# Copyright (c) 2010-2012 OpenStack Foundation # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or # implied. # See the License for the specific language governing permissions and # limitations under the License. """ Database code for Swift """ from contextlib import contextmanager, closing import hashlib import json import logging import os from uuid import uuid4 import sys import time import errno import six import six.moves.cPickle as pickle from swift import gettext_ as _ from tempfile import mkstemp from eventlet import sleep, Timeout import sqlite3 from swift.common.constraints import MAX_META_COUNT, MAX_META_OVERALL_SIZE, \ check_utf8 from swift.common.utils import Timestamp, renamer, \ mkdirs, lock_parent_directory, fallocate from swift.common.exceptions import LockTimeout from swift.common.swob import HTTPBadRequest #: Whether calls will be made to preallocate disk space for database files. DB_PREALLOCATION = False #: Timeout for trying to connect to a DB BROKER_TIMEOUT = 25 #: Pickle protocol to use PICKLE_PROTOCOL = 2 #: Max size of .pending file in bytes. When this is exceeded, the pending # records will be merged. PENDING_CAP = 131072 def utf8encode(*args): return [(s.encode('utf8') if isinstance(s, six.text_type) else s) for s in args] def utf8encodekeys(metadata): uni_keys = [k for k in metadata if isinstance(k, six.text_type)] for k in uni_keys: sv = metadata[k] del metadata[k] metadata[k.encode('utf-8')] = sv def _db_timeout(timeout, db_file, call): with LockTimeout(timeout, db_file): retry_wait = 0.001 while True: try: return call() except sqlite3.OperationalError as e: if 'locked' not in str(e): raise sleep(retry_wait) retry_wait = min(retry_wait * 2, 0.05) class DatabaseConnectionError(sqlite3.DatabaseError): """More friendly error messages for DB Errors.""" def __init__(self, path, msg, timeout=0): self.path = path self.timeout = timeout self.msg = msg def __str__(self): return 'DB connection error (%s, %s):\n%s' % ( self.path, self.timeout, self.msg) class DatabaseAlreadyExists(sqlite3.DatabaseError): """More friendly error messages for DB Errors.""" def __init__(self, path): self.path = path def __str__(self): return 'DB %s already exists' % self.path class GreenDBConnection(sqlite3.Connection): """SQLite DB Connection handler that plays well with eventlet.""" def __init__(self, database, timeout=None, *args, **kwargs): if timeout is None: timeout = BROKER_TIMEOUT self.timeout = timeout self.db_file = database super(GreenDBConnection, self).__init__(database, 0, *args, **kwargs) def cursor(self, cls=None): if cls is None: cls = GreenDBCursor return sqlite3.Connection.cursor(self, cls) def commit(self): return _db_timeout( self.timeout, self.db_file, lambda: sqlite3.Connection.commit(self)) class GreenDBCursor(sqlite3.Cursor): """SQLite Cursor handler that plays well with eventlet.""" def __init__(self, *args, **kwargs): self.timeout = args[0].timeout self.db_file = args[0].db_file super(GreenDBCursor, self).__init__(*args, **kwargs) def execute(self, *args, **kwargs): return _db_timeout( self.timeout, self.db_file, lambda: sqlite3.Cursor.execute( self, *args, **kwargs)) def dict_factory(crs, row): """ This should only be used when you need a real dict, i.e. when you're going to serialize the results. """ return dict( ((col[0], row[idx]) for idx, col in enumerate(crs.description))) def chexor(old, name, timestamp): """ Each entry in the account and container databases is XORed by the 128-bit hash on insert or delete. This serves as a rolling, order-independent hash of the contents. (check + XOR) :param old: hex representation of the current DB hash :param name: name of the object or container being inserted :param timestamp: internalized timestamp of the new record :returns: a hex representation of