You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
382 lines
13 KiB
382 lines
13 KiB
# sqlalchemy/pool/events.py
|
|
# Copyright (C) 2005-2023 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
|
|
from __future__ import annotations
|
|
|
|
import typing
|
|
from typing import Any
|
|
from typing import Optional
|
|
from typing import Type
|
|
from typing import Union
|
|
|
|
from .base import ConnectionPoolEntry
|
|
from .base import Pool
|
|
from .base import PoolProxiedConnection
|
|
from .base import PoolResetState
|
|
from .. import event
|
|
from .. import util
|
|
|
|
if typing.TYPE_CHECKING:
|
|
from ..engine import Engine
|
|
from ..engine.interfaces import DBAPIConnection
|
|
|
|
|
|
class PoolEvents(event.Events[Pool]):
|
|
"""Available events for :class:`_pool.Pool`.
|
|
|
|
The methods here define the name of an event as well
|
|
as the names of members that are passed to listener
|
|
functions.
|
|
|
|
e.g.::
|
|
|
|
from sqlalchemy import event
|
|
|
|
def my_on_checkout(dbapi_conn, connection_rec, connection_proxy):
|
|
"handle an on checkout event"
|
|
|
|
event.listen(Pool, 'checkout', my_on_checkout)
|
|
|
|
In addition to accepting the :class:`_pool.Pool` class and
|
|
:class:`_pool.Pool` instances, :class:`_events.PoolEvents` also accepts
|
|
:class:`_engine.Engine` objects and the :class:`_engine.Engine` class as
|
|
targets, which will be resolved to the ``.pool`` attribute of the
|
|
given engine or the :class:`_pool.Pool` class::
|
|
|
|
engine = create_engine("postgresql+psycopg2://scott:tiger@localhost/test")
|
|
|
|
# will associate with engine.pool
|
|
event.listen(engine, 'checkout', my_on_checkout)
|
|
|
|
""" # noqa: E501
|
|
|
|
_target_class_doc = "SomeEngineOrPool"
|
|
_dispatch_target = Pool
|
|
|
|
@util.preload_module("sqlalchemy.engine")
|
|
@classmethod
|
|
def _accept_with(
|
|
cls,
|
|
target: Union[Pool, Type[Pool], Engine, Type[Engine]],
|
|
identifier: str,
|
|
) -> Optional[Union[Pool, Type[Pool]]]:
|
|
if not typing.TYPE_CHECKING:
|
|
Engine = util.preloaded.engine.Engine
|
|
|
|
if isinstance(target, type):
|
|
if issubclass(target, Engine):
|
|
return Pool
|
|
else:
|
|
assert issubclass(target, Pool)
|
|
return target
|
|
elif isinstance(target, Engine):
|
|
return target.pool
|
|
elif isinstance(target, Pool):
|
|
return target
|
|
elif hasattr(target, "_no_async_engine_events"):
|
|
target._no_async_engine_events()
|
|
else:
|
|
return None
|
|
|
|
@classmethod
|
|
def _listen( # type: ignore[override] # would rather keep **kw
|
|
cls,
|
|
event_key: event._EventKey[Pool],
|
|
**kw: Any,
|
|
) -> None:
|
|
target = event_key.dispatch_target
|
|
|
|
kw.setdefault("asyncio", target._is_asyncio)
|
|
|
|
event_key.base_listen(**kw)
|
|
|
|
def connect(
|
|
self,
|
|
dbapi_connection: DBAPIConnection,
|
|
connection_record: ConnectionPoolEntry,
|
|
) -> None:
|
|
"""Called at the moment a particular DBAPI connection is first
|
|
created for a given :class:`_pool.Pool`.
|
|
|
|
This event allows one to capture the point directly after which
|
|
the DBAPI module-level ``.connect()`` method has been used in order
|
|
to produce a new DBAPI connection.
|
|
|
|
:param dbapi_connection: a DBAPI connection.
|
|
The :attr:`.ConnectionPoolEntry.dbapi_connection` attribute.
|
|
|
|
:param connection_record: the :class:`.ConnectionPoolEntry` managing
|
|
the DBAPI connection.
|
|
|
|
"""
|
|
|
|
def first_connect(
|
|
self,
|
|
dbapi_connection: DBAPIConnection,
|
|
connection_record: ConnectionPoolEntry,
|
|
) -> None:
|
|
"""Called exactly once for the first time a DBAPI connection is
|
|
checked out from a particular :class:`_pool.Pool`.
|
|
|
|
The rationale for :meth:`_events.PoolEvents.first_connect`
|
|
is to determine
|
|
information about a particular series of database connections based
|
|
on the settings used for all connections. Since a particular
|
|
:class:`_pool.Pool`
|
|
refers to a single "creator" function (which in terms
|
|
of a :class:`_engine.Engine`
|
|
refers to the URL and connection options used),
|
|
it is typically valid to make observations about a single connection
|
|
that can be safely assumed to be valid about all subsequent
|
|
connections, such as the database version, the server and client
|
|
encoding settings, collation settings, and many others.
