# Copyright 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.

"""
Dummy share driver for testing Manila APIs and other interfaces.

This driver simulates support of:
- Both available driver modes: DHSS=True/False
- NFS and CIFS protocols
- IP access for NFS shares and USER access for CIFS shares
- CIFS shares in DHSS=True driver mode
- Creation and deletion of share snapshots
- Share replication (readable)
- Share migration
- Consistency groups
- Resize of a share (extend/shrink)

"""

import functools
import time

from oslo_config import cfg
from oslo_log import log
from oslo_serialization import jsonutils
from oslo_utils import timeutils

from manila.common import constants
from manila import exception
from manila.i18n import _
from manila.share import configuration
from manila.share import driver
from manila.share.manager import share_manager_opts  # noqa
from manila.share import utils as share_utils

LOG = log.getLogger(__name__)


dummy_opts = [
    cfg.FloatOpt(
        "dummy_driver_default_driver_method_delay",
        help="Defines default time delay in seconds for each dummy driver "
             "method. To redefine some specific method delay use other "
             "'dummy_driver_driver_methods_delays' config opt. Optional.",
        default=2.0,
        min=0,
    ),
    cfg.DictOpt(
        "dummy_driver_driver_methods_delays",
        help="It is dictionary-like config option, that consists of "
             "driver method names as keys and integer/float values that are "
             "time delay in seconds. Optional.",
        default={
            "ensure_share": "1.05",
            "create_share": "3.98",
            "get_pool": "0.5",
            "do_setup": "0.05",

            "_get_pools_info": "0.1",
            "_update_share_stats": "0.3",

            "create_replica": "3.99",
            "delete_replica": "2.98",
            "promote_replica": "0.75",
            "update_replica_state": "0.85",
            "create_replicated_snapshot": "4.15",
            "delete_replicated_snapshot": "3.16",
            "update_replicated_snapshot": "1.17",

            "migration_start": 1.01,
            "migration_continue": 1.02,  # it will be called 2 times
            "migration_complete": 1.03,
            "migration_cancel": 1.04,
            "migration_get_progress": 1.05,
            "migration_check_compatibility": 0.05,
        },
    ),
]

CONF = cfg.CONF


def slow_me_down(f):

    @functools.wraps(f)
    def wrapped_func(self, *args, **kwargs):
        sleep_time = self.configuration.safe_get(
            "dummy_driver_driver_methods_delays").get(
                f.__name__,
                self.configuration.safe_get(
                    "dummy_driver_default_driver_method_delay")
            )
        time.sleep(float(sleep_time))
        return f(self, *args, **kwargs)

    return wrapped_func


def get_backend_configuration(backend_name):
    config_stanzas = CONF.list_all_sections()
    if backend_name not in config_stanzas:
        msg = _("Could not find backend stanza %(backend_name)s in "
                "configuration which is required for share replication and "
                "migration. Available stanzas are %(stanzas)s")
        params = {
            "stanzas": config_stanzas,
            "backend_name": backend_name,
        }
        raise exception.BadConfigurationException(reason=msg % params)

    config = configuration.Configuration(
        driver.share_opts, config_group=backend_name)
    config.append_config_values(dummy_opts)
    config.append_config_values(share_manager_opts)
    config.append_config_values(driver.ssh_opts)

    return config


class DummyDriver(driver.ShareDriver):
    """Dummy share driver that implements all share driver interfaces."""

    def __init__(self, *args, **kwargs):
        """Do initialization."""
        super(DummyDriver, self).__init__(
            [False, True], *args, config_opts=[dummy_opts], **kwargs)
        self._verify_configuration()
        self.private_storage = kwargs.get('private_storage')
        self.backend_name = self.configuration.safe_get(
            "share_backend_name") or "DummyDriver"
        self.migration_progress = {}
        self.security_service_update_support = True
        self.network_allocation_update_support = True