the new hash value """ if name is None: raise Exception('name is None!') new = hashlib.md5(('%s-%s' % (name, timestamp)).encode('utf8')).hexdigest() return '%032x' % (int(old, 16) ^ int(new, 16)) def get_db_connection(path, timeout=30, okay_to_create=False): """ Returns a properly configured SQLite database connection. :param path: path to DB :param timeout: timeout for connection :param okay_to_create: if True, create the DB if it doesn't exist :returns: DB connection object """ try: connect_time = time.time() conn = sqlite3.connect(path, check_same_thread=False, factory=GreenDBConnection, timeout=timeout) if path != ':memory:' and not okay_to_create: # attempt to detect and fail when connect creates the db file stat = os.stat(path) if stat.st_size == 0 and stat.st_ctime >= connect_time: os.unlink(path) raise DatabaseConnectionError(path, 'DB file created by connect?') conn.row_factory = sqlite3.Row conn.text_factory = str with closing(conn.cursor()) as cur: cur.execute('PRAGMA synchronous = NORMAL') cur.execute('PRAGMA count_changes = OFF') cur.execute('PRAGMA temp_store = MEMORY') cur.execute('PRAGMA journal_mode = DELETE') conn.create_function('chexor', 3, chexor) except sqlite3.DatabaseError: import traceback raise DatabaseConnectionError(path, traceback.format_exc(), timeout=timeout) return conn class DatabaseBroker(object): """Encapsulates working with a database.""" def __init__(self, db_file, timeout=BROKER_TIMEOUT, logger=None, account=None, container=None, pending_timeout=None, stale_reads_ok=False): """Encapsulates working with a database.""" self.conn = None self._db_file = db_file self.pending_file = self._db_file + '.pending' self.pending_timeout = pending_timeout or 10 self.stale_reads_ok = stale_reads_ok self.db_dir = os.path.dirname(db_file) self.timeout = timeout self.logger = logger or logging.getLogger() self.account = account self.container = container self._db_version = -1 def __str__(self): """ Returns a string identifying the entity under broker to a human. The baseline implementation returns a full pathname to a database. This is vital for useful diagnostics. """ return self.db_file def initialize(self, put_timestamp=None, storage_policy_index=None): """ Create the DB The storage_policy_index is passed through to the subclass's ``_initialize`` method. It is ignored by ``AccountBroker``. :param put_timestamp: internalized timestamp of initial PUT request :param storage_policy_index: only required for containers """ if self._db_file == ':memory:': tmp_db_file = None conn = get_db_connection(self._db_file, self.timeout) else: mkdirs(self.db_dir) fd, tmp_db_file = mkstemp(suffix='.tmp', dir=self.db_dir) os.close(fd) conn = sqlite3.connect(tmp_db_file, check_same_thread=False, factory=GreenDBConnection, timeout=0) # creating dbs implicitly does a lot of transactions, so we # pick fast, unsafe options here and do a big fsync at the end. with closing(conn.cursor()) as cur: cur.execute('PRAGMA synchronous = OFF') cur.execute('PRAGMA temp_store = MEMORY') cur.execute('PRAGMA journal_mode = MEMORY') conn.create_function('chexor', 3, chexor) conn.row_factory = sqlite3.Row conn.text_factory = str conn.executescript(""" CREATE TABLE outgoing_sync ( remote_id TEXT UNIQUE, sync_point INTEGER, updated_at TEXT DEFAULT 0 ); CREATE TABLE incoming_sync ( remote_id TEXT UNIQUE, sync_point INTEGER, updated_at TEXT DEFAULT 0 ); CREATE TRIGGER outgoing_sync_insert AFTER INSERT ON outgoing_sync BEGIN UPDATE outgoing_sync SET updated_at = STRFTIME('%s', 'NOW') WHERE ROWID = new.ROWID; END; CREATE TRIGGER outgoing_sync_update AFTER UPDATE ON outgoing_sync BEGIN UPDATE outgoing_sync SET updated_at = STRFTIME('%s', 'NOW') WHERE ROWID = new.ROWID; END; CREATE TRIGGER incoming_sync_insert AFTER INSERT ON incoming_sync BEGIN UPDATE