# ext/asyncio/session.py
# Copyright (C) 2020-2024 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 asyncio
from typing import Any
from typing import Awaitable
from typing import Callable
from typing import cast
from typing import Dict
from typing import Generic
from typing import Iterable
from typing import Iterator
from typing import NoReturn
from typing import Optional
from typing import overload
from typing import Sequence
from typing import Tuple
from typing import Type
from typing import TYPE_CHECKING
from typing import TypeVar
from typing import Union
from . import engine
from .base import ReversibleProxy
from .base import StartableContext
from .result import _ensure_sync_result
from .result import AsyncResult
from .result import AsyncScalarResult
from ... import util
from ...orm import close_all_sessions as _sync_close_all_sessions
from ...orm import object_session
from ...orm import Session
from ...orm import SessionTransaction
from ...orm import state as _instance_state
from ...util.concurrency import greenlet_spawn
from ...util.typing import Concatenate
from ...util.typing import ParamSpec
if TYPE_CHECKING:
from .engine import AsyncConnection
from .engine import AsyncEngine
from ...engine import Connection
from ...engine import CursorResult
from ...engine import Engine
from ...engine import Result
from ...engine import Row
from ...engine import RowMapping
from ...engine import ScalarResult
from ...engine.interfaces import _CoreAnyExecuteParams
from ...engine.interfaces import CoreExecuteOptionsParameter
from ...event import dispatcher
from ...orm._typing import _IdentityKeyType
from ...orm._typing import _O
from ...orm._typing import OrmExecuteOptionsParameter
from ...orm.identity import IdentityMap
from ...orm.interfaces import ORMOption
from ...orm.session import _BindArguments
from ...orm.session import _EntityBindKey
from ...orm.session import _PKIdentityArgument
from ...orm.session import _SessionBind
from ...orm.session import _SessionBindKey
from ...sql._typing import _InfoType
from ...sql.base import Executable
from ...sql.dml import UpdateBase
from ...sql.elements import ClauseElement
from ...sql.selectable import ForUpdateParameter
from ...sql.selectable import TypedReturnsRows
_AsyncSessionBind = Union["AsyncEngine", "AsyncConnection"]
_P = ParamSpec("_P")
_T = TypeVar("_T", bound=Any)
_EXECUTE_OPTIONS = util.immutabledict({"prebuffer_rows": True})
_STREAM_OPTIONS = util.immutabledict({"stream_results": True})
class AsyncAttrs:
"""Mixin class which provides an awaitable accessor for all attributes.
E.g.::
from __future__ import annotations
from typing import List
from sqlalchemy import ForeignKey
from sqlalchemy import func
from sqlalchemy.ext.asyncio import AsyncAttrs
from sqlalchemy.orm import DeclarativeBase
from sqlalchemy.orm import Mapped
from sqlalchemy.orm import mapped_column
from sqlalchemy.orm import relationship
class Base(AsyncAttrs, DeclarativeBase):
pass
class A(Base):
__tablename__ = "a"
id: Mapped[int] = mapped_column(primary_key=True)
data: Mapped[str]
bs: Mapped[List[B]] = relationship()
class B(Base):
__tablename__ = "b"
id: Mapped[int] = mapped_column(primary_key=True)
a_id: Mapped[int] = mapped_column(ForeignKey("a.id"))
data: Mapped[str]
In the above example, the :class:`_asyncio.AsyncAttrs` mixin is applied to
the declarative ``Base`` class where it takes effect for all subclasses.
This mixin adds a single new attribute
:attr:`_asyncio.AsyncAttrs.awaitable_attrs` to all classes, which will
yield the value of any attribute as an awaitable. This allows attributes
which may be subject to lazy loading or deferred / unexpiry loading to be
accessed such that IO can still be emitted::
a1 = (await async_session.scalars(select(A).where(A.id == 5))).one()
# use the lazy loader on ``a1.bs`` via the ``.awaitable_attrs``
# interface, so that it may be awaited
for b1 in await a1.awaitable_attrs.bs:
print(b1)
The :attr:`_asyncio.AsyncAttrs.awaitable_attrs` performs a call against the
attribute that is approximately equivalent to using the
:meth:`_asyncio.AsyncSession.run_sync` method, e.g.::
for b1 in await async_session.run_sync(lambda sess: a1.bs):
print(b1)
.. versionadded:: 2.0.13
.. seealso::
:ref:`asyncio_orm_avoid_lazyloads`
"""
class _AsyncAttrGetitem:
__slots__ = "_instance"
def __init__(self, _instance: Any):
self._instance = _instance
def __getattr__(self, name: str) -> Awaitable[Any]:
return greenlet_spawn(getattr, self._instance, name)
@property
def awaitable_attrs(self) -> AsyncAttrs._AsyncAttrGetitem:
"""provide a namespace of all attributes on this object wrapped
as awaitables.
e.g.::
a1 = (await async_session.scalars(select(A).where(A.id == 5))).one()
some_attribute = await a1.awaitable_attrs.some_deferred_attribute
some_collection = await a1.awaitable_attrs.some_collection
""" # noqa: E501
return AsyncAttrs._AsyncAttrGetitem(self)
@util.create_proxy_methods(
Session,
":class:`_orm.Session`",
":class:`_asyncio.AsyncSession`",
classmethods=["object_session", "identity_key"],
methods=[
"__contains__",
"__iter__",
"add",
"add_all",
"expire",
"expire_all",
"expunge",
"expunge_all",
"is_modified",
"in_transaction",
"in_nested_transaction",
],
attributes=[
"dirty",
"deleted",
"new",
"identity_map",
"is_active",
"autoflush",
"no_autoflush",
"info",
],
)
class AsyncSession(ReversibleProxy[Session]):
"""Asyncio version of :class:`_orm.Session`.
The :class:`_asyncio.AsyncSession` is a proxy for a traditional
:class:`_orm.Session` instance.
The :class:`_asyncio.AsyncSession` is **not safe for use in concurrent
tasks.**. See :ref:`session_faq_threadsafe` for background.
.. versionadded:: 1.4
To use an :class:`_asyncio.AsyncSession` with custom :class:`_orm.Session`
implementations, see the
:paramref:`_asyncio.AsyncSession.sync_session_class` parameter.
"""
_is_asyncio = True
dispatch: dispatcher[Session]
def __init__(
self,
bind: Optional[_AsyncSessionBind] = None,
*,
binds: Optional[Dict[_SessionBindKey, _AsyncSessionBind]] = None,
sync_session_class: Optional[Type[Session]] = None,
**kw: Any,
):
r"""Construct a new :class:`_asyncio.AsyncSession`.