    def _verify_configuration(self):
        allowed_driver_methods = [m for m in dir(self) if m[0] != '_']
        allowed_driver_methods.extend([
            "_setup_server",
            "_teardown_server",
            "_get_pools_info",
            "_update_share_stats",
        ])
        disallowed_driver_methods = (
            "get_admin_network_allocations_number",
            "get_network_allocations_number",
            "get_share_server_pools",
        )
        for k, v in self.configuration.safe_get(
                "dummy_driver_driver_methods_delays").items():
            if k not in allowed_driver_methods:
                raise exception.BadConfigurationException(reason=(
                    "Dummy driver does not have '%s' method." % k
                ))
            elif k in disallowed_driver_methods:
                raise exception.BadConfigurationException(reason=(
                    "Method '%s' does not support delaying." % k
                ))
            try:
                float(v)
            except (TypeError, ValueError):
                raise exception.BadConfigurationException(reason=(
                    "Wrong value (%(v)s) for '%(k)s' dummy driver method time "
                    "delay is set in 'dummy_driver_driver_methods_delays' "
                    "config option." % {"k": k, "v": v}
                ))

    def _get_share_name(self, share):
        return "share_%(s_id)s_%(si_id)s" % {
            "s_id": share["share_id"].replace("-", "_"),
            "si_id": share["id"].replace("-", "_")}

    def _get_snapshot_name(self, snapshot):
        return "snapshot_%(s_id)s_%(si_id)s" % {
            "s_id": snapshot["snapshot_id"].replace("-", "_"),
            "si_id": snapshot["id"].replace("-", "_")}

    def _get_export(self, mountpoint, ip, is_admin_only, preferred):
        return {
            "path": "%(ip)s:%(mp)s" % {"ip": ip, "mp": mountpoint},
            "metadata": {
                "preferred": preferred,
            },
            "is_admin_only": is_admin_only,
        }

    def _get_subnet_allocations_from_backend_details(self, backend_details):
        """Reads subnet_allocations info from backend details"""
        # NOTE(sfernand): Ensure backward compatibility for share servers
        # created prior to the addition of support to multiple subnets per AZ,
        # by read ip information using the old format in case
        # subnet_allocations does not exist.
        if 'subnet_allocations' in backend_details:
            subnet_allocations = jsonutils.loads(
                backend_details['subnet_allocations'])
        else:
            subnet_allocations = [{
                'primary_public_ip':
                    backend_details['primary_public_ip'],
                'secondary_public_ip':
                    backend_details['secondary_public_ip']
            }]
        return subnet_allocations

    def _generate_export_locations(self, mountpoint, share_server=None):
        if share_server:
            backend_details = share_server['backend_details']
            subnet_allocations = (
                self._get_subnet_allocations_from_backend_details(
                    backend_details))
            service_ip = backend_details["service_ip"]
        else:
            subnet_allocations = [{
                "primary_public_ip": "10.0.0.10",
                "secondary_public_ip": "10.0.0.20",
            }]
            service_ip = "11.0.0.11"

        export_locations = [
            self._get_export(mountpoint, service_ip, True, False)]
        for subnet_allocation in subnet_allocations:
            export_locations.append(
                self._get_export(
                    mountpoint, subnet_allocation["primary_public_ip"],
                    False, True))
            export_locations.append(
                self._get_export(
                    mountpoint, subnet_allocation["secondary_public_ip"],
                    False, False))

        return export_locations

    def _create_share(self, share, share_server=None):
        share_proto = share["share_proto"]
        if share_proto not in ("NFS", "CIFS"):
            msg = _("Unsupported share protocol provided - %s.") % share_proto
            raise exception.InvalidShareAccess(reason=msg)

        share_name = self._get_share_name(share)
        mountpoint = "/path/to/fake/share/%s" % share_name
        self.private_storage.update(
            share["id"], {
                "fake_provider_share_name": share_name,
                "fake_provider_location": mountpoint,
            }
        )
        return self._generate_export_locations(
            mountpoint, share_server=share_server)

    @slow_me_down
    def create_share(self, context, share, share_server=None):
        """Is called to create share."""
        return self._create_share(share, share_server=share_server)

