# Copyright (c) 2016 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.

"""Container Driver for shares.

This driver uses a container as a share server.
Current implementation suggests that a container when started by Docker will
be plugged into a Linux bridge. Also it is suggested that all interfaces
willing to talk to each other reside in an OVS bridge."""

import re

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

from manila import exception
from manila.i18n import _
from manila.i18n import _LI
from manila.i18n import _LW
from manila.share import driver
from manila import utils


CONF = cfg.CONF
LOG = log.getLogger(__name__)


container_opts = [
    cfg.StrOpt("container_linux_bridge_name",
               default="docker0",
               required=True,
               help="Linux bridge used by container hypervisor to plug "
                    "host-side veth to. It will be unplugged from here "
                    "by the driver."),
    cfg.StrOpt("container_ovs_bridge_name",
               default="br-int",
               required=True,
               help="OVS bridge to use to plug a container to."),
    cfg.BoolOpt("container_cifs_guest_ok",
                default=True,
                help="Determines whether to allow guest access to CIFS share "
                     "or not."),
    cfg.StrOpt("container_image_name",
               default="manila-docker-container",
               help="Image to be used for a container-based share server."),
    cfg.StrOpt("container_helper",
               default="manila.share.drivers.container.container_helper."
               "DockerExecHelper",
               help="Container helper which provides container-related "
                    "operations to the driver."),
    cfg.StrOpt("container_protocol_helper",
               default="manila.share.drivers.container.protocol_helper."
               "DockerCIFSHelper",
               help="Helper which facilitates interaction with share server."),
    cfg.StrOpt("container_storage_helper",
               default="manila.share.drivers.container.storage_helper."
               "LVMHelper",
               help="Helper which facilitates interaction with storage "
                    "solution used to actually store data. By default LVM "
                    "is used to provide storage for a share."),
]


class ContainerShareDriver(driver.ShareDriver, driver.ExecuteMixin):
    def __init__(self, *args, **kwargs):
        super(ContainerShareDriver, self).__init__([True], *args, **kwargs)
        self.configuration.append_config_values(container_opts)
        self.backend_name = self.configuration.safe_get(
            "share_backend_name") or "Docker"
        self.container = importutils.import_class(
            self.configuration.container_helper)(
                configuration=self.configuration)
        self.storage = importutils.import_class(
            self.configuration.container_storage_helper)(
                configuration=self.configuration)
        self._helpers = {}

    def _get_helper(self, share):
        if share["share_proto"].upper() == "CIFS":
            helper = self._helpers.get("CIFS")
            if helper is not None:
                return helper(self.container,
                              share=share,
                              config=self.configuration)
            self._helpers["CIFS"] = importutils.import_class(
                self.configuration.container_protocol_helper)
            return self._helpers["CIFS"](self.container,
                                         share=share,
                                         config=self.configuration)
        else:
            raise exception.InvalidShare(
                reason=_("Wrong, unsupported or disabled protocol."))

    def _update_share_stats(self):
        data = {
            'share_backend_name': self.backend_name,
            'storage_protocol': 'CIFS',
            'reserved_percentage':
                self.configuration.reserved_share_percentage,
            'consistency_group_support': None,
            'snapshot_support': False,
            'driver_name': 'ContainerShareDriver',
            'pools': self.storage.get_share_server_pools()
        }
        super(ContainerShareDriver, self)._update_share_stats(data)

    def create_share(self, context, share, share_server=None):
        LOG.debug("Create share on server '%s'." % share_server["id"])
        server_id = self._get_container_name(share_server["id"])
        share_name = share.share_id
        self.container.execute(
            server_id,
            ["mkdir", "-m", "750", "/shares/%s" % share_name]
        )
        self.storage.provide_storage(share)
        location = self._get_helper(share).create_share(server_id)
        return location

    def delete_share(self, context, share, share_server=None):
        LOG.debug("Deleting share %(share)s on server '%(server)s'." %
                  {"server": share_server["id"],
                   "share": share.share_id})
        server_id = self._get_container_name(share_server["id"])
        self._get_helper(share).delete_share(server_id)

        self.storage.remove_storage(share)
        self.container.execute(
            server_id,
            ["rm", "-fR", "/shares/%s" % share.share_id]
        )
        LOG.debug("Deletion of share %s is completed!", share.share_id)

    def extend_share(self, share, new_size, share_server=None):
        self.storage.extend_share(share, new_size, share_server)

    def ensure_share(self, context, share, share_server=None):
        pass

    def update_access(self, context, share, access_rules, add_rules,
                      delete_rules, share_server=None):
        server_id = self._get_container_name(share_server["id"])
        LOG.debug("Updating access to share %(share)s at "
                  "share server %(share_server)s.",
                  {"share_server": share_server["id"],
                   "share": share.share_id})
        self._get_helper(share).update_access(server_id,
                                              access_rules, add_rules,
                                              delete_rules)

    def get_network_allocations_number(self):
        return 1

    def _get_container_name(self, server_id):
        return "manila_%s" % server_id.replace("-", "_")