All parameters other than ``sync_session_class`` are passed to the
``sync_session_class`` callable directly to instantiate a new
:class:`_orm.Session`. Refer to :meth:`_orm.Session.__init__` for
parameter documentation.
:param sync_session_class:
A :class:`_orm.Session` subclass or other callable which will be used
to construct the :class:`_orm.Session` which will be proxied. This
parameter may be used to provide custom :class:`_orm.Session`
subclasses. Defaults to the
:attr:`_asyncio.AsyncSession.sync_session_class` class-level
attribute.
.. versionadded:: 1.4.24
"""
sync_bind = sync_binds = None
if bind:
self.bind = bind
sync_bind = engine._get_sync_engine_or_connection(bind)
if binds:
self.binds = binds
sync_binds = {
key: engine._get_sync_engine_or_connection(b)
for key, b in binds.items()
}
if sync_session_class:
self.sync_session_class = sync_session_class
self.sync_session = self._proxied = self._assign_proxied(
self.sync_session_class(bind=sync_bind, binds=sync_binds, **kw)
)
sync_session_class: Type[Session] = Session
"""The class or callable that provides the
underlying :class:`_orm.Session` instance for a particular
:class:`_asyncio.AsyncSession`.
At the class level, this attribute is the default value for the
:paramref:`_asyncio.AsyncSession.sync_session_class` parameter. Custom
subclasses of :class:`_asyncio.AsyncSession` can override this.
At the instance level, this attribute indicates the current class or
callable that was used to provide the :class:`_orm.Session` instance for
this :class:`_asyncio.AsyncSession` instance.
.. versionadded:: 1.4.24
"""
sync_session: Session
"""Reference to the underlying :class:`_orm.Session` this
:class:`_asyncio.AsyncSession` proxies requests towards.
This instance can be used as an event target.
.. seealso::
:ref:`asyncio_events`
"""
@classmethod
def _no_async_engine_events(cls) -> NoReturn:
raise NotImplementedError(
"asynchronous events are not implemented at this time. Apply "
"synchronous listeners to the AsyncSession.sync_session."
)
async def refresh(
self,
instance: object,
attribute_names: Optional[Iterable[str]] = None,
with_for_update: ForUpdateParameter = None,
) -> None:
"""Expire and refresh the attributes on the given instance.
A query will be issued to the database and all attributes will be
refreshed with their current database value.
This is the async version of the :meth:`_orm.Session.refresh` method.
See that method for a complete description of all options.
.. seealso::
:meth:`_orm.Session.refresh` - main documentation for refresh
"""
await greenlet_spawn(
self.sync_session.refresh,
instance,
attribute_names=attribute_names,
with_for_update=with_for_update,
)
async def run_sync(
self,
fn: Callable[Concatenate[Session, _P], _T],
*arg: _P.args,
**kw: _P.kwargs,
) -> _T:
"""Invoke the given synchronous (i.e. not async) callable,
passing a synchronous-style :class:`_orm.Session` as the first
argument.
This method allows traditional synchronous SQLAlchemy functions to
run within the context of an asyncio application.
E.g.::
def some_business_method(session: Session, param: str) -> str:
'''A synchronous function that does not require awaiting
:param session: a SQLAlchemy Session, used synchronously
:return: an optional return value is supported
'''
session.add(MyObject(param=param))
session.flush()
return "success"
async def do_something_async(async_engine: AsyncEngine) -> None:
'''an async function that uses awaiting'''
with AsyncSession(async_engine) as async_session:
# run some_business_method() with a sync-style
# Session, proxied into an awaitable
return_code = await async_session.run_sync(some_business_method, param="param1")
print(return_code)
This method maintains the asyncio event loop all the way through
to the database connection by running the given callable in a
specially instrumented greenlet.
.. tip::
The provided callable is invoked inline within the asyncio event
loop, and will block on traditional IO calls. IO within this
callable should only call into SQLAlchemy's asyncio database
APIs which will be properly adapted to the greenlet context.
.. seealso::
:class:`.AsyncAttrs` - a mixin for ORM mapped classes that provides
a similar feature more succinctly on a per-attribute basis
:meth:`.AsyncConnection.run_sync`
:ref:`session_run_sync`
""" # noqa: E501
return await greenlet_spawn(
fn, self.sync_session, *arg, _require_await=False, **kw
)
@overload
async def execute(
self,
statement: TypedReturnsRows[_T],
params: Optional[_CoreAnyExecuteParams] = None,
*,
execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
bind_arguments: Optional[_BindArguments] = None,
_parent_execute_state: Optional[Any] = None,
_add_event: Optional[Any] = None,
) -> Result[_T]: ...
@overload
async def execute(
self,
statement: UpdateBase,
params: Optional[_CoreAnyExecuteParams] = None,
*,
execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
bind_arguments: Optional[_BindArguments] = None,
_parent_execute_state: Optional[Any] = None,
_add_event: Optional[Any] = None,
) -> CursorResult[Any]: ...
@overload
async def execute(
self,
statement: Executable,
params: Optional[_CoreAnyExecuteParams] = None,
*,
execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
bind_arguments: Optional[_BindArguments] = None,
_parent_execute_state: Optional[Any] = None,
_add_event: Optional[Any] = None,
) -> Result[Any]: ...
async def execute(
self,
statement: Executable,
params: Optional[_CoreAnyExecuteParams] = None,
*,
execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
bind_arguments: Optional[_BindArguments] = None,
**kw: Any,
) -> Result[Any]:
"""Execute a statement and return a buffered
:class:`_engine.Result` object.
.. seealso::
:meth:`_orm.Session.execute` - main documentation for execute
"""
if execution_options:
execution_options = util.immutabledict(execution_options).union(
_EXECUTE_OPTIONS
)
else:
execution_options = _EXECUTE_OPTIONS
result = await greenlet_spawn(
self.sync_session.execute,
statement,
params=params,
execution_options=execution_options,
bind_arguments=bind_arguments,
**kw,
)
return await _ensure_sync_result(result, self.execute)
@overload
async def scalar(
self,
statement: TypedReturnsRows[Tuple[_T]],
params: Optional[_CoreAnyExecuteParams] = None,
*,
execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
bind_arguments: Optional[_BindArguments] = None,
**kw: Any,
) -> Optional[_T]: ...