incoming_sync SET updated_at = STRFTIME('%s', 'NOW') WHERE ROWID = new.ROWID; END; CREATE TRIGGER incoming_sync_update AFTER UPDATE ON incoming_sync BEGIN UPDATE incoming_sync SET updated_at = STRFTIME('%s', 'NOW') WHERE ROWID = new.ROWID; END; """) if not put_timestamp: put_timestamp = Timestamp(0).internal self._initialize(conn, put_timestamp, storage_policy_index=storage_policy_index) conn.commit() if tmp_db_file: conn.close() with open(tmp_db_file, 'r+b') as fp: os.fsync(fp.fileno()) with lock_parent_directory(self.db_file, self.pending_timeout): if self._db_exists(): # It's as if there was a "condition" where different parts # of the system were "racing" each other. raise DatabaseAlreadyExists(self.db_file) renamer(tmp_db_file, self.db_file) self.conn = get_db_connection(self.db_file, self.timeout) else: self.conn = conn def delete_db(self, timestamp): """ Mark the DB as deleted :param timestamp: internalized delete timestamp """ # first, clear the metadata cleared_meta = {} for k in self.metadata: cleared_meta[k] = ('', timestamp) self.update_metadata(cleared_meta) # then mark the db as deleted with self.get() as conn: self._delete_db(conn, timestamp) conn.commit() def possibly_quarantine(self, exc_type, exc_value, exc_traceback): """ Checks the exception info to see if it indicates a quarantine situation (malformed or corrupted database). If not, the original exception will be reraised. If so, the database will be quarantined and a new sqlite3.DatabaseError will be raised indicating the action taken. """ if 'database disk image is malformed' in str(exc_value): exc_hint = 'malformed' elif 'malformed database schema' in str(exc_value): exc_hint = 'malformed' elif ' is not a database' in str(exc_value): # older versions said 'file is not a database' # now 'file is encrypted or is not a database' exc_hint = 'corrupted' elif 'disk I/O error' in str(exc_value): exc_hint = 'disk error while accessing' else: six.reraise(exc_type, exc_value, exc_traceback) prefix_path = os.path.dirname(self.db_dir) partition_path = os.path.dirname(prefix_path) dbs_path = os.path.dirname(partition_path) device_path = os.path.dirname(dbs_path) quar_path = os.path.join(device_path, 'quarantined', self.db_type + 's', os.path.basename(self.db_dir)) try: renamer(self.db_dir, quar_path, fsync=False) except OSError as e: if e.errno not in (errno.EEXIST, errno.ENOTEMPTY): raise quar_path = "%s-%s" % (quar_path, uuid4().hex) renamer(self.db_dir, quar_path, fsync=False) detail = _('Quarantined %(db_dir)s to %(quar_path)s due to ' '%(exc_hint)s database') % {'db_dir': self.db_dir, 'quar_path': quar_path, 'exc_hint': exc_hint} self.logger.error(detail) raise sqlite3.DatabaseError(detail) def _db_exists(self): return self.db_file == ':memory:' or os.path.exists(self.db_file) @property def db_file(self): return self._db_file def _create_connection(self, db_file=None): if not db_file: db_file = self.db_file if self.db_file == ':memory:': return try: self.conn = get_db_connection(db_file, self.timeout) except (sqlite3.DatabaseError, DatabaseConnectionError): self.possibly_quarantine(*sys.exc_info()) @contextmanager def get(self): """Use with the "with" statement; returns a database connection.""" if not self.conn: if self.db_file != ':memory:' and os.path.exists(self.db_file): try: self.conn = get_db_connection(self.db_file, self.timeout) except (sqlite3.DatabaseError, DatabaseConnectionError): self.possibly_quarantine(*sys.exc_info()) else: raise DatabaseConnectionError(self.db_file, "DB doesn't exist") conn = self.conn self.conn = None try: yield conn conn.rollback() self.conn = conn except sqlite3.DatabaseError: try: conn.close() except Exception: pass self.possibly_quarantine(*sys.exc_info()) except (Exception, Timeout): conn.close() raise @contextmanager