コード例 #1
0
ファイル: session.py プロジェクト: n-nishida/rack
def _set_session_sql_mode(dbapi_con, connection_rec,
                          connection_proxy, sql_mode=None):
    """Set the sql_mode session variable.

    MySQL supports several server modes. The default is None, but sessions
    may choose to enable server modes like TRADITIONAL, ANSI,
    several STRICT_* modes and others.

    Note: passing in '' (empty string) for sql_mode clears
    the SQL mode for the session, overriding a potentially set
    server default. Passing in None (the default) makes this
    a no-op, meaning if a server-side SQL mode is set, it still applies.
    """
    cursor = dbapi_con.cursor()
    if sql_mode is not None:
        cursor.execute("SET SESSION sql_mode = %s", [sql_mode])

    # Check against the real effective SQL mode. Even when unset by
    # our own config, the server may still be operating in a specific
    # SQL mode as set by the server configuration
    cursor.execute("SHOW VARIABLES LIKE 'sql_mode'")
    row = cursor.fetchone()
    if row is None:
        LOG.warning(_LW('Unable to detect effective SQL mode'))
        return
    realmode = row[1]
    LOG.info(_LI('MySQL server mode set to %s') % realmode)
    # 'TRADITIONAL' mode enables several other modes, so
    # we need a substring match here
    if not ('TRADITIONAL' in realmode.upper() or
            'STRICT_ALL_TABLES' in realmode.upper()):
        LOG.warning(_LW("MySQL SQL mode is '%s', "
                        "consider enabling TRADITIONAL or STRICT_ALL_TABLES")
                    % realmode)
コード例 #2
0
ファイル: session.py プロジェクト: n-nishida/rack
def _ping_listener(engine, dbapi_conn, connection_rec, connection_proxy):
    """Ensures that MySQL and DB2 connections are alive.

    Borrowed from:
    http://groups.google.com/group/sqlalchemy/msg/a4ce563d802c929f
    """
    cursor = dbapi_conn.cursor()
    try:
        ping_sql = 'select 1'
        if engine.name == 'ibm_db_sa':
            # DB2 requires a table expression
            ping_sql = 'select 1 from (values (1)) AS t1'
        cursor.execute(ping_sql)
    except Exception as ex:
        if engine.dialect.is_disconnect(ex, dbapi_conn, cursor):
            msg = _LW('Database server has gone away: %s') % ex
            LOG.warning(msg)
            raise sqla_exc.DisconnectionError(msg)
        else:
            raise
コード例 #3
0
ファイル: utils.py プロジェクト: n-nishida/rack
def paginate_query(query, model, limit, sort_keys, marker=None,
                   sort_dir=None, sort_dirs=None):
    """Returns a query with sorting / pagination criteria added.

    Pagination works by requiring a unique sort_key, specified by sort_keys.
    (If sort_keys is not unique, then we risk looping through values.)
    We use the last row in the previous page as the 'marker' for pagination.
    So we must return values that follow the passed marker in the order.
    With a single-valued sort_key, this would be easy: sort_key > X.
    With a compound-values sort_key, (k1, k2, k3) we must do this to repeat
    the lexicographical ordering:
    (k1 > X1) or (k1 == X1 && k2 > X2) or (k1 == X1 && k2 == X2 && k3 > X3)

    We also have to cope with different sort_directions.

    Typically, the id of the last row is used as the client-facing pagination
    marker, then the actual marker object must be fetched from the db and
    passed in to us as marker.

    :param query: the query object to which we should add paging/sorting
    :param model: the ORM model class
    :param limit: maximum number of items to return
    :param sort_keys: array of attributes by which results should be sorted
    :param marker: the last item of the previous page; we returns the next
                    results after this value.
    :param sort_dir: direction in which results should be sorted (asc, desc)
    :param sort_dirs: per-column array of sort_dirs, corresponding to sort_keys

    :rtype: sqlalchemy.orm.query.Query
    :return: The query with sorting/pagination added.
    """

    if 'id' not in sort_keys:
        # TODO(justinsb): If this ever gives a false-positive, check
        # the actual primary key, rather than assuming its id
        LOG.warning(_LW('Id not in sort_keys; is sort_keys unique?'))

    assert(not (sort_dir and sort_dirs))

    # Default the sort direction to ascending
    if sort_dirs is None and sort_dir is None:
        sort_dir = 'asc'

    # Ensure a per-column sort direction
    if sort_dirs is None:
        sort_dirs = [sort_dir for _sort_key in sort_keys]

    assert(len(sort_dirs) == len(sort_keys))

