from oslo_log import log
from oslo_utils import importutils
from oslo_utils import netutils

from manila.common import constants as const
from manila import compute
from manila import context
from manila import exception
from manila.i18n import _
from manila import image
from manila.network.linux import ip_lib
from manila.network.neutron import api as neutron
from manila import utils

LOG = log.getLogger(__name__)
NEUTRON_NAME = "neutron"

share_servers_handling_mode_opts = [
    cfg.StrOpt(
        "service_image_name",
        default="manila-service-image",
        help="Name of image in Glance, that will be used for service instance "
             "creation. Only used if driver_handles_share_servers=True."),
    cfg.StrOpt(
        "service_instance_name_template",
        default="%s",
        help="Name of service instance. "
             "Only used if driver_handles_share_servers=True."),
    cfg.StrOpt(
        "manila_service_keypair_name",
        default="manila-service",
        help="Keypair name that will be created and used for service "
             "instances. Only used if driver_handles_share_servers=True."),
    cfg.StrOpt(
        "path_to_public_key",
        default="~/.ssh/id_rsa.pub",
        help="Path to hosts public key. "
             "Only used if driver_handles_share_servers=True."),
    cfg.StrOpt(
        "service_instance_security_group",
        default="manila-service",
        help="Security group name, that will be used for "
             "service instance creation. "
             "Only used if driver_handles_share_servers=True."),
    cfg.StrOpt(
        "service_instance_flavor_id",
        default="100",
        help="ID of flavor, that will be used for service instance "
             "creation. Only used if driver_handles_share_servers=True."),
    cfg.StrOpt(
        "service_network_name",
        default="manila_service_network",
        help="Name of manila service network. Used only with Neutron. "
             "Only used if driver_handles_share_servers=True."),
    cfg.StrOpt(
        "service_network_cidr",
        default="10.254.0.0/16",
        help="CIDR of manila service network. Used only with Neutron and "
             "if driver_handles_share_servers=True."),
    cfg.IntOpt(
        "service_network_division_mask",
        default=28,
        help="This mask is used for dividing service network into "
             "subnets, IP capacity of subnet with this mask directly "
             "defines possible amount of created service VMs "
             "per tenant's subnet. Used only with Neutron "
             "and if driver_handles_share_servers=True."),
    cfg.StrOpt(
        "interface_driver",
        default="manila.network.linux.interface.OVSInterfaceDriver",
        help="Module path to the Virtual Interface (VIF) driver class. This "
             "option is used only by drivers operating in "
             "`driver_handles_share_servers=True` mode that provision "
             "OpenStack compute instances as share servers. This option is "
             "only supported with Neutron networking. "
             "Drivers provided in tree work with Linux Bridge "
             "(manila.network.linux.interface.BridgeInterfaceDriver) and OVS "
             "(manila.network.linux.interface.OVSInterfaceDriver). If the "
             "manila-share service is running on a host that is connected to "
             "the administrator network, a no-op driver "
             "(manila.network.linux.interface.NoopInterfaceDriver) may "
             "be used."),
    cfg.BoolOpt(
        "connect_share_server_to_tenant_network",
        default=False,
        help="Attach share server directly to share network. "
             "Used only with Neutron and "
             "if driver_handles_share_servers=True."),
    cfg.StrOpt(
        "admin_network_id",
        help="ID of neutron network used to communicate with admin network,"
             " to create additional admin export locations on."),
    cfg.StrOpt(
        "admin_subnet_id",
        help="ID of neutron subnet used to communicate with admin network,"
             " to create additional admin export locations on. "
             "Related to 'admin_network_id'."),
]

no_share_servers_handling_mode_opts = [
    cfg.StrOpt(
        "service_instance_name_or_id",
        help="Name or ID of service instance in Nova to use for share "
             "exports. Used only when share servers handling is disabled."),
    cfg.HostAddressOpt(
        "service_net_name_or_ip",
        help="Can be either name of network that is used by service "
             "instance within Nova to get IP address or IP address itself "
             "(either IPv4 or IPv6) for managing shares there. "
             "Used only when share servers handling is disabled."),
    cfg.HostAddressOpt(
        "tenant_net_name_or_ip",
        help="Can be either name of network that is used by service "
             "instance within Nova to get IP address or IP address itself "
             "(either IPv4 or IPv6) for exporting shares. "
             "Used only when share servers handling is disabled."),
]

common_opts = [
    cfg.StrOpt(
        "service_instance_user",
        help="User in service instance that will be used for authentication."),
    cfg.StrOpt(
        "service_instance_password",
        secret=True,
        help="Password for service instance user."),
    cfg.StrOpt(
        "path_to_private_key",
        help="Path to host's private key."),
    cfg.IntOpt(
        "max_time_to_build_instance",
        default=300,
        help="Maximum time in seconds to wait for creating service instance."),
    cfg.BoolOpt(
        "limit_ssh_access",
        default=False,
        help="Block SSH connection to the service instance from other "
             "networks than service network."),
]

CONF = cfg.CONF


class ServiceInstanceManager(object):
    """Manages nova instances for various share drivers.