def lock(self): """Use with the "with" statement; locks a database.""" if not self.conn: if self.db_file != ':memory:' and self._db_exists(): self.conn = get_db_connection(self.db_file, self.timeout) else: raise DatabaseConnectionError(self.db_file, "DB doesn't exist") conn = self.conn self.conn = None orig_isolation_level = conn.isolation_level conn.isolation_level = None conn.execute('BEGIN IMMEDIATE') try: yield True except (Exception, Timeout): pass try: conn.execute('ROLLBACK') conn.isolation_level = orig_isolation_level self.conn = conn except (Exception, Timeout): logging.exception( _('Broker error trying to rollback locked connection')) conn.close() def newid(self, remote_id): """ Re-id the database. This should be called after an rsync. :param remote_id: the ID of the remote database being rsynced in """ with self.get() as conn: row = conn.execute(''' UPDATE %s_stat SET id=? ''' % self.db_type, (str(uuid4()),)) row = conn.execute(''' SELECT ROWID FROM %s ORDER BY ROWID DESC LIMIT 1 ''' % self.db_contains_type).fetchone() sync_point = row['ROWID'] if row else -1 conn.execute(''' INSERT OR REPLACE INTO incoming_sync (sync_point, remote_id) VALUES (?, ?) ''', (sync_point, remote_id)) self._newid(conn) conn.commit() def _newid(self, conn): # Override for additional work when receiving an rsynced db. pass def _is_deleted(self, conn): """ Check if the database is considered deleted :param conn: database conn :returns: True if the DB is considered to be deleted, False otherwise """ raise NotImplementedError() def is_deleted(self): """ Check if the DB is considered to be deleted. :returns: True if the DB is considered to be deleted, False otherwise """ if self.db_file != ':memory:' and not self._db_exists(): return True self._commit_puts_stale_ok() with self.get() as conn: return self._is_deleted(conn) def merge_timestamps(self, created_at, put_timestamp, delete_timestamp): """ Used in replication to handle updating timestamps. :param created_at: create timestamp :param put_timestamp: put timestamp :param delete_timestamp: delete timestamp """ with self.get() as conn: old_status = self._is_deleted(conn) conn.execute(''' UPDATE %s_stat SET created_at=MIN(?, created_at), put_timestamp=MAX(?, put_timestamp), delete_timestamp=MAX(?, delete_timestamp) ''' % self.db_type, (created_at, put_timestamp, delete_timestamp)) if old_status != self._is_deleted(conn): timestamp = Timestamp.now() self._update_status_changed_at(conn, timestamp.internal) conn.commit() def get_items_since(self, start, count): """ Get a list of objects in the database between start and end. :param start: start ROWID :param count: number to get :returns: list of objects between start and end """ self._commit_puts_stale_ok() with self.get() as conn: curs = conn.execute(''' SELECT * FROM %s WHERE ROWID > ? ORDER BY ROWID ASC LIMIT ? ''' % self.db_contains_type, (start, count)) curs.row_factory = dict_factory return [r for r in curs] def get_other_replication_items(self): """ Subclasses may override this method to return a list of items that should be replicated in addition to the list of objects returned by :meth:`~get_items_since`. The list should contain objects that can be JSON serialized and are suitable to be passed to the :meth:`merge_items` method of the same class. :return: a list, or None """ return None def get_sync(self, id, incoming=True): """ Gets the most recent sync point for a server from the sync table. :param id: remote ID to get the sync_point for :param incoming: if True, get the last incoming sync, otherwise get the last outgoing sync :returns: the sync point, or -1 if the id doesn't exist. """ with self.get() as conn: row = conn.execute( "SELECT sync_point FROM %s_sync WHERE remote_id=?" % ('incoming' if incoming else 'outgoing'), (id,)).fetchone() if