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1122 lines
38 KiB
1122 lines
38 KiB
# sqlalchemy/pool.py
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# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
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# <see AUTHORS file>
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#
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# This module is part of SQLAlchemy and is released under
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# the MIT License: https://www.opensource.org/licenses/mit-license.php
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"""Base constructs for connection pools.
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"""
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from collections import deque
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import time
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import weakref
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from .. import event
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from .. import exc
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from .. import log
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from .. import util
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reset_rollback = util.symbol("reset_rollback")
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reset_commit = util.symbol("reset_commit")
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reset_none = util.symbol("reset_none")
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class _ConnDialect(object):
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"""partial implementation of :class:`.Dialect`
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which provides DBAPI connection methods.
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When a :class:`_pool.Pool` is combined with an :class:`_engine.Engine`,
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the :class:`_engine.Engine` replaces this with its own
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:class:`.Dialect`.
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"""
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is_async = False
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def do_rollback(self, dbapi_connection):
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dbapi_connection.rollback()
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def do_commit(self, dbapi_connection):
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dbapi_connection.commit()
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def do_close(self, dbapi_connection):
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dbapi_connection.close()
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def do_ping(self, dbapi_connection):
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raise NotImplementedError(
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"The ping feature requires that a dialect is "
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"passed to the connection pool."
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)
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def get_driver_connection(self, connection):
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return connection
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class _AsyncConnDialect(_ConnDialect):
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is_async = True
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class Pool(log.Identified):
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"""Abstract base class for connection pools."""
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_dialect = _ConnDialect()
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def __init__(
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self,
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creator,
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recycle=-1,
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echo=None,
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logging_name=None,
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reset_on_return=True,
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events=None,
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dialect=None,
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pre_ping=False,
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_dispatch=None,
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):
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"""
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Construct a Pool.
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:param creator: a callable function that returns a DB-API
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connection object. The function will be called with
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parameters.
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:param recycle: If set to a value other than -1, number of
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seconds between connection recycling, which means upon
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checkout, if this timeout is surpassed the connection will be
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closed and replaced with a newly opened connection. Defaults to -1.
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:param logging_name: String identifier which will be used within
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the "name" field of logging records generated within the
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"sqlalchemy.pool" logger. Defaults to a hexstring of the object's
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id.
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:param echo: if True, the connection pool will log
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informational output such as when connections are invalidated
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as well as when connections are recycled to the default log handler,
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which defaults to ``sys.stdout`` for output.. If set to the string
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``"debug"``, the logging will include pool checkouts and checkins.
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The :paramref:`_pool.Pool.echo` parameter can also be set from the
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:func:`_sa.create_engine` call by using the
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:paramref:`_sa.create_engine.echo_pool` parameter.
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.. seealso::
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:ref:`dbengine_logging` - further detail on how to configure
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logging.
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:param reset_on_return: Determine steps to take on
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connections as they are returned to the pool, which were
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not otherwise handled by a :class:`_engine.Connection`.
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reset_on_return can have any of these values:
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* ``"rollback"`` - call rollback() on the connection,
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to release locks and transaction resources.
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This is the default value. The vast majority
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of use cases should leave this value set.
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* ``True`` - same as 'rollback', this is here for
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backwards compatibility.
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* ``"commit"`` - call commit() on the connection,
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to release locks and transaction resources.
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A commit here may be desirable for databases that
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cache query plans if a commit is emitted,
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such as Microsoft SQL Server. However, this
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value is more dangerous than 'rollback' because
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any data changes present on the transaction
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are committed unconditionally.
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* ``None`` - don't do anything on the connection.
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This setting is only appropriate if the database / DBAPI
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works in pure "autocommit" mode at all times, or if the
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application uses the :class:`_engine.Engine` with consistent
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connectivity patterns. See the section
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:ref:`pool_reset_on_return` for more details.
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* ``False`` - same as None, this is here for
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backwards compatibility.
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.. seealso::
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:ref:`pool_reset_on_return`
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:param events: a list of 2-tuples, each of the form
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``(callable, target)`` which will be passed to :func:`.event.listen`
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upon construction. Provided here so that event listeners
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can be assigned via :func:`_sa.create_engine` before dialect-level
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listeners are applied.
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:param dialect: a :class:`.Dialect` that will handle the job
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of calling rollback(), close(), or commit() on DBAPI connections.
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If omitted, a built-in "stub" dialect is used. Applications that
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make use of :func:`_sa.create_engine` should not use this parameter
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as it is handled by the engine creation strategy.
