migrate.py 3.03 KB
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#!/usr/bin/env python

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# Copyright 2011-2012 GRNET S.A. All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or
# without modification, are permitted provided that the following
# conditions are met:
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#
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#   1. Redistributions of source code must retain the above
#      copyright notice, this list of conditions and the following
#      disclaimer.
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#
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#   2. Redistributions in binary form must reproduce the above
#      copyright notice, this list of conditions and the following
#      disclaimer in the documentation and/or other materials
#      provided with the distribution.
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#
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# THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS
# OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR
# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
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#
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# The views and conclusions contained in the software and
# documentation are those of the authors and should not be
# interpreted as representing official policies, either expressed
# or implied, of GRNET S.A.

from sqlalchemy import create_engine
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from sqlalchemy import Table, Column, String, MetaData
from sqlalchemy.sql import select
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from django.conf import settings

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from pithos.backends.modular import ModularBackend

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class Migration(object):
    def __init__(self, db):
        self.engine = create_engine(db)
        self.metadata = MetaData(self.engine)
        #self.engine.echo = True
        self.conn = self.engine.connect()
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        options = getattr(settings, 'BACKEND', None)[1]
        self.backend = ModularBackend(*options)
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    def execute(self):
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        pass

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class Cache():
    def __init__(self, db):
        self.engine = create_engine(db)
        metadata = MetaData(self.engine)
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        columns = []
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        columns.append(Column('path', String(2048), primary_key=True))
        columns.append(Column('hash', String(255)))
        self.files = Table('files', metadata, *columns)
        self.conn = self.engine.connect()
        self.engine.echo = True
        metadata.create_all(self.engine)
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    def put(self, path, hash):
        # Insert or replace.
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        s = self.files.delete().where(self.files.c.path == path)
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        r = self.conn.execute(s)
        r.close()
        s = self.files.insert()
        r = self.conn.execute(s, {'path': path, 'hash': hash})
        r.close()
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    def get(self, path):
        s = select([self.files.c.hash], self.files.c.path == path)
        r = self.conn.execute(s)
        l = r.fetchone()
        r.close()
        if not l:
            return l
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        return l[0]