#!/usr/bin/env python
#
# Tests for incremental drive-backup
#
# Copyright (C) 2015 John Snow for Red Hat, Inc.
#
# Based on 056.
#
# 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 2 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 <http://www.gnu.org/licenses/>.
#

import os
import iotests


def io_write_patterns(img, patterns):
    for pattern in patterns:
        iotests.qemu_io('-c', 'write -P%s %s %s' % pattern, img)


def try_remove(img):
    try:
        os.remove(img)
    except OSError:
        pass


def transaction_action(action, **kwargs):
    return {
        'type': action,
        'data': dict((k.replace('_', '-'), v) for k, v in kwargs.iteritems())
    }


def transaction_bitmap_clear(node, name, **kwargs):
    return transaction_action('block-dirty-bitmap-clear',
                              node=node, name=name, **kwargs)


def transaction_drive_backup(device, target, **kwargs):
    return transaction_action('drive-backup', job_id=device, device=device,
                              target=target, **kwargs)


class Bitmap:
    def __init__(self, name, drive):
        self.name = name
        self.drive = drive
        self.num = 0
        self.backups = list()

    def base_target(self):
        return (self.drive['backup'], None)

    def new_target(self, num=None):
        if num is None:
            num = self.num
        self.num = num + 1
        base = os.path.join(iotests.test_dir,
                            "%s.%s." % (self.drive['id'], self.name))
        suff = "%i.%s" % (num, self.drive['fmt'])
        target = base + "inc" + suff
        reference = base + "ref" + suff
        self.backups.append((target, reference))
        return (target, reference)

    def last_target(self):
        if self.backups:
            return self.backups[-1]
        return self.base_target()

    def del_target(self):
        for image in self.backups.pop():
            try_remove(image)
        self.num -= 1

    def cleanup(self):
        for backup in self.backups:
            for image in backup:
                try_remove(image)


class TestIncrementalBackupBase(iotests.QMPTestCase):
    def __init__(self, *args):
        super(TestIncrementalBackupBase, self).__init__(*args)
        self.bitmaps = list()
        self.files = list()
        self.drives = list()
        self.vm = iotests.VM()
        self.err_img = os.path.join(iotests.test_dir, 'err.%s' % iotests.imgfmt)


    def setUp(self):
        # Create a base image with a distinctive patterning
        drive0 = self.add_node('drive0')
        self.img_create(drive0['file'], drive0['fmt'])
        self.vm.add_drive(drive0['file'])
        self.write_default_pattern(drive0['file'])
        self.vm.launch()


    def write_default_pattern(self, target):
        io_write_patterns(target, (('0x41', 0, 512),
                                   ('0xd5', '1M', '32k'),
                                   ('0xdc', '32M', '124k')))


    def add_node(self, node_id, fmt=iotests.imgfmt, path=None, backup=None):
        if path is None:
            path = os.path.join(iotests.test_dir, '%s.%s' % (node_id, fmt))
        if backup is None:
            backup = os.path.join(iotests.test_dir,
                                  '%s.full.backup.%s' % (node_id, fmt))

        self.drives.append({
            'id': node_id,
            'file': path,
            'backup': backup,
            'fmt': fmt })
        return self.drives[-1]


    def img_create(self, img, fmt=iotests.imgfmt, size='64M',
                   parent=None, parentFormat=None, **kwargs):
        optargs = []
        for k,v in kwargs.iteritems():
            optargs = optargs + ['-o', '%s=%s' % (k,v)]
        args = ['create', '-f', fmt] + optargs + [img, size]
        if parent:
            if parentFormat is None:
                parentFormat = fmt
            args = args + ['-b', parent, '-F', parentFormat]
        iotests.qemu_img(*args)
        self.files.append(img)


    def do_qmp_backup(self, error='Input/output error', **kwargs):
        res = self.vm.qmp('drive-backup', **kwargs)
        self.assert_qmp(res, 'return', {})
        return self.wait_qmp_backup(kwargs['device'], error)


    def wait_qmp_backup(self, device, error='Input/output error'):
        event = self.vm.event_wait(name="BLOCK_JOB_COMPLETED",
                                   match={'data': {'device': device}})
        self.assertNotEqual(event, None)