    @slow_me_down
    def create_share_from_snapshot(self, context, share, snapshot,
                                   share_server=None, parent_share=None):
        """Is called to create share from snapshot."""
        export_locations = self._create_share(share, share_server=share_server)
        return {
            'export_locations': export_locations,
            'status': constants.STATUS_AVAILABLE
        }

    def _create_snapshot(self, snapshot, share_server=None):
        snapshot_name = self._get_snapshot_name(snapshot)
        mountpoint = "/path/to/fake/snapshot/%s" % snapshot_name
        self.private_storage.update(
            snapshot["id"], {
                "fake_provider_snapshot_name": snapshot_name,
                "fake_provider_location": mountpoint,
            }
        )
        return {
            'fake_key1': 'fake_value1',
            'fake_key2': 'fake_value2',
            'fake_key3': 'fake_value3',
            "provider_location": mountpoint,
            "export_locations": self._generate_export_locations(
                mountpoint, share_server=share_server)
        }

    @slow_me_down
    def create_snapshot(self, context, snapshot, share_server=None):
        """Is called to create snapshot."""
        return self._create_snapshot(snapshot, share_server)

    @slow_me_down
    def delete_share(self, context, share, share_server=None):
        """Is called to remove share."""
        self.private_storage.delete(share["id"])

    @slow_me_down
    def delete_snapshot(self, context, snapshot, share_server=None):
        """Is called to remove snapshot."""
        LOG.debug('Deleting snapshot with following data: %s', snapshot)
        self.private_storage.delete(snapshot["id"])

    @slow_me_down
    def get_pool(self, share):
        """Return pool name where the share resides on."""
        pool_name = share_utils.extract_host(share["host"], level="pool")
        return pool_name

    @slow_me_down
    def ensure_share(self, context, share, share_server=None):
        """Invoked to ensure that share is exported."""

    @slow_me_down
    def update_access(self, context, share, access_rules, add_rules,
                      delete_rules, share_server=None):
        """Update access rules for given share."""
        for rule in add_rules + access_rules:
            share_proto = share["share_proto"].lower()
            access_type = rule["access_type"].lower()
            if not (
                    (share_proto == "nfs" and access_type == "ip") or
                    (share_proto == "cifs" and access_type == "user")):
                msg = _("Unsupported '%(access_type)s' access type provided "
                        "for '%(share_proto)s' share protocol.") % {
                    "access_type": access_type, "share_proto": share_proto}
                raise exception.InvalidShareAccess(reason=msg)

    @slow_me_down
    def snapshot_update_access(self, context, snapshot, access_rules,
                               add_rules, delete_rules, share_server=None):
        """Update access rules for given snapshot."""
        self.update_access(context, snapshot['share'], access_rules,
                           add_rules, delete_rules, share_server)

    @slow_me_down
    def do_setup(self, context):
        """Any initialization the share driver does while starting."""

    @slow_me_down
    def manage_existing(self, share, driver_options):
        """Brings an existing share under Manila management."""
        new_export = share['export_location']
        old_share_id = self._get_share_id_from_export(new_export)
        old_export = self.private_storage.get(
            old_share_id, key='export_location')
        if old_export.split(":/")[-1] == new_export.split(":/")[-1]:
            result = {"size": 1, "export_locations": self._create_share(share)}
            self.private_storage.delete(old_share_id)
            return result
        else:
            msg = ("Invalid export specified, existing share %s"
                   " could not be found" % old_share_id)
            raise exception.ShareBackendException(msg=msg)

    @slow_me_down
    def manage_existing_with_server(
            self, share, driver_options, share_server=None):
        return self.manage_existing(share, driver_options)

    def _get_share_id_from_export(self, export_location):
        values = export_location.split('share_')
        if len(values) > 1:
            return values[1][37:].replace("_", "-")
        else:
            return export_location

    @slow_me_down
    def unmanage(self, share):
        """Removes the specified share from Manila management."""
        self.private_storage.update(
            share['id'], {'export_location': share['export_location']})

    @slow_me_down
    def unmanage_with_server(self, share, share_server=None):
        self.unmanage(share)

    @slow_me_down
    def manage_existing_snapshot_with_server(self, snapshot, driver_options,
                                             share_server=None):
        return self.manage_existing_snapshot(snapshot, driver_options)