@overload
async def scalar(
self,
statement: Executable,
params: Optional[_CoreAnyExecuteParams] = None,
*,
execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
bind_arguments: Optional[_BindArguments] = None,
**kw: Any,
) -> Any: ...
async def scalar(
self,
statement: Executable,
params: Optional[_CoreAnyExecuteParams] = None,
*,
execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
bind_arguments: Optional[_BindArguments] = None,
**kw: Any,
) -> Any:
"""Execute a statement and return a scalar result.
.. seealso::
:meth:`_orm.Session.scalar` - main documentation for scalar
"""
if execution_options:
execution_options = util.immutabledict(execution_options).union(
_EXECUTE_OPTIONS
)
else:
execution_options = _EXECUTE_OPTIONS
return await greenlet_spawn(
self.sync_session.scalar,
statement,
params=params,
execution_options=execution_options,
bind_arguments=bind_arguments,
**kw,
)
@overload
async def scalars(
self,
statement: TypedReturnsRows[Tuple[_T]],
params: Optional[_CoreAnyExecuteParams] = None,
*,
execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
bind_arguments: Optional[_BindArguments] = None,
**kw: Any,
) -> ScalarResult[_T]: ...
@overload
async def scalars(
self,
statement: Executable,
params: Optional[_CoreAnyExecuteParams] = None,
*,
execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
bind_arguments: Optional[_BindArguments] = None,
**kw: Any,
) -> ScalarResult[Any]: ...
async def scalars(
self,
statement: Executable,
params: Optional[_CoreAnyExecuteParams] = None,
*,
execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
bind_arguments: Optional[_BindArguments] = None,
**kw: Any,
) -> ScalarResult[Any]:
"""Execute a statement and return scalar results.
:return: a :class:`_result.ScalarResult` object
.. versionadded:: 1.4.24 Added :meth:`_asyncio.AsyncSession.scalars`
.. versionadded:: 1.4.26 Added
:meth:`_asyncio.async_scoped_session.scalars`
.. seealso::
:meth:`_orm.Session.scalars` - main documentation for scalars
:meth:`_asyncio.AsyncSession.stream_scalars` - streaming version
"""
result = await self.execute(
statement,
params=params,
execution_options=execution_options,
bind_arguments=bind_arguments,
**kw,
)
return result.scalars()
async def get(
self,
entity: _EntityBindKey[_O],
ident: _PKIdentityArgument,
*,
options: Optional[Sequence[ORMOption]] = None,
populate_existing: bool = False,
with_for_update: ForUpdateParameter = None,
identity_token: Optional[Any] = None,
execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
) -> Union[_O, None]:
"""Return an instance based on the given primary key identifier,
or ``None`` if not found.
.. seealso::
:meth:`_orm.Session.get` - main documentation for get
"""
return await greenlet_spawn(
cast("Callable[..., _O]", self.sync_session.get),
entity,
ident,
options=options,
populate_existing=populate_existing,
with_for_update=with_for_update,
identity_token=identity_token,
execution_options=execution_options,
)
async def get_one(
self,
entity: _EntityBindKey[_O],
ident: _PKIdentityArgument,
*,
options: Optional[Sequence[ORMOption]] = None,
populate_existing: bool = False,
with_for_update: ForUpdateParameter = None,
identity_token: Optional[Any] = None,
execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
) -> _O:
"""Return an instance based on the given primary key identifier,
or raise an exception if not found.
Raises ``sqlalchemy.orm.exc.NoResultFound`` if the query selects
no rows.
..versionadded: 2.0.22
.. seealso::
:meth:`_orm.Session.get_one` - main documentation for get_one
"""
return await greenlet_spawn(
cast("Callable[..., _O]", self.sync_session.get_one),
entity,
ident,
options=options,
populate_existing=populate_existing,
with_for_update=with_for_update,
identity_token=identity_token,
execution_options=execution_options,
)
@overload
async def stream(
self,
statement: TypedReturnsRows[_T],
params: Optional[_CoreAnyExecuteParams] = None,
*,
execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
bind_arguments: Optional[_BindArguments] = None,
**kw: Any,
) -> AsyncResult[_T]: ...
@overload
async def stream(
self,
statement: Executable,
params: Optional[_CoreAnyExecuteParams] = None,
*,
execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
bind_arguments: Optional[_BindArguments] = None,
**kw: Any,
) -> AsyncResult[Any]: ...
async def stream(
self,
statement: Executable,
params: Optional[_CoreAnyExecuteParams] = None,
*,
execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
bind_arguments: Optional[_BindArguments] = None,
**kw: Any,
) -> AsyncResult[Any]:
"""Execute a statement and return a streaming
:class:`_asyncio.AsyncResult` object.
"""
if execution_options:
execution_options = util.immutabledict(execution_options).union(
_STREAM_OPTIONS
)
else:
execution_options = _STREAM_OPTIONS
result = await greenlet_spawn(
self.sync_session.execute,
statement,
params=params,
execution_options=execution_options,
bind_arguments=bind_arguments,
**kw,
)
return AsyncResult(result)
@overload
async def stream_scalars(
self,
statement: TypedReturnsRows[Tuple[_T]],
params: Optional[_CoreAnyExecuteParams] = None,
*,
execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
bind_arguments: Optional[_BindArguments] = None,
**kw: Any,
) -> AsyncScalarResult[_T]: ...
@overload
async def stream_scalars(
self,
statement: Executable,
params: Optional[_CoreAnyExecuteParams] = None,
*,
execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
bind_arguments: Optional[_BindArguments] = None,
**kw: Any,
) -> AsyncScalarResult[Any]: ...
async def stream_scalars(
self,
statement: Executable,
params: Optional[_CoreAnyExecuteParams] = None,
*,
execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
bind_arguments: Optional[_BindArguments] = None,
**kw: Any,
) -> AsyncScalarResult[Any]:
"""Execute a statement and return a stream of scalar results.
:return: an :class:`_asyncio.AsyncScalarResult` object
.. versionadded:: 1.4.24
.. seealso::
:meth:`_orm.Session.scalars` - main documentation for scalars
:meth:`_asyncio.AsyncSession.scalars` - non streaming version
"""
result = await self.stream(
statement,
params=params,
execution_options=execution_options,
bind_arguments=bind_arguments,
**kw,
)
return result.scalars()
async def delete(self, instance: object) -> None:
"""Mark an instance as deleted.
The database delete operation occurs upon ``flush()``.