        try:
            failure = self.dictpath(event, 'data/error')
        except AssertionError:
            # Backup succeeded.
            self.assert_qmp(event, 'data/offset', event['data']['len'])
            return True
        else:
            # Backup failed.
            self.assert_qmp(event, 'data/error', error)
            return False


    def wait_qmp_backup_cancelled(self, device):
        event = self.vm.event_wait(name='BLOCK_JOB_CANCELLED',
                                   match={'data': {'device': device}})
        self.assertNotEqual(event, None)


    def create_anchor_backup(self, drive=None):
        if drive is None:
            drive = self.drives[-1]
        res = self.do_qmp_backup(job_id=drive['id'],
                                 device=drive['id'], sync='full',
                                 format=drive['fmt'], target=drive['backup'])
        self.assertTrue(res)
        self.files.append(drive['backup'])
        return drive['backup']


    def make_reference_backup(self, bitmap=None):
        if bitmap is None:
            bitmap = self.bitmaps[-1]
        _, reference = bitmap.last_target()
        res = self.do_qmp_backup(job_id=bitmap.drive['id'],
                                 device=bitmap.drive['id'], sync='full',
                                 format=bitmap.drive['fmt'], target=reference)
        self.assertTrue(res)


    def add_bitmap(self, name, drive, **kwargs):
        bitmap = Bitmap(name, drive)
        self.bitmaps.append(bitmap)
        result = self.vm.qmp('block-dirty-bitmap-add', node=drive['id'],
                             name=bitmap.name, **kwargs)
        self.assert_qmp(result, 'return', {})
        return bitmap


    def prepare_backup(self, bitmap=None, parent=None):
        if bitmap is None:
            bitmap = self.bitmaps[-1]
        if parent is None:
            parent, _ = bitmap.last_target()

        target, _ = bitmap.new_target()
        self.img_create(target, bitmap.drive['fmt'], parent=parent)
        return target


    def create_incremental(self, bitmap=None, parent=None,
                           parentFormat=None, validate=True):
        if bitmap is None:
            bitmap = self.bitmaps[-1]
        if parent is None:
            parent, _ = bitmap.last_target()

        target = self.prepare_backup(bitmap, parent)
        res = self.do_qmp_backup(job_id=bitmap.drive['id'],
                                 device=bitmap.drive['id'],
                                 sync='incremental', bitmap=bitmap.name,
                                 format=bitmap.drive['fmt'], target=target,
                                 mode='existing')
        if not res:
            bitmap.del_target();
            self.assertFalse(validate)
        else:
            self.make_reference_backup(bitmap)
        return res


    def check_backups(self):
        for bitmap in self.bitmaps:
            for incremental, reference in bitmap.backups:
                self.assertTrue(iotests.compare_images(incremental, reference))
            last = bitmap.last_target()[0]
            self.assertTrue(iotests.compare_images(last, bitmap.drive['file']))


    def hmp_io_writes(self, drive, patterns):
        for pattern in patterns:
            self.vm.hmp_qemu_io(drive, 'write -P%s %s %s' % pattern)
        self.vm.hmp_qemu_io(drive, 'flush')


    def do_incremental_simple(self, **kwargs):
        self.create_anchor_backup()
        self.add_bitmap('bitmap0', self.drives[0], **kwargs)

        # Sanity: Create a "hollow" incremental backup
        self.create_incremental()
        # Three writes: One complete overwrite, one new segment,
        # and one partial overlap.
        self.hmp_io_writes(self.drives[0]['id'], (('0xab', 0, 512),
                                                  ('0xfe', '16M', '256k'),
                                                  ('0x64', '32736k', '64k')))
        self.create_incremental()
        # Three more writes, one of each kind, like above
        self.hmp_io_writes(self.drives[0]['id'], (('0x9a', 0, 512),
                                                  ('0x55', '8M', '352k'),
                                                  ('0x78', '15872k', '1M')))
        self.create_incremental()
        self.vm.shutdown()
        self.check_backups()


    def tearDown(self):
        self.vm.shutdown()
        for bitmap in self.bitmaps:
            bitmap.cleanup()
        for filename in self.files:
            try_remove(filename)



class TestIncrementalBackup(TestIncrementalBackupBase):
    def test_incremental_simple(self):
        '''
        Test: Create and verify three incremental backups.