not row: return -1 return row['sync_point'] def get_syncs(self, incoming=True): """ Get a serialized copy of the sync table. :param incoming: if True, get the last incoming sync, otherwise get the last outgoing sync :returns: list of {'remote_id', 'sync_point'} """ with self.get() as conn: curs = conn.execute(''' SELECT remote_id, sync_point FROM %s_sync ''' % ('incoming' if incoming else 'outgoing')) result = [] for row in curs: result.append({'remote_id': row[0], 'sync_point': row[1]}) return result def get_max_row(self, table=None): if not table: table = self.db_contains_type query = ''' SELECT SQLITE_SEQUENCE.seq FROM SQLITE_SEQUENCE WHERE SQLITE_SEQUENCE.name == '%s' LIMIT 1 ''' % (table) with self.get() as conn: row = conn.execute(query).fetchone() return row[0] if row else -1 def get_replication_info(self): """ Get information about the DB required for replication. :returns: dict containing keys from get_info plus max_row and metadata Note:: get_info's _count is translated to just "count" and metadata is the raw string. """ info = self.get_info() info['count'] = info.pop('%s_count' % self.db_contains_type) info['metadata'] = self.get_raw_metadata() info['max_row'] = self.get_max_row() return info def get_info(self): self._commit_puts_stale_ok() with self.get() as conn: curs = conn.execute('SELECT * from %s_stat' % self.db_type) curs.row_factory = dict_factory return curs.fetchone() def put_record(self, record): if self._db_file == ':memory:': self.merge_items([record]) return if not self._db_exists(): raise DatabaseConnectionError(self.db_file, "DB doesn't exist") with lock_parent_directory(self.pending_file, self.pending_timeout): pending_size = 0 try: pending_size = os.path.getsize(self.pending_file) except OSError as err: if err.errno != errno.ENOENT: raise if pending_size > PENDING_CAP: self._commit_puts([record]) else: with open(self.pending_file, 'a+b') as fp: # Colons aren't used in base64 encoding; so they are our # delimiter fp.write(':') fp.write(pickle.dumps( self.make_tuple_for_pickle(record), protocol=PICKLE_PROTOCOL).encode('base64')) fp.flush() def _commit_puts(self, item_list=None): """ Scan for .pending files and commit the found records by feeding them to merge_items(). Assume that lock_parent_directory has already been called. :param item_list: A list of items to commit in addition to .pending """ if self._db_file == ':memory:' or not \ os.path.exists(self.pending_file): return if item_list is None: item_list = [] self._preallocate() if not os.path.getsize(self.pending_file): if item_list: self.merge_items(item_list) return with open(self.pending_file, 'r+b') as fp: for entry in fp.read().split(':'): if entry: try: self._commit_puts_load(item_list, entry) except Exception: self.logger.exception( _('Invalid pending entry %(file)s: %(entry)s'), {'file': self.pending_file, 'entry': entry}) if item_list: self.merge_items(item_list) try: os.ftruncate(fp.fileno(), 0) except OSError as err: if err.errno != errno.ENOENT: raise def _commit_puts_stale_ok(self): """ Catch failures of _commit_puts() if broker is intended for reading of stats, and thus does not care for pending updates. """ if self._db_file == ':memory:' or not \ os.path.exists(self.pending_file): return try: with lock_parent_directory(self.pending_file, self.pending_timeout): self._commit_puts() except (LockTimeout, sqlite3.OperationalError): if not self.stale_reads_ok: raise def _commit_puts_load(self, item_list, entry): """ Unmarshall the :param:entry and append it to :param:item_list. This is implemented by a particular broker to be compatible with its :func:`merge_items`. """ raise NotImplementedError def make_tuple_for_pickle(self, record): """ Turn this db record dict into the format this service uses for pending pickles. """ raise