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.. versionadded:: 1.1 - ``dialect`` is now a public parameter
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to the :class:`_pool.Pool`.
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:param pre_ping: if True, the pool will emit a "ping" (typically
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"SELECT 1", but is dialect-specific) on the connection
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upon checkout, to test if the connection is alive or not. If not,
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the connection is transparently re-connected and upon success, all
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other pooled connections established prior to that timestamp are
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invalidated. Requires that a dialect is passed as well to
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interpret the disconnection error.
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.. versionadded:: 1.2
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"""
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if logging_name:
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self.logging_name = self._orig_logging_name = logging_name
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else:
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self._orig_logging_name = None
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log.instance_logger(self, echoflag=echo)
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self._creator = creator
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self._recycle = recycle
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self._invalidate_time = 0
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self._pre_ping = pre_ping
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self._reset_on_return = util.symbol.parse_user_argument(
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reset_on_return,
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{
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reset_rollback: ["rollback", True],
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reset_none: ["none", None, False],
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reset_commit: ["commit"],
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},
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"reset_on_return",
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resolve_symbol_names=False,
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)
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self.echo = echo
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if _dispatch:
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self.dispatch._update(_dispatch, only_propagate=False)
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if dialect:
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self._dialect = dialect
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if events:
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for fn, target in events:
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event.listen(self, target, fn)
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@util.hybridproperty
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def _is_asyncio(self):
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return self._dialect.is_async
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@property
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def _creator(self):
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return self.__dict__["_creator"]
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@_creator.setter
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def _creator(self, creator):
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self.__dict__["_creator"] = creator
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self._invoke_creator = self._should_wrap_creator(creator)
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def _should_wrap_creator(self, creator):
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"""Detect if creator accepts a single argument, or is sent
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as a legacy style no-arg function.
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"""
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try:
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argspec = util.get_callable_argspec(self._creator, no_self=True)
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except TypeError:
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return lambda crec: creator()
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defaulted = argspec[3] is not None and len(argspec[3]) or 0
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positionals = len(argspec[0]) - defaulted
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# look for the exact arg signature that DefaultStrategy
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# sends us
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if (argspec[0], argspec[3]) == (["connection_record"], (None,)):
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return creator
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# or just a single positional
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elif positionals == 1:
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return creator
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# all other cases, just wrap and assume legacy "creator" callable
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# thing
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else:
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return lambda crec: creator()
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def _close_connection(self, connection):
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self.logger.debug("Closing connection %r", connection)
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try:
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self._dialect.do_close(connection)
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except Exception:
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self.logger.error(
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"Exception closing connection %r", connection, exc_info=True
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)
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def _create_connection(self):
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"""Called by subclasses to create a new ConnectionRecord."""
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return _ConnectionRecord(self)
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def _invalidate(self, connection, exception=None, _checkin=True):
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"""Mark all connections established within the generation
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of the given connection as invalidated.
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If this pool's last invalidate time is before when the given
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connection was created, update the timestamp til now. Otherwise,
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no action is performed.
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Connections with a start time prior to this pool's invalidation
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time will be recycled upon next checkout.
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"""
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rec = getattr(connection, "_connection_record", None)
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if not rec or self._invalidate_time < rec.starttime:
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self._invalidate_time = time.time()
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if _checkin and getattr(connection, "is_valid", False):
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connection.invalidate(exception)
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def recreate(self):
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"""Return a new :class:`_pool.Pool`, of the same class as this one
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and configured with identical creation arguments.
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This method is used in conjunction with :meth:`dispose`
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to close out an entire :class:`_pool.Pool` and create a new one in
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its place.
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"""
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raise NotImplementedError()
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def dispose(self):
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"""Dispose of this pool.
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This method leaves the possibility of checked-out connections
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remaining open, as it only affects connections that are
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idle in the pool.
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.. seealso::
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:meth:`Pool.recreate`
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"""
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raise NotImplementedError()
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def connect(self):
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"""Return a DBAPI connection from the pool.
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The connection is instrumented such that when its
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``close()`` method is called, the connection will be returned to
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the pool.
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"""
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return _ConnectionFairy._checkout(self)
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def _return_conn(self, record):
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"""Given a _ConnectionRecord, return it to the :class:`_pool.Pool`.
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This method is called when an instrumented DBAPI connection
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has its ``close()`` method called.
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"""
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self._do_return_conn(record)
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def _do_get(self):
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"""Implementation for :meth:`get`, supplied by subclasses."""
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raise NotImplementedError()
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def _do_return_conn(self, conn):
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"""Implementation for :meth:`return_conn`, supplied by subclasses."""
