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Diffstat (limited to 'venv/lib/python3.11/site-packages/sqlalchemy/engine/create.py')
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diff --git a/venv/lib/python3.11/site-packages/sqlalchemy/engine/create.py b/venv/lib/python3.11/site-packages/sqlalchemy/engine/create.py new file mode 100644 index 0000000..74a3cf8 --- /dev/null +++ b/venv/lib/python3.11/site-packages/sqlalchemy/engine/create.py @@ -0,0 +1,875 @@ +# engine/create.py +# Copyright (C) 2005-2024 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 inspect +import typing +from typing import Any +from typing import Callable +from typing import cast +from typing import Dict +from typing import List +from typing import Optional +from typing import overload +from typing import Type +from typing import Union + +from . import base +from . import url as _url +from .interfaces import DBAPIConnection +from .mock import create_mock_engine +from .. import event +from .. import exc +from .. import util +from ..pool import _AdhocProxiedConnection +from ..pool import ConnectionPoolEntry +from ..sql import compiler +from ..util import immutabledict + +if typing.TYPE_CHECKING: + from .base import Engine + from .interfaces import _ExecuteOptions + from .interfaces import _ParamStyle + from .interfaces import IsolationLevel + from .url import URL + from ..log import _EchoFlagType + from ..pool import _CreatorFnType + from ..pool import _CreatorWRecFnType + from ..pool import _ResetStyleArgType + from ..pool import Pool + from ..util.typing import Literal + + +@overload +def create_engine( + url: Union[str, URL], + *, + connect_args: Dict[Any, Any] = ..., + convert_unicode: bool = ..., + creator: Union[_CreatorFnType, _CreatorWRecFnType] = ..., + echo: _EchoFlagType = ..., + echo_pool: _EchoFlagType = ..., + enable_from_linting: bool = ..., + execution_options: _ExecuteOptions = ..., + future: Literal[True], + hide_parameters: bool = ..., + implicit_returning: Literal[True] = ..., + insertmanyvalues_page_size: int = ..., + isolation_level: IsolationLevel = ..., + json_deserializer: Callable[..., Any] = ..., + json_serializer: Callable[..., Any] = ..., + label_length: Optional[int] = ..., + logging_name: str = ..., + max_identifier_length: Optional[int] = ..., + max_overflow: int = ..., + module: Optional[Any] = ..., + paramstyle: Optional[_ParamStyle] = ..., + pool: Optional[Pool] = ..., + poolclass: Optional[Type[Pool]] = ..., + pool_logging_name: str = ..., + pool_pre_ping: bool = ..., + pool_size: int = ..., + pool_recycle: int = ..., + pool_reset_on_return: Optional[_ResetStyleArgType] = ..., + pool_timeout: float = ..., + pool_use_lifo: bool = ..., + plugins: List[str] = ..., + query_cache_size: int = ..., + use_insertmanyvalues: bool = ..., + **kwargs: Any, +) -> Engine: ... + + +@overload +def create_engine(url: Union[str, URL], **kwargs: Any) -> Engine: ... + + +@util.deprecated_params( + strategy=( + "1.4", + "The :paramref:`_sa.create_engine.strategy` keyword is deprecated, " + "and the only argument accepted is 'mock'; please use " + ":func:`.create_mock_engine` going forward. For general " + "customization of create_engine which may have been accomplished " + "using strategies, see :class:`.CreateEnginePlugin`.", + ), + empty_in_strategy=( + "1.4", + "The :paramref:`_sa.create_engine.empty_in_strategy` keyword is " + "deprecated, and no longer has any effect. All IN expressions " + "are now rendered using " + 'the "expanding parameter" strategy which renders a set of bound' + 'expressions, or an "empty set" SELECT, at statement execution' + "time.", + ), + implicit_returning=( + "2.0", + "The :paramref:`_sa.create_engine.implicit_returning` parameter " + "is deprecated and will be removed in a future release. ", + ), +) +def create_engine(url: Union[str, _url.URL], **kwargs: Any) -> Engine: + """Create a new :class:`_engine.Engine` instance. + + The standard calling form is to send the :ref:`URL <database_urls>` as the + first positional argument, usually a string + that indicates database dialect and connection arguments:: + + engine = create_engine("postgresql+psycopg2://scott:tiger@localhost/test") + + .. note:: + + Please review :ref:`database_urls` for general guidelines in composing + URL strings. In particular, special characters, such as those often + part of passwords, must be URL encoded to be properly parsed. + + Additional keyword arguments may then follow it which + establish various options on the resulting :class:`_engine.Engine` + and its underlying :class:`.Dialect` and :class:`_pool.Pool` + constructs:: + + engine = create_engine("mysql+mysqldb://scott:tiger@hostname/dbname", + pool_recycle=3600, echo=True) + + The string form of the URL is + ``dialect[+driver]://user:password@host/dbname[?key=value..]