As this operation may need to cascade along unloaded relationships,
it is awaitable to allow for those queries to take place.
.. seealso::
:meth:`_orm.Session.delete` - main documentation for delete
"""
await greenlet_spawn(self.sync_session.delete, instance)
async def merge(
self,
instance: _O,
*,
load: bool = True,
options: Optional[Sequence[ORMOption]] = None,
) -> _O:
"""Copy the state of a given instance into a corresponding instance
within this :class:`_asyncio.AsyncSession`.
.. seealso::
:meth:`_orm.Session.merge` - main documentation for merge
"""
return await greenlet_spawn(
self.sync_session.merge, instance, load=load, options=options
)
async def flush(self, objects: Optional[Sequence[Any]] = None) -> None:
"""Flush all the object changes to the database.
.. seealso::
:meth:`_orm.Session.flush` - main documentation for flush
"""
await greenlet_spawn(self.sync_session.flush, objects=objects)
def get_transaction(self) -> Optional[AsyncSessionTransaction]:
"""Return the current root transaction in progress, if any.
:return: an :class:`_asyncio.AsyncSessionTransaction` object, or
``None``.
.. versionadded:: 1.4.18
"""
trans = self.sync_session.get_transaction()
if trans is not None:
return AsyncSessionTransaction._retrieve_proxy_for_target(trans)
else:
return None
def get_nested_transaction(self) -> Optional[AsyncSessionTransaction]:
"""Return the current nested transaction in progress, if any.
:return: an :class:`_asyncio.AsyncSessionTransaction` object, or
``None``.
.. versionadded:: 1.4.18
"""
trans = self.sync_session.get_nested_transaction()
if trans is not None:
return AsyncSessionTransaction._retrieve_proxy_for_target(trans)
else:
return None
def get_bind(
self,
mapper: Optional[_EntityBindKey[_O]] = None,
clause: Optional[ClauseElement] = None,
bind: Optional[_SessionBind] = None,
**kw: Any,
) -> Union[Engine, Connection]:
"""Return a "bind" to which the synchronous proxied :class:`_orm.Session`
is bound.
Unlike the :meth:`_orm.Session.get_bind` method, this method is
currently **not** used by this :class:`.AsyncSession` in any way
in order to resolve engines for requests.
.. note::
This method proxies directly to the :meth:`_orm.Session.get_bind`
method, however is currently **not** useful as an override target,
in contrast to that of the :meth:`_orm.Session.get_bind` method.
The example below illustrates how to implement custom
:meth:`_orm.Session.get_bind` schemes that work with
:class:`.AsyncSession` and :class:`.AsyncEngine`.
The pattern introduced at :ref:`session_custom_partitioning`
illustrates how to apply a custom bind-lookup scheme to a
:class:`_orm.Session` given a set of :class:`_engine.Engine` objects.
To apply a corresponding :meth:`_orm.Session.get_bind` implementation
for use with a :class:`.AsyncSession` and :class:`.AsyncEngine`
objects, continue to subclass :class:`_orm.Session` and apply it to
:class:`.AsyncSession` using
:paramref:`.AsyncSession.sync_session_class`. The inner method must
continue to return :class:`_engine.Engine` instances, which can be
acquired from a :class:`_asyncio.AsyncEngine` using the
:attr:`_asyncio.AsyncEngine.sync_engine` attribute::
# using example from "Custom Vertical Partitioning"
import random
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy.ext.asyncio import create_async_engine
from sqlalchemy.ext.asyncio import async_sessionmaker
from sqlalchemy.orm import Session
# construct async engines w/ async drivers
engines = {
'leader':create_async_engine("sqlite+aiosqlite:///leader.db"),
'other':create_async_engine("sqlite+aiosqlite:///other.db"),
'follower1':create_async_engine("sqlite+aiosqlite:///follower1.db"),
'follower2':create_async_engine("sqlite+aiosqlite:///follower2.db"),
}
class RoutingSession(Session):
def get_bind(self, mapper=None, clause=None, **kw):
# within get_bind(), return sync engines
if mapper and issubclass(mapper.class_, MyOtherClass):
return engines['other'].sync_engine
elif self._flushing or isinstance(clause, (Update, Delete)):
return engines['leader'].sync_engine
else:
return engines[
random.choice(['follower1','follower2'])
].sync_engine
# apply to AsyncSession using sync_session_class
AsyncSessionMaker = async_sessionmaker(
sync_session_class=RoutingSession
)
The :meth:`_orm.Session.get_bind` method is called in a non-asyncio,
implicitly non-blocking context in the same manner as ORM event hooks
and functions that are invoked via :meth:`.AsyncSession.run_sync`, so
routines that wish to run SQL commands inside of
:meth:`_orm.Session.get_bind` can continue to do so using
blocking-style code, which will be translated to implicitly async calls
at the point of invoking IO on the database drivers.
""" # noqa: E501
return self.sync_session.get_bind(
mapper=mapper, clause=clause, bind=bind, **kw
)
async def connection(
self,
bind_arguments: Optional[_BindArguments] = None,
execution_options: Optional[CoreExecuteOptionsParameter] = None,
**kw: Any,
) -> AsyncConnection:
r"""Return a :class:`_asyncio.AsyncConnection` object corresponding to
this :class:`.Session` object's transactional state.
This method may also be used to establish execution options for the
database connection used by the current transaction.
.. versionadded:: 1.4.24 Added \**kw arguments which are passed
through to the underlying :meth:`_orm.Session.connection` method.
.. seealso::
:meth:`_orm.Session.connection` - main documentation for
"connection"
"""
sync_connection = await greenlet_spawn(
self.sync_session.connection,
bind_arguments=bind_arguments,
execution_options=execution_options,
**kw,
)
return engine.AsyncConnection._retrieve_proxy_for_target(
sync_connection
)
def begin(self) -> AsyncSessionTransaction:
"""Return an :class:`_asyncio.AsyncSessionTransaction` object.
The underlying :class:`_orm.Session` will perform the
"begin" action when the :class:`_asyncio.AsyncSessionTransaction`
object is entered::
async with async_session.begin():
# .. ORM transaction is begun
Note that database IO will not normally occur when the session-level
transaction is begun, as database transactions begin on an
on-demand basis. However, the begin block is async to accommodate
for a :meth:`_orm.SessionEvents.after_transaction_create`
event hook that may perform IO.
For a general description of ORM begin, see
:meth:`_orm.Session.begin`.