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raise NotImplementedError()
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def status(self):
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raise NotImplementedError()
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class _ConnectionRecord(object):
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"""Internal object which maintains an individual DBAPI connection
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referenced by a :class:`_pool.Pool`.
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The :class:`._ConnectionRecord` object always exists for any particular
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DBAPI connection whether or not that DBAPI connection has been
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"checked out". This is in contrast to the :class:`._ConnectionFairy`
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which is only a public facade to the DBAPI connection while it is checked
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out.
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A :class:`._ConnectionRecord` may exist for a span longer than that
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of a single DBAPI connection. For example, if the
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:meth:`._ConnectionRecord.invalidate`
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method is called, the DBAPI connection associated with this
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:class:`._ConnectionRecord`
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will be discarded, but the :class:`._ConnectionRecord` may be used again,
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in which case a new DBAPI connection is produced when the
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:class:`_pool.Pool`
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next uses this record.
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The :class:`._ConnectionRecord` is delivered along with connection
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pool events, including :meth:`_events.PoolEvents.connect` and
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:meth:`_events.PoolEvents.checkout`, however :class:`._ConnectionRecord`
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still
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remains an internal object whose API and internals may change.
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.. seealso::
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:class:`._ConnectionFairy`
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"""
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def __init__(self, pool, connect=True):
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self.__pool = pool
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if connect:
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self.__connect()
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self.finalize_callback = deque()
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fresh = False
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fairy_ref = None
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starttime = None
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dbapi_connection = None
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"""A reference to the actual DBAPI connection being tracked.
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May be ``None`` if this :class:`._ConnectionRecord` has been marked
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as invalidated; a new DBAPI connection may replace it if the owning
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pool calls upon this :class:`._ConnectionRecord` to reconnect.
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For adapted drivers, like the Asyncio implementations, this is a
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:class:`.AdaptedConnection` that adapts the driver connection
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to the DBAPI protocol.
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Use :attr:`._ConnectionRecord.driver_connection` to obtain the
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connection objected returned by the driver.
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.. versionadded:: 1.4.24
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"""
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@property
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def driver_connection(self):
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"""The connection object as returned by the driver after a connect.
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For normal sync drivers that support the DBAPI protocol, this object
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is the same as the one referenced by
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:attr:`._ConnectionRecord.dbapi_connection`.
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For adapted drivers, like the Asyncio ones, this is the actual object
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that was returned by the driver ``connect`` call.
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As :attr:`._ConnectionRecord.dbapi_connection` it may be ``None``
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if this :class:`._ConnectionRecord` has been marked as invalidated.
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.. versionadded:: 1.4.24
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"""
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if self.dbapi_connection is None:
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return None
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else:
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return self.__pool._dialect.get_driver_connection(
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self.dbapi_connection
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)
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@property
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def connection(self):
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"""An alias to :attr:`._ConnectionRecord.dbapi_connection`.
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This alias is deprecated, please use the new name.
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.. deprecated:: 1.4.24
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"""
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return self.dbapi_connection
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@connection.setter
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def connection(self, value):
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self.dbapi_connection = value
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_soft_invalidate_time = 0
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@util.memoized_property
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def info(self):
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"""The ``.info`` dictionary associated with the DBAPI connection.
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This dictionary is shared among the :attr:`._ConnectionFairy.info`
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and :attr:`_engine.Connection.info` accessors.
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.. note::
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The lifespan of this dictionary is linked to the
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DBAPI connection itself, meaning that it is **discarded** each time
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the DBAPI connection is closed and/or invalidated. The
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:attr:`._ConnectionRecord.record_info` dictionary remains
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persistent throughout the lifespan of the
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:class:`._ConnectionRecord` container.
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"""
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return {}
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@util.memoized_property
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def record_info(self):
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"""An "info' dictionary associated with the connection record
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itself.
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Unlike the :attr:`._ConnectionRecord.info` dictionary, which is linked
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to the lifespan of the DBAPI connection, this dictionary is linked
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to the lifespan of the :class:`._ConnectionRecord` container itself
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and will remain persistent throughout the life of the
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:class:`._ConnectionRecord`.