|
|
|
|
:param dbapi_connection: a DBAPI connection.
|
|
The :attr:`.ConnectionPoolEntry.dbapi_connection` attribute.
|
|
|
|
:param connection_record: the :class:`.ConnectionPoolEntry` managing
|
|
the DBAPI connection.
|
|
|
|
"""
|
|
|
|
def checkout(
|
|
self,
|
|
dbapi_connection: DBAPIConnection,
|
|
connection_record: ConnectionPoolEntry,
|
|
connection_proxy: PoolProxiedConnection,
|
|
) -> None:
|
|
"""Called when a connection is retrieved from the Pool.
|
|
|
|
:param dbapi_connection: a DBAPI connection.
|
|
The :attr:`.ConnectionPoolEntry.dbapi_connection` attribute.
|
|
|
|
:param connection_record: the :class:`.ConnectionPoolEntry` managing
|
|
the DBAPI connection.
|
|
|
|
:param connection_proxy: the :class:`.PoolProxiedConnection` object
|
|
which will proxy the public interface of the DBAPI connection for the
|
|
lifespan of the checkout.
|
|
|
|
If you raise a :class:`~sqlalchemy.exc.DisconnectionError`, the current
|
|
connection will be disposed and a fresh connection retrieved.
|
|
Processing of all checkout listeners will abort and restart
|
|
using the new connection.
|
|
|
|
.. seealso:: :meth:`_events.ConnectionEvents.engine_connect`
|
|
- a similar event
|
|
which occurs upon creation of a new :class:`_engine.Connection`.
|
|
|
|
"""
|
|
|
|
def checkin(
|
|
self,
|
|
dbapi_connection: DBAPIConnection,
|
|
connection_record: ConnectionPoolEntry,
|
|
) -> None:
|
|
"""Called when a connection returns to the pool.
|
|
|
|
Note that the connection may be closed, and may be None if the
|
|
connection has been invalidated. ``checkin`` will not be called
|
|
for detached connections. (They do not return to the pool.)
|
|
|
|
:param dbapi_connection: a DBAPI connection.
|
|
The :attr:`.ConnectionPoolEntry.dbapi_connection` attribute.
|
|
|
|
:param connection_record: the :class:`.ConnectionPoolEntry` managing
|
|
the DBAPI connection.
|
|
|
|
"""
|
|
|
|
@event._legacy_signature(
|
|
"2.0",
|
|
["dbapi_connection", "connection_record"],
|
|
lambda dbapi_connection, connection_record, reset_state: (
|
|
dbapi_connection,
|
|
connection_record,
|
|
),
|
|
)
|
|
def reset(
|
|
self,
|
|
dbapi_connection: DBAPIConnection,
|
|
connection_record: ConnectionPoolEntry,
|
|
reset_state: PoolResetState,
|
|
) -> None:
|
|
"""Called before the "reset" action occurs for a pooled connection.
|
|
|
|
This event represents
|
|
when the ``rollback()`` method is called on the DBAPI connection
|
|
before it is returned to the pool or discarded.
|
|
A custom "reset" strategy may be implemented using this event hook,
|
|
which may also be combined with disabling the default "reset"
|
|
behavior using the :paramref:`_pool.Pool.reset_on_return` parameter.
|
|
|
|
The primary difference between the :meth:`_events.PoolEvents.reset` and
|
|
:meth:`_events.PoolEvents.checkin` events are that
|
|
:meth:`_events.PoolEvents.reset` is called not just for pooled
|
|
connections that are being returned to the pool, but also for
|
|
connections that were detached using the
|
|
:meth:`_engine.Connection.detach` method as well as asyncio connections
|
|
that are being discarded due to garbage collection taking place on
|
|
connections before the connection was checked in.
|
|
|
|
Note that the event **is not** invoked for connections that were
|
|
invalidated using :meth:`_engine.Connection.invalidate`. These
|
|
events may be intercepted using the :meth:`.PoolEvents.soft_invalidate`
|
|
and :meth:`.PoolEvents.invalidate` event hooks, and all "connection
|
|
close" events may be intercepted using :meth:`.PoolEvents.close`.
|
|
|
|
The :meth:`_events.PoolEvents.reset` event is usually followed by the
|
|
:meth:`_events.PoolEvents.checkin` event, except in those
|
|
cases where the connection is discarded immediately after reset.
|
|
|
|
:param dbapi_connection: a DBAPI connection.
|
|
The :attr:`.ConnectionPoolEntry.dbapi_connection` attribute.
|
|
|
|
:param connection_record: the :class:`.ConnectionPoolEntry` managing
|
|
the DBAPI connection.
|
|
|
|
:param reset_state: :class:`.PoolResetState` instance which provides
|
|
information about the circumstances under which the connection
|
|
is being reset.