"""
return AsyncSessionTransaction(self)
def begin_nested(self) -> AsyncSessionTransaction:
"""Return an :class:`_asyncio.AsyncSessionTransaction` object
which will begin a "nested" transaction, e.g. SAVEPOINT.
Behavior is the same as that of :meth:`_asyncio.AsyncSession.begin`.
For a general description of ORM begin nested, see
:meth:`_orm.Session.begin_nested`.
.. seealso::
:ref:`aiosqlite_serializable` - special workarounds required
with the SQLite asyncio driver in order for SAVEPOINT to work
correctly.
"""
return AsyncSessionTransaction(self, nested=True)
async def rollback(self) -> None:
"""Rollback the current transaction in progress.
.. seealso::
:meth:`_orm.Session.rollback` - main documentation for
"rollback"
"""
await greenlet_spawn(self.sync_session.rollback)
async def commit(self) -> None:
"""Commit the current transaction in progress.
.. seealso::
:meth:`_orm.Session.commit` - main documentation for
"commit"
"""
await greenlet_spawn(self.sync_session.commit)
async def close(self) -> None:
"""Close out the transactional resources and ORM objects used by this
:class:`_asyncio.AsyncSession`.
.. seealso::
:meth:`_orm.Session.close` - main documentation for
"close"
:ref:`session_closing` - detail on the semantics of
:meth:`_asyncio.AsyncSession.close` and
:meth:`_asyncio.AsyncSession.reset`.
"""
await greenlet_spawn(self.sync_session.close)
async def reset(self) -> None:
"""Close out the transactional resources and ORM objects used by this
:class:`_orm.Session`, resetting the session to its initial state.
.. versionadded:: 2.0.22
.. seealso::
:meth:`_orm.Session.reset` - main documentation for
"reset"
:ref:`session_closing` - detail on the semantics of
:meth:`_asyncio.AsyncSession.close` and
:meth:`_asyncio.AsyncSession.reset`.
"""
await greenlet_spawn(self.sync_session.reset)
async def aclose(self) -> None:
"""A synonym for :meth:`_asyncio.AsyncSession.close`.
The :meth:`_asyncio.AsyncSession.aclose` name is specifically
to support the Python standard library ``@contextlib.aclosing``
context manager function.
.. versionadded:: 2.0.20
"""
await self.close()
async def invalidate(self) -> None:
"""Close this Session, using connection invalidation.
For a complete description, see :meth:`_orm.Session.invalidate`.
"""
await greenlet_spawn(self.sync_session.invalidate)
@classmethod
@util.deprecated(
"2.0",
"The :meth:`.AsyncSession.close_all` method is deprecated and will be "
"removed in a future release. Please refer to "
":func:`_asyncio.close_all_sessions`.",
)
async def close_all(cls) -> None:
"""Close all :class:`_asyncio.AsyncSession` sessions."""
await close_all_sessions()
async def __aenter__(self: _AS) -> _AS:
return self
async def __aexit__(self, type_: Any, value: Any, traceback: Any) -> None:
task = asyncio.create_task(self.close())
await asyncio.shield(task)
def _maker_context_manager(self: _AS) -> _AsyncSessionContextManager[_AS]:
return _AsyncSessionContextManager(self)
# START PROXY METHODS AsyncSession
# code within this block is **programmatically,
# statically generated** by tools/generate_proxy_methods.py
def __contains__(self, instance: object) -> bool:
r"""Return True if the instance is associated with this session.
.. container:: class_bases
Proxied for the :class:`_orm.Session` class on
behalf of the :class:`_asyncio.AsyncSession` class.
The instance may be pending or persistent within the Session for a
result of True.
""" # noqa: E501
return self._proxied.__contains__(instance)
def __iter__(self) -> Iterator[object]:
r"""Iterate over all pending or persistent instances within this
Session.
.. container:: class_bases
Proxied for the :class:`_orm.Session` class on
behalf of the :class:`_asyncio.AsyncSession` class.
""" # noqa: E501
return self._proxied.__iter__()
def add(self, instance: object, _warn: bool = True) -> None:
r"""Place an object into this :class:`_orm.Session`.
.. container:: class_bases
Proxied for the :class:`_orm.Session` class on
behalf of the :class:`_asyncio.AsyncSession` class.
Objects that are in the :term:`transient` state when passed to the
:meth:`_orm.Session.add` method will move to the
:term:`pending` state, until the next flush, at which point they
will move to the :term:`persistent` state.
Objects that are in the :term:`detached` state when passed to the
:meth:`_orm.Session.add` method will move to the :term:`persistent`
state directly.
If the transaction used by the :class:`_orm.Session` is rolled back,
objects which were transient when they were passed to
:meth:`_orm.Session.add` will be moved back to the
:term:`transient` state, and will no longer be present within this
:class:`_orm.Session`.
.. seealso::
:meth:`_orm.Session.add_all`
:ref:`session_adding` - at :ref:`session_basics`
""" # noqa: E501
return self._proxied.add(instance, _warn=_warn)
def add_all(self, instances: Iterable[object]) -> None:
r"""Add the given collection of instances to this :class:`_orm.Session`.
.. container:: class_bases
Proxied for the :class:`_orm.Session` class on
behalf of the :class:`_asyncio.AsyncSession` class.
See the documentation for :meth:`_orm.Session.add` for a general
behavioral description.
.. seealso::
:meth:`_orm.Session.add`
:ref:`session_adding` - at :ref:`session_basics`
""" # noqa: E501
return self._proxied.add_all(instances)
def expire(
self, instance: object, attribute_names: Optional[Iterable[str]] = None
) -> None:
r"""Expire the attributes on an instance.
.. container:: class_bases
Proxied for the :class:`_orm.Session` class on
behalf of the :class:`_asyncio.AsyncSession` class.
Marks the attributes of an instance as out of date. When an expired
attribute is next accessed, a query will be issued to the
:class:`.Session` object's current transactional context in order to
load all expired attributes for the given instance. Note that
a highly isolated transaction will return the same values as were
previously read in that same transaction, regardless of changes
in database state outside of that transaction.
To expire all objects in the :class:`.Session` simultaneously,
use :meth:`Session.expire_all`.
The :class:`.Session` object's default behavior is to
expire all state whenever the :meth:`Session.rollback`
or :meth:`Session.commit` methods are called, so that new
state can be loaded for the new transaction. For this reason,
calling :meth:`Session.expire` only makes sense for the specific
case that a non-ORM SQL statement was emitted in the current
transaction.