        Create a bitmap and a full backup before VM execution begins,
        then create a series of three incremental backups "during execution,"
        i.e.; after IO requests begin modifying the drive.
        '''
        return self.do_incremental_simple()


    def test_small_granularity(self):
        '''
        Test: Create and verify backups made with a small granularity bitmap.

        Perform the same test as test_incremental_simple, but with a granularity
        of only 32KiB instead of the present default of 64KiB.
        '''
        return self.do_incremental_simple(granularity=32768)


    def test_large_granularity(self):
        '''
        Test: Create and verify backups made with a large granularity bitmap.

        Perform the same test as test_incremental_simple, but with a granularity
        of 128KiB instead of the present default of 64KiB.
        '''
        return self.do_incremental_simple(granularity=131072)


    def test_larger_cluster_target(self):
        '''
        Test: Create and verify backups made to a larger cluster size target.

        With a default granularity of 64KiB, verify that backups made to a
        larger cluster size target of 128KiB without a backing file works.
        '''
        drive0 = self.drives[0]

        # Create a cluster_size=128k full backup / "anchor" backup
        self.img_create(drive0['backup'], cluster_size='128k')
        self.assertTrue(self.do_qmp_backup(device=drive0['id'], sync='full',
                                           format=drive0['fmt'],
                                           target=drive0['backup'],
                                           mode='existing'))

        # Create bitmap and dirty it with some new writes.
        # overwrite [32736, 32799] which will dirty bitmap clusters at
        # 32M-64K and 32M. 32M+64K will be left undirtied.
        bitmap0 = self.add_bitmap('bitmap0', drive0)
        self.hmp_io_writes(drive0['id'],
                           (('0xab', 0, 512),
                            ('0xfe', '16M', '256k'),
                            ('0x64', '32736k', '64k')))
        # Check the dirty bitmap stats
        result = self.vm.qmp('query-block')
        self.assert_qmp(result, 'return[0]/dirty-bitmaps[0]/name', 'bitmap0')
        self.assert_qmp(result, 'return[0]/dirty-bitmaps[0]/count', 458752)
        self.assert_qmp(result, 'return[0]/dirty-bitmaps[0]/granularity', 65536)
        self.assert_qmp(result, 'return[0]/dirty-bitmaps[0]/status', 'active')

        # Prepare a cluster_size=128k backup target without a backing file.
        (target, _) = bitmap0.new_target()
        self.img_create(target, bitmap0.drive['fmt'], cluster_size='128k')

        # Perform Incremental Backup
        self.assertTrue(self.do_qmp_backup(device=bitmap0.drive['id'],
                                           sync='incremental',
                                           bitmap=bitmap0.name,
                                           format=bitmap0.drive['fmt'],
                                           target=target,
                                           mode='existing'))
        self.make_reference_backup(bitmap0)

        # Add the backing file, then compare and exit.
        iotests.qemu_img('rebase', '-f', drive0['fmt'], '-u', '-b',
                         drive0['backup'], '-F', drive0['fmt'], target)
        self.vm.shutdown()
        self.check_backups()


    def test_incremental_transaction(self):
        '''Test: Verify backups made from transactionally created bitmaps.

        Create a bitmap "before" VM execution begins, then create a second
        bitmap AFTER writes have already occurred. Use transactions to create
        a full backup and synchronize both bitmaps to this backup.
        Create an incremental backup through both bitmaps and verify that
        both backups match the current drive0 image.
        '''

        drive0 = self.drives[0]
        bitmap0 = self.add_bitmap('bitmap0', drive0)
        self.hmp_io_writes(drive0['id'], (('0xab', 0, 512),
                                          ('0xfe', '16M', '256k'),
                                          ('0x64', '32736k', '64k')))
        bitmap1 = self.add_bitmap('bitmap1', drive0)

        result = self.vm.qmp('transaction', actions=[
            transaction_bitmap_clear(bitmap0.drive['id'], bitmap0.name),
            transaction_bitmap_clear(bitmap1.drive['id'], bitmap1.name),
            transaction_drive_backup(drive0['id'], drive0['backup'],
                                     sync='full', format=drive0['fmt'])
        ])
        self.assert_qmp(result, 'return', {})
        self.wait_until_completed(drive0['id'])
        self.files.append(drive0['backup'])