``, where + ``dialect`` is a database name such as ``mysql``, ``oracle``, + ``postgresql``, etc., and ``driver`` the name of a DBAPI, such as + ``psycopg2``, ``pyodbc``, ``cx_oracle``, etc. Alternatively, + the URL can be an instance of :class:`~sqlalchemy.engine.url.URL`. + + ``**kwargs`` takes a wide variety of options which are routed + towards their appropriate components. Arguments may be specific to + the :class:`_engine.Engine`, the underlying :class:`.Dialect`, + as well as the + :class:`_pool.Pool`. Specific dialects also accept keyword arguments that + are unique to that dialect. Here, we describe the parameters + that are common to most :func:`_sa.create_engine()` usage. + + Once established, the newly resulting :class:`_engine.Engine` will + request a connection from the underlying :class:`_pool.Pool` once + :meth:`_engine.Engine.connect` is called, or a method which depends on it + such as :meth:`_engine.Engine.execute` is invoked. The + :class:`_pool.Pool` in turn + will establish the first actual DBAPI connection when this request + is received. The :func:`_sa.create_engine` call itself does **not** + establish any actual DBAPI connections directly. + + .. seealso:: + + :doc:`/core/engines` + + :doc:`/dialects/index` + + :ref:`connections_toplevel` + + :param connect_args: a dictionary of options which will be + passed directly to the DBAPI's ``connect()`` method as + additional keyword arguments. See the example + at :ref:`custom_dbapi_args`. + + :param creator: a callable which returns a DBAPI connection. + This creation function will be passed to the underlying + connection pool and will be used to create all new database + connections. Usage of this function causes connection + parameters specified in the URL argument to be bypassed. + + This hook is not as flexible as the newer + :meth:`_events.DialectEvents.do_connect` hook which allows complete + control over how a connection is made to the database, given the full + set of URL arguments and state beforehand. + + .. seealso:: + + :meth:`_events.DialectEvents.do_connect` - event hook that allows + full control over DBAPI connection mechanics. + + :ref:`custom_dbapi_args` + + :param echo=False: if True, the Engine will log all statements + as well as a ``repr()`` of their parameter lists to the default log + handler, which defaults to ``sys.stdout`` for output. If set to the + string ``"debug"``, result rows will be printed to the standard output + as well. The ``echo`` attribute of ``Engine`` can be modified at any + time to turn logging on and off; direct control of logging is also + available using the standard Python ``logging`` module. + + .. seealso:: + + :ref:`dbengine_logging` - further detail on how to configure + logging. + + + :param echo_pool=False: 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. + Direct control of logging is also available using the standard Python + ``logging`` module. + + .. seealso:: + + :ref:`dbengine_logging` - further detail on how to configure + logging. + + + :param empty_in_strategy: No longer used; SQLAlchemy now uses + "empty set" behavior for IN in all cases. + + :param enable_from_linting: defaults to True. Will emit a warning + if a given SELECT statement is found to have un-linked FROM elements + which would cause a cartesian product. + + .. versionadded:: 1.4 + + .. seealso:: + + :ref:`change_4737` + + :param execution_options: Dictionary execution options which will + be applied to all connections. See + :meth:`~sqlalchemy.engine.Connection.execution_options` + + :param future: Use the 2.0 style :class:`_engine.Engine` and + :class:`_engine.Connection` API. + + As of SQLAlchemy 2.0, this parameter is present for backwards + compatibility only and must remain at its default value of ``True``. + + The :paramref:`_sa.create_engine.future` parameter will be + deprecated in a subsequent 2.x release and eventually removed. + + .. versionadded:: 1.4 + + .. versionchanged:: 2.0 All :class:`_engine.Engine` objects are + "future" style engines and there is no longer a ``future=False`` + mode of operation. + + .. seealso:: + + :ref:`migration_20_toplevel` + + :param hide_parameters: Boolean, when set to True, SQL statement parameters + will not be displayed in INFO logging nor will they be formatted into + the string representation of :class:`.StatementError` objects. + + .. versionadded:: 1.3.8 + + .. seealso:: + + :ref:`dbengine_logging` - further detail on how to configure + logging. + + :param implicit_returning=True: Legacy parameter that may only be set + to True. In SQLAlchemy 2.0, this parameter does nothing. In order to + disable "implicit returning" for statements invoked by the ORM, + configure this on a per-table basis using the + :paramref:`.Table.implicit_returning` parameter. + + + :param insertmanyvalues_page_size: number of rows to format into an + INSERT statement when the statement uses "insertmanyvalues" mode, which is + a paged form of bulk insert