#!/usr/bin/env python3

# CephInstance.py - Class implementing a PVC node Ceph instance
# Part of the Parallel Virtual Cluster (PVC) system
#
#    Copyright (C) 2018-2021 Joshua M. Boniface <joshua@boniface.me>
#
#    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, version 3.
#
#    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 time
import json
import psutil

import daemon_lib.common as common

from distutils.util import strtobool
from re import match


class CephOSDInstance(object):
    def __init__(self, zkhandler, this_node, osd_id):
        self.zkhandler = zkhandler
        self.this_node = this_node
        self.osd_id = osd_id
        self.node = None
        self.size = None
        self.stats = dict()

        @self.zkhandler.zk_conn.DataWatch(self.zkhandler.schema.path('osd.node', self.osd_id))
        def watch_osd_node(data, stat, event=''):
            if event and event.type == 'DELETED':
                # The key has been deleted after existing before; terminate this watcher
                # because this class instance is about to be reaped in Daemon.py
                return False

            try:
                data = data.decode('ascii')
            except AttributeError:
                data = ''

            if data and data != self.node:
                self.node = data

        @self.zkhandler.zk_conn.DataWatch(self.zkhandler.schema.path('osd.stats', self.osd_id))
        def watch_osd_stats(data, stat, event=''):
            if event and event.type == 'DELETED':
                # The key has been deleted after existing before; terminate this watcher
                # because this class instance is about to be reaped in Daemon.py
                return False

            try:
                data = data.decode('ascii')
            except AttributeError:
                data = ''

            if data and data != self.stats:
                self.stats = json.loads(data)

    @staticmethod
    def add_osd(zkhandler, logger, node, device, weight, ext_db_flag=False, ext_db_ratio=0.05):
        # We are ready to create a new OSD on this node
        logger.out('Creating new OSD disk on block device {}'.format(device), state='i')
        try:
            # 1. Create an OSD; we do this so we know what ID will be gen'd
            retcode, stdout, stderr = common.run_os_command('ceph osd create')
            if retcode:
                print('ceph osd create')
                print(stdout)
                print(stderr)
                raise Exception
            osd_id = stdout.rstrip()

            # 2. Remove that newly-created OSD
            retcode, stdout, stderr = common.run_os_command('ceph osd rm {}'.format(osd_id))
            if retcode:
                print('ceph osd rm')
                print(stdout)
                print(stderr)
                raise Exception

            # 3a. Zap the disk to ensure it is ready to go
            logger.out('Zapping disk {}'.format(device), state='i')
            retcode, stdout, stderr = common.run_os_command('ceph-volume lvm zap --destroy {}'.format(device))
            if retcode:
                print('ceph-volume lvm zap')
                print(stdout)
                print(stderr)
                raise Exception

            dev_flags = "--data {}".format(device)

            # 3b. Prepare the logical volume if ext_db_flag
            if ext_db_flag:
                _, osd_size_bytes, _ = common.run_os_command('blockdev --getsize64 {}'.format(device))
                osd_size_bytes = int(osd_size_bytes)
                result = CephOSDInstance.create_osd_db_lv(zkhandler, logger, osd_id, ext_db_ratio, osd_size_bytes)
                if not result:
                    raise Exception
                db_device = "osd-db/osd-{}".format(osd_id)
                dev_flags += " --block.db {}".format(db_device)
            else:
                db_device = ""

            # 3c. Create the OSD for real
            logger.out('Preparing LVM for new OSD disk with ID {} on {}'.format(osd_id, device), state='i')
            retcode, stdout, stderr = common.run_os_command(
                'ceph-volume lvm prepare --bluestore {devices}'.format(
                    osdid=osd_id,
                    devices=dev_flags
                )
            )
            if retcode:
                print('ceph-volume lvm prepare')
                print(stdout)
                print(stderr)
                raise Exception

