import os import tempfile import shutil import unittest import sqlite3 import uuid import fcntl Binary = sqlite3.Binary class BandStore(object): """ """ class DoesNotExist(KeyError): """""" class AlreadyExists(KeyError): """""" IDLE = 'Idle' OPEN = 'Open' ACTIVE = 'Active' BAND_LIMIT = 1 * 1024 * 1024 def __init__(self, path): self.read_fd = None self.write_fd = None if not os.path.exists(path): self.create(path) self.open(path) def open(self, path): if not os.path.isdir(path): raise Exception('%s Does not look like a store') db_path = os.path.join(path, 'dedupestore.db') if not os.path.exists(db_path): raise Exception('%s Does not look like a store2') self.lock_fd = open(os.path.join(path, 'lock'), 'w') fcntl.flock(self.lock_fd, fcntl.LOCK_EX) self.path = path self.cnx = sqlite3.connect(db_path) self.cnx.text_factory = str self.cursor = self.cnx.cursor() self._begin() def _begin(self): if self.read_fd: self.read_fd.close() self.read_fd = None if self.write_fd: self.write_fd.close() self.write_fd = None row = self.cursor.execute('SELECT uuid, tid, nextband, version, ' 'bandlimit FROM system').fetchone() self.uuid, self.tid, self.nextband, version, self.bandlimit = row assert version == 1 self.state = self.OPEN self.read_band = None self.write_band = None self.to_delete = set() band = self.nextband while os.path.exists(self.band_filename(band)): os.unlink(self.band_filename(band)) band += 1 def create(self, path): os.mkdir(path) os.mkdir(os.path.join(path, 'bands')) cnx = sqlite3.connect(os.path.join(path, 'dedupestore.db')) cnx.execute('CREATE TABLE objects(ns BINARY NOT NULL, id BINARY NOT NULL, ' 'band NOT NULL, offset NOT NULL, size NOT NULL)') cnx.execute('CREATE UNIQUE INDEX objects_pk ON objects(ns, id)') cnx.execute('CREATE TABLE system(uuid NOT NULL, tid NOT NULL, ' 'nextband NOT NULL, version NOT NULL, bandlimit NOT NULL)') cnx.execute('INSERT INTO system VALUES(?,?,?,?,?)', (uuid.uuid1().hex, 0, 0, 1, self.BAND_LIMIT)) cnx.commit() def close(self): self.rollback() self.cnx.close() self.lock_fd.close() os.unlink(os.path.join(self.path, 'lock')) def commit(self): """ """ self.band = None self.delete_bands() self.tid += 1 self._begin() def delete_bands(self): for b in self.to_delete: objects = self.cursor.execute('SELECT ns, id, offset, size ' 'FROM objects WHERE band=? ORDER BY offset', (b,)).fetchall() for o in objects: band, offset, size = self.store_data(self.retrieve_data(b, *o[2:])) self.cursor.execute('UPDATE objects SET band=?, offset=?, size=? ' 'WHERE ns=? AND id=?', (band, offset, size, Binary(o[0]), Binary(o[1]))) self.cursor.execute('UPDATE system SET tid=tid+1, nextband=?', (self.nextband,)) self.cnx.commit() for b in self.to_delete: os.unlink(self.band_filename(b)) def rollback(self): """ """ self.cnx.rollback() self._begin() def get(self, ns, id): """ """ self.cursor.execute('SELECT band, offset, size FROM objects WHERE ns=? and id=?', (Binary(ns), Binary(id))) row = self.cursor.fetchone() if row: return self.retrieve_data(*row) else: raise self.DoesNotExist def band_filename(self, band): return os.path.join(self.path, 'bands', str(band / 1000), str(band)) def retrieve_data(self, band, offset, size): if self.write_band == band: self.write_fd.flush() if self.read_band != band: self.read_band = band if self.read_fd: self.read_fd.close() self.read_fd = open(self.band_filename(band), 'rb') self.read_fd.seek(offset) return self.read_fd.read(size) def store_data(self, data): if self.write_band is None: self.write_band = self.nextband self.nextband += 1 if self.write_band % 1000 == 0: path = os.path.join(self.path, 'bands', str(self.write_band / 1000)) if not os.path.exists(path): os.mkdir(path) assert not os.path.exists(self.band_filename(self.write_band)) self.write_fd = open(self.band_filename(self.write_band), 'ab') band = self.write_band offset = self.write_fd.tell() self.write_fd.write(data) if offset + len(data) > self.bandlimit: self.write_band = None return band, offset, len(data) def put(self, ns, id, data): """ """ try: band, offset, size = self.store_data(data) self.cursor.execute('INSERT INTO objects (ns, id, band, offset, size) ' 'VALUES(?, ?, ?, ?, ?)', (Binary(ns), Binary(id), band, offset, size)) except sqlite3.IntegrityError: raise self.AlreadyExists def delete(self, ns, id): """ """ self.cursor.execute('SELECT band FROM objects WHERE ns=? and id=?', (Binary(ns), Binary(id))) row = self.cursor.fetchone() if not row: raise self.DoesNotExist self.cursor.execute('DELETE FROM objects WHERE ns=? AND id=?', (Binary(ns), Binary(id))) self.to_delete.add(row[0]) def list(self, ns, prefix='', marker=None, max_keys=1000000): """ """ sql = 'SELECT id FROM objects WHERE ns=:ns' args = dict(ns=Binary(ns)) if prefix: args['prefix'] = Binary(prefix) args['end'] = Binary(prefix + chr(255)) sql += ' AND id >= :prefix AND id < :end' if marker: sql += ' AND id >= :marker' args['marker'] = Binary(marker) for row in self.cursor.execute(sql + ' LIMIT ' + str(max_keys), args): yield str(row[0]) class BandStoreTestCase(unittest.TestCase): def setUp(self): self.tmppath = tempfile.mkdtemp() self.store = BandStore(os.path.join(self.tmppath, 'store')) def tearDown(self): shutil.rmtree(self.tmppath) def test1(self): self.assertEqual(self.store.tid, 0) self.assertEqual(self.store.state, self.store.OPEN) self.store.put('SOMENS', 'SOMEID', 'SOMEDATA') self.assertRaises(self.store.AlreadyExists, lambda: self.store.put('SOMENS', 'SOMEID', 'SOMEDATA')) self.assertEqual(self.store.get('SOMENS', 'SOMEID'), 'SOMEDATA') self.store.rollback() self.assertRaises(self.store.DoesNotExist, lambda: self.store.get('SOMENS', 'SOMEID')) self.assertEqual(self.store.tid, 0) def test2(self): self.assertEqual(self.store.tid, 0) self.assertEqual(self.store.state, self.store.OPEN) self.store.put('SOMENS', 'SOMEID', 'SOMEDATA') self.assertEqual(self.store.get('SOMENS', 'SOMEID'), 'SOMEDATA') self.store.commit() self.assertEqual(self.store.tid, 1) self.assertEqual(self.store.get('SOMENS', 'SOMEID'), 'SOMEDATA') self.store.delete('SOMENS', 'SOMEID') self.assertRaises(self.store.DoesNotExist, lambda: self.store.get('SOMENS', 'SOMEID')) self.store.rollback() self.assertEqual(self.store.get('SOMENS', 'SOMEID'), 'SOMEDATA') self.store.delete('SOMENS', 'SOMEID') self.assertRaises(self.store.DoesNotExist, lambda: self.store.get('SOMENS', 'SOMEID')) self.store.commit() self.assertEqual(self.store.tid, 2) self.assertRaises(self.store.DoesNotExist, lambda: self.store.get('SOMENS', 'SOMEID')) def test_list(self): self.store.put('SOMENS', 'SOMEID12', 'SOMEDATA') self.store.put('SOMENS', 'SOMEID', 'SOMEDATA') self.store.put('SOMENS', 'SOMEID1', 'SOMEDATA') self.store.put('SOMENS', 'SOMEID123', 'SOMEDATA') self.store.commit() self.assertEqual(list(self.store.list('SOMENS', max_keys=3)), ['SOMEID', 'SOMEID1', 'SOMEID12']) self.assertEqual(list(self.store.list('SOMENS', marker='SOMEID12')), ['SOMEID12', 'SOMEID123']) self.assertEqual(list(self.store.list('SOMENS', prefix='SOMEID1', max_keys=2)), ['SOMEID1', 'SOMEID12']) self.assertEqual(list(self.store.list('SOMENS', prefix='SOMEID1', marker='SOMEID12')), ['SOMEID12', 'SOMEID123']) def suite(): return unittest.TestLoader().loadTestsFromTestCase(BandStoreTestCase) if __name__ == '__main__': unittest.main()