that is used for many backends when using + :term:`executemany` execution typically in conjunction with RETURNING. + Defaults to 1000, but may also be subject to dialect-specific limiting + factors which may override this value on a per-statement basis. + + .. versionadded:: 2.0 + + .. seealso:: + + :ref:`engine_insertmanyvalues` + + :ref:`engine_insertmanyvalues_page_size` + + :paramref:`_engine.Connection.execution_options.insertmanyvalues_page_size` + + :param isolation_level: optional string name of an isolation level + which will be set on all new connections unconditionally. + Isolation levels are typically some subset of the string names + ``"SERIALIZABLE"``, ``"REPEATABLE READ"``, + ``"READ COMMITTED"``, ``"READ UNCOMMITTED"`` and ``"AUTOCOMMIT"`` + based on backend. + + The :paramref:`_sa.create_engine.isolation_level` parameter is + in contrast to the + :paramref:`.Connection.execution_options.isolation_level` + execution option, which may be set on an individual + :class:`.Connection`, as well as the same parameter passed to + :meth:`.Engine.execution_options`, where it may be used to create + multiple engines with different isolation levels that share a common + connection pool and dialect. + + .. versionchanged:: 2.0 The + :paramref:`_sa.create_engine.isolation_level` + parameter has been generalized to work on all dialects which support + the concept of isolation level, and is provided as a more succinct, + up front configuration switch in contrast to the execution option + which is more of an ad-hoc programmatic option. + + .. seealso:: + + :ref:`dbapi_autocommit` + + :param json_deserializer: for dialects that support the + :class:`_types.JSON` + datatype, this is a Python callable that will convert a JSON string + to a Python object. By default, the Python ``json.loads`` function is + used. + + .. versionchanged:: 1.3.7 The SQLite dialect renamed this from + ``_json_deserializer``. + + :param json_serializer: for dialects that support the :class:`_types.JSON` + datatype, this is a Python callable that will render a given object + as JSON. By default, the Python ``json.dumps`` function is used. + + .. versionchanged:: 1.3.7 The SQLite dialect renamed this from + ``_json_serializer``. + + + :param label_length=None: optional integer value which limits + the size of dynamically generated column labels to that many + characters. If less than 6, labels are generated as + "_(counter)". If ``None``, the value of + ``dialect.max_identifier_length``, which may be affected via the + :paramref:`_sa.create_engine.max_identifier_length` parameter, + is used instead. The value of + :paramref:`_sa.create_engine.label_length` + may not be larger than that of + :paramref:`_sa.create_engine.max_identfier_length`. + + .. seealso:: + + :paramref:`_sa.create_engine.max_identifier_length` + + :param logging_name: String identifier which will be used within + the "name" field of logging records generated within the + "sqlalchemy.engine" logger. Defaults to a hexstring of the + object's id. + + .. seealso:: + + :ref:`dbengine_logging` - further detail on how to configure + logging. + + :paramref:`_engine.Connection.execution_options.logging_token` + + :param max_identifier_length: integer; override the max_identifier_length + determined by the dialect. if ``None`` or zero, has no effect. This + is the database's configured maximum number of characters that may be + used in a SQL identifier such as a table name, column name, or label + name. All dialects determine this value automatically, however in the + case of a new database version for which this value has changed but + SQLAlchemy's dialect has not been adjusted, the value may be passed + here. + + .. versionadded:: 1.3.9 + + .. seealso:: + + :paramref:`_sa.create_engine.label_length` + + :param max_overflow=10: the number of connections to allow in + connection pool "overflow", that is connections that can be + opened above and beyond the pool_size setting, which defaults + to five. this is only used with :class:`~sqlalchemy.pool.QueuePool`. + + :param module=None: reference to a Python module object (the module + itself, not its string name). Specifies an alternate DBAPI module to + be used by the engine's dialect. Each sub-dialect references a + specific DBAPI which will be imported before first connect. This + parameter causes the import to be bypassed, and the given module to + be used instead. Can be used for testing of DBAPIs as well as to + inject "mock" DBAPI implementations into the :class:`_engine.Engine`. + + :param paramstyle=None: The `paramstyle <https://legacy.python.org/dev/peps/pep-0249/#paramstyle>`_ + to use when rendering bound parameters. This style defaults to the + one recommended by the DBAPI itself, which is retrieved from the + ``.paramstyle`` attribute of the DBAPI. However, most DBAPIs accept + more than one paramstyle, and in