:param instance: The instance to be refreshed.
:param attribute_names: optional list of string attribute names
indicating a subset of attributes to be expired.
.. seealso::
:ref:`session_expire` - introductory material
:meth:`.Session.expire`
:meth:`.Session.refresh`
:meth:`_orm.Query.populate_existing`
""" # noqa: E501
return self._proxied.expire(instance, attribute_names=attribute_names)
def expire_all(self) -> None:
r"""Expires all persistent instances within this Session.
.. container:: class_bases
Proxied for the :class:`_orm.Session` class on
behalf of the :class:`_asyncio.AsyncSession` class.
When any attributes on a persistent instance is next accessed,
a query will be issued using the
:class:`.Session` object's current transactional context in order to
load all expired attributes for the given instance. Note that
a highly isolated transaction will return the same values as were
previously read in that same transaction, regardless of changes
in database state outside of that transaction.
To expire individual objects and individual attributes
on those objects, use :meth:`Session.expire`.
The :class:`.Session` object's default behavior is to
expire all state whenever the :meth:`Session.rollback`
or :meth:`Session.commit` methods are called, so that new
state can be loaded for the new transaction. For this reason,
calling :meth:`Session.expire_all` is not usually needed,
assuming the transaction is isolated.
.. seealso::
:ref:`session_expire` - introductory material
:meth:`.Session.expire`
:meth:`.Session.refresh`
:meth:`_orm.Query.populate_existing`
""" # noqa: E501
return self._proxied.expire_all()
def expunge(self, instance: object) -> None:
r"""Remove the `instance` from this ``Session``.
.. container:: class_bases
Proxied for the :class:`_orm.Session` class on
behalf of the :class:`_asyncio.AsyncSession` class.
This will free all internal references to the instance. Cascading
will be applied according to the *expunge* cascade rule.
""" # noqa: E501
return self._proxied.expunge(instance)
def expunge_all(self) -> None:
r"""Remove all object instances from this ``Session``.
.. container:: class_bases
Proxied for the :class:`_orm.Session` class on
behalf of the :class:`_asyncio.AsyncSession` class.
This is equivalent to calling ``expunge(obj)`` on all objects in this
``Session``.
""" # noqa: E501
return self._proxied.expunge_all()
def is_modified(
self, instance: object, include_collections: bool = True
) -> bool:
r"""Return ``True`` if the given instance has locally
modified attributes.
.. container:: class_bases
Proxied for the :class:`_orm.Session` class on
behalf of the :class:`_asyncio.AsyncSession` class.
This method retrieves the history for each instrumented
attribute on the instance and performs a comparison of the current
value to its previously flushed or committed value, if any.
It is in effect a more expensive and accurate
version of checking for the given instance in the
:attr:`.Session.dirty` collection; a full test for
each attribute's net "dirty" status is performed.
E.g.::
return session.is_modified(someobject)
A few caveats to this method apply:
* Instances present in the :attr:`.Session.dirty` collection may
report ``False`` when tested with this method. This is because
the object may have received change events via attribute mutation,
thus placing it in :attr:`.Session.dirty`, but ultimately the state
is the same as that loaded from the database, resulting in no net
change here.
* Scalar attributes may not have recorded the previously set
value when a new value was applied, if the attribute was not loaded,
or was expired, at the time the new value was received - in these
cases, the attribute is assumed to have a change, even if there is
ultimately no net change against its database value. SQLAlchemy in
most cases does not need the "old" value when a set event occurs, so
it skips the expense of a SQL call if the old value isn't present,
based on the assumption that an UPDATE of the scalar value is
usually needed, and in those few cases where it isn't, is less
expensive on average than issuing a defensive SELECT.
The "old" value is fetched unconditionally upon set only if the
attribute container has the ``active_history`` flag set to ``True``.
This flag is set typically for primary key attributes and scalar
object references that are not a simple many-to-one. To set this
flag for any arbitrary mapped column, use the ``active_history``
argument with :func:`.column_property`.
:param instance: mapped instance to be tested for pending changes.
:param include_collections: Indicates if multivalued collections
should be included in the operation. Setting this to ``False`` is a
way to detect only local-column based properties (i.e. scalar columns
or many-to-one foreign keys) that would result in an UPDATE for this
instance upon flush.
""" # noqa: E501
return self._proxied.is_modified(
instance, include_collections=include_collections
)
def in_transaction(self) -> bool:
r"""Return True if this :class:`_orm.Session` has begun a transaction.
.. container:: class_bases
Proxied for the :class:`_orm.Session` class on
behalf of the :class:`_asyncio.AsyncSession` class.
.. versionadded:: 1.4
.. seealso::
:attr:`_orm.Session.is_active`
""" # noqa: E501
return self._proxied.in_transaction()
def in_nested_transaction(self) -> bool:
r"""Return True if this :class:`_orm.Session` has begun a nested
transaction, e.g. SAVEPOINT.
.. container:: class_bases
Proxied for the :class:`_orm.Session` class on
behalf of the :class:`_asyncio.AsyncSession` class.
.. versionadded:: 1.4
""" # noqa: E501
return self._proxied.in_nested_transaction()
@property
def dirty(self) -> Any:
r"""The set of all persistent instances considered dirty.
.. container:: class_bases
Proxied for the :class:`_orm.Session` class
on behalf of the :class:`_asyncio.AsyncSession` class.
E.g.::
some_mapped_object in session.dirty
Instances are considered dirty when they were modified but not
deleted.
Note that this 'dirty' calculation is 'optimistic'; most
attribute-setting or collection modification operations will
mark an instance as 'dirty' and place it in this set, even if
there is no net change to the attribute's value. At flush
time, the value of each attribute is compared to its
previously saved value, and if there's no net change, no SQL
operation will occur (this is a more expensive operation so
it's only done at flush time).
To check if an instance has actionable net changes to its
attributes, use the :meth:`.Session.is_modified` method.
""" # noqa: E501
return self._proxied.dirty
@property
def deleted(self) -> Any:
r"""The set of all instances marked as 'deleted' within this ``Session``
.. container:: class_bases
Proxied for the :class:`_orm.Session` class
on behalf of the :class:`_asyncio.AsyncSession` class.
""" # noqa: E501
return self._proxied.deleted
@property
def new(self) -> Any:
r"""The set of all instances marked as 'new' within this ``Session``.
.. container:: class_bases
Proxied for the :class:`_orm.Session` class
on behalf of the :class:`_asyncio.AsyncSession` class.
