Account DB and Container DB

DB

Database code for Swift

swift.common.db.BROKER_TIMEOUT = 25

Timeout for trying to connect to a DB

swift.common.db.DB_PREALLOCATION = True

Whether calls will be made to preallocate disk space for database files.

exception swift.common.db.DatabaseAlreadyExists(path)

Bases: sqlite3.DatabaseError

More friendly error messages for DB Errors.

class swift.common.db.DatabaseBroker(db_file, timeout=25, logger=None, account=None, container=None, pending_timeout=None, stale_reads_ok=False)

Bases: object

Encapsulates working with a database.

delete_db(timestamp)

Mark the DB as deleted

Parameters:timestamp – delete timestamp

get(*args, **kwds)

Use with the “with” statement; returns a database connection.

get_items_since(start, count)

Get a list of objects in the database between start and end.

Parameters:

• start – start ROWID
• count – number to get

Returns:

list of objects between start and end

get_replication_info()

Get information about the DB required for replication.

Returns:dict containing keys: hash, id, created_at, put_timestamp, delete_timestamp, count, max_row, and metadata

get_sync(id, incoming=True)

Gets the most recent sync point for a server from the sync table.

Parameters:

• id – remote ID to get the sync_point for
• 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.

get_syncs(incoming=True)

Get a serialized copy of the sync table.

Parameters:incoming – if True, get the last incoming sync, otherwise get the last outgoing sync Returns:list of {‘remote_id’, ‘sync_point’}

initialize(put_timestamp=None)

Create the DB

Parameters:put_timestamp – timestamp of initial PUT request

lock(*args, **kwds)

Use with the “with” statement; locks a database.

merge_syncs(sync_points, incoming=True)

Merge a list of sync points with the incoming sync table.

Parameters:

• sync_points – list of sync points where a sync point is a dict of {‘sync_point’, ‘remote_id’}
• incoming – if True, get the last incoming sync, otherwise get the last outgoing sync

merge_timestamps(created_at, put_timestamp, delete_timestamp)

Used in replication to handle updating timestamps.

Parameters:

• created_at – create timestamp
• put_timestamp – put timestamp
• delete_timestamp – delete timestamp

metadata

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.

newid(remote_id)

Re-id the database. This should be called after an rsync.

Parameters:remote_id – the ID of the remote database being rsynced in

possibly_quarantine(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.

reclaim(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 _reclaim() method.

Parameters:

• age_timestamp – max created_at timestamp of object rows to delete
• sync_timestamp – max update_at timestamp of sync rows to delete

update_metadata(metadata_updates)

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 reclaim()

update_put_timestamp(timestamp)

Update the put_timestamp. Only modifies it if it is greater than the current timestamp.

Parameters:timestamp – put timestamp

exception swift.common.db.DatabaseConnectionError(path, msg, timeout=0)

Bases: sqlite3.DatabaseError

More friendly error messages for DB Errors.

class swift.common.db.GreenDBConnection(database, timeout=None, *args, **kwargs)

Bases: sqlite3.Connection

SQLite DB Connection handler that plays well with eventlet.

commit()

cursor(cls=None)

class swift.common.db.GreenDBCursor(*args, **kwargs)

Bases: sqlite3.Cursor

SQLite Cursor handler that plays well with eventlet.

execute(*args, **kwargs)

swift.common.db.PENDING_CAP = 131072

Max number of pending entries

swift.common.db.PICKLE_PROTOCOL = 2

Pickle protocol to use

swift.common.db.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)

Parameters:

• old – hex representation of the current DB hash
• name – name of the object or container being inserted
• timestamp – timestamp of the new record

Returns:

a hex representation of the new hash value

swift.common.db.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.

swift.common.db.get_db_connection(path, timeout=30, okay_to_create=False)

Returns a properly configured SQLite database connection.

Parameters:

• path – path to DB
• timeout – timeout for connection
• okay_to_create – if True, create the DB if it doesn’t exist

Returns:

DB connection object

swift.common.db.utf8encode(*args)

swift.common.db.utf8encodekeys(metadata)

DB replicator

class swift.common.db_replicator.ReplConnection(node, partition, hash_, logger)

Bases: swift.common.bufferedhttp.BufferedHTTPConnection

Helper to simplify REPLICATEing to a remote server.

replicate(*args)

Make an HTTP REPLICATE request

Parameters:args – list of json-encodable objects Returns:bufferedhttp response object

class swift.common.db_replicator.Replicator(conf)

Bases: swift.common.daemon.Daemon

Implements the logic for directing db replication.

delete_db(object_file)

extract_device(object_file)

Extract the device name from an object path. Returns “UNKNOWN” if the path could not be extracted successfully for some reason.

Parameters:object_file – the path to a database file.

report_up_to_date(full_info)

run_forever(*args, **kwargs)

Replicate dbs under the given root in an infinite loop.

run_once(*args, **kwargs)

Run a replication pass once.

class swift.common.db_replicator.ReplicatorRpc(root, datadir, broker_class, mount_check=True, logger=None)

Bases: object

Handle Replication RPC calls. TODO(redbo): document please :)

complete_rsync(drive, db_file, args)

dispatch(replicate_args, args)

merge_items(broker, args)

merge_syncs(broker, args)

rsync_then_merge(drive, db_file, args)

sync(broker, args)

swift.common.db_replicator.quarantine_db(object_file, server_type)

In the case that a corrupt file is found, move it to a quarantined area to allow replication to fix it.

Parameters:

• object_file – path to corrupt file
• server_type – type of file that is corrupt (‘container’ or ‘account’)

swift.common.db_replicator.roundrobin_datadirs(datadirs)

Generator to walk the data dirs in a round robin manner, evenly hitting each device on the system, and yielding any .db files found (in their proper places). The partitions within each data dir are walked randomly, however.

Parameters:datadirs – a list of (path, node_id) to walk Returns:A generator of (partition, path_to_db_file, node_id)