    @slow_me_down
    def manage_existing_snapshot(self, snapshot, driver_options):
        """Brings an existing snapshot under Manila management."""
        old_snap_id = self._get_snap_id_from_provider_location(
            snapshot['provider_location'])
        old_provider_location = self.private_storage.get(
            old_snap_id, key='provider_location')
        if old_provider_location == snapshot['provider_location']:
            self._create_snapshot(snapshot)
            self.private_storage.delete(old_snap_id)
            return {"size": 1,
                    "provider_location": snapshot["provider_location"]}
        else:
            msg = ("Invalid provider location specified, existing snapshot %s"
                   " could not be found" % old_snap_id)
            raise exception.ShareBackendException(msg=msg)

    def _get_snap_id_from_provider_location(self, provider_location):
        values = provider_location.split('snapshot_')
        if len(values) > 1:
            return values[1][37:].replace("_", "-")
        else:
            return provider_location

    @slow_me_down
    def unmanage_snapshot(self, snapshot):
        """Removes the specified snapshot from Manila management."""
        self.private_storage.update(
            snapshot['id'],
            {'provider_location': snapshot['provider_location']})

    @slow_me_down
    def unmanage_snapshot_with_server(self, snapshot, share_server=None):
        self.unmanage_snapshot(snapshot)

    @slow_me_down
    def revert_to_snapshot(self, context, snapshot, share_access_rules,
                           snapshot_access_rules, share_server=None):
        """Reverts a share (in place) to the specified snapshot."""

    @slow_me_down
    def extend_share(self, share, new_size, share_server=None):
        """Extends size of existing share."""

    @slow_me_down
    def shrink_share(self, share, new_size, share_server=None):
        """Shrinks size of existing share."""

    def get_network_allocations_number(self):
        """Returns number of network allocations for creating VIFs."""
        return 2

    def get_admin_network_allocations_number(self):
        return 1

    @slow_me_down
    def _setup_server(self, network_info, metadata=None):
        """Sets up and configures share server with given network parameters.

        Redefine it within share driver when it is going to handle share
        servers.
        """
        common_net_info = network_info[0]
        server_details = {
            "service_ip": common_net_info[
                "admin_network_allocations"][0]["ip_address"],
            "username": "fake_username",
            "server_id": common_net_info['server_id'],
        }

        subnet_allocations = []
        for subnet_info in network_info:
            subnet_allocations.append({
                "primary_public_ip": subnet_info[
                    "network_allocations"][0]["ip_address"],
                "secondary_public_ip": subnet_info[
                    "network_allocations"][1]["ip_address"]
            })

        server_details['subnet_allocations'] = jsonutils.dumps(
            subnet_allocations)
        return server_details

    @slow_me_down
    def _teardown_server(self, server_details, security_services=None):
        """Tears down share server."""

    @slow_me_down
    def _get_pools_info(self):
        pools = [{
            "pool_name": "fake_pool_for_%s" % self.backend_name,
            "total_capacity_gb": 1230.0,
            "free_capacity_gb": 1210.0,
            "reserved_percentage":
                self.configuration.reserved_share_percentage,
            "reserved_snapshot_percentage":
                self.configuration.reserved_share_from_snapshot_percentage,
            "reserved_share_extend_percentage":
                self.configuration.reserved_share_extend_percentage
        }]
        if self.configuration.replication_domain:
            pools[0]["replication_type"] = "readable"
        return pools

    @slow_me_down
    def _update_share_stats(self, data=None):
        """Retrieve stats info from share group."""
        data = {
            "share_backend_name": self.backend_name,
            "storage_protocol": "NFS_CIFS",
            "reserved_percentage":
                self.configuration.reserved_share_percentage,
            "reserved_snapshot_percentage":
                self.configuration.reserved_share_from_snapshot_percentage,
            "reserved_share_extend_percentage":
                self.configuration.reserved_share_extend_percentage,
            "snapshot_support": True,
            "create_share_from_snapshot_support": True,
            "revert_to_snapshot_support": True,
            "mount_snapshot_support": True,
            "driver_name": "Dummy",
            "pools": self._get_pools_info(),
            "share_group_stats": {
                "consistent_snapshot_support": "pool",
            },
            'share_server_multiple_subnet_support': True,
        }
        if self.configuration.replication_domain:
            data["replication_type"] = "readable"
        super(DummyDriver, self)._update_share_stats(data)

    def get_share_server_pools(self, share_server):
        """Return list of pools related to a particular share server."""
        return []

