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JmedChat/venv/lib/python3.10/site-packages/sqlalchemy/pool/base.py

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# sqlalchemy/pool.py
# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
# <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: https://www.opensource.org/licenses/mit-license.php
"""Base constructs for connection pools.
"""
from collections import deque
import time
import weakref
from .. import event
from .. import exc
from .. import log
from .. import util
reset_rollback = util.symbol("reset_rollback")
reset_commit = util.symbol("reset_commit")
reset_none = util.symbol("reset_none")
class _ConnDialect(object):
"""partial implementation of :class:`.Dialect`
which provides DBAPI connection methods.
When a :class:`_pool.Pool` is combined with an :class:`_engine.Engine`,
the :class:`_engine.Engine` replaces this with its own
:class:`.Dialect`.
"""
is_async = False
def do_rollback(self, dbapi_connection):
dbapi_connection.rollback()
def do_commit(self, dbapi_connection):
dbapi_connection.commit()
def do_close(self, dbapi_connection):
dbapi_connection.close()
def do_ping(self, dbapi_connection):
raise NotImplementedError(
"The ping feature requires that a dialect is "
"passed to the connection pool."
)
def get_driver_connection(self, connection):
return connection
class _AsyncConnDialect(_ConnDialect):
is_async = True
class Pool(log.Identified):
"""Abstract base class for connection pools."""
_dialect = _ConnDialect()
def __init__(
self,
creator,
recycle=-1,
echo=None,
logging_name=None,
reset_on_return=True,
events=None,
dialect=None,
pre_ping=False,
_dispatch=None,
):
"""
Construct a Pool.
:param creator: a callable function that returns a DB-API
connection object. The function will be called with
parameters.
:param recycle: If set to a value other than -1, number of
seconds between connection recycling, which means upon
checkout, if this timeout is surpassed the connection will be
closed and replaced with a newly opened connection. Defaults to -1.
:param logging_name: String identifier which will be used within
the "name" field of logging records generated within the
"sqlalchemy.pool" logger. Defaults to a hexstring of the object's
id.
:param echo: if True, the connection pool will log
informational output such as when connections are invalidated
as well as when connections are recycled to the default log handler,
which defaults to ``sys.stdout`` for output.. If set to the string
``"debug"``, the logging will include pool checkouts and checkins.
The :paramref:`_pool.Pool.echo` parameter can also be set from the
:func:`_sa.create_engine` call by using the
:paramref:`_sa.create_engine.echo_pool` parameter.
.. seealso::
:ref:`dbengine_logging` - further detail on how to configure
logging.
:param reset_on_return: Determine steps to take on
connections as they are returned to the pool, which were
not otherwise handled by a :class:`_engine.Connection`.
reset_on_return can have any of these values:
* ``"rollback"`` - call rollback() on the connection,
to release locks and transaction resources.
This is the default value. The vast majority
of use cases should leave this value set.
* ``True`` - same as 'rollback', this is here for
backwards compatibility.
* ``"commit"`` - call commit() on the connection,
to release locks and transaction resources.
A commit here may be desirable for databases that
cache query plans if a commit is emitted,
such as Microsoft SQL Server. However, this
value is more dangerous than 'rollback' because
any data changes present on the transaction
are committed unconditionally.
* ``None`` - don't do anything on the connection.
This setting is only appropriate if the database / DBAPI
works in pure "autocommit" mode at all times, or if the
application uses the :class:`_engine.Engine` with consistent
connectivity patterns. See the section
:ref:`pool_reset_on_return` for more details.
* ``False`` - same as None, this is here for
backwards compatibility.
.. seealso::
:ref:`pool_reset_on_return`
:param events: a list of 2-tuples, each of the form
``(callable, target)`` which will be passed to :func:`.event.listen`
upon construction. Provided here so that event listeners
can be assigned via :func:`_sa.create_engine` before dialect-level
listeners are applied.
:param dialect: a :class:`.Dialect` that will handle the job
of calling rollback(), close(), or commit() on DBAPI connections.
If omitted, a built-in "stub" dialect is used. Applications that
make use of :func:`_sa.create_engine` should not use this parameter
as it is handled by the engine creation strategy.
.. versionadded:: 1.1 - ``dialect`` is now a public parameter
to the :class:`_pool.Pool`.
:param pre_ping: if True, the pool will emit a "ping" (typically
"SELECT 1", but is dialect-specific) on the connection
upon checkout, to test if the connection is alive or not. If not,
the connection is transparently re-connected and upon success, all
other pooled connections established prior to that timestamp are
invalidated. Requires that a dialect is passed as well to
interpret the disconnection error.