        self.hmp_io_writes(drive0['id'], (('0x9a', 0, 512),
                                          ('0x55', '8M', '352k'),
                                          ('0x78', '15872k', '1M')))
        # Both bitmaps should be correctly in sync.
        self.create_incremental(bitmap0)
        self.create_incremental(bitmap1)
        self.vm.shutdown()
        self.check_backups()


    def do_transaction_failure_test(self, race=False):
        # Create a second drive, with pattern:
        drive1 = self.add_node('drive1')
        self.img_create(drive1['file'], drive1['fmt'])
        io_write_patterns(drive1['file'], (('0x14', 0, 512),
                                           ('0x5d', '1M', '32k'),
                                           ('0xcd', '32M', '124k')))

        # Create a blkdebug interface to this img as 'drive1'
        result = self.vm.qmp('blockdev-add',
            node_name=drive1['id'],
            driver=drive1['fmt'],
            file={
                'driver': 'blkdebug',
                'image': {
                    'driver': 'file',
                    'filename': drive1['file']
                },
                'set-state': [{
                    'event': 'flush_to_disk',
                    'state': 1,
                    'new_state': 2
                }],
                'inject-error': [{
                    'event': 'read_aio',
                    'errno': 5,
                    'state': 2,
                    'immediately': False,
                    'once': True
                }],
            }
        )
        self.assert_qmp(result, 'return', {})

        # Create bitmaps and full backups for both drives
        drive0 = self.drives[0]
        dr0bm0 = self.add_bitmap('bitmap0', drive0)
        dr1bm0 = self.add_bitmap('bitmap0', drive1)
        self.create_anchor_backup(drive0)
        self.create_anchor_backup(drive1)
        self.assert_no_active_block_jobs()
        self.assertFalse(self.vm.get_qmp_events(wait=False))

        # Emulate some writes
        if not race:
            self.hmp_io_writes(drive0['id'], (('0xab', 0, 512),
                                              ('0xfe', '16M', '256k'),
                                              ('0x64', '32736k', '64k')))
        self.hmp_io_writes(drive1['id'], (('0xba', 0, 512),
                                          ('0xef', '16M', '256k'),
                                          ('0x46', '32736k', '64k')))

        # Create incremental backup targets
        target0 = self.prepare_backup(dr0bm0)
        target1 = self.prepare_backup(dr1bm0)

        # Ask for a new incremental backup per-each drive,
        # expecting drive1's backup to fail. In the 'race' test,
        # we expect drive1 to attempt to cancel the empty drive0 job.
        transaction = [
            transaction_drive_backup(drive0['id'], target0, sync='incremental',
                                     format=drive0['fmt'], mode='existing',
                                     bitmap=dr0bm0.name),
            transaction_drive_backup(drive1['id'], target1, sync='incremental',
                                     format=drive1['fmt'], mode='existing',
                                     bitmap=dr1bm0.name)
        ]
        result = self.vm.qmp('transaction', actions=transaction,
                             properties={'completion-mode': 'grouped'} )
        self.assert_qmp(result, 'return', {})

        # Observe that drive0's backup is cancelled and drive1 completes with
        # an error.
        self.wait_qmp_backup_cancelled(drive0['id'])
        self.assertFalse(self.wait_qmp_backup(drive1['id']))
        error = self.vm.event_wait('BLOCK_JOB_ERROR')
        self.assert_qmp(error, 'data', {'device': drive1['id'],
                                        'action': 'report',
                                        'operation': 'read'})
        self.assertFalse(self.vm.get_qmp_events(wait=False))
        self.assert_no_active_block_jobs()

        # Delete drive0's successful target and eliminate our record of the
        # unsuccessful drive1 target.
        dr0bm0.del_target()
        dr1bm0.del_target()
        if race:
            # Don't re-run the transaction, we only wanted to test the race.
            self.vm.shutdown()
            return

        # Re-run the same transaction:
        target0 = self.prepare_backup(dr0bm0)
        target1 = self.prepare_backup(dr1bm0)

        # Re-run the exact same transaction.
        result = self.vm.qmp('transaction', actions=transaction,
                             properties={'completion-mode':'grouped'})
        self.assert_qmp(result, 'return', {})

        # Both should complete successfully this time.
        self.assertTrue(self.wait_qmp_backup(drive0['id']))
        self.assertTrue(self.wait_qmp_backup(drive1['id']))
        self.make_reference_backup(dr0bm0)
        self.make_reference_backup(dr1bm0)
        self.assertFalse(self.vm.get_qmp_events(wait=False))
        self.assert_no_active_block_jobs()

        # And the images should of course validate.
        self.vm.shutdown()
        self.check_backups()

    def test_transaction_failure(self):
        '''Test: Verify backups made from a transaction that partially fails.