NotImplementedError def merge_syncs(self, sync_points, incoming=True): """ Merge a list of sync points with the incoming sync table. :param sync_points: list of sync points where a sync point is a dict of {'sync_point', 'remote_id'} :param incoming: if True, get the last incoming sync, otherwise get the last outgoing sync """ with self.get() as conn: for rec in sync_points: try: conn.execute(''' INSERT INTO %s_sync (sync_point, remote_id) VALUES (?, ?) ''' % ('incoming' if incoming else 'outgoing'), (rec['sync_point'], rec['remote_id'])) except sqlite3.IntegrityError: conn.execute(''' UPDATE %s_sync SET sync_point=max(?, sync_point) WHERE remote_id=? ''' % ('incoming' if incoming else 'outgoing'), (rec['sync_point'], rec['remote_id'])) conn.commit() def _preallocate(self): """ The idea is to allocate space in front of an expanding db. If it gets within 512k of a boundary, it allocates to the next boundary. Boundaries are 2m, 5m, 10m, 25m, 50m, then every 50m after. """ if not DB_PREALLOCATION or self._db_file == ':memory:': return MB = (1024 * 1024) def prealloc_points(): for pm in (1, 2, 5, 10, 25, 50): yield pm * MB while True: pm += 50 yield pm * MB stat = os.stat(self.db_file) file_size = stat.st_size allocated_size = stat.st_blocks * 512 for point in prealloc_points(): if file_size <= point - MB / 2: prealloc_size = point break if allocated_size < prealloc_size: with open(self.db_file, 'rb+') as fp: fallocate(fp.fileno(), int(prealloc_size)) def get_raw_metadata(self): with self.get() as conn: try: metadata = conn.execute('SELECT metadata FROM %s_stat' % self.db_type).fetchone()[0] except sqlite3.OperationalError as err: if 'no such column: metadata' not in str(err): raise metadata = '' return metadata @property def metadata(self): """ Returns the metadata dict for the database. The metadata dict values are tuples of (value, timestamp) where the timestamp indicates when that key was set to that value. """ metadata = self.get_raw_metadata() if metadata: metadata = json.loads(metadata) utf8encodekeys(metadata) else: metadata = {} return metadata @staticmethod def validate_metadata(metadata): """ Validates that metadata falls within acceptable limits. :param metadata: to be validated :raises HTTPBadRequest: if MAX_META_COUNT or MAX_META_OVERALL_SIZE is exceeded, or if metadata contains non-UTF-8 data """ meta_count = 0 meta_size = 0 for key, (value, timestamp) in metadata.items(): key = key.lower() if value != '' and (key.startswith('x-account-meta') or key.startswith('x-container-meta')): prefix = 'x-account-meta-' if key.startswith('x-container-meta-'): prefix = 'x-container-meta-' key = key[len(prefix):] meta_count = meta_count + 1 meta_size = meta_size + len(key) + len(value) bad_key = key and not check_utf8(key) bad_value = value and not check_utf8(value) if bad_key or bad_value: raise HTTPBadRequest('Metadata must be valid UTF-8') if meta_count > MAX_META_COUNT: raise HTTPBadRequest('Too many metadata items; max %d' % MAX_META_COUNT) if meta_size > MAX_META_OVERALL_SIZE: raise HTTPBadRequest('Total metadata too large; max %d' % MAX_META_OVERALL_SIZE) def update_metadata(self, metadata_updates, validate_metadata=False): """ Updates the metadata dict for the database. The metadata dict values are tuples of (value, timestamp) where the timestamp indicates when that key was set to that value. Key/values will only be overwritten if the timestamp is newer. To delete a key, set its value to ('', timestamp). These empty keys will eventually be removed by :func:`reclaim` """ old_metadata = self.metadata if set(metadata_updates).issubset(set(old_metadata)): for key, (value, timestamp) in metadata_updates.items(): if timestamp > old_metadata[key][1]: break else: return with self.get() as conn: try: md = conn.execute('SELECT