.. versionadded:: 1.2
"""
if logging_name:
self.logging_name = self._orig_logging_name = logging_name
else:
self._orig_logging_name = None
log.instance_logger(self, echoflag=echo)
self._creator = creator
self._recycle = recycle
self._invalidate_time = 0
self._pre_ping = pre_ping
self._reset_on_return = util.symbol.parse_user_argument(
reset_on_return,
{
reset_rollback: ["rollback", True],
reset_none: ["none", None, False],
reset_commit: ["commit"],
},
"reset_on_return",
resolve_symbol_names=False,
)
self.echo = echo
if _dispatch:
self.dispatch._update(_dispatch, only_propagate=False)
if dialect:
self._dialect = dialect
if events:
for fn, target in events:
event.listen(self, target, fn)
@util.hybridproperty
def _is_asyncio(self):
return self._dialect.is_async
@property
def _creator(self):
return self.__dict__["_creator"]
@_creator.setter
def _creator(self, creator):
self.__dict__["_creator"] = creator
self._invoke_creator = self._should_wrap_creator(creator)
def _should_wrap_creator(self, creator):
"""Detect if creator accepts a single argument, or is sent
as a legacy style no-arg function.
"""
try:
argspec = util.get_callable_argspec(self._creator, no_self=True)
except TypeError:
return lambda crec: creator()
defaulted = argspec[3] is not None and len(argspec[3]) or 0
positionals = len(argspec[0]) - defaulted
# look for the exact arg signature that DefaultStrategy
# sends us
if (argspec[0], argspec[3]) == (["connection_record"], (None,)):
return creator
# or just a single positional
elif positionals == 1:
return creator
# all other cases, just wrap and assume legacy "creator" callable
# thing
else:
return lambda crec: creator()
def _close_connection(self, connection):
self.logger.debug("Closing connection %r", connection)
try:
self._dialect.do_close(connection)
except Exception:
self.logger.error(
"Exception closing connection %r", connection, exc_info=True
)
def _create_connection(self):
"""Called by subclasses to create a new ConnectionRecord."""
return _ConnectionRecord(self)
def _invalidate(self, connection, exception=None, _checkin=True):
"""Mark all connections established within the generation
of the given connection as invalidated.
If this pool's last invalidate time is before when the given
connection was created, update the timestamp til now. Otherwise,
no action is performed.
Connections with a start time prior to this pool's invalidation
time will be recycled upon next checkout.
"""
rec = getattr(connection, "_connection_record", None)
if not rec or self._invalidate_time < rec.starttime:
self._invalidate_time = time.time()
if _checkin and getattr(connection, "is_valid", False):
connection.invalidate(exception)
def recreate(self):
"""Return a new :class:`_pool.Pool`, of the same class as this one
and configured with identical creation arguments.
This method is used in conjunction with :meth:`dispose`
to close out an entire :class:`_pool.Pool` and create a new one in
its place.
"""
raise NotImplementedError()
def dispose(self):
"""Dispose of this pool.
This method leaves the possibility of checked-out connections
remaining open, as it only affects connections that are
idle in the pool.
.. seealso::
:meth:`Pool.recreate`
"""
raise NotImplementedError()
def connect(self):
"""Return a DBAPI connection from the pool.
The connection is instrumented such that when its
``close()`` method is called, the connection will be returned to
the pool.
"""
return _ConnectionFairy._checkout(self)
def _return_conn(self, record):
"""Given a _ConnectionRecord, return it to the :class:`_pool.Pool`.
This method is called when an instrumented DBAPI connection
has its ``close()`` method called.
"""
self._do_return_conn(record)
def _do_get(self):
"""Implementation for :meth:`get`, supplied by subclasses."""
raise NotImplementedError()
def _do_return_conn(self, conn):
"""Implementation for :meth:`return_conn`, supplied by subclasses."""
raise NotImplementedError()
def status(self):
raise NotImplementedError()
class _ConnectionRecord(object):
"""Internal object which maintains an individual DBAPI connection
referenced by a :class:`_pool.Pool`.
The :class:`._ConnectionRecord` object always exists for any particular
DBAPI connection whether or not that DBAPI connection has been
"checked out". This is in contrast to the :class:`._ConnectionFairy`
which is only a public facade to the DBAPI connection while it is checked
out.
A :class:`._ConnectionRecord` may exist for a span longer than that
of a single DBAPI connection. For example, if the
:meth:`._ConnectionRecord.invalidate`
method is called, the DBAPI connection associated with this
:class:`._ConnectionRecord`
will be discarded, but the :class:`._ConnectionRecord` may be used again,
in which case a new DBAPI connection is produced when the
:class:`_pool.Pool`
next uses this record.
The :class:`._ConnectionRecord` is delivered along with connection
pool events, including :meth:`_events.PoolEvents.connect` and
:meth:`_events.PoolEvents.checkout`, however :class:`._ConnectionRecord`
still
remains an internal object whose API and internals may change.