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.. versionadded:: 1.1
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"""
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return {}
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@classmethod
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def checkout(cls, pool):
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rec = pool._do_get()
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try:
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dbapi_connection = rec.get_connection()
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except Exception as err:
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with util.safe_reraise():
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rec._checkin_failed(err, _fairy_was_created=False)
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echo = pool._should_log_debug()
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fairy = _ConnectionFairy(dbapi_connection, rec, echo)
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rec.fairy_ref = ref = weakref.ref(
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fairy,
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lambda ref: _finalize_fairy
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and _finalize_fairy(None, rec, pool, ref, echo, True),
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)
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_strong_ref_connection_records[ref] = rec
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if echo:
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pool.logger.debug(
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"Connection %r checked out from pool", dbapi_connection
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)
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return fairy
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|
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def _checkin_failed(self, err, _fairy_was_created=True):
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self.invalidate(e=err)
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self.checkin(
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_fairy_was_created=_fairy_was_created,
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)
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def checkin(self, _fairy_was_created=True):
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if self.fairy_ref is None and _fairy_was_created:
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# _fairy_was_created is False for the initial get connection phase;
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# meaning there was no _ConnectionFairy and we must unconditionally
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# do a checkin.
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#
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# otherwise, if fairy_was_created==True, if fairy_ref is None here
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# that means we were checked in already, so this looks like
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# a double checkin.
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util.warn("Double checkin attempted on %s" % self)
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return
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self.fairy_ref = None
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connection = self.dbapi_connection
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pool = self.__pool
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|
while self.finalize_callback:
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|
finalizer = self.finalize_callback.pop()
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|
finalizer(connection)
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|
if pool.dispatch.checkin:
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pool.dispatch.checkin(connection, self)
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pool._return_conn(self)
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|
@property
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|
def in_use(self):
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return self.fairy_ref is not None
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@property
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|
def last_connect_time(self):
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return self.starttime
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def close(self):
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if self.dbapi_connection is not None:
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self.__close()
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def invalidate(self, e=None, soft=False):
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"""Invalidate the DBAPI connection held by this
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:class:`._ConnectionRecord`.
|
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|
This method is called for all connection invalidations, including
|
|
when the :meth:`._ConnectionFairy.invalidate` or
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|
:meth:`_engine.Connection.invalidate` methods are called,
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|
as well as when any
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so-called "automatic invalidation" condition occurs.
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|
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|
:param e: an exception object indicating a reason for the
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invalidation.
|
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:param soft: if True, the connection isn't closed; instead, this
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connection will be recycled on next checkout.
|
|
|
|
.. versionadded:: 1.0.3
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.. seealso::
|
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|
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:ref:`pool_connection_invalidation`
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|
|
"""
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# already invalidated
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if self.dbapi_connection is None:
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return
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if soft:
|
|
self.__pool.dispatch.soft_invalidate(
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self.dbapi_connection, self, e
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)
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|
else:
|
|
self.__pool.dispatch.invalidate(self.dbapi_connection, self, e)
|
|
if e is not None:
|
|
self.__pool.logger.info(
|
|
"%sInvalidate connection %r (reason: %s:%s)",
|
|
"Soft " if soft else "",
|
|
self.dbapi_connection,
|
|
e.__class__.__name__,
|
|
e,
|
|
)
|
|
else:
|
|
self.__pool.logger.info(
|
|
"%sInvalidate connection %r",
|
|
"Soft " if soft else "",
|
|
self.dbapi_connection,
|
|
)
|
|
|
|
if soft:
|
|
self._soft_invalidate_time = time.time()
|
|
else:
|
|
self.__close()
|
|
self.dbapi_connection = None
|
|
|
|
def get_connection(self):