            # 4a. Get OSD FSID
            logger.out('Getting OSD FSID for ID {} on {}'.format(osd_id, device), state='i')
            retcode, stdout, stderr = common.run_os_command(
                'ceph-volume lvm list {device}'.format(
                    osdid=osd_id,
                    device=device
                )
            )
            for line in stdout.split('\n'):
                if 'osd fsid' in line:
                    osd_fsid = line.split()[-1]

            if not osd_fsid:
                print('ceph-volume lvm list')
                print('Could not find OSD fsid in data:')
                print(stdout)
                print(stderr)
                raise Exception

            # 4b. Activate the OSD
            logger.out('Activating new OSD disk with ID {}'.format(osd_id, device), state='i')
            retcode, stdout, stderr = common.run_os_command(
                'ceph-volume lvm activate --bluestore {osdid} {osdfsid}'.format(
                    osdid=osd_id,
                    osdfsid=osd_fsid
                )
            )
            if retcode:
                print('ceph-volume lvm activate')
                print(stdout)
                print(stderr)
                raise Exception

            # 5. Add it to the crush map
            logger.out('Adding new OSD disk with ID {} to CRUSH map'.format(osd_id), state='i')
            retcode, stdout, stderr = common.run_os_command(
                'ceph osd crush add osd.{osdid} {weight} root=default host={node}'.format(
                    osdid=osd_id,
                    weight=weight,
                    node=node
                )
            )
            if retcode:
                print('ceph osd crush add')
                print(stdout)
                print(stderr)
                raise Exception
            time.sleep(0.5)

            # 6. Verify it started
            retcode, stdout, stderr = common.run_os_command(
                'systemctl status ceph-osd@{osdid}'.format(
                    osdid=osd_id
                )
            )
            if retcode:
                print('systemctl status')
                print(stdout)
                print(stderr)
                raise Exception

            # 7. Add the new OSD to the list
            logger.out('Adding new OSD disk with ID {} to Zookeeper'.format(osd_id), state='i')
            zkhandler.write([
                (('osd', osd_id), ''),
                (('osd.node', osd_id), node),
                (('osd.device', osd_id), device),
                (('osd.db_device', osd_id), db_device),
                (('osd.stats', osd_id), '{}'),
            ])

            # Log it
            logger.out('Created new OSD disk with ID {}'.format(osd_id), state='o')
            return True
        except Exception as e:
            # Log it
            logger.out('Failed to create new OSD disk: {}'.format(e), state='e')
            return False

    @staticmethod
    def remove_osd(zkhandler, logger, osd_id, osd_obj):
        logger.out('Removing OSD disk {}'.format(osd_id), state='i')
        try:
            # 1. Verify the OSD is present
            retcode, stdout, stderr = common.run_os_command('ceph osd ls')
            osd_list = stdout.split('\n')
            if osd_id not in osd_list:
                logger.out('Could not find OSD {} in the cluster'.format(osd_id), state='e')
                return True

            # 1. Set the OSD out so it will flush
            logger.out('Setting out OSD disk with ID {}'.format(osd_id), state='i')
            retcode, stdout, stderr = common.run_os_command('ceph osd out {}'.format(osd_id))
            if retcode:
                print('ceph osd out')
                print(stdout)
                print(stderr)
                raise Exception

            # 2. Wait for the OSD to flush
            logger.out('Flushing OSD disk with ID {}'.format(osd_id), state='i')
            osd_string = str()
            while True:
                try:
                    retcode, stdout, stderr = common.run_os_command('ceph pg dump osds --format json')
                    dump_string = json.loads(stdout)
                    for osd in dump_string:
                        if str(osd['osd']) == osd_id:
                            osd_string = osd
                    num_pgs = osd_string['num_pgs']
                    if num_pgs > 0:
                        time.sleep(5)
                    else:
                        raise Exception
                except Exception:
                    break

            # 3. Stop the OSD process and wait for it to be terminated
            logger.out('Stopping OSD disk with ID {}'.format(osd_id), state='i')
            retcode, stdout, stderr = common.run_os_command('systemctl stop ceph-osd@{}'.format(osd_id))
            if retcode:
                print('systemctl stop')
                print(stdout)
                print(stderr)
                raise Exception