    @slow_me_down
    def create_consistency_group(self, context, cg_dict, share_server=None):
        """Create a consistency group."""
        LOG.debug(
            "Successfully created dummy Consistency Group with ID: %s.",
            cg_dict["id"])

    @slow_me_down
    def delete_consistency_group(self, context, cg_dict, share_server=None):
        """Delete a consistency group."""
        LOG.debug(
            "Successfully deleted dummy consistency group with ID %s.",
            cg_dict["id"])

    @slow_me_down
    def create_cgsnapshot(self, context, snap_dict, share_server=None):
        """Create a consistency group snapshot."""
        LOG.debug("Successfully created CG snapshot %s.", snap_dict["id"])
        return None, None

    @slow_me_down
    def delete_cgsnapshot(self, context, snap_dict, share_server=None):
        """Delete a consistency group snapshot."""
        LOG.debug("Successfully deleted CG snapshot %s.", snap_dict["id"])
        return None, None

    @slow_me_down
    def create_consistency_group_from_cgsnapshot(
            self, context, cg_dict, cgsnapshot_dict, share_server=None):
        """Create a consistency group from a cgsnapshot."""
        LOG.debug(
            ("Successfully created dummy Consistency Group (%(cg_id)s) "
             "from CG snapshot (%(cg_snap_id)s)."),
            {"cg_id": cg_dict["id"], "cg_snap_id": cgsnapshot_dict["id"]})
        return None, []

    @slow_me_down
    def create_replica(self, context, replica_list, new_replica,
                       access_rules, replica_snapshots, share_server=None):
        """Replicate the active replica to a new replica on this backend."""
        replica_name = self._get_share_name(new_replica)
        mountpoint = "/path/to/fake/share/%s" % replica_name
        self.private_storage.update(
            new_replica["id"], {
                "fake_provider_replica_name": replica_name,
                "fake_provider_location": mountpoint,
            }
        )
        return {
            "export_locations": self._generate_export_locations(
                mountpoint, share_server=share_server),
            "replica_state": constants.REPLICA_STATE_IN_SYNC,
            "access_rules_status": constants.STATUS_ACTIVE,
        }

    @slow_me_down
    def delete_replica(self, context, replica_list, replica_snapshots,
                       replica, share_server=None):
        """Delete a replica."""
        self.private_storage.delete(replica["id"])

    @slow_me_down
    def promote_replica(self, context, replica_list, replica, access_rules,
                        share_server=None, quiesce_wait_time=None):
        """Promote a replica to 'active' replica state."""
        return_replica_list = []
        for r in replica_list:
            if r["id"] == replica["id"]:
                replica_state = constants.REPLICA_STATE_ACTIVE
            else:
                replica_state = constants.REPLICA_STATE_IN_SYNC
            return_replica_list.append(
                {"id": r["id"], "replica_state": replica_state})
        return return_replica_list

    @slow_me_down
    def update_replica_state(self, context, replica_list, replica,
                             access_rules, replica_snapshots,
                             share_server=None):
        """Update the replica_state of a replica."""
        return constants.REPLICA_STATE_IN_SYNC

    @slow_me_down
    def create_replicated_snapshot(self, context, replica_list,
                                   replica_snapshots, share_server=None):
        """Create a snapshot on active instance and update across the replicas.

        """
        return_replica_snapshots = []
        for r in replica_snapshots:
            return_replica_snapshots.append(
                {"id": r["id"], "status": constants.STATUS_AVAILABLE})
        return return_replica_snapshots

    @slow_me_down
    def revert_to_replicated_snapshot(self, context, active_replica,
                                      replica_list, active_replica_snapshot,
                                      replica_snapshots, share_access_rules,
                                      snapshot_access_rules,
                                      share_server=None):
        """Reverts a replicated share (in place) to the specified snapshot."""