|
|
recycle = False
|
|
|
|
# NOTE: the various comparisons here are assuming that measurable time
|
|
# passes between these state changes. however, time.time() is not
|
|
# guaranteed to have sub-second precision. comparisons of
|
|
# "invalidation time" to "starttime" should perhaps use >= so that the
|
|
# state change can take place assuming no measurable time has passed,
|
|
# however this does not guarantee correct behavior here as if time
|
|
# continues to not pass, it will try to reconnect repeatedly until
|
|
# these timestamps diverge, so in that sense using > is safer. Per
|
|
# https://stackoverflow.com/a/1938096/34549, Windows time.time() may be
|
|
# within 16 milliseconds accuracy, so unit tests for connection
|
|
# invalidation need a sleep of at least this long between initial start
|
|
# time and invalidation for the logic below to work reliably.
|
|
if self.dbapi_connection is None:
|
|
self.info.clear()
|
|
self.__connect()
|
|
elif (
|
|
self.__pool._recycle > -1
|
|
and time.time() - self.starttime > self.__pool._recycle
|
|
):
|
|
self.__pool.logger.info(
|
|
"Connection %r exceeded timeout; recycling",
|
|
self.dbapi_connection,
|
|
)
|
|
recycle = True
|
|
elif self.__pool._invalidate_time > self.starttime:
|
|
self.__pool.logger.info(
|
|
"Connection %r invalidated due to pool invalidation; "
|
|
+ "recycling",
|
|
self.dbapi_connection,
|
|
)
|
|
recycle = True
|
|
elif self._soft_invalidate_time > self.starttime:
|
|
self.__pool.logger.info(
|
|
"Connection %r invalidated due to local soft invalidation; "
|
|
+ "recycling",
|
|
self.dbapi_connection,
|
|
)
|
|
recycle = True
|
|
|
|
if recycle:
|
|
self.__close()
|
|
self.info.clear()
|
|
|
|
self.__connect()
|
|
return self.dbapi_connection
|
|
|
|
def _is_hard_or_soft_invalidated(self):
|
|
return (
|
|
self.dbapi_connection is None
|
|
or self.__pool._invalidate_time > self.starttime
|
|
or (self._soft_invalidate_time > self.starttime)
|
|
)
|
|
|
|
def __close(self):
|
|
self.finalize_callback.clear()
|
|
if self.__pool.dispatch.close:
|
|
self.__pool.dispatch.close(self.dbapi_connection, self)
|
|
self.__pool._close_connection(self.dbapi_connection)
|
|
self.dbapi_connection = None
|
|
|
|
def __connect(self):
|
|
pool = self.__pool
|
|
|
|
# ensure any existing connection is removed, so that if
|
|
# creator fails, this attribute stays None
|
|
self.dbapi_connection = None
|
|
try:
|
|
self.starttime = time.time()
|
|
self.dbapi_connection = connection = pool._invoke_creator(self)
|
|
pool.logger.debug("Created new connection %r", connection)
|
|
self.fresh = True
|
|
except Exception as e:
|
|
with util.safe_reraise():
|
|
pool.logger.debug("Error on connect(): %s", e)
|
|
else:
|
|
# in SQLAlchemy 1.4 the first_connect event is not used by
|
|
# the engine, so this will usually not be set
|
|
if pool.dispatch.first_connect:
|
|
pool.dispatch.first_connect.for_modify(
|
|
pool.dispatch
|
|
).exec_once_unless_exception(self.dbapi_connection, self)
|
|
|
|
# init of the dialect now takes place within the connect
|
|
# event, so ensure a mutex is used on the first run
|
|
pool.dispatch.connect.for_modify(
|
|
pool.dispatch
|
|
)._exec_w_sync_on_first_run(self.dbapi_connection, self)
|
|
|
|
|
|
def _finalize_fairy(
|
|
dbapi_connection,
|
|
connection_record,
|
|
pool,
|
|
ref, # this is None when called directly, not by the gc
|
|
echo,
|
|
reset=True,
|
|
fairy=None,
|
|
):
|
|
"""Cleanup for a :class:`._ConnectionFairy` whether or not it's already
|
|
been garbage collected.
|
|
|
|
When using an async dialect no IO can happen here (without using
|
|
a dedicated thread), since this is called outside the greenlet
|
|
context and with an already running loop. In this case function
|
|
will only log a message and raise a warning.
|
|
"""
|
|
|
|
if ref:
|
|
_strong_ref_connection_records.pop(ref, None)
|
|
elif fairy:
|
|
_strong_ref_connection_records.pop(weakref.ref(fairy), None)
|
|
|
|
if ref is not None:
|
|
if connection_record.fairy_ref is not ref:
|
|
return
|
|
assert dbapi_connection is None
|
|
dbapi_connection = connection_record.dbapi_connection
|
|
|
|
# null pool is not _is_asyncio but can be used also with async dialects
|
|
dont_restore_gced = pool._dialect.is_async
|
|
|
|
if dont_restore_gced:
|
|
detach = not connection_record or ref
|
|
can_manipulate_connection = not ref
|
|
else:
|
|
detach = not connection_record
|
|
can_manipulate_connection = True
|
|
|
|
if dbapi_connection is not None:
|
|
if connection_record and echo:
|
|
pool.logger.debug(
|
|
"Connection %r being returned to pool%s",
|
|
dbapi_connection,
|
|
", transaction state was already reset by caller"
|
|
if not reset
|
|
else "",
|
|
)
|
|
|
|
try:
|
|
fairy = fairy or _ConnectionFairy(
|
|
dbapi_connection,
|
|
connection_record,
|
|
echo,
|
|
)
|
|
assert fairy.dbapi_connection is dbapi_connection
|
|
if reset and can_manipulate_connection:
|
|
fairy._reset(pool)
|
|
|
|
if detach:
|
|
if connection_record:
|
|
fairy._pool = pool
|
|
fairy.detach()
|
|
|
|
if can_manipulate_connection:
|
|
if pool.dispatch.close_detached:
|
|
pool.dispatch.close_detached(dbapi_connection)
|
|
|
|
pool._close_connection(dbapi_connection)
|
|
else:
|
|
message = (
|
|
"The garbage collector is trying to clean up "
|
|
"connection %r. This feature is unsupported on async "
|
|
"dbapi, since no IO can be performed at this stage to "
|
|
"reset the connection. Please close out all "
|
|
"connections when they are no longer used, calling "
|
|
"``close()`` or using a context manager to "
|
|
"manage their lifetime."