            # FIXME: There has to be a better way to do this /shrug
            while True:
                is_osd_up = False
                # Find if there is a process named ceph-osd with arg '--id {id}'
                for p in psutil.process_iter(attrs=['name', 'cmdline']):
                    if 'ceph-osd' == p.info['name'] and '--id {}'.format(osd_id) in ' '.join(p.info['cmdline']):
                        is_osd_up = True
                # If there isn't, continue
                if not is_osd_up:
                    break

            # 4. Determine the block devices
            retcode, stdout, stderr = common.run_os_command('readlink /var/lib/ceph/osd/ceph-{}/block'.format(osd_id))
            vg_name = stdout.split('/')[-2]  # e.g. /dev/ceph-<uuid>/osd-block-<uuid>
            retcode, stdout, stderr = common.run_os_command('vgs --separator , --noheadings -o pv_name {}'.format(vg_name))
            pv_block = stdout.strip()

            # 5. Zap the volumes
            logger.out('Zapping OSD disk with ID {} on {}'.format(osd_id, pv_block), state='i')
            retcode, stdout, stderr = common.run_os_command('ceph-volume lvm zap --destroy {}'.format(pv_block))
            if retcode:
                print('ceph-volume lvm zap')
                print(stdout)
                print(stderr)
                raise Exception

            # 6. Purge the OSD from Ceph
            logger.out('Purging OSD disk with ID {}'.format(osd_id), state='i')
            retcode, stdout, stderr = common.run_os_command('ceph osd purge {} --yes-i-really-mean-it'.format(osd_id))
            if retcode:
                print('ceph osd purge')
                print(stdout)
                print(stderr)
                raise Exception

            # 7. Remove the DB device
            if zkhandler.exists(('osd.db_device', osd_id)):
                db_device = zkhandler.read(('osd.db_device', osd_id))
                logger.out('Removing OSD DB logical volume "{}"'.format(db_device), state='i')
                retcode, stdout, stderr = common.run_os_command('lvremove --yes --force {}'.format(db_device))

            # 8. Delete OSD from ZK
            logger.out('Deleting OSD disk with ID {} from Zookeeper'.format(osd_id), state='i')
            zkhandler.delete(('osd', osd_id), recursive=True)

            # Log it
            logger.out('Removed OSD disk with ID {}'.format(osd_id), state='o')
            return True
        except Exception as e:
            # Log it
            logger.out('Failed to purge OSD disk with ID {}: {}'.format(osd_id, e), state='e')
            return False

    @staticmethod
    def add_db_vg(zkhandler, logger, device):
        logger.out('Creating new OSD database volume group on block device {}'.format(device), state='i')
        try:
            # 0. Check if an existsing volume group exists
            retcode, stdout, stderr = common.run_os_command(
                'vgdisplay osd-db'
            )
            if retcode != 5:
                logger.out('Ceph OSD database VG "osd-db" already exists', state='e')
                return False

            # 1. Create an empty partition table
            logger.out('Creating partitons on block device {}'.format(device), state='i')
            retcode, stdout, stderr = common.run_os_command(
                'sgdisk --clear {}'.format(device)
            )
            if retcode:
                print('sgdisk create partition table')
                print(stdout)
                print(stderr)
                raise Exception

            retcode, stdout, stderr = common.run_os_command(
                'sgdisk --new 1:: --typecore 1:8e00 {}'.format(device)
            )
            if retcode:
                print('sgdisk create pv partition')
                print(stdout)
                print(stderr)
                raise Exception

            # Handle the partition ID portion
            if match(r'by-path', device) or match(r'by-id', device):
                # /dev/disk/by-path/pci-0000:03:00.0-scsi-0:1:0:0 -> pci-0000:03:00.0-scsi-0:1:0:0-part1
                partition = '{}-part1'.format(device)
            elif match(r'nvme', device):
                # /dev/nvme0n1 -> nvme0n1p1
                partition = '{}p1'.format(device)
            else:
                # /dev/sda -> sda1
                # No other '/dev/disk/by-*' types are valid for raw block devices anyways
                partition = '{}1'.format(device)