    @slow_me_down
    def delete_replicated_snapshot(self, context, replica_list,
                                   replica_snapshots, share_server=None):
        """Delete a snapshot by deleting its instances across the replicas."""
        return_replica_snapshots = []
        for r in replica_snapshots:
            return_replica_snapshots.append(
                {"id": r["id"], "status": constants.STATUS_DELETED})
        return return_replica_snapshots

    @slow_me_down
    def update_replicated_snapshot(self, context, replica_list,
                                   share_replica, replica_snapshots,
                                   replica_snapshot, share_server=None):
        """Update the status of a snapshot instance that lives on a replica."""
        return {
            "id": replica_snapshot["id"], "status": constants.STATUS_AVAILABLE}

    @slow_me_down
    def migration_check_compatibility(
            self, context, source_share, destination_share,
            share_server=None, destination_share_server=None):
        """Is called to test compatibility with destination backend."""
        backend_name = share_utils.extract_host(
            destination_share['host'], level='backend_name')
        config = get_backend_configuration(backend_name)
        compatible = 'Dummy' in config.share_driver
        return {
            'compatible': compatible,
            'writable': compatible,
            'preserve_metadata': compatible,
            'nondisruptive': False,
            'preserve_snapshots': compatible,
        }

    @slow_me_down
    def migration_start(
            self, context, source_share, destination_share, source_snapshots,
            snapshot_mappings, share_server=None,
            destination_share_server=None):
        """Is called to perform 1st phase of driver migration of a given share.

        """
        LOG.debug(
            "Migration of dummy share with ID '%s' has been started.",
            source_share["id"])
        self.migration_progress[source_share['share_id']] = 0

    @slow_me_down
    def migration_continue(
            self, context, source_share, destination_share, source_snapshots,
            snapshot_mappings, share_server=None,
            destination_share_server=None):

        if source_share["id"] not in self.migration_progress:
            self.migration_progress[source_share["id"]] = 0

        self.migration_progress[source_share["id"]] += 50

        LOG.debug(
            "Migration of dummy share with ID '%s' is continuing, %s.",
            source_share["id"],
            self.migration_progress[source_share["id"]])

        return self.migration_progress[source_share["id"]] == 100

    @slow_me_down
    def migration_complete(
            self, context, source_share, destination_share, source_snapshots,
            snapshot_mappings, share_server=None,
            destination_share_server=None):
        """Is called to perform 2nd phase of driver migration of a given share.

        """
        snapshot_updates = {}
        for src_snap_ins, dest_snap_ins in snapshot_mappings.items():
            snapshot_updates[dest_snap_ins['id']] = self._create_snapshot(
                dest_snap_ins)
        return {
            'snapshot_updates': snapshot_updates,
            'export_locations': self._do_migration(
                source_share, destination_share, share_server)
        }

    def _do_migration(self, source_share_ref, dest_share_ref, share_server):
        share_name = self._get_share_name(dest_share_ref)
        mountpoint = "/path/to/fake/share/%s" % share_name
        self.private_storage.delete(source_share_ref["id"])
        self.private_storage.update(
            dest_share_ref["id"], {
                "fake_provider_share_name": share_name,
                "fake_provider_location": mountpoint,
            }
        )
        LOG.debug(
            "Migration of dummy share with ID '%s' has been completed.",
            source_share_ref["id"])
        self.migration_progress.pop(source_share_ref["id"], None)

        return self._generate_export_locations(
            mountpoint, share_server=share_server)

    @slow_me_down
    def migration_cancel(
            self, context, source_share, destination_share, source_snapshots,
            snapshot_mappings, share_server=None,
            destination_share_server=None):
        """Is called to cancel driver migration."""
        LOG.debug(
            "Migration of dummy share with ID '%s' has been canceled.",
            source_share["id"])
        self.migration_progress.pop(source_share["id"], None)

    @slow_me_down
    def migration_get_progress(
            self, context, source_share, destination_share, source_snapshots,
            snapshot_mappings, share_server=None,
            destination_share_server=None):
        """Is called to get migration progress."""
        # Simulate migration progress.
        if source_share["id"] not in self.migration_progress:
            self.migration_progress[source_share["id"]] = 0
        total_progress = self.migration_progress[source_share["id"]]
        LOG.debug("Progress of current dummy share migration "
                  "with ID '%(id)s' is %(progress)s.", {
                      "id": source_share["id"],
                      "progress": total_progress
                  })
        return {"total_progress": total_progress}

    def share_server_migration_check_compatibility(
            self, context, share_server, dest_host, old_share_network,
            new_share_network, shares_request_spec):
        """Is called to check migration compatibility for a share server."""
        backend_name = share_utils.extract_host(
            dest_host, level='backend_name')
        config = get_backend_configuration(backend_name)
        compatible = 'Dummy' in config.share_driver
        return {
            'compatible': compatible,
            'writable': compatible,
            'preserve_snapshots': compatible,
            'nondisruptive': False,
            'share_network_id': new_share_network['id'],
            'migration_cancel': compatible,
            'migration_get_progress': compatible,
        }