|
|
) % dbapi_connection
|
|
pool.logger.error(message)
|
|
util.warn(message)
|
|
|
|
except BaseException as e:
|
|
pool.logger.error(
|
|
"Exception during reset or similar", exc_info=True
|
|
)
|
|
if connection_record:
|
|
connection_record.invalidate(e=e)
|
|
if not isinstance(e, Exception):
|
|
raise
|
|
|
|
if connection_record and connection_record.fairy_ref is not None:
|
|
connection_record.checkin()
|
|
|
|
|
|
# a dictionary of the _ConnectionFairy weakrefs to _ConnectionRecord, so that
|
|
# GC under pypy will call ConnectionFairy finalizers. linked directly to the
|
|
# weakref that will empty itself when collected so that it should not create
|
|
# any unmanaged memory references.
|
|
_strong_ref_connection_records = {}
|
|
|
|
|
|
class _ConnectionFairy(object):
|
|
|
|
"""Proxies a DBAPI connection and provides return-on-dereference
|
|
support.
|
|
|
|
This is an internal object used by the :class:`_pool.Pool` implementation
|
|
to provide context management to a DBAPI connection delivered by
|
|
that :class:`_pool.Pool`.
|
|
|
|
The name "fairy" is inspired by the fact that the
|
|
:class:`._ConnectionFairy` object's lifespan is transitory, as it lasts
|
|
only for the length of a specific DBAPI connection being checked out from
|
|
the pool, and additionally that as a transparent proxy, it is mostly
|
|
invisible.
|
|
|
|
.. seealso::
|
|
|
|
:class:`._ConnectionRecord`
|
|
|
|
"""
|
|
|
|
def __init__(self, dbapi_connection, connection_record, echo):
|
|
self.dbapi_connection = dbapi_connection
|
|
self._connection_record = connection_record
|
|
self._echo = echo
|
|
|
|
dbapi_connection = None
|
|
"""A reference to the actual DBAPI connection being tracked.
|
|
|
|
.. versionadded:: 1.4.24
|
|
|
|
.. seealso::
|
|
|
|
:attr:`._ConnectionFairy.driver_connection`
|
|
|
|
:attr:`._ConnectionRecord.dbapi_connection`
|
|
|
|
:ref:`faq_dbapi_connection`
|
|
|
|
"""
|
|
|
|
_connection_record = None
|
|
"""A reference to the :class:`._ConnectionRecord` object associated
|
|
with the DBAPI connection.
|
|
|
|
This is currently an internal accessor which is subject to change.
|
|
|
|
"""
|
|
|
|
@property
|
|
def driver_connection(self):
|
|
"""The connection object as returned by the driver after a connect.
|
|
|
|
.. versionadded:: 1.4.24
|
|
|
|
.. seealso::
|
|
|
|
:attr:`._ConnectionFairy.dbapi_connection`
|
|
|
|
:attr:`._ConnectionRecord.driver_connection`
|
|
|
|
:ref:`faq_dbapi_connection`
|
|
|
|
"""
|
|
return self._connection_record.driver_connection
|
|
|
|
@property
|
|
def connection(self):
|
|
"""An alias to :attr:`._ConnectionFairy.dbapi_connection`.
|
|
|
|
This alias is deprecated, please use the new name.