    This class provides following external methods:

    1. set_up_service_instance: creates instance and sets up share
       infrastructure.
    2. ensure_service_instance: ensure service instance is available.
    3. delete_service_instance: removes service instance and network
       infrastructure.
    """
    _INSTANCE_CONNECTION_PROTO = "SSH"

    def get_config_option(self, key):
        """Returns value of config option.

        :param key: key of config' option.
        :returns: str -- value of config's option.
                  first priority is driver's config,
                  second priority is global config.
        """
        if self.driver_config:
            return self.driver_config.safe_get(key)
        return CONF.get(key)

    def _get_network_helper(self):
        # Historically, there were multiple types of network helper,
        # but currently the only network helper type is Neutron.
        return NeutronNetworkHelper(self)

    def __init__(self, driver_config=None):

        super(ServiceInstanceManager, self).__init__()
        self.driver_config = driver_config

        if self.driver_config:
            self.driver_config.append_config_values(common_opts)
            if self.get_config_option("driver_handles_share_servers"):
                self.driver_config.append_config_values(
                    share_servers_handling_mode_opts)
            else:
                self.driver_config.append_config_values(
                    no_share_servers_handling_mode_opts)
        else:
            CONF.register_opts(common_opts)
            if self.get_config_option("driver_handles_share_servers"):
                CONF.register_opts(share_servers_handling_mode_opts)
            else:
                CONF.register_opts(no_share_servers_handling_mode_opts)

        if not self.get_config_option("service_instance_user"):
            raise exception.ServiceInstanceException(
                _('Service instance user is not specified.'))
        self.admin_context = context.get_admin_context()

        self.image_api = image.API()
        self.compute_api = compute.API()

        self.path_to_private_key = self.get_config_option(
            "path_to_private_key")
        self.max_time_to_build_instance = self.get_config_option(
            "max_time_to_build_instance")

        self.availability_zone = self.get_config_option(
            'backend_availability_zone') or CONF.storage_availability_zone

        if self.get_config_option("driver_handles_share_servers"):
            self.path_to_public_key = self.get_config_option(
                "path_to_public_key")
            self._network_helper = None

    @property
    @utils.synchronized("instantiate_network_helper")
    def network_helper(self):
        if not self._network_helper:
            self._network_helper = self._get_network_helper()
            self._network_helper.setup_connectivity_with_service_instances()
        return self._network_helper

    def get_common_server(self):
        data = {
            'public_address': None,
            'private_address': None,
            'service_net_name_or_ip': self.get_config_option(
                'service_net_name_or_ip'),
            'tenant_net_name_or_ip': self.get_config_option(
                'tenant_net_name_or_ip'),
        }

        data['instance'] = self.compute_api.server_get_by_name_or_id(
            self.admin_context,
            self.get_config_option('service_instance_name_or_id'))

        if netutils.is_valid_ip(data['service_net_name_or_ip']):
            data['private_address'] = [data['service_net_name_or_ip']]
        else:
            data['private_address'] = self._get_addresses_by_network_name(
                data['service_net_name_or_ip'], data['instance'])

        if netutils.is_valid_ip(data['tenant_net_name_or_ip']):
            data['public_address'] = [data['tenant_net_name_or_ip']]
        else:
            data['public_address'] = self._get_addresses_by_network_name(
                data['tenant_net_name_or_ip'], data['instance'])

        if not (data['public_address'] and data['private_address']):
            raise exception.ManilaException(
                "Can not find one of net addresses for service instance. "
                "Instance: %(instance)s, "
                "private_address: %(private_address)s, "
                "public_address: %(public_address)s." % data)

        share_server = {
            'username': self.get_config_option('service_instance_user'),
            'password': self.get_config_option('service_instance_password'),
            'pk_path': self.path_to_private_key,
            'instance_id': data['instance']['id'],
        }
        for key in ('private_address', 'public_address'):
            data[key + '_first'] = None
            for address in data[key]:
                if netutils.is_valid_ip(address):
                    data[key + '_first'] = address
                    break
        share_server['ip'] = data['private_address_first']
        share_server['public_address'] = data['public_address_first']
        return {'backend_details': share_server}

    def _get_addresses_by_network_name(self, net_name, server):
        net_ips = []
        if 'networks' in server and net_name in server['networks']:
            net_ips = server['networks'][net_name]
        elif 'addresses' in server and net_name in server['addresses']:
            net_ips = [addr['addr'] for addr in server['addresses'][net_name]]
        return net_ips

