class PurgeBatchesCommand(commands.Subcommand):

    """

    .. highlight:: sh

    Purges stale batches from the database; called as::

      rattail purge-batches

    """

    name = 'purge-batches'

    description = "Purge stale batches from the database"

    def run(self, args):

        from rattail.db.batches.util import purge_batches

        edbob.init_modules(['edbob.db', 'rattail.db'])

        print "Purging batches from database:"

        print "    %s" % edbob.engine.url

        session = edbob.Session()

        purged = purge_batches(session)

        session.commit()

        session.close()

        print "\nPurged %d batches" % purged

#!/usr/bin/env python

# -*- coding: utf-8  -*-

################################################################################

#

#  Rattail -- Retail Software Framework

#  Copyright © 2010-2012 Lance Edgar

#

#  This file is part of Rattail.

#

#  Rattail is free software: you can redistribute it and/or modify it under the

#  terms of the GNU Affero General Public License as published by the Free

#  Software Foundation, either version 3 of the License, or (at your option)

#  any later version.

#

#  Rattail 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 Affero General Public License for

#  more details.

#

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

#  along with Rattail.  If not, see <http://www.gnu.org/licenses/>.

#

################################################################################

"""

``rattail.db.batches.util`` -- Batch Utilities

"""

import re

from sqlalchemy import MetaData

import edbob

from edbob.time import local_time

import rattail

from rattail.db.extension.model import Batch

def purge_batches(session, effective_date=None):

    """

    Purge batches from the database which are considered old.

    :param session: Active database session.

    :type session: ``sqlalchemy.orm.Session`` instance

    :param effective_date: Date against which comparisons should be made when

       determining if a batch is "old" (based on its

       :attr:`rattail.db.model.Batch.purge` attribute).  If no value is

       provided, then :func:`rattail.time.local_time()` is called to determine

       the current date.

    :type effective_date: ``datetime.date`` instance, or ``None``

    :returns: ``None``

    """

    if effective_date is None:

        edbob.init_modules(['edbob.time'])

        effective_date = local_time().date()

    purged = 0

    q = session.query(Batch)

    q = q.filter(Batch.purge != None)

    q = q.filter(Batch.purge < effective_date)

    for batch in q:

        batch.drop_table()

        session.delete(batch)

        session.flush()

        purged += 1

    # This should theoretically not be necessary, if/when the batch processing

    # is cleaning up after itself properly.  For now though, it seems that

    # orphaned data tables are sometimes being left behind.

    batch_pattern = re.compile(r'^batch\.[0-9a-f]{32}$')

    current_batches = []

    for batch in session.query(Batch):

        current_batches.append('batch.%s' % batch.uuid)

    def orphaned_batches(name, metadata):

        if batch_pattern.match(name):

            if name not in current_batches:

                return True

        return False

    metadata = MetaData(session.bind)

    metadata.reflect(only=orphaned_batches)

    for table in reversed(metadata.sorted_tables):

        table.drop()

    return purged

purge-batches = rattail.commands:PurgeBatchesCommand