|
|
|
|
.. deprecated:: 1.4.24
|
|
|
|
"""
|
|
return self.dbapi_connection
|
|
|
|
@connection.setter
|
|
def connection(self, value):
|
|
self.dbapi_connection = value
|
|
|
|
@classmethod
|
|
def _checkout(cls, pool, threadconns=None, fairy=None):
|
|
if not fairy:
|
|
fairy = _ConnectionRecord.checkout(pool)
|
|
|
|
fairy._pool = pool
|
|
fairy._counter = 0
|
|
|
|
if threadconns is not None:
|
|
threadconns.current = weakref.ref(fairy)
|
|
|
|
if fairy.dbapi_connection is None:
|
|
raise exc.InvalidRequestError("This connection is closed")
|
|
fairy._counter += 1
|
|
if (
|
|
not pool.dispatch.checkout and not pool._pre_ping
|
|
) or fairy._counter != 1:
|
|
return fairy
|
|
|
|
# Pool listeners can trigger a reconnection on checkout, as well
|
|
# as the pre-pinger.
|
|
# there are three attempts made here, but note that if the database
|
|
# is not accessible from a connection standpoint, those won't proceed
|
|
# here.
|
|
attempts = 2
|
|
while attempts > 0:
|
|
connection_is_fresh = fairy._connection_record.fresh
|
|
fairy._connection_record.fresh = False
|
|
try:
|
|
if pool._pre_ping:
|
|
if not connection_is_fresh:
|
|
if fairy._echo:
|
|
pool.logger.debug(
|
|
"Pool pre-ping on connection %s",
|
|
fairy.dbapi_connection,
|
|
)
|
|
result = pool._dialect.do_ping(fairy.dbapi_connection)
|
|
if not result:
|
|
if fairy._echo:
|
|
pool.logger.debug(
|
|
"Pool pre-ping on connection %s failed, "
|
|
"will invalidate pool",
|
|
fairy.dbapi_connection,
|
|
)
|
|
raise exc.InvalidatePoolError()
|
|
elif fairy._echo:
|
|
pool.logger.debug(
|
|
"Connection %s is fresh, skipping pre-ping",
|
|
fairy.dbapi_connection,
|
|
)
|
|
|
|
pool.dispatch.checkout(
|
|
fairy.dbapi_connection, fairy._connection_record, fairy
|
|
)
|
|
return fairy
|
|
except exc.DisconnectionError as e:
|
|
if e.invalidate_pool:
|
|
pool.logger.info(
|
|
"Disconnection detected on checkout, "
|
|
"invalidating all pooled connections prior to "
|
|
"current timestamp (reason: %r)",
|
|
e,
|
|
)
|
|
fairy._connection_record.invalidate(e)
|
|
pool._invalidate(fairy, e, _checkin=False)
|
|
else:
|
|
pool.logger.info(
|
|
"Disconnection detected on checkout, "
|
|
"invalidating individual connection %s (reason: %r)",
|
|
fairy.dbapi_connection,
|
|
e,
|
|
)
|
|
fairy._connection_record.invalidate(e)
|
|
try:
|
|
fairy.dbapi_connection = (
|
|
fairy._connection_record.get_connection()
|
|
)
|
|
except Exception as err:
|
|
with util.safe_reraise():
|
|
fairy._connection_record._checkin_failed(
|
|
err,
|
|
_fairy_was_created=True,
|
|
)
|
|
|
|
# prevent _ConnectionFairy from being carried
|
|
# in the stack trace. Do this after the
|
|
# connection record has been checked in, so that
|
|
# if the del triggers a finalize fairy, it won't
|
|
# try to checkin a second time.
|
|
del fairy
|
|
|
|
attempts -= 1
|
|
|
|
pool.logger.info("Reconnection attempts exhausted on checkout")
|
|
fairy.invalidate()
|
|
raise exc.InvalidRequestError("This connection is closed")
|
|
|
|
def _checkout_existing(self):
|
|
return _ConnectionFairy._checkout(self._pool, fairy=self)
|
|
|
|
def _checkin(self, reset=True):
|
|
_finalize_fairy(
|
|
self.dbapi_connection,
|
|
self._connection_record,
|
|
self._pool,
|
|
None,
|
|
self._echo,
|
|
reset=reset,
|
|
fairy=self,
|
|
)
|
|
self.dbapi_connection = None
|
|
self._connection_record = None
|
|
|
|
_close = _checkin
|
|
|
|
def _reset(self, pool):
|
|
if pool.dispatch.reset:
|
|
pool.dispatch.reset(self, self._connection_record)
|
|
if pool._reset_on_return is reset_rollback:
|
|
if self._echo:
|
|
pool.logger.debug(
|
|
"Connection %s rollback-on-return", self.dbapi_connection
|
|
)
|
|
pool._dialect.do_rollback(self)
|
|
elif pool._reset_on_return is reset_commit:
|
|
if self._echo:
|
|
pool.logger.debug(
|
|
"Connection %s commit-on-return",
|
|
self.dbapi_connection,
|
|
)
|
|
pool._dialect.do_commit(self)
|
|
|
|
@property
|
|
def _logger(self):
|
|
return self._pool.logger
|
|
|
|
@property
|
|
def is_valid(self):
|
|
"""Return True if this :class:`._ConnectionFairy` still refers
|
|
to an active DBAPI connection."""