    def _get_service_instance_name(self, share_server_id):
        """Returns service vms name."""
        if self.driver_config and self.driver_config.config_group:
            # Make service instance name unique for multibackend installation
            name = "%s_%s" % (self.driver_config.config_group, share_server_id)
        else:
            name = share_server_id
        return self.get_config_option("service_instance_name_template") % name

    def _get_server_ip(self, server, net_name):
        """Returns service IP address of service instance."""
        net_ips = self._get_addresses_by_network_name(net_name, server)
        if not net_ips:
            msg = _("Failed to get service instance IP address. "
                    "Service network name is '%(net_name)s' "
                    "and provided data are '%(data)s'.")
            msg = msg % {'net_name': net_name, 'data': str(server)}
            raise exception.ServiceInstanceException(msg)
        return net_ips[0]

    def _get_or_create_security_groups(self, context, name=None,
                                       description=None,
                                       allow_ssh_subnet=False):
        """Get or create security group for service_instance.

        :param context: context, that should be used
        :param name: this is used for selection/creation of sec.group
        :param description: this is used on sec.group creation step only
        :param allow_ssh_subnet: subnet details to allow ssh connection from,
         if not supplied ssh will be allowed from any host
        :returns: SecurityGroup -- security group instance from Nova
        :raises: exception.ServiceInstanceException.
        """

        sgs = []
        # Common security group
        name = name or self.get_config_option(
            "service_instance_security_group")
        if not name:
            LOG.warning("Name for service instance security group is not "
                        "provided. Skipping security group step.")
            return None
        if not description:
            description = ("This security group is intended "
                           "to be used by share service.")
        sec_group_data = const.SERVICE_INSTANCE_SECGROUP_DATA
        if not allow_ssh_subnet:
            sec_group_data += const.SSH_PORTS

        sgs.append(self._get_or_create_security_group(name, description,
                                                      sec_group_data))
        if allow_ssh_subnet:
            if "cidr" not in allow_ssh_subnet or 'id' not in allow_ssh_subnet:
                raise exception.ManilaException(
                    "Unable to limit SSH access")
            ssh_sg_name = "manila-service-subnet-{}".format(
                allow_ssh_subnet["id"])
            sgs.append(self._get_or_create_security_group(
                ssh_sg_name, description,
                const.SSH_PORTS, allow_ssh_subnet["cidr"]))
        return sgs

    @utils.synchronized(
        "service_instance_get_or_create_security_group", external=True)
    def _get_or_create_security_group(self, name,
                                      description, sec_group_data,
                                      cidr="0.0.0.0/0"):
        s_groups = self.network_helper.neutron_api.security_group_list({
            "name": name,
        })['security_groups']
        s_groups = [s for s in s_groups if s['name'] == name]
        if not s_groups:
            LOG.debug("Creating security group with name '%s'.", name)
            sg = self.network_helper.neutron_api.security_group_create(
                name, description)['security_group']
            for protocol, ports in sec_group_data:
                self.network_helper.neutron_api.security_group_rule_create(
                    parent_group_id=sg['id'],
                    ip_protocol=protocol,
                    from_port=ports[0],
                    to_port=ports[1],
                    cidr=cidr,
                )
        elif len(s_groups) > 1:
            msg = _("Ambiguous security_groups.")
            raise exception.ServiceInstanceException(msg)
        else:
            sg = s_groups[0]
        return sg

    def ensure_service_instance(self, context, server):
        """Ensures that server exists and active."""
        if 'instance_id' not in server:
            LOG.warning("Unable to check server existence since "
                        "'instance_id' key is not set in share server "
                        "backend details.")
            return False
        try:
            inst = self.compute_api.server_get(self.admin_context,
                                               server['instance_id'])
        except exception.InstanceNotFound:
            LOG.warning("Service instance %s does not exist.",
                        server['instance_id'])
            return False
        if inst['status'] == 'ACTIVE':
            return self._check_server_availability(server)
        return False

    def _delete_server(self, context, server_id):
        """Deletes the server."""
        try:
            self.compute_api.server_get(context, server_id)
        except exception.InstanceNotFound:
            LOG.debug("Service instance '%s' was not found. "
                      "Nothing to delete, skipping.", server_id)
            return

        self.compute_api.server_delete(context, server_id)

        t = time.time()
        while time.time() - t < self.max_time_to_build_instance:
            try:
                inst = self.compute_api.server_get(context, server_id)
                if inst.get("status").lower() == "soft_deleted":
                    LOG.debug("Service instance '%s' was soft-deleted "
                              "successfully.", server_id)
                    break
            except exception.InstanceNotFound:
                LOG.debug("Service instance '%s' was deleted "
                          "successfully.", server_id)
                break
            time.sleep(2)
        else:
            raise exception.ServiceInstanceException(
                _("Instance '%(id)s' has not been deleted in %(s)ss. "
                  "Giving up.") % {
                      'id': server_id, 's': self.max_time_to_build_instance})

    def set_up_service_instance(self, context, network_info):
        """Finds or creates and sets up service vm.