particular it may be desirable + to change a "named" paramstyle into a "positional" one, or vice versa. + When this attribute is passed, it should be one of the values + ``"qmark"``, ``"numeric"``, ``"named"``, ``"format"`` or + ``"pyformat"``, and should correspond to a parameter style known + to be supported by the DBAPI in use. + + :param pool=None: an already-constructed instance of + :class:`~sqlalchemy.pool.Pool`, such as a + :class:`~sqlalchemy.pool.QueuePool` instance. If non-None, this + pool will be used directly as the underlying connection pool + for the engine, bypassing whatever connection parameters are + present in the URL argument. For information on constructing + connection pools manually, see :ref:`pooling_toplevel`. + + :param poolclass=None: a :class:`~sqlalchemy.pool.Pool` + subclass, which will be used to create a connection pool + instance using the connection parameters given in the URL. Note + this differs from ``pool`` in that you don't actually + instantiate the pool in this case, you just indicate what type + of pool to be used. + + :param pool_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. + + .. seealso:: + + :ref:`dbengine_logging` - further detail on how to configure + logging. + + :param pool_pre_ping: boolean, if True will enable the connection pool + "pre-ping" feature that tests connections for liveness upon + each checkout. + + .. versionadded:: 1.2 + + .. seealso:: + + :ref:`pool_disconnects_pessimistic` + + :param pool_size=5: the number of connections to keep open + inside the connection pool. This used with + :class:`~sqlalchemy.pool.QueuePool` as + well as :class:`~sqlalchemy.pool.SingletonThreadPool`. With + :class:`~sqlalchemy.pool.QueuePool`, a ``pool_size`` setting + of 0 indicates no limit; to disable pooling, set ``poolclass`` to + :class:`~sqlalchemy.pool.NullPool` instead. + + :param pool_recycle=-1: this setting causes the pool to recycle + connections after the given number of seconds has passed. It + defaults to -1, or no timeout. For example, setting to 3600 + means connections will be recycled after one hour. Note that + MySQL in particular will disconnect automatically if no + activity is detected on a connection for eight hours (although + this is configurable with the MySQLDB connection itself and the + server configuration as well). + + .. seealso:: + + :ref:`pool_setting_recycle` + + :param pool_reset_on_return='rollback': set the + :paramref:`_pool.Pool.reset_on_return` parameter of the underlying + :class:`_pool.Pool` object, which can be set to the values + ``"rollback"``, ``"commit"``, or ``None``. + + .. seealso:: + + :ref:`pool_reset_on_return` + + :param pool_timeout=30: number of seconds to wait before giving + up on getting a connection from the pool. This is only used + with :class:`~sqlalchemy.pool.QueuePool`. This can be a float but is + subject to the limitations of Python time functions which may not be + reliable in the tens of milliseconds. + + .. note: don't use 30.0 above, it seems to break with the :param tag + + :param pool_use_lifo=False: use LIFO (last-in-first-out) when retrieving + connections from :class:`.QueuePool` instead of FIFO + (first-in-first-out). Using LIFO, a server-side timeout scheme can + reduce the number of connections used during non- peak periods of + use. When planning for server-side timeouts, ensure that a recycle or + pre-ping strategy is in use to gracefully handle stale connections. + + .. versionadded:: 1.3 + + .. seealso:: + + :ref:`pool_use_lifo` + + :ref:`pool_disconnects` + + :param plugins: string list of plugin names to load. See + :class:`.CreateEnginePlugin` for background. + + .. versionadded:: 1.2.3 + + :param query_cache_size: size of the cache used to cache the SQL string + form of queries. Set to zero to disable caching. + + The cache is pruned of its least recently used items when its size reaches + N * 1.5. Defaults to 500, meaning the cache will always store at least + 500 SQL statements when filled, and will grow up to 750 items at which + point it is pruned back down to 500 by removing the 250 least recently + used items. + + Caching is accomplished on a per-statement basis by generating a + cache key that represents the statement's structure, then generating + string SQL for the current dialect only if that key is not present + in the cache. All statements support caching, however some features + such as an INSERT with a large set of parameters will intentionally + bypass the cache. SQL logging will indicate statistics for each + statement whether or not it were pull from the cache. + + .. note:: some ORM functions related to unit-of-work persistence as well + as some attribute loading strategies will make use of individual + per-mapper caches outside of the main cache. + + + .. seealso:: + + :ref:`sql_caching` + + .. versionadded:: 1.4 + + :param use_insertmanyvalues: True by