""" # noqa: E501
return self._proxied.new
@property
def identity_map(self) -> IdentityMap:
r"""Proxy for the :attr:`_orm.Session.identity_map` attribute
on behalf of the :class:`_asyncio.AsyncSession` class.
""" # noqa: E501
return self._proxied.identity_map
@identity_map.setter
def identity_map(self, attr: IdentityMap) -> None:
self._proxied.identity_map = attr
@property
def is_active(self) -> Any:
r"""True if this :class:`.Session` not in "partial rollback" state.
.. container:: class_bases
Proxied for the :class:`_orm.Session` class
on behalf of the :class:`_asyncio.AsyncSession` class.
.. versionchanged:: 1.4 The :class:`_orm.Session` no longer begins
a new transaction immediately, so this attribute will be False
when the :class:`_orm.Session` is first instantiated.
"partial rollback" state typically indicates that the flush process
of the :class:`_orm.Session` has failed, and that the
:meth:`_orm.Session.rollback` method must be emitted in order to
fully roll back the transaction.
If this :class:`_orm.Session` is not in a transaction at all, the
:class:`_orm.Session` will autobegin when it is first used, so in this
case :attr:`_orm.Session.is_active` will return True.
Otherwise, if this :class:`_orm.Session` is within a transaction,
and that transaction has not been rolled back internally, the
:attr:`_orm.Session.is_active` will also return True.
.. seealso::
:ref:`faq_session_rollback`
:meth:`_orm.Session.in_transaction`
""" # noqa: E501
return self._proxied.is_active
@property
def autoflush(self) -> bool:
r"""Proxy for the :attr:`_orm.Session.autoflush` attribute
on behalf of the :class:`_asyncio.AsyncSession` class.
""" # noqa: E501
return self._proxied.autoflush
@autoflush.setter
def autoflush(self, attr: bool) -> None:
self._proxied.autoflush = attr
@property
def no_autoflush(self) -> Any:
r"""Return a context manager that disables autoflush.
.. container:: class_bases
Proxied for the :class:`_orm.Session` class
on behalf of the :class:`_asyncio.AsyncSession` class.
e.g.::
with session.no_autoflush:
some_object = SomeClass()
session.add(some_object)
# won't autoflush
some_object.related_thing = session.query(SomeRelated).first()
Operations that proceed within the ``with:`` block
will not be subject to flushes occurring upon query
access. This is useful when initializing a series
of objects which involve existing database queries,
where the uncompleted object should not yet be flushed.
""" # noqa: E501
return self._proxied.no_autoflush
@property
def info(self) -> Any:
r"""A user-modifiable dictionary.
.. container:: class_bases
Proxied for the :class:`_orm.Session` class
on behalf of the :class:`_asyncio.AsyncSession` class.
The initial value of this dictionary can be populated using the
``info`` argument to the :class:`.Session` constructor or
:class:`.sessionmaker` constructor or factory methods. The dictionary
here is always local to this :class:`.Session` and can be modified
independently of all other :class:`.Session` objects.
""" # noqa: E501
return self._proxied.info
@classmethod
def object_session(cls, instance: object) -> Optional[Session]:
r"""Return the :class:`.Session` to which an object belongs.
.. container:: class_bases
Proxied for the :class:`_orm.Session` class on
behalf of the :class:`_asyncio.AsyncSession` class.
This is an alias of :func:`.object_session`.
""" # noqa: E501
return Session.object_session(instance)
@classmethod
def identity_key(
cls,
class_: Optional[Type[Any]] = None,
ident: Union[Any, Tuple[Any, ...]] = None,
*,
instance: Optional[Any] = None,
row: Optional[Union[Row[Any], RowMapping]] = None,
identity_token: Optional[Any] = None,
) -> _IdentityKeyType[Any]:
r"""Return an identity key.
.. container:: class_bases
Proxied for the :class:`_orm.Session` class on
behalf of the :class:`_asyncio.AsyncSession` class.
This is an alias of :func:`.util.identity_key`.
""" # noqa: E501
return Session.identity_key(
class_=class_,
ident=ident,
instance=instance,
row=row,
identity_token=identity_token,
)
# END PROXY METHODS AsyncSession
_AS = TypeVar("_AS", bound="AsyncSession")
class async_sessionmaker(Generic[_AS]):
"""A configurable :class:`.AsyncSession` factory.
The :class:`.async_sessionmaker` factory works in the same way as the
:class:`.sessionmaker` factory, to generate new :class:`.AsyncSession`
objects when called, creating them given
the configurational arguments established here.
e.g.::
from sqlalchemy.ext.asyncio import create_async_engine
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy.ext.asyncio import async_sessionmaker
async def run_some_sql(async_session: async_sessionmaker[AsyncSession]) -> None:
async with async_session() as session:
session.add(SomeObject(data="object"))
session.add(SomeOtherObject(name="other object"))
await session.commit()
async def main() -> None:
# an AsyncEngine, which the AsyncSession will use for connection
# resources
engine = create_async_engine('postgresql+asyncpg://scott:tiger@localhost/')
# create a reusable factory for new AsyncSession instances
async_session = async_sessionmaker(engine)
await run_some_sql(async_session)
await engine.dispose()
The :class:`.async_sessionmaker` is useful so that different parts
of a program can create new :class:`.AsyncSession` objects with a
fixed configuration established up front. Note that :class:`.AsyncSession`
objects may also be instantiated directly when not using
:class:`.async_sessionmaker`.
.. versionadded:: 2.0 :class:`.async_sessionmaker` provides a
:class:`.sessionmaker` class that's dedicated to the
:class:`.AsyncSession` object, including pep-484 typing support.
.. seealso::
:ref:`asyncio_orm` - shows example use
:class:`.sessionmaker` - general overview of the
:class:`.sessionmaker` architecture
:ref:`session_getting` - introductory text on creating
sessions using :class:`.sessionmaker`.
""" # noqa E501
class_: Type[_AS]
@overload
def __init__(
self,
bind: Optional[_AsyncSessionBind] = ...,
*,
class_: Type[_AS],
autoflush: bool = ...,
expire_on_commit: bool = ...,
info: Optional[_InfoType] = ...,
**kw: Any,
): ...
