1021 lines
35 KiB
Python
1021 lines
35 KiB
Python
|
# sqlalchemy/pool.py
|
||
|
|
# Copyright (C) 2005-2021 the SQLAlchemy authors and contributors
|
||
|
|
# <see AUTHORS file>
|
||
|
|
#
|
||
|
|
# This module is part of SQLAlchemy and is released under
|
||
|
|
# the MIT License: http://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."
|
||
|
|
)
|
||
|
|
|
||
|
|
|
||
|
|
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
|
||
|
|
|
||
|
|
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.
|
||
|
|
|
||
|
|
"""
|
||
|
|
|
||
|
|
_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.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.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.connection is None:
|
||
|
|
return
|
||
|
|
if soft:
|
||
|
|
self.__pool.dispatch.soft_invalidate(self.connection, self, e)
|
||
|
|
else:
|
||
|
|
self.__pool.dispatch.invalidate(self.connection, self, e)
|
||
|
|
if e is not None:
|
||
|
|
self.__pool.logger.info(
|
||
|
|
"%sInvalidate connection %r (reason: %s:%s)",
|
||
|
|
"Soft " if soft else "",
|
||
|
|
self.connection,
|
||
|
|
e.__class__.__name__,
|
||
|
|
e,
|
||
|
|
)
|
||
|
|
else:
|
||
|
|
self.__pool.logger.info(
|
||
|
|
"%sInvalidate connection %r",
|
||
|
|
"Soft " if soft else "",
|
||
|
|
self.connection,
|
||
|
|
)
|
||
|
|
|
||
|
|
if soft:
|
||
|
|
self._soft_invalidate_time = time.time()
|
||
|
|
else:
|
||
|
|
self.__close()
|
||
|
|
self.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.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.connection
|
||
|
|
)
|
||
|
|
recycle = True
|
||
|
|
elif self.__pool._invalidate_time > self.starttime:
|
||
|
|
self.__pool.logger.info(
|
||
|
|
"Connection %r invalidated due to pool invalidation; "
|
||
|
|
+ "recycling",
|
||
|
|
self.connection,
|
||
|
|
)
|
||
|
|
recycle = True
|
||
|
|
elif self._soft_invalidate_time > self.starttime:
|
||
|
|
self.__pool.logger.info(
|
||
|
|
"Connection %r invalidated due to local soft invalidation; "
|
||
|
|
+ "recycling",
|
||
|
|
self.connection,
|
||
|
|
)
|
||
|
|
recycle = True
|
||
|
|
|
||
|
|
if recycle:
|
||
|
|
self.__close()
|
||
|
|
self.info.clear()
|
||
|
|
|
||
|
|
self.__connect()
|
||
|
|
return self.connection
|
||
|
|
|
||
|
|
def _is_hard_or_soft_invalidated(self):
|
||
|
|
return (
|
||
|
|
self.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.connection, self)
|
||
|
|
self.__pool._close_connection(self.connection)
|
||
|
|
self.connection = None
|
||
|
|
|
||
|
|
def __connect(self):
|
||
|
|
pool = self.__pool
|
||
|
|
|
||
|
|
# ensure any existing connection is removed, so that if
|
||
|
|
# creator fails, this attribute stays None
|
||
|
|
self.connection = None
|
||
|
|
try:
|
||
|
|
self.starttime = time.time()
|
||
|
|
connection = pool._invoke_creator(self)
|
||
|
|
pool.logger.debug("Created new connection %r", connection)
|
||
|
|
self.connection = 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.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.connection, self)
|
||
|
|
|
||
|
|
|
||
|
|
def _finalize_fairy(
|
||
|
|
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 connection is None
|
||
|
|
connection = connection_record.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 connection is not None:
|
||
|
|
if connection_record and echo:
|
||
|
|
pool.logger.debug(
|
||
|
|
"Connection %r being returned to pool%s",
|
||
|
|
connection,
|
||
|
|
", transaction state was already reset by caller"
|
||
|
|
if not reset
|
||
|
|
else "",
|
||
|
|
)
|
||
|
|
|
||
|
|
try:
|
||
|
|
fairy = fairy or _ConnectionFairy(
|
||
|
|
connection, connection_record, echo
|
||
|
|
)
|
||
|
|
assert fairy.connection is 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(connection)
|
||
|
|
|
||
|
|
pool._close_connection(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."
|
||
|
|
) % 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.connection = dbapi_connection
|
||
|
|
self._connection_record = connection_record
|
||
|
|
self._echo = echo
|
||
|
|
|
||
|
|
connection = None
|
||
|
|
"""A reference to the actual DBAPI connection being tracked."""
|
||
|
|
|
||
|
|
_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.
|
||
|
|
|
||
|
|
"""
|
||
|
|
|
||
|
|
@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.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.connection,
|
||
|
|
)
|
||
|
|
result = pool._dialect.do_ping(fairy.connection)
|
||
|
|
if not result:
|
||
|
|
if fairy._echo:
|
||
|
|
pool.logger.debug(
|
||
|
|
"Pool pre-ping on connection %s failed, "
|
||
|
|
"will invalidate pool",
|
||
|
|
fairy.connection,
|
||
|
|
)
|
||
|
|
raise exc.InvalidatePoolError()
|
||
|
|
elif fairy._echo:
|
||
|
|
pool.logger.debug(
|
||
|
|
"Connection %s is fresh, skipping pre-ping",
|
||
|
|
fairy.connection,
|
||
|
|
)
|
||
|
|
|
||
|
|
pool.dispatch.checkout(
|
||
|
|
fairy.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.connection,
|
||
|
|
e,
|
||
|
|
)
|
||
|
|
fairy._connection_record.invalidate(e)
|
||
|
|
try:
|
||
|
|
fairy.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.connection,
|
||
|
|
self._connection_record,
|
||
|
|
self._pool,
|
||
|
|
None,
|
||
|
|
self._echo,
|
||
|
|
reset=reset,
|
||
|
|
fairy=self,
|
||
|
|
)
|
||
|
|
self.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.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.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.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.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.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.connection.cursor(*args, **kwargs)
|
||
|
|
|
||
|
|
def __getattr__(self, key):
|
||
|
|
return getattr(self.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.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.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)
|