        :param context: defines context, that should be used
        :param network_info: network info for getting allocations
        :returns: dict with service instance details
        :raises: exception.ServiceInstanceException
        """
        instance_name = self._get_service_instance_name(
            network_info['server_id'])
        server = self._create_service_instance(
            context, instance_name, network_info)
        instance_details = self._get_new_instance_details(server)

        if not self._check_server_availability(instance_details):
            e = exception.ServiceInstanceException(
                _('%(conn_proto)s connection has not been '
                  'established to %(server)s in %(time)ss. Giving up.') % {
                      'conn_proto': self._INSTANCE_CONNECTION_PROTO,
                      'server': server['ip'],
                      'time': self.max_time_to_build_instance})
            e.detail_data = {'server_details': instance_details}
            raise e

        return instance_details

    def _get_new_instance_details(self, server):
        instance_details = {
            'instance_id': server['id'],
            'ip': server['ip'],
            'pk_path': server.get('pk_path'),
            'subnet_id': server.get('subnet_id'),
            'password': self.get_config_option('service_instance_password'),
            'username': self.get_config_option('service_instance_user'),
            'public_address': server['public_address'],
        }
        if server.get('admin_ip'):
            instance_details['admin_ip'] = server['admin_ip']
        if server.get('router_id'):
            instance_details['router_id'] = server['router_id']
        if server.get('service_port_id'):
            instance_details['service_port_id'] = server['service_port_id']
        if server.get('public_port_id'):
            instance_details['public_port_id'] = server['public_port_id']
        if server.get('admin_port_id'):
            instance_details['admin_port_id'] = server['admin_port_id']

        for key in ('password', 'pk_path', 'subnet_id'):
            if not instance_details[key]:
                instance_details.pop(key)
        return instance_details

    def _load_public_key(self, path):
        with open(path, 'r') as f:
            public_key = f.read()
        return public_key

    @utils.synchronized("service_instance_get_key", external=True)
    def _get_key(self, context):
        """Get ssh key.

        :param context: defines context, that should be used
        :returns: tuple with keypair name and path to private key.
        """
        if not (self.path_to_public_key and self.path_to_private_key):
            return (None, None)
        path_to_public_key = os.path.expanduser(self.path_to_public_key)
        path_to_private_key = os.path.expanduser(self.path_to_private_key)
        if (not os.path.exists(path_to_public_key) or
                not os.path.exists(path_to_private_key)):
            return (None, None)
        keypair_name = self.get_config_option("manila_service_keypair_name")
        keypairs = [k for k in self.compute_api.keypair_list(context)
                    if k.name == keypair_name]
        if len(keypairs) > 1:
            raise exception.ServiceInstanceException(_('Ambiguous keypairs.'))

        public_key = self._load_public_key(path_to_public_key)
        if not keypairs:
            keypair = self.compute_api.keypair_import(
                context, keypair_name, public_key)
        else:
            keypair = keypairs[0]
            if keypair.public_key != public_key:
                LOG.debug('Public key differs from existing keypair. '
                          'Creating new keypair.')
                self.compute_api.keypair_delete(context, keypair.id)
                keypair = self.compute_api.keypair_import(
                    context, keypair_name, public_key)

        return keypair.name, path_to_private_key

    def _get_service_image(self, context):
        """Returns ID of service image for service vm creating."""
        service_image_name = self.get_config_option("service_image_name")
        images = [image.id for image in self.image_api.image_list(context)
                  if image.name == service_image_name
                  and image.status == 'active']
        if not images:
            raise exception.ServiceInstanceException(
                _("Image with name '%s' was not found or is not in "
                  "'active' state.") % service_image_name)
        if len(images) != 1:
            raise exception.ServiceInstanceException(
                _("Multiple 'active' state images found with name '%s'!") %
                service_image_name)
        return images[0]

    def _create_service_instance(self, context, instance_name, network_info):
        """Creates service vm and sets up networking for it."""
        service_image_id = self._get_service_image(context)
        key_name, key_path = self._get_key(context)
        if not (self.get_config_option("service_instance_password") or
                key_name):
            raise exception.ServiceInstanceException(
                _('Neither service instance password nor key are available.'))
        if not key_path:
            LOG.warning(
                'No key path is available. May be non-existent key path is '
                'provided. Check path_to_private_key (current value '
                '%(private_path)s) and path_to_public_key (current value '
                '%(public_path)s) in manila configuration file.', dict(
                    private_path=self.path_to_private_key,
                    public_path=self.path_to_public_key))
        network_data = self.network_helper.setup_network(network_info)
        fail_safe_data = dict(
            router_id=network_data.get('router_id'),
            subnet_id=network_data.get('subnet_id'))
        if network_data.get('service_port'):
            fail_safe_data['service_port_id'] = (
                network_data['service_port']['id'])
        if network_data.get('public_port'):
            fail_safe_data['public_port_id'] = (
                network_data['public_port']['id'])
        if network_data.get('admin_port'):
            fail_safe_data['admin_port_id'] = (
                network_data['admin_port']['id'])
        try:
            create_kwargs = self._get_service_instance_create_kwargs()
            service_instance = self.compute_api.server_create(
                context,
                name=instance_name,
                image=service_image_id,
                flavor=self.get_config_option("service_instance_flavor_id"),
                key_name=key_name,
                nics=network_data['nics'],
                availability_zone=self.availability_zone,
                **create_kwargs)