.. seealso::
:class:`._ConnectionFairy`
"""
def __init__(self, pool, connect=True):
self.__pool = pool
if connect:
self.__connect()
self.finalize_callback = deque()
fresh = False
fairy_ref = None
starttime = None
dbapi_connection = None
"""A reference to the actual DBAPI connection being tracked.
May be ``None`` if this :class:`._ConnectionRecord` has been marked
as invalidated; a new DBAPI connection may replace it if the owning
pool calls upon this :class:`._ConnectionRecord` to reconnect.
For adapted drivers, like the Asyncio implementations, this is a
:class:`.AdaptedConnection` that adapts the driver connection
to the DBAPI protocol.
Use :attr:`._ConnectionRecord.driver_connection` to obtain the
connection objected returned by the driver.
.. versionadded:: 1.4.24
"""
@property
def driver_connection(self):
"""The connection object as returned by the driver after a connect.
For normal sync drivers that support the DBAPI protocol, this object
is the same as the one referenced by
:attr:`._ConnectionRecord.dbapi_connection`.
For adapted drivers, like the Asyncio ones, this is the actual object
that was returned by the driver ``connect`` call.
As :attr:`._ConnectionRecord.dbapi_connection` it may be ``None``
if this :class:`._ConnectionRecord` has been marked as invalidated.
.. versionadded:: 1.4.24
"""
if self.dbapi_connection is None:
return None
else:
return self.__pool._dialect.get_driver_connection(
self.dbapi_connection
)
@property
def connection(self):
"""An alias to :attr:`._ConnectionRecord.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
_soft_invalidate_time = 0
@util.memoized_property
def info(self):
"""The ``.info`` dictionary associated with the DBAPI connection.
This dictionary is shared among the :attr:`._ConnectionFairy.info`
and :attr:`_engine.Connection.info` accessors.
.. note::
The lifespan of this dictionary is linked to the
DBAPI connection itself, meaning that it is **discarded** each time
the DBAPI connection is closed and/or invalidated. The
:attr:`._ConnectionRecord.record_info` dictionary remains
persistent throughout the lifespan of the
:class:`._ConnectionRecord` container.
"""
return {}
@util.memoized_property
def record_info(self):
"""An "info' dictionary associated with the connection record
itself.
Unlike the :attr:`._ConnectionRecord.info` dictionary, which is linked
to the lifespan of the DBAPI connection, this dictionary is linked
to the lifespan of the :class:`._ConnectionRecord` container itself
and will remain persistent throughout the life of the
:class:`._ConnectionRecord`.
.. versionadded:: 1.1
"""
return {}
@classmethod
def checkout(cls, pool):
rec = pool._do_get()
try:
dbapi_connection = rec.get_connection()
except Exception as err:
with util.safe_reraise():
rec._checkin_failed(err, _fairy_was_created=False)
echo = pool._should_log_debug()
fairy = _ConnectionFairy(dbapi_connection, rec, echo)
rec.fairy_ref = ref = weakref.ref(
fairy,
lambda ref: _finalize_fairy
and _finalize_fairy(None, rec, pool, ref, echo, True),
)
_strong_ref_connection_records[ref] = rec
if echo:
pool.logger.debug(
"Connection %r checked out from pool", dbapi_connection
)
return fairy
def _checkin_failed(self, err, _fairy_was_created=True):
self.invalidate(e=err)
self.checkin(
_fairy_was_created=_fairy_was_created,
)
def checkin(self, _fairy_was_created=True):
if self.fairy_ref is None and _fairy_was_created:
# _fairy_was_created is False for the initial get connection phase;
# meaning there was no _ConnectionFairy and we must unconditionally
# do a checkin.
#
# otherwise, if fairy_was_created==True, if fairy_ref is None here
# that means we were checked in already, so this looks like
# a double checkin.
util.warn("Double checkin attempted on %s" % self)
return
self.fairy_ref = None
connection = self.dbapi_connection
pool = self.__pool
while self.finalize_callback:
finalizer = self.finalize_callback.pop()
finalizer(connection)
if pool.dispatch.checkin:
pool.dispatch.checkin(connection, self)
pool._return_conn(self)
@property
def in_use(self):
return self.fairy_ref is not None
@property
def last_connect_time(self):
return self.starttime
def close(self):
if self.dbapi_connection is not None:
self.__close()
def invalidate(self, e=None, soft=False):
"""Invalidate the DBAPI connection held by this
:class:`._ConnectionRecord`.
This method is called for all connection invalidations, including
when the :meth:`._ConnectionFairy.invalidate` or
:meth:`_engine.Connection.invalidate` methods are called,
as well as when any
so-called "automatic invalidation" condition occurs.
: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`
"""
# already invalidated
if self.dbapi_connection is None:
return
if soft:
self.__pool.dispatch.soft_invalidate(
self.dbapi_connection, self, e
)
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)