            # 2. Create the PV
            logger.out('Creating PV on block device {}'.format(partition), state='i')
            retcode, stdout, stderr = common.run_os_command(
                'pvcreate --force {}'.format(partition)
            )
            if retcode:
                print('pv creation')
                print(stdout)
                print(stderr)
                raise Exception

            # 2. Create the VG (named 'osd-db')
            logger.out('Creating VG "osd-db" on block device {}'.format(partition), state='i')
            retcode, stdout, stderr = common.run_os_command(
                'vgcreate --force osd-db {}'.format(partition)
            )
            if retcode:
                print('vg creation')
                print(stdout)
                print(stderr)
                raise Exception

            # Log it
            logger.out('Created new OSD database volume group on block device {}'.format(device), state='o')
            return True
        except Exception as e:
            # Log it
            logger.out('Failed to create OSD database volume group: {}'.format(e), state='e')
            return False

    @staticmethod
    def create_osd_db_lv(zkhandler, logger, osd_id, ext_db_ratio, osd_size_bytes):
        logger.out('Creating new OSD database logical volume for OSD ID {}'.format(osd_id), state='i')
        try:
            # 0. Check if an existsing logical volume exists
            retcode, stdout, stderr = common.run_os_command(
                'lvdisplay osd-db/osd{}'.format(osd_id)
            )
            if retcode != 5:
                logger.out('Ceph OSD database LV "osd-db/osd{}" already exists'.format(osd_id), state='e')
                return False

            # 1. Determine LV sizing
            osd_db_size = int(osd_size_bytes * ext_db_ratio / 1024 / 1024)

            # 2. Create the LV
            logger.out('Creating DB LV "osd-db/osd-{}" of {}M ({} * {})'.format(osd_id, osd_db_size, osd_size_bytes, ext_db_ratio), state='i')
            retcode, stdout, stderr = common.run_os_command(
                'lvcreate --yes --name osd-{} --size {} osd-db'.format(osd_id, osd_db_size)
            )
            if retcode:
                print('db lv creation')
                print(stdout)
                print(stderr)
                raise Exception

            # Log it
            logger.out('Created new OSD database logical volume "osd-db/osd-{}"'.format(osd_id), state='o')
            return True
        except Exception as e:
            # Log it
            logger.out('Failed to create OSD database logical volume: {}'.format(e), state='e')
            return False


class CephPoolInstance(object):
    def __init__(self, zkhandler, this_node, name):
        self.zkhandler = zkhandler
        self.this_node = this_node
        self.name = name
        self.pgs = ''
        self.stats = dict()

        @self.zkhandler.zk_conn.DataWatch(self.zkhandler.schema.path('pool.pgs', self.name))
        def watch_pool_node(data, stat, event=''):
            if event and event.type == 'DELETED':
                # The key has been deleted after existing before; terminate this watcher
                # because this class instance is about to be reaped in Daemon.py
                return False

            try:
                data = data.decode('ascii')
            except AttributeError:
                data = ''

            if data and data != self.pgs:
                self.pgs = data

        @self.zkhandler.zk_conn.DataWatch(self.zkhandler.schema.path('pool.stats', self.name))
        def watch_pool_stats(data, stat, event=''):
            if event and event.type == 'DELETED':
                # The key has been deleted after existing before; terminate this watcher
                # because this class instance is about to be reaped in Daemon.py
                return False

            try:
                data = data.decode('ascii')
            except AttributeError:
                data = ''

            if data and data != self.stats:
                self.stats = json.loads(data)


class CephVolumeInstance(object):
    def __init__(self, zkhandler, this_node, pool, name):
        self.zkhandler = zkhandler
        self.this_node = this_node
        self.pool = pool
        self.name = name
        self.stats = dict()