    def do_setup(self, *args, **kwargs):
        pass

    def check_for_setup_error(self, *args, **kwargs):
        host_id = self.configuration.safe_get("neutron_host_id")
        neutron_class = importutils.import_class(
            'manila.network.neutron.neutron_network_plugin.'
            'NeutronNetworkPlugin'
        )
        actual_class = importutils.import_class(
            self.configuration.safe_get("network_api_class"))
        if host_id is None and issubclass(actual_class, neutron_class):
            msg = _("%s requires neutron_host_id to be "
                    "specified.") % neutron_class
            raise exception.ManilaException(msg)
        elif host_id is None:
            LOG.warning(_LW("neutron_host_id is not specified. This driver "
                            "might not work as expected without it."))

    def _connect_to_network(self, server_id, network_info, host_veth):
        LOG.debug("Attempting to connect container to neutron network.")
        network_allocation = network_info['network_allocations'][0]
        port_address = network_allocation.ip_address
        port_mac = network_allocation.mac_address
        port_id = network_allocation.id
        self.container.execute(
            server_id,
            ["ifconfig", "eth0", port_address, "up"]
        )
        self.container.execute(
            server_id,
            ["ip", "link", "set", "dev", "eth0", "address", port_mac]
        )
        msg_helper = {
            'id': server_id, 'veth': host_veth,
            'lb': self.configuration.container_linux_bridge_name,
            'ovsb': self.configuration.container_ovs_bridge_name,
            'ip': port_address,
            'subnet': network_info['neutron_subnet_id'],
        }
        LOG.debug("Container %(id)s veth is %(veth)s.", msg_helper)
        LOG.debug("Removing %(veth)s from %(lb)s.", msg_helper)
        self._execute("brctl", "delif",
                      self.configuration.container_linux_bridge_name,
                      host_veth,
                      run_as_root=True)

        LOG.debug("Plugging %(veth)s into %(ovsb)s.", msg_helper)
        set_if = ['--', 'set', 'interface', host_veth]
        e_mac = set_if + ['external-ids:attached-mac="%s"' % port_mac]
        e_id = set_if + ['external-ids:iface-id="%s"' % port_id]
        e_status = set_if + ['external-ids:iface-status=active']
        e_mcid = set_if + ['external-ids:manila-container=%s' % server_id]
        self._execute("ovs-vsctl", "--", "add-port",
                      self.configuration.container_ovs_bridge_name, host_veth,
                      *(e_mac + e_id + e_status + e_mcid), run_as_root=True)
        LOG.debug("Now container %(id)s should be accessible from network "
                  "%(subnet)s by address %(ip)s." % msg_helper)

    def _teardown_server(self, *args, **kwargs):
        server_id = self._get_container_name(kwargs["server_details"]["id"])
        self.container.stop_container(server_id)
        interfaces = self._execute("ovs-vsctl", "list", "interface",
                                   run_as_root=True)[0]
        veths = re.findall("veth[0-9a-zA-Z]{7}", interfaces)
        manila_re = ("manila_[0-9a-f]{8}_[0-9a-f]{4}_[0-9a-f]{4}_[0-9a-f]{4}_"
                     "[0-9a-f]{12}")
        for veth in veths:
            iface_data = self._execute("ovs-vsctl", "list", "interface", veth,
                                       run_as_root=True)[0]
            container_id = re.findall(manila_re, iface_data)
            if container_id == []:
                continue
            elif container_id[0] == server_id:
                LOG.debug("Deleting veth %s.", veth)
                self._execute("ovs-vsctl", "--", "del-port",
                              self.configuration.container_ovs_bridge_name,
                              veth, run_as_root=True)

    def _get_veth_state(self):
        result = self._execute("brctl", "show",
                               self.configuration.container_linux_bridge_name,
                               run_as_root=True)
        veths = re.findall("veth.*\\n", result[0])
        veths = [x.rstrip('\n') for x in veths]
        msg = ("The following veth interfaces are plugged into %s now: " %
               self.configuration.container_linux_bridge_name)
        LOG.debug(msg + ", ".join(veths))
        return veths

    def _get_corresponding_veth(self, before, after):
        result = list(set(after) ^ set(before))
        if len(result) != 1:
            raise exception.ManilaException(_("Multiple veths for container."))
        return result[0]

    @utils.synchronized("veth-lock", external=True)
    def _setup_server(self, network_info, metadata=None):
        msg = "Creating share server '%s'."
        server_id = self._get_container_name(network_info["server_id"])
        LOG.debug(msg % server_id)

        veths_before = self._get_veth_state()
        try:
            self.container.start_container(server_id)
        except Exception as e:
            raise exception.ManilaException(_("Cannot create container: %s") %
                                            e)
        veths_after = self._get_veth_state()

        veth = self._get_corresponding_veth(veths_before, veths_after)
        self._connect_to_network(server_id, network_info, veth)
        LOG.info(_LI("Container %s was created."), server_id)
        return {"id": network_info["server_id"]}
