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#!/usr/bin/env python 

# 

# Copyright (C) 2020  Vates SAS - ronan.abhamon@vates.fr 

# 

# This program is free software: you can redistribute it and/or modify 

# it under the terms of the GNU General Public License as published by 

# the Free Software Foundation, either version 3 of the License, or 

# (at your option) any later version. 

# This program is distributed in the hope that it will be useful, 

# but WITHOUT ANY WARRANTY; without even the implied warranty of 

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 

# GNU General Public License for more details. 

# 

# You should have received a copy of the GNU General Public License 

# along with this program.  If not, see <https://www.gnu.org/licenses/>. 

 

import base64 

import distutils.util 

import errno 

import json 

import socket 

import util 

import vhdutil 

import xs_errors 

 

MANAGER_PLUGIN = 'linstor-manager' 

 

 

def linstorhostcall(local_method, remote_method): 

    def decorated(func): 

        def wrapper(*args, **kwargs): 

            self = args[0] 

            vdi_uuid = args[1] 

 

            device_path = self._linstor.build_device_path( 

                self._linstor.get_volume_name(vdi_uuid) 

            ) 

 

            # A. Try a call using directly the DRBD device to avoid 

            # remote request. 

 

            # Try to read locally if the device is not in use or if the device 

            # is up to date and not diskless. 

            (node_names, in_use) = \ 

                self._linstor.find_up_to_date_diskfull_nodes(vdi_uuid) 

 

            try: 

                if not in_use or socket.gethostname() in node_names: 

                    return local_method(device_path, *args[2:], **kwargs) 

            except util.CommandException as e: 

                # EMEDIUMTYPE constant (124) is not available in python2. 

                if e.code != errno.EROFS and e.code != 124: 

                    raise 

 

            # B. Execute the plugin on master or slave. 

            def exec_remote_method(): 

                host_ref = self._get_readonly_host( 

                    vdi_uuid, device_path, node_names 

                ) 

                args = { 

                    'devicePath': device_path, 

                    'groupName': self._linstor.group_name 

                } 

                args.update(**kwargs) 

 

                try: 

                    response = self._session.xenapi.host.call_plugin( 

                        host_ref, MANAGER_PLUGIN, remote_method, args 

                    ) 

                except Exception as e: 

                    util.SMlog('call-plugin ({} with {}) exception: {}'.format( 

                        remote_method, args, e 

                    )) 

                    raise 

 

                util.SMlog('call-plugin ({} with {}) returned: {}'.format( 

                    remote_method, args, response 

                )) 

                if response == 'False': 

                    raise xs_errors.XenError( 

                        'VDIUnavailable', 

                        opterr='Plugin {} failed'.format(MANAGER_PLUGIN) 

                    ) 

                kwargs['response'] = response 

 

            util.retry(exec_remote_method, 5, 3) 

            return func(*args, **kwargs) 

        return wrapper 

    return decorated 

 

 

class LinstorVhdUtil: 

    def __init__(self, session, linstor): 

        self._session = session 

        self._linstor = linstor 

 

    @linstorhostcall(vhdutil.check, 'check') 

    def check(self, vdi_uuid, **kwargs): 

        return distutils.util.strtobool(kwargs['response']) 

 

    def get_vhd_info(self, vdi_uuid, include_parent=True): 

        kwargs = {'includeParent': str(include_parent)} 

        return self._get_vhd_info(vdi_uuid, self._extract_uuid, **kwargs) 

 

    @linstorhostcall(vhdutil.getVHDInfo, 'getVHDInfo') 

    def _get_vhd_info(self, vdi_uuid, *args, **kwargs): 

        obj = json.loads(kwargs['response']) 

 

        vhd_info = vhdutil.VHDInfo(vdi_uuid) 

        vhd_info.sizeVirt = obj['sizeVirt'] 

        vhd_info.sizePhys = obj['sizePhys'] 

        if 'parentPath' in obj: 

            vhd_info.parentPath = obj['parentPath'] 

            vhd_info.parentUuid = obj['parentUuid'] 

        vhd_info.hidden = obj['hidden'] 

        vhd_info.path = obj['path'] 

 

        return vhd_info 

 

    @linstorhostcall(vhdutil.hasParent, 'hasParent') 

    def has_parent(self, vdi_uuid, **kwargs): 

        return distutils.util.strtobool(kwargs['response']) 

 

    def get_parent(self, vdi_uuid): 

        return self._get_parent(vdi_uuid, self._extract_uuid) 

 

    @linstorhostcall(vhdutil.getParent, 'getParent') 

    def _get_parent(self, vdi_uuid, *args, **kwargs): 

        return kwargs['response'] 

 

    @linstorhostcall(vhdutil.getSizeVirt, 'getSizeVirt') 

    def get_size_virt(self, vdi_uuid, **kwargs): 

        return int(kwargs['response']) 

 

    @linstorhostcall(vhdutil.getSizePhys, 'getSizePhys') 

    def get_size_phys(self, vdi_uuid, **kwargs): 

        return int(kwargs['response']) 

 

    @linstorhostcall(vhdutil.getDepth, 'getDepth') 

    def get_depth(self, vdi_uuid, **kwargs): 

        return int(kwargs['response']) 

 

    @linstorhostcall(vhdutil.getKeyHash, 'getKeyHash') 

    def get_key_hash(self, vdi_uuid, **kwargs): 

        return kwargs['response'] or None 

 

    @linstorhostcall(vhdutil.getBlockBitmap, 'getBlockBitmap') 

    def get_block_bitmap(self, vdi_uuid, **kwargs): 

        return base64.b64decode(kwargs['response']) 

 

    # -------------------------------------------------------------------------- 

    # Helpers. 

    # -------------------------------------------------------------------------- 

 

    def _extract_uuid(self, device_path): 

        # TODO: Remove new line in the vhdutil module. Not here. 

        return self._linstor.get_volume_uuid_from_device_path( 

            device_path.rstrip('\n') 

        ) 

 

    def _get_readonly_host(self, vdi_uuid, device_path, node_names): 

        """ 

        When vhd-util is called to fetch VDI info we must find a 

        diskfull DRBD disk to read the data. It's the goal of this function. 

        Why? Because when a VHD is open in RO mode, the LVM layer is used 

        directly to bypass DRBD verifications (we can have only one process 

        that reads/writes to disk with DRBD devices). 

        """ 

 

        if not node_names: 

            raise xs_errors.XenError( 

                'VDIUnavailable', 

                opterr='Unable to find diskfull node: {} (path={})' 

                .format(vdi_uuid, device_path) 

            ) 

 

        hosts = self._session.xenapi.host.get_all_records() 

        for host_ref, host_record in hosts.items(): 

            if host_record['hostname'] in node_names: 

                return host_ref 

 

        raise xs_errors.XenError( 

            'VDIUnavailable', 

            opterr='Unable to find a valid host from VDI: {} (path={})' 

            .format(vdi_uuid, device_path) 

        )