        Add a second drive with its own unique pattern, and add a bitmap to each
        drive. Use blkdebug to interfere with the backup on just one drive and
        attempt to create a coherent incremental backup across both drives.

        verify a failure in one but not both, then delete the failed stubs and
        re-run the same transaction.

        verify that both incrementals are created successfully.
        '''
        self.do_transaction_failure_test()

    def test_transaction_failure_race(self):
        '''Test: Verify that transactions with jobs that have no data to
        transfer do not cause race conditions in the cancellation of the entire
        transaction job group.
        '''
        self.do_transaction_failure_test(race=True)


    def test_sync_dirty_bitmap_missing(self):
        self.assert_no_active_block_jobs()
        self.files.append(self.err_img)
        result = self.vm.qmp('drive-backup', device=self.drives[0]['id'],
                             sync='incremental', format=self.drives[0]['fmt'],
                             target=self.err_img)
        self.assert_qmp(result, 'error/class', 'GenericError')


    def test_sync_dirty_bitmap_not_found(self):
        self.assert_no_active_block_jobs()
        self.files.append(self.err_img)
        result = self.vm.qmp('drive-backup', device=self.drives[0]['id'],
                             sync='incremental', bitmap='unknown',
                             format=self.drives[0]['fmt'], target=self.err_img)
        self.assert_qmp(result, 'error/class', 'GenericError')


    def test_sync_dirty_bitmap_bad_granularity(self):
        '''
        Test: Test what happens if we provide an improper granularity.

        The granularity must always be a power of 2.
        '''
        self.assert_no_active_block_jobs()
        self.assertRaises(AssertionError, self.add_bitmap,
                          'bitmap0', self.drives[0],
                          granularity=64000)


class TestIncrementalBackupBlkdebug(TestIncrementalBackupBase):
    '''Incremental backup tests that utilize a BlkDebug filter on drive0.'''

    def setUp(self):
        drive0 = self.add_node('drive0')
        self.img_create(drive0['file'], drive0['fmt'])
        self.write_default_pattern(drive0['file'])
        self.vm.launch()

    def test_incremental_failure(self):
        '''Test: Verify backups made after a failure are correct.

        Simulate a failure during an incremental backup block job,
        emulate additional writes, then create another incremental backup
        afterwards and verify that the backup created is correct.
        '''

        drive0 = self.drives[0]
        result = self.vm.qmp('blockdev-add',
            node_name=drive0['id'],
            driver=drive0['fmt'],
            file={
                'driver': 'blkdebug',
                'image': {
                    'driver': 'file',
                    'filename': drive0['file']
                },
                'set-state': [{
                    'event': 'flush_to_disk',
                    'state': 1,
                    'new_state': 2
                }],
                'inject-error': [{
                    'event': 'read_aio',
                    'errno': 5,
                    'state': 2,
                    'immediately': False,
                    'once': True
                }],
            }
        )
        self.assert_qmp(result, 'return', {})

        self.create_anchor_backup(drive0)
        self.add_bitmap('bitmap0', drive0)
        # Note: at this point, during a normal execution,
        # Assume that the VM resumes and begins issuing IO requests here.

        self.hmp_io_writes(drive0['id'], (('0xab', 0, 512),
                                          ('0xfe', '16M', '256k'),
                                          ('0x64', '32736k', '64k')))

        result = self.create_incremental(validate=False)
        self.assertFalse(result)
        self.hmp_io_writes(drive0['id'], (('0x9a', 0, 512),
                                          ('0x55', '8M', '352k'),
                                          ('0x78', '15872k', '1M')))
        self.create_incremental()
        self.vm.shutdown()
        self.check_backups()


if __name__ == '__main__':
    iotests.main(supported_fmts=['qcow2'])