        @self.zkhandler.zk_conn.DataWatch(self.zkhandler.schema.path('volume.stats', f'{self.pool}/{self.name}'))
        def watch_volume_stats(data, stat, event=''):
            if event and event.type == 'DELETED':
                # The key has been deleted after existing before; terminate this watcher
                # because this class instance is about to be reaped in Daemon.py
                return False

            try:
                data = data.decode('ascii')
            except AttributeError:
                data = ''

            if data and data != self.stats:
                self.stats = json.loads(data)


class CephSnapshotInstance(object):
    def __init__(self, zkhandler, this_node, pool, volume, name):
        self.zkhandler = zkhandler
        self.this_node = this_node
        self.pool = pool
        self.volume = volume
        self.name = name
        self.stats = dict()

        @self.zkhandler.zk_conn.DataWatch(self.zkhandler.schema.path('snapshot.stats', f'{self.pool}/{self.volume}/{self.name}'))
        def watch_snapshot_stats(data, stat, event=''):
            if event and event.type == 'DELETED':
                # The key has been deleted after existing before; terminate this watcher
                # because this class instance is about to be reaped in Daemon.py
                return False

            try:
                data = data.decode('ascii')
            except AttributeError:
                data = ''

            if data and data != self.stats:
                self.stats = json.loads(data)


# Primary command function
# This command pipe is only used for OSD adds and removes
def ceph_command(zkhandler, logger, this_node, data, d_osd):
    # Get the command and args
    command, args = data.split()

    # Adding a new OSD
    if command == 'osd_add':
        node, device, weight, ext_db_flag, ext_db_ratio = args.split(',')
        ext_db_flag = bool(strtobool(ext_db_flag))
        ext_db_ratio = float(ext_db_ratio)
        if node == this_node.name:
            # Lock the command queue
            zk_lock = zkhandler.writelock('base.cmd.ceph')
            with zk_lock:
                # Add the OSD
                result = CephOSDInstance.add_osd(zkhandler, logger, node, device, weight, ext_db_flag, ext_db_ratio)
                # Command succeeded
                if result:
                    # Update the command queue
                    zkhandler.write([
                        ('base.cmd.ceph', 'success-{}'.format(data))
                    ])
                # Command failed
                else:
                    # Update the command queue
                    zkhandler.write([
                        ('base.cmd.ceph', 'failure-{}'.format(data))
                    ])
                # Wait 1 seconds before we free the lock, to ensure the client hits the lock
                time.sleep(1)

    # Removing an OSD
    elif command == 'osd_remove':
        osd_id = args

        # Verify osd_id is in the list
        if d_osd[osd_id] and d_osd[osd_id].node == this_node.name:
            # Lock the command queue
            zk_lock = zkhandler.writelock('base.cmd.ceph')
            with zk_lock:
                # Remove the OSD
                result = CephOSDInstance.remove_osd(zkhandler, logger, osd_id, d_osd[osd_id])
                # Command succeeded
                if result:
                    # Update the command queue
                    zkhandler.write([
                        ('base.cmd.ceph', 'success-{}'.format(data))
                    ])
                # Command failed
                else:
                    # Update the command queue
                    zkhandler.write([
                        ('base.cmd.ceph', 'failure-{}'.format(data))
                    ])
                # Wait 1 seconds before we free the lock, to ensure the client hits the lock
                time.sleep(1)

    # Adding a new DB VG
    elif command == 'db_vg_add':
        node, device = args.split(',')
        if node == this_node.name:
            # Lock the command queue
            zk_lock = zkhandler.writelock('base.cmd.ceph')
            with zk_lock:
                # Add the VG
                result = CephOSDInstance.add_db_vg(zkhandler, logger, device)
                # Command succeeded
                if result:
                    # Update the command queue
                    zkhandler.write([
                        ('base.cmd.ceph', 'success-{}'.format(data))
                    ])
                # Command failed
                else:
                    # Update the command queue
                    zkhandler.write([
                        ('base.cmd.ceph', 'failure={}'.format(data))
                    ])
                # Wait 1 seconds before we free the lock, to ensure the client hits the lock
                time.sleep(1)