    @slow_me_down
    def share_server_migration_start(self, context, src_share_server,
                                     dest_share_server, shares, snapshots):
        """Is called to perform 1st phase of migration of a share server."""
        LOG.debug(
            "Migration of dummy share server with ID '%s' has been started.",
            src_share_server["id"])
        self.migration_progress[src_share_server['id']] = 0

    @slow_me_down
    def share_server_migration_continue(self, context, src_share_server,
                                        dest_share_server, shares, snapshots):
        """Is called to continue the migration of a share server."""
        if src_share_server["id"] not in self.migration_progress:
            self.migration_progress[src_share_server["id"]] = 0

        self.migration_progress[src_share_server["id"]] += 50

        LOG.debug(
            "Migration of dummy share server with ID '%s' is continuing, %s.",
            src_share_server["id"],
            self.migration_progress[src_share_server["id"]])

        return self.migration_progress[src_share_server["id"]] >= 100

    @slow_me_down
    def share_server_migration_complete(self, context, source_share_server,
                                        dest_share_server, shares, snapshots,
                                        new_network_allocations):
        """Is called to complete the migration of a share server."""
        shares_updates = {}
        pools = self._get_pools_info()
        for instance in shares:

            share_name = self._get_share_name(instance)
            mountpoint = "/path/to/fake/share/%s" % share_name
            export_locations = self._generate_export_locations(
                mountpoint, share_server=dest_share_server)
            dest_pool = pools[0]['pool_name']
            shares_updates.update(
                {instance['id']: {'export_locations': export_locations,
                                  'pool_name': dest_pool}}
            )

        snapshot_updates = {}
        for instance in snapshots:
            snapshot_name = self._get_snapshot_name(instance)
            mountpoint = "/path/to/fake/snapshot/%s" % snapshot_name
            snap_export_locations = self._generate_export_locations(
                mountpoint, share_server=dest_share_server)
            snapshot_updates.update(
                {instance['id']: {
                    'provider_location': mountpoint,
                    'export_locations': snap_export_locations}}
            )

        LOG.debug(
            "Migration of dummy share server with ID '%s' has been completed.",
            source_share_server["id"])
        self.migration_progress.pop(source_share_server["id"], None)

        return {
            'share_updates': shares_updates,
            'snapshot_updates': snapshot_updates,
        }

    @slow_me_down
    def share_server_migration_cancel(self, context, src_share_server,
                                      dest_share_server, shares, snapshots):
        """Is called to cancel a share server migration."""
        LOG.debug(
            "Migration of dummy share server with ID '%s' has been canceled.",
            src_share_server["id"])
        self.migration_progress.pop(src_share_server["id"], None)

    @slow_me_down
    def share_server_migration_get_progress(self, context, src_share_server,
                                            dest_share_server, shares,
                                            snapshots):
        """Is called to get share server migration progress."""
        if src_share_server["id"] not in self.migration_progress:
            self.migration_progress[src_share_server["id"]] = 0
        total_progress = self.migration_progress[src_share_server["id"]]
        LOG.debug("Progress of current dummy share server migration "
                  "with ID '%(id)s' is %(progress)s.", {
                      "id": src_share_server["id"],
                      "progress": total_progress
                  })
        return {"total_progress": total_progress}

    def update_share_usage_size(self, context, shares):
        share_updates = []
        gathered_at = timeutils.utcnow()
        for s in shares:
            share_updates.append({'id': s['id'],
                                  'used_size': 1,
                                  'gathered_at': gathered_at})
        return share_updates