|
|
|
|
return self.dbapi_connection is not None
|
|
|
|
@util.memoized_property
|
|
def info(self):
|
|
"""Info dictionary associated with the underlying DBAPI connection
|
|
referred to by this :class:`.ConnectionFairy`, allowing user-defined
|
|
data to be associated with the connection.
|
|
|
|
The data here will follow along with the DBAPI connection including
|
|
after it is returned to the connection pool and used again
|
|
in subsequent instances of :class:`._ConnectionFairy`. It is shared
|
|
with the :attr:`._ConnectionRecord.info` and
|
|
:attr:`_engine.Connection.info`
|
|
accessors.
|
|
|
|
The dictionary associated with a particular DBAPI connection is
|
|
discarded when the connection itself is discarded.
|
|
|
|
"""
|
|
return self._connection_record.info
|
|
|
|
@property
|
|
def record_info(self):
|
|
"""Info dictionary associated with the :class:`._ConnectionRecord
|
|
container referred to by this :class:`.ConnectionFairy`.
|
|
|
|
Unlike the :attr:`._ConnectionFairy.info` dictionary, the lifespan
|
|
of this dictionary is persistent across connections that are
|
|
disconnected and/or invalidated within the lifespan of a
|
|
:class:`._ConnectionRecord`.
|
|
|
|
.. versionadded:: 1.1
|
|
|
|
"""
|
|
if self._connection_record:
|
|
return self._connection_record.record_info
|
|
else:
|
|
return None
|
|
|
|
def invalidate(self, e=None, soft=False):
|
|
"""Mark this connection as invalidated.
|
|
|
|
This method can be called directly, and is also called as a result
|
|
of the :meth:`_engine.Connection.invalidate` method. When invoked,
|
|
the DBAPI connection is immediately closed and discarded from
|
|
further use by the pool. The invalidation mechanism proceeds
|
|
via the :meth:`._ConnectionRecord.invalidate` internal method.
|
|
|
|
:param e: an exception object indicating a reason for the invalidation.
|
|
|
|
:param soft: if True, the connection isn't closed; instead, this
|
|
connection will be recycled on next checkout.
|
|
|
|
.. versionadded:: 1.0.3
|
|
|
|
.. seealso::
|
|
|
|
:ref:`pool_connection_invalidation`
|
|
|
|
"""
|
|
|
|
if self.dbapi_connection is None:
|
|
util.warn("Can't invalidate an already-closed connection.")
|
|
return
|
|
if self._connection_record:
|
|
self._connection_record.invalidate(e=e, soft=soft)
|
|
if not soft:
|
|
self.dbapi_connection = None
|
|
self._checkin()
|
|
|
|
def cursor(self, *args, **kwargs):
|
|
"""Return a new DBAPI cursor for the underlying connection.
|
|
|
|
This method is a proxy for the ``connection.cursor()`` DBAPI
|
|
method.
|
|
|
|
"""
|
|
return self.dbapi_connection.cursor(*args, **kwargs)
|
|
|
|
def __getattr__(self, key):
|
|
return getattr(self.dbapi_connection, key)
|
|
|
|
def detach(self):
|
|
"""Separate this connection from its Pool.
|
|
|
|
This means that the connection will no longer be returned to the
|
|
pool when closed, and will instead be literally closed. The
|
|
containing ConnectionRecord is separated from the DB-API connection,
|
|
and will create a new connection when next used.
|
|
|
|
Note that any overall connection limiting constraints imposed by a
|
|
Pool implementation may be violated after a detach, as the detached
|
|
connection is removed from the pool's knowledge and control.
|
|
"""
|
|
|
|
if self._connection_record is not None:
|
|
rec = self._connection_record
|
|
rec.fairy_ref = None
|
|
rec.dbapi_connection = None
|
|
# TODO: should this be _return_conn?
|
|
self._pool._do_return_conn(self._connection_record)
|
|
self.info = self.info.copy()
|
|
self._connection_record = None
|
|
|
|
if self._pool.dispatch.detach:
|
|
self._pool.dispatch.detach(self.dbapi_connection, rec)
|
|
|
|
def close(self):
|
|
self._counter -= 1
|
|
if self._counter == 0:
|
|
self._checkin()
|
|
|
|
def _close_no_reset(self):
|
|
self._counter -= 1
|
|
if self._counter == 0:
|
|
self._checkin(reset=False)
|