            fail_safe_data['instance_id'] = service_instance['id']

            service_instance = self.wait_for_instance_to_be_active(
                service_instance['id'],
                self.max_time_to_build_instance)

            if self.get_config_option("limit_ssh_access"):
                try:
                    service_subnet = network_data['service_subnet']
                except KeyError:
                    LOG.error(
                        "Unable to limit ssh access to instance id: '%s'!",
                        fail_safe_data['instance_id'])
                    raise exception.ManilaException(
                        "Unable to limit SSH access - "
                        "invalid service subnet details provided")
            else:
                service_subnet = False

            sec_groups = self._get_or_create_security_groups(
                context, allow_ssh_subnet=service_subnet)

            for sg in sec_groups:
                sg_id = sg['id']
                LOG.debug(
                    "Adding security group '%(sg)s' to server '%(si)s'.",
                    dict(sg=sg_id, si=service_instance["id"]))
                self.compute_api.add_security_group_to_server(
                    context, service_instance["id"], sg_id)

            ip = (network_data.get('service_port',
                                   network_data.get(
                                       'admin_port'))['fixed_ips'])
            service_instance['ip'] = ip[0]['ip_address']
            public_ip = (network_data.get('public_port', network_data.get(
                'service_port'))['fixed_ips'])
            service_instance['public_address'] = public_ip[0]['ip_address']

        except Exception as e:
            e.detail_data = {'server_details': fail_safe_data}
            raise

        service_instance.update(fail_safe_data)
        service_instance['pk_path'] = key_path
        for pair in [('router', 'router_id'), ('service_subnet', 'subnet_id')]:
            if pair[0] in network_data and 'id' in network_data[pair[0]]:
                service_instance[pair[1]] = network_data[pair[0]]['id']

        admin_port = network_data.get('admin_port')
        if admin_port:
            try:
                service_instance['admin_ip'] = (
                    admin_port['fixed_ips'][0]['ip_address'])
            except Exception:
                msg = _("Admin port is being used but Admin IP was not found.")
                LOG.exception(msg)
                raise exception.AdminIPNotFound(reason=msg)

        return service_instance

    def _get_service_instance_create_kwargs(self):
        """Specify extra arguments used when creating the service instance.

        Classes inheriting the service instance manager can use this to easily
        pass extra arguments such as user data or metadata.
        """
        return {}

    def _check_server_availability(self, instance_details):
        t = time.time()
        while time.time() - t < self.max_time_to_build_instance:
            LOG.debug('Checking server availability.')
            if not self._test_server_connection(instance_details):
                time.sleep(5)
            else:
                return True
        return False

    def _test_server_connection(self, server):
        try:
            socket.socket().connect((server['ip'], 22))
            LOG.debug('Server %s is available via SSH.',
                      server['ip'])
            return True
        except socket.error as e:
            LOG.debug(e)
            LOG.debug("Server %s is not available via SSH. Waiting...",
                      server['ip'])
            return False

    def delete_service_instance(self, context, server_details):
        """Removes share infrastructure.

        Deletes service vm and subnet, associated to share network.
        """
        instance_id = server_details.get("instance_id")
        self._delete_server(context, instance_id)
        self.network_helper.teardown_network(server_details)

    def wait_for_instance_to_be_active(self, instance_id, timeout):
        t = time.time()
        while time.time() - t < timeout:
            try:
                service_instance = self.compute_api.server_get(
                    self.admin_context,
                    instance_id)
            except exception.InstanceNotFound as e:
                LOG.debug(e)
                time.sleep(1)
                continue

            instance_status = service_instance['status']
            # NOTE(vponomaryov): emptiness of 'networks' field checked as
            #                    workaround for nova/neutron bug #1210483.
            if (instance_status == 'ACTIVE' and
                    service_instance.get('networks', {})):
                return service_instance
            elif service_instance['status'] == 'ERROR':
                break

            LOG.debug("Waiting for instance %(instance_id)s to be active. "
                      "Current status: %(instance_status)s.",
                      dict(instance_id=instance_id,
                           instance_status=instance_status))
            time.sleep(1)
        raise exception.ServiceInstanceException(
            _("Instance %(instance_id)s failed to reach active state "
              "in %(timeout)s seconds. "
              "Current status: %(instance_status)s.") %
            dict(instance_id=instance_id,
                 timeout=timeout,
                 instance_status=instance_status))

    def reboot_server(self, server, soft_reboot=False):
        self.compute_api.server_reboot(self.admin_context,
                                       server['instance_id'],
                                       soft_reboot)


class BaseNetworkhelper(metaclass=abc.ABCMeta):

    @property
    @abc.abstractmethod
    def NAME(self):
        """Returns code name of network helper."""