|
|
|
|
.. versionadded:: 2.0
|
|
|
|
.. seealso::
|
|
|
|
:ref:`pool_reset_on_return`
|
|
|
|
:meth:`_events.ConnectionEvents.rollback`
|
|
|
|
:meth:`_events.ConnectionEvents.commit`
|
|
|
|
"""
|
|
|
|
def invalidate(
|
|
self,
|
|
dbapi_connection: DBAPIConnection,
|
|
connection_record: ConnectionPoolEntry,
|
|
exception: Optional[BaseException],
|
|
) -> None:
|
|
"""Called when a DBAPI connection is to be "invalidated".
|
|
|
|
This event is called any time the
|
|
:meth:`.ConnectionPoolEntry.invalidate` method is invoked, either from
|
|
API usage or via "auto-invalidation", without the ``soft`` flag.
|
|
|
|
The event occurs before a final attempt to call ``.close()`` on the
|
|
connection occurs.
|
|
|
|
:param dbapi_connection: a DBAPI connection.
|
|
The :attr:`.ConnectionPoolEntry.dbapi_connection` attribute.
|
|
|
|
:param connection_record: the :class:`.ConnectionPoolEntry` managing
|
|
the DBAPI connection.
|
|
|
|
:param exception: the exception object corresponding to the reason
|
|
for this invalidation, if any. May be ``None``.
|
|
|
|
.. versionadded:: 0.9.2 Added support for connection invalidation
|
|
listening.
|
|
|
|
.. seealso::
|
|
|
|
:ref:`pool_connection_invalidation`
|
|
|
|
"""
|
|
|
|
def soft_invalidate(
|
|
self,
|
|
dbapi_connection: DBAPIConnection,
|
|
connection_record: ConnectionPoolEntry,
|
|
exception: Optional[BaseException],
|
|
) -> None:
|
|
"""Called when a DBAPI connection is to be "soft invalidated".
|
|
|
|
This event is called any time the
|
|
:meth:`.ConnectionPoolEntry.invalidate`
|
|
method is invoked with the ``soft`` flag.
|
|
|
|
Soft invalidation refers to when the connection record that tracks
|
|
this connection will force a reconnect after the current connection
|
|
is checked in. It does not actively close the dbapi_connection
|
|
at the point at which it is called.
|
|
|
|
.. versionadded:: 1.0.3
|
|
|
|
:param dbapi_connection: a DBAPI connection.
|
|
The :attr:`.ConnectionPoolEntry.dbapi_connection` attribute.
|
|
|
|
:param connection_record: the :class:`.ConnectionPoolEntry` managing
|
|
the DBAPI connection.
|
|
|
|
:param exception: the exception object corresponding to the reason
|
|
for this invalidation, if any. May be ``None``.
|
|
|
|
"""
|
|
|
|
def close(
|
|
self,
|
|
dbapi_connection: DBAPIConnection,
|
|
connection_record: ConnectionPoolEntry,
|
|
) -> None:
|
|
"""Called when a DBAPI connection is closed.
|
|
|
|
The event is emitted before the close occurs.
|
|
|
|
The close of a connection can fail; typically this is because
|
|
the connection is already closed. If the close operation fails,
|
|
the connection is discarded.
|
|
|
|
The :meth:`.close` event corresponds to a connection that's still
|
|
associated with the pool. To intercept close events for detached
|
|
connections use :meth:`.close_detached`.
|
|
|
|
.. versionadded:: 1.1
|
|
|
|
:param dbapi_connection: a DBAPI connection.
|
|
The :attr:`.ConnectionPoolEntry.dbapi_connection` attribute.
|
|
|
|
:param connection_record: the :class:`.ConnectionPoolEntry` managing
|
|
the DBAPI connection.
|
|
|
|
"""
|
|
|
|
def detach(
|
|
self,
|
|
dbapi_connection: DBAPIConnection,
|
|
connection_record: ConnectionPoolEntry,
|
|
) -> None:
|
|
"""Called when a DBAPI connection is "detached" from a pool.
|
|
|
|
This event is emitted after the detach occurs. The connection
|
|
is no longer associated with the given connection record.
|
|
|
|
.. versionadded:: 1.1
|
|
|
|
:param dbapi_connection: a DBAPI connection.
|
|
The :attr:`.ConnectionPoolEntry.dbapi_connection` attribute.
|
|
|
|
:param connection_record: the :class:`.ConnectionPoolEntry` managing
|
|
the DBAPI connection.
|
|
|
|
"""
|
|
|
|
def close_detached(self, dbapi_connection: DBAPIConnection) -> None:
|
|
"""Called when a detached DBAPI connection is closed.
|
|
|
|
The event is emitted before the close occurs.
|
|
|
|
The close of a connection can fail; typically this is because
|
|
the connection is already closed. If the close operation fails,
|
|
the connection is discarded.
|
|
|
|
.. versionadded:: 1.1
|
|
|
|
:param dbapi_connection: a DBAPI connection.
|
|
The :attr:`.ConnectionPoolEntry.dbapi_connection` attribute.
|
|
|
|
"""
|