    @slow_me_down
    def get_share_server_network_info(
            self, context, share_server, identifier, driver_options):
        try:
            server_details = self.private_storage.get(identifier)
        except Exception:
            msg = ("Unable to find share server %s in "
                   "private storage." % identifier)
            raise exception.ShareBackendException(msg=msg)

        ips = [server_details['service_ip']]

        subnet_allocations = (
            self._get_subnet_allocations_from_backend_details(server_details))

        for subnet_allocation in subnet_allocations:
            ips += list(subnet_allocation.values())
        return ips

    @slow_me_down
    def manage_server(self, context, share_server, identifier, driver_options):
        server_details = self.private_storage.get(identifier)
        self.private_storage.delete(identifier)
        return identifier, server_details

    def unmanage_server(self, server_details, security_services=None):
        server_details = server_details or {}
        if not server_details or 'server_id' not in server_details:
            # This share server doesn't have any network details. Since it's
            # just being cleaned up, we'll log a warning and return without
            # errors.
            LOG.warning("Share server does not have network information. "
                        "It is being unmanaged, but cannot be re-managed "
                        "without first creating network allocations in this "
                        "driver's private storage.")
            return
        self.private_storage.update(server_details['server_id'],
                                    server_details)

    def get_share_status(self, share, share_server=None):
        return {
            'status': constants.STATUS_AVAILABLE,
            'export_locations': self.private_storage.get(share['id'],
                                                         key='export_location')
        }

    @slow_me_down
    def update_share_server_security_service(self, context, share_server,
                                             network_info, share_instances,
                                             share_instance_rules,
                                             new_security_service,
                                             current_security_service=None):
        if current_security_service:
            msg = _("Replacing security service %(cur_sec_serv_id)s by "
                    "security service %(new_sec_serv_id)s on share server "
                    "%(server_id)s."
                    ) % {
                'cur_sec_serv_id': current_security_service['id'],
                'new_sec_serv_id': new_security_service['id'],
                'server_id': share_server['id']
            }
        else:
            msg = _("Adding security service %(sec_serv_id)s on share server "
                    "%(server_id)s."
                    ) % {
                'sec_serv_id': new_security_service['id'],
                'server_id': share_server['id']
            }

        LOG.debug(msg)

    def check_update_share_server_security_service(
            self, context, share_server, network_info, share_instances,
            share_instance_rules, new_security_service,
            current_security_service=None):
        return True

    def check_update_share_server_network_allocations(
            self, context, share_server, current_network_allocations,
            new_share_network_subnet, security_services, share_instances,
            share_instances_rules):

        LOG.debug("Share server %(server)s can be updated with allocations "
                  "from new subnet.", {'server': share_server['id']})
        return True

    def update_share_server_network_allocations(
            self, context, share_server, current_network_allocations,
            new_network_allocations, security_services, shares, snapshots):

        backend_details = share_server['backend_details']
        subnet_allocations = (
            self._get_subnet_allocations_from_backend_details(backend_details))

        subnet_allocations.append({
            'primary_public_ip': new_network_allocations[
                'network_allocations'][0]['ip_address'],
            'secondary_public_ip': new_network_allocations[
                'network_allocations'][1]['ip_address'],
        })
        new_server = {
            "backend_details": {
                "subnet_allocations": jsonutils.dumps(subnet_allocations),
                "service_ip": backend_details["service_ip"],
            }
        }
        shares_updates = {}
        for instance in shares:

            share_name = self._get_share_name(instance)
            mountpoint = "/path/to/fake/share/%s" % share_name
            export_locations = self._generate_export_locations(
                mountpoint, share_server=new_server)
            shares_updates.update(
                {instance['id']: export_locations}
            )

        snapshot_updates = {}
        for instance in snapshots:
            snapshot_name = self._get_snapshot_name(instance)
            mountpoint = "/path/to/fake/snapshot/%s" % snapshot_name
            snap_export_locations = self._generate_export_locations(
                mountpoint, share_server=new_server)
            snapshot_updates.update(
                {instance['id']: {
                    'provider_location': mountpoint,
                    'export_locations': snap_export_locations}}
            )

        LOG.debug(
            "Network update allocations of dummy share server with ID '%s' "
            "has been completed.", share_server["id"])
        return {
            "share_updates": shares_updates,
            "snapshot_updates": snapshot_updates,
            "server_details": {
                "subnet_allocations": (
                    new_server["backend_details"]["subnet_allocations"])
            },
        }