@overload
def __init__(
self: "async_sessionmaker[AsyncSession]",
bind: Optional[_AsyncSessionBind] = ...,
*,
autoflush: bool = ...,
expire_on_commit: bool = ...,
info: Optional[_InfoType] = ...,
**kw: Any,
): ...
def __init__(
self,
bind: Optional[_AsyncSessionBind] = None,
*,
class_: Type[_AS] = AsyncSession, # type: ignore
autoflush: bool = True,
expire_on_commit: bool = True,
info: Optional[_InfoType] = None,
**kw: Any,
):
r"""Construct a new :class:`.async_sessionmaker`.
All arguments here except for ``class_`` correspond to arguments
accepted by :class:`.Session` directly. See the
:meth:`.AsyncSession.__init__` docstring for more details on
parameters.
"""
kw["bind"] = bind
kw["autoflush"] = autoflush
kw["expire_on_commit"] = expire_on_commit
if info is not None:
kw["info"] = info
self.kw = kw
self.class_ = class_
def begin(self) -> _AsyncSessionContextManager[_AS]:
"""Produce a context manager that both provides a new
:class:`_orm.AsyncSession` as well as a transaction that commits.
e.g.::
async def main():
Session = async_sessionmaker(some_engine)
async with Session.begin() as session:
session.add(some_object)
# commits transaction, closes session
"""
session = self()
return session._maker_context_manager()
def __call__(self, **local_kw: Any) -> _AS:
"""Produce a new :class:`.AsyncSession` object using the configuration
established in this :class:`.async_sessionmaker`.
In Python, the ``__call__`` method is invoked on an object when
it is "called" in the same way as a function::
AsyncSession = async_sessionmaker(async_engine, expire_on_commit=False)
session = AsyncSession() # invokes sessionmaker.__call__()
""" # noqa E501
for k, v in self.kw.items():
if k == "info" and "info" in local_kw:
d = v.copy()
d.update(local_kw["info"])
local_kw["info"] = d
else:
local_kw.setdefault(k, v)
return self.class_(**local_kw)
def configure(self, **new_kw: Any) -> None:
"""(Re)configure the arguments for this async_sessionmaker.
e.g.::
AsyncSession = async_sessionmaker(some_engine)
AsyncSession.configure(bind=create_async_engine('sqlite+aiosqlite://'))
""" # noqa E501
self.kw.update(new_kw)
def __repr__(self) -> str:
return "%s(class_=%r, %s)" % (
self.__class__.__name__,
self.class_.__name__,
", ".join("%s=%r" % (k, v) for k, v in self.kw.items()),
)
class _AsyncSessionContextManager(Generic[_AS]):
__slots__ = ("async_session", "trans")
async_session: _AS
trans: AsyncSessionTransaction
def __init__(self, async_session: _AS):
self.async_session = async_session
async def __aenter__(self) -> _AS:
self.trans = self.async_session.begin()
await self.trans.__aenter__()
return self.async_session
async def __aexit__(self, type_: Any, value: Any, traceback: Any) -> None:
async def go() -> None:
await self.trans.__aexit__(type_, value, traceback)
await self.async_session.__aexit__(type_, value, traceback)
task = asyncio.create_task(go())
await asyncio.shield(task)
class AsyncSessionTransaction(
ReversibleProxy[SessionTransaction],
StartableContext["AsyncSessionTransaction"],
):
"""A wrapper for the ORM :class:`_orm.SessionTransaction` object.
This object is provided so that a transaction-holding object
for the :meth:`_asyncio.AsyncSession.begin` may be returned.
The object supports both explicit calls to
:meth:`_asyncio.AsyncSessionTransaction.commit` and
:meth:`_asyncio.AsyncSessionTransaction.rollback`, as well as use as an
async context manager.
.. versionadded:: 1.4
"""
__slots__ = ("session", "sync_transaction", "nested")
session: AsyncSession
sync_transaction: Optional[SessionTransaction]
def __init__(self, session: AsyncSession, nested: bool = False):
self.session = session
self.nested = nested
self.sync_transaction = None
@property
def is_active(self) -> bool:
return (
self._sync_transaction() is not None
and self._sync_transaction().is_active
)
def _sync_transaction(self) -> SessionTransaction:
if not self.sync_transaction:
self._raise_for_not_started()
return self.sync_transaction
async def rollback(self) -> None:
"""Roll back this :class:`_asyncio.AsyncTransaction`."""
await greenlet_spawn(self._sync_transaction().rollback)
async def commit(self) -> None:
"""Commit this :class:`_asyncio.AsyncTransaction`."""
await greenlet_spawn(self._sync_transaction().commit)
async def start(
self, is_ctxmanager: bool = False
) -> AsyncSessionTransaction:
self.sync_transaction = self._assign_proxied(
await greenlet_spawn(
self.session.sync_session.begin_nested # type: ignore
if self.nested
else self.session.sync_session.begin
)
)
if is_ctxmanager:
self.sync_transaction.__enter__()
return self
async def __aexit__(self, type_: Any, value: Any, traceback: Any) -> None:
await greenlet_spawn(
self._sync_transaction().__exit__, type_, value, traceback
)
def async_object_session(instance: object) -> Optional[AsyncSession]:
"""Return the :class:`_asyncio.AsyncSession` to which the given instance
belongs.
This function makes use of the sync-API function
:class:`_orm.object_session` to retrieve the :class:`_orm.Session` which
refers to the given instance, and from there links it to the original
:class:`_asyncio.AsyncSession`.
If the :class:`_asyncio.AsyncSession` has been garbage collected, the
return value is ``None``.
This functionality is also available from the
:attr:`_orm.InstanceState.async_session` accessor.
:param instance: an ORM mapped instance
:return: an :class:`_asyncio.AsyncSession` object, or ``None``.
.. versionadded:: 1.4.18
"""
session = object_session(instance)
if session is not None:
return async_session(session)
else:
return None
def async_session(session: Session) -> Optional[AsyncSession]:
"""Return the :class:`_asyncio.AsyncSession` which is proxying the given
:class:`_orm.Session` object, if any.
:param session: a :class:`_orm.Session` instance.
:return: a :class:`_asyncio.AsyncSession` instance, or ``None``.
.. versionadded:: 1.4.18
"""
return AsyncSession._retrieve_proxy_for_target(session, regenerate=False)
async def close_all_sessions() -> None:
"""Close all :class:`_asyncio.AsyncSession` sessions.
.. versionadded:: 2.0.23
.. seealso::
:func:`.session.close_all_sessions`
"""
await greenlet_spawn(_sync_close_all_sessions)
_instance_state._async_provider = async_session # type: ignore
advanced_alchemy