    @abc.abstractmethod
    def __init__(self, service_instance_manager):
        """Instantiates class and its attrs."""

    @abc.abstractmethod
    def get_network_name(self, network_info):
        """Returns name of network for service instance."""

    @abc.abstractmethod
    def setup_connectivity_with_service_instances(self):
        """Sets up connectivity between Manila host and service instances."""

    @abc.abstractmethod
    def setup_network(self, network_info):
        """Sets up network for service instance."""

    @abc.abstractmethod
    def teardown_network(self, server_details):
        """Teardowns network resources provided for service instance."""


class NeutronNetworkHelper(BaseNetworkhelper):

    def __init__(self, service_instance_manager):
        self.get_config_option = service_instance_manager.get_config_option
        self.vif_driver = importutils.import_class(
            self.get_config_option("interface_driver"))()

        if service_instance_manager.driver_config:
            self._network_config_group = (
                service_instance_manager.driver_config.network_config_group or
                service_instance_manager.driver_config.config_group)
        else:
            self._network_config_group = None

        self.use_admin_port = False
        self.use_service_network = True
        self._neutron_api = None
        self._service_network_id = None
        self.connect_share_server_to_tenant_network = (
            self.get_config_option('connect_share_server_to_tenant_network'))

        self.admin_network_id = self.get_config_option('admin_network_id')
        self.admin_subnet_id = self.get_config_option('admin_subnet_id')

        if self.admin_network_id and self.admin_subnet_id:
            self.use_admin_port = True
        if self.use_admin_port and self.connect_share_server_to_tenant_network:
            self.use_service_network = False

    @property
    def NAME(self):
        return NEUTRON_NAME

    @property
    def admin_project_id(self):
        return self.neutron_api.admin_project_id

    @property
    @utils.synchronized("instantiate_neutron_api_neutron_net_helper")
    def neutron_api(self):
        if not self._neutron_api:
            self._neutron_api = neutron.API(
                config_group_name=self._network_config_group)
        return self._neutron_api

    @property
    @utils.synchronized("service_network_id_neutron_net_helper")
    def service_network_id(self):
        if not self._service_network_id:
            self._service_network_id = self._get_service_network_id()
        return self._service_network_id

    def get_network_name(self, network_info):
        """Returns name of network for service instance."""
        net = self.neutron_api.get_network(network_info['neutron_net_id'])
        return net['name']

    @utils.synchronized("service_instance_get_service_network", external=True)
    def _get_service_network_id(self):
        """Finds existing or creates new service network."""
        service_network_name = self.get_config_option("service_network_name")
        networks = []
        for network in self.neutron_api.get_all_admin_project_networks():
            if network['name'] == service_network_name:
                networks.append(network)
        if len(networks) > 1:
            raise exception.ServiceInstanceException(
                _('Ambiguous service networks.'))
        elif not networks:
            return self.neutron_api.network_create(
                self.admin_project_id, service_network_name)['id']
        else:
            return networks[0]['id']

    @utils.synchronized(
        "service_instance_setup_and_teardown_network_for_instance",
        external=True)
    def teardown_network(self, server_details):
        subnet_id = server_details.get("subnet_id")
        router_id = server_details.get("router_id")

        service_port_id = server_details.get("service_port_id")
        public_port_id = server_details.get("public_port_id")
        admin_port_id = server_details.get("admin_port_id")
        for port_id in (service_port_id, public_port_id, admin_port_id):
            if port_id:
                try:
                    self.neutron_api.delete_port(port_id)
                except exception.NetworkException as e:
                    if e.kwargs.get('code') != 404:
                        raise
                    LOG.debug("Failed to delete port %(port_id)s with error: "
                              "\n %(exc)s", {"port_id": port_id, "exc": e})

        if router_id and subnet_id:
            ports = self.neutron_api.list_ports(
                fields=['device_id', 'device_owner'],
                fixed_ips=['subnet_id=%s' % subnet_id])
            # NOTE(vponomaryov): iterate ports to get to know whether current
            # subnet is used or not. We will not remove it from router if it
            # is used.
            for port in ports:
                # NOTE(vponomaryov): if device_id is present, then we know that
                # this port is used. Also, if device owner is 'compute:*', then
                # we know that it is VM. We continue only if both are 'True'.
                if (port['device_id'] and
                        port['device_owner'].startswith('compute:')):
                    # NOTE(vponomaryov): There are other share servers
                    # exist that use this subnet. So, do not remove it
                    # from router.
                    return
            try:
                # NOTE(vponomaryov): there is no other share servers or
                # some VMs that use this subnet. So, remove it from router.
                self.neutron_api.router_remove_interface(
                    router_id, subnet_id)
            except exception.NetworkException as e:
                if e.kwargs['code'] != 404:
                    raise
                LOG.debug('Subnet %(subnet_id)s is not attached to the '
                          'router %(router_id)s.',
                          {'subnet_id': subnet_id, 'router_id': router_id})
            self.neutron_api.update_subnet(subnet_id, '')