metadata FROM %s_stat' % self.db_type).fetchone()[0] md = json.loads(md) if md else {} utf8encodekeys(md) except sqlite3.OperationalError as err: if 'no such column: metadata' not in str(err): raise conn.execute(""" ALTER TABLE %s_stat ADD COLUMN metadata TEXT DEFAULT '' """ % self.db_type) md = {} for key, value_timestamp in metadata_updates.items(): value, timestamp = value_timestamp if key not in md or timestamp > md[key][1]: md[key] = value_timestamp if validate_metadata: DatabaseBroker.validate_metadata(md) conn.execute('UPDATE %s_stat SET metadata = ?' % self.db_type, (json.dumps(md),)) conn.commit() def reclaim(self, age_timestamp, sync_timestamp): """ Delete rows from the db_contains_type table that are marked deleted and whose created_at timestamp is < age_timestamp. Also deletes rows from incoming_sync and outgoing_sync where the updated_at timestamp is < sync_timestamp. In addition, this calls the DatabaseBroker's :func:`_reclaim` method. :param age_timestamp: max created_at timestamp of object rows to delete :param sync_timestamp: max update_at timestamp of sync rows to delete """ if self._db_file != ':memory:' and os.path.exists(self.pending_file): with lock_parent_directory(self.pending_file, self.pending_timeout): self._commit_puts() with self.get() as conn: conn.execute(''' DELETE FROM %s WHERE deleted = 1 AND %s < ? ''' % (self.db_contains_type, self.db_reclaim_timestamp), (age_timestamp,)) try: conn.execute(''' DELETE FROM outgoing_sync WHERE updated_at < ? ''', (sync_timestamp,)) conn.execute(''' DELETE FROM incoming_sync WHERE updated_at < ? ''', (sync_timestamp,)) except sqlite3.OperationalError as err: # Old dbs didn't have updated_at in the _sync tables. if 'no such column: updated_at' not in str(err): raise DatabaseBroker._reclaim(self, conn, age_timestamp) conn.commit() def _reclaim(self, conn, timestamp): """ Removes any empty metadata values older than the timestamp using the given database connection. This function will not call commit on the conn, but will instead return True if the database needs committing. This function was created as a worker to limit transactions and commits from other related functions. :param conn: Database connection to reclaim metadata within. :param timestamp: Empty metadata items last updated before this timestamp will be removed. :returns: True if conn.commit() should be called """ try: md = conn.execute('SELECT metadata FROM %s_stat' % self.db_type).fetchone()[0] if md: md = json.loads(md) keys_to_delete = [] for key, (value, value_timestamp) in md.items(): if value == '' and value_timestamp < timestamp: keys_to_delete.append(key) if keys_to_delete: for key in keys_to_delete: del md[key] conn.execute('UPDATE %s_stat SET metadata = ?' % self.db_type, (json.dumps(md),)) return True except sqlite3.OperationalError as err: if 'no such column: metadata' not in str(err): raise return False def update_put_timestamp(self, timestamp): """ Update the put_timestamp. Only modifies it if it is greater than the current timestamp. :param timestamp: internalized put timestamp """ with self.get() as conn: conn.execute( 'UPDATE %s_stat SET put_timestamp = ?' ' WHERE put_timestamp < ?' % self.db_type, (timestamp, timestamp)) conn.commit() def update_status_changed_at(self, timestamp): """ Update the status_changed_at field in the stat table. Only modifies status_changed_at if the timestamp is greater than the current status_changed_at timestamp. :param timestamp: internalized timestamp """ with self.get() as conn: self._update_status_changed_at(conn, timestamp) conn.commit() def _update_status_changed_at(self, conn, timestamp): conn.execute( 'UPDATE %s_stat SET status_changed_at = ?' ' WHERE status_changed_at < ?' % self.db_type, (timestamp, timestamp)) def get_brokers(self): return [self]