    # Add sorting
    for current_sort_key, current_sort_dir in zip(sort_keys, sort_dirs):
        try:
            sort_dir_func = {
                'asc': sqlalchemy.asc,
                'desc': sqlalchemy.desc,
            }[current_sort_dir]
        except KeyError:
            raise ValueError(_("Unknown sort direction, "
                               "must be 'desc' or 'asc'"))
        try:
            sort_key_attr = getattr(model, current_sort_key)
        except AttributeError:
            raise InvalidSortKey()
        query = query.order_by(sort_dir_func(sort_key_attr))

    # Add pagination
    if marker is not None:
        marker_values = []
        for sort_key in sort_keys:
            v = getattr(marker, sort_key)
            marker_values.append(v)

        # Build up an array of sort criteria as in the docstring
        criteria_list = []
        for i in range(len(sort_keys)):
            crit_attrs = []
            for j in range(i):
                model_attr = getattr(model, sort_keys[j])
                crit_attrs.append((model_attr == marker_values[j]))

            model_attr = getattr(model, sort_keys[i])
            if sort_dirs[i] == 'desc':
                crit_attrs.append((model_attr < marker_values[i]))
            else:
                crit_attrs.append((model_attr > marker_values[i]))

            criteria = sqlalchemy.sql.and_(*crit_attrs)
            criteria_list.append(criteria)

        f = sqlalchemy.sql.or_(*criteria_list)
        query = query.filter(f)

    if limit is not None:
        query = query.limit(limit)

    return query
コード例 #4
0
ファイル: session.py プロジェクト: n-nishida/rack
def create_engine(sql_connection, sqlite_fk=False, mysql_sql_mode=None,
                  mysql_traditional_mode=False, idle_timeout=3600,
                  connection_debug=0, max_pool_size=None, max_overflow=None,
                  pool_timeout=None, sqlite_synchronous=True,
                  connection_trace=False, max_retries=10, retry_interval=10):
    """Return a new SQLAlchemy engine."""

    connection_dict = sqlalchemy.engine.url.make_url(sql_connection)

    engine_args = {
        "pool_recycle": idle_timeout,
        'convert_unicode': True,
    }

    logger = logging.getLogger('sqlalchemy.engine')

    # Map SQL debug level to Python log level
    if connection_debug >= 100:
        logger.setLevel(logging.DEBUG)
    elif connection_debug >= 50:
        logger.setLevel(logging.INFO)
    else:
        logger.setLevel(logging.WARNING)

    if "sqlite" in connection_dict.drivername:
        if sqlite_fk:
            engine_args["listeners"] = [SqliteForeignKeysListener()]
        engine_args["poolclass"] = NullPool

        if sql_connection == "sqlite://":
            engine_args["poolclass"] = StaticPool
            engine_args["connect_args"] = {'check_same_thread': False}
    else:
        if max_pool_size is not None:
            engine_args['pool_size'] = max_pool_size
        if max_overflow is not None:
            engine_args['max_overflow'] = max_overflow
        if pool_timeout is not None:
            engine_args['pool_timeout'] = pool_timeout

    engine = sqlalchemy.create_engine(sql_connection, **engine_args)

    sqlalchemy.event.listen(engine, 'checkin', _thread_yield)

    if engine.name in ['mysql', 'ibm_db_sa']:
        ping_callback = functools.partial(_ping_listener, engine)
        sqlalchemy.event.listen(engine, 'checkout', ping_callback)
        if engine.name == 'mysql':
            if mysql_traditional_mode:
                mysql_sql_mode = 'TRADITIONAL'
            if mysql_sql_mode:
                mode_callback = functools.partial(_set_session_sql_mode,
                                                  sql_mode=mysql_sql_mode)
                sqlalchemy.event.listen(engine, 'checkout', mode_callback)
    elif 'sqlite' in connection_dict.drivername:
        if not sqlite_synchronous:
            sqlalchemy.event.listen(engine, 'connect',
                                    _synchronous_switch_listener)
        sqlalchemy.event.listen(engine, 'connect', _add_regexp_listener)

    if connection_trace and engine.dialect.dbapi.__name__ == 'MySQLdb':
        _patch_mysqldb_with_stacktrace_comments()

    try:
        engine.connect()
    except sqla_exc.OperationalError as e:
        if not _is_db_connection_error(e.args[0]):
            raise

        remaining = max_retries
        if remaining == -1:
            remaining = 'infinite'
        while True:
            msg = _LW('SQL connection failed. %s attempts left.')
            LOG.warning(msg % remaining)
            if remaining != 'infinite':
                remaining -= 1
            time.sleep(retry_interval)
            try:
                engine.connect()
                break
            except sqla_exc.OperationalError as e:
                if (remaining != 'infinite' and remaining == 0) or \
                        not _is_db_connection_error(e.args[0]):
                    raise
    return engine