    @utils.synchronized(
        "service_instance_setup_and_teardown_network_for_instance",
        external=True)
    def setup_network(self, network_info):
        neutron_net_id = network_info['neutron_net_id']
        neutron_subnet_id = network_info['neutron_subnet_id']
        network_data = dict()
        subnet_name = ('service_subnet_for_handling_of_share_server_for_'
                       'tenant_subnet_%s' % neutron_subnet_id)

        if self.use_service_network:
            network_data['service_subnet'] = self._get_service_subnet(
                subnet_name)
            if not network_data['service_subnet']:
                network_data['service_subnet'] = (
                    self.neutron_api.subnet_create(
                        self.admin_project_id, self.service_network_id,
                        subnet_name, self._get_cidr_for_subnet(),
                        self.connect_share_server_to_tenant_network))

        network_data['ports'] = []

        if not self.connect_share_server_to_tenant_network:
            network_data['router'] = self._get_private_router(
                neutron_net_id, neutron_subnet_id)
            try:
                self.neutron_api.router_add_interface(
                    network_data['router']['id'],
                    network_data['service_subnet']['id'])
            except exception.NetworkException as e:
                if e.kwargs['code'] != 400:
                    raise
                LOG.debug('Subnet %(subnet_id)s is already attached to the '
                          'router %(router_id)s.',
                          {'subnet_id': network_data['service_subnet']['id'],
                           'router_id': network_data['router']['id']})
        else:
            network_data['public_port'] = self.neutron_api.create_port(
                self.admin_project_id, neutron_net_id,
                subnet_id=neutron_subnet_id, device_owner='manila')
            network_data['ports'].append(network_data['public_port'])

        if self.use_service_network:
            network_data['service_port'] = self.neutron_api.create_port(
                self.admin_project_id, self.service_network_id,
                subnet_id=network_data['service_subnet']['id'],
                device_owner='manila')
            network_data['ports'].append(network_data['service_port'])

        if self.use_admin_port:
            network_data['admin_port'] = self.neutron_api.create_port(
                self.admin_project_id, self.admin_network_id,
                subnet_id=self.admin_subnet_id, device_owner='manila')
            network_data['ports'].append(network_data['admin_port'])

        try:
            self.setup_connectivity_with_service_instances()
        except Exception:
            for port in network_data['ports']:
                self.neutron_api.delete_port(port['id'])
            raise

        network_data['nics'] = [
            {'port-id': port['id']} for port in network_data['ports']]
        public_ip = network_data.get(
            'public_port', network_data.get('service_port'))
        network_data['ip_address'] = public_ip['fixed_ips'][0]['ip_address']

        return network_data

    def _get_cidr_for_subnet(self):
        """Returns not used cidr for service subnet creating."""
        subnets = self._get_all_service_subnets()
        used_cidrs = set(subnet['cidr'] for subnet in subnets)
        serv_cidr = netaddr.IPNetwork(
            self.get_config_option("service_network_cidr"))
        division_mask = self.get_config_option("service_network_division_mask")
        for subnet in serv_cidr.subnet(division_mask):
            cidr = str(subnet.cidr)
            if cidr not in used_cidrs:
                return cidr
        else:
            raise exception.ServiceInstanceException(_('No available cidrs.'))

    def setup_connectivity_with_service_instances(self):
        """Sets up connectivity with service instances.

        Creates host port in service network and/or admin network, creating
        and setting up required network devices.
        """
        if self.use_service_network:
            LOG.debug("Plugging service instance into service network %s.",
                      self.service_network_id)
            port = self._get_service_port(
                self.service_network_id, None, 'manila-share')
            port = self._add_fixed_ips_to_service_port(port)
            interface_name = self.vif_driver.get_device_name(port)
            device = ip_lib.IPDevice(interface_name)
            self._plug_interface_in_host(interface_name, device, port)

        if self.use_admin_port:
            LOG.debug("Plugging service instance into admin network %s.",
                      self.admin_network_id)
            port = self._get_service_port(
                self.admin_network_id, self.admin_subnet_id,
                'manila-admin-share')
            interface_name = self.vif_driver.get_device_name(port)
            device = ip_lib.IPDevice(interface_name)
            self._plug_interface_in_host(interface_name, device, port,
                                         clear_outdated_routes=True)

    @utils.synchronized("service_instance_plug_interface_in_host",
                        external=True)
    def _plug_interface_in_host(self, interface_name, device, port,
                                clear_outdated_routes=False):

        LOG.debug("Plug interface into host - interface_name: %s, "
                  "device: %s, port: %s", interface_name, device, port)
        self.vif_driver.plug(interface_name, port['id'], port['mac_address'])
        cidrs_to_clear = []
        ip_cidrs = []
        for fixed_ip in port['fixed_ips']:
            subnet = self.neutron_api.get_subnet(fixed_ip['subnet_id'])
            if clear_outdated_routes:
                cidrs_to_clear.append(subnet['cidr'])

            net = netaddr.IPNetwork(subnet['cidr'])
            ip_cidr = '%s/%s' % (fixed_ip['ip_address'], net.prefixlen)
            ip_cidrs.append(ip_cidr)

        self.vif_driver.init_l3(interface_name, ip_cidrs,
                                clear_cidrs=cidrs_to_clear)

    @utils.synchronized("service_instance_get_service_port", external=True)
    def _get_service_port(self, network_id, subnet_id, device_id):
        """Find or creates service neutron port.

        This port will be used for connectivity with service instances.
        """
        host = CONF.host
        search_opts = {'device_id': device_id,
                       'binding:host_id': host}
        ports = [port for port in self.neutron_api.
                 list_ports(**search_opts)]
        if len(ports) > 1:
            raise exception.ServiceInstanceException(
                _('Error. Ambiguous service ports.'))
        elif not ports:
            port = self.neutron_api.create_port(
                self.admin_project_id, network_id, subnet_id=subnet_id,
                device_id=device_id, device_owner='manila:share', host_id=host,
                port_security_enabled=False)
        else:
            port = ports[0]
        return port

    @utils.synchronized(
        "service_instance_add_fixed_ips_to_service_port", external=True)
    def _add_fixed_ips_to_service_port(self, port):
        network = self.neutron_api.get_network(self.service_network_id)
        subnets = set(network['subnets'])
        port_fixed_ips = []
        for fixed_ip in port['fixed_ips']:
            port_fixed_ips.append({'subnet_id': fixed_ip['subnet_id'],
                                   'ip_address': fixed_ip['ip_address']})
            if fixed_ip['subnet_id'] in subnets:
                subnets.remove(fixed_ip['subnet_id'])

        # If there are subnets here that means that
        # we need to add those to the port and call update.
        if subnets:
            port_fixed_ips.extend([dict(subnet_id=s) for s in subnets])
            port = self.neutron_api.update_port_fixed_ips(
                port['id'], {'fixed_ips': port_fixed_ips})

        return port

    @utils.synchronized("service_instance_get_private_router", external=True)
    def _get_private_router(self, neutron_net_id, neutron_subnet_id):
        """Returns router attached to private subnet gateway."""
        private_subnet = self.neutron_api.get_subnet(neutron_subnet_id)
        if not private_subnet['gateway_ip']:
            raise exception.ServiceInstanceException(
                _('Subnet must have gateway.'))
        private_network_ports = [p for p in self.neutron_api.list_ports(
                                 network_id=neutron_net_id)]
        for p in private_network_ports:
            fixed_ip = p['fixed_ips'][0]
            if (fixed_ip['subnet_id'] == private_subnet['id'] and
                    fixed_ip['ip_address'] == private_subnet['gateway_ip']):
                private_subnet_gateway_port = p
                break
        else:
            raise exception.ServiceInstanceException(
                _('Subnet gateway is not attached to the router.'))
        private_subnet_router = self.neutron_api.show_router(
            private_subnet_gateway_port['device_id'])
        return private_subnet_router

    @utils.synchronized("service_instance_get_service_subnet", external=True)
    def _get_service_subnet(self, subnet_name):
        all_service_subnets = self._get_all_service_subnets()
        service_subnets = [subnet for subnet in all_service_subnets
                           if subnet['name'] == subnet_name]
        if len(service_subnets) == 1:
            return service_subnets[0]
        elif not service_subnets:
            unused_service_subnets = [subnet for subnet in all_service_subnets
                                      if subnet['name'] == '']
            if unused_service_subnets:
                service_subnet = unused_service_subnets[0]
                self.neutron_api.update_subnet(
                    service_subnet['id'], subnet_name)
                return service_subnet
            return None
        else:
            raise exception.ServiceInstanceException(
                _('Ambiguous service subnets.'))

    @utils.synchronized(
        "service_instance_get_all_service_subnets", external=True)
    def _get_all_service_subnets(self):
        service_network = self.neutron_api.get_network(self.service_network_id)
        subnets = []
        for subnet_id in service_network['subnets']:
            subnets.append(self.neutron_api.get_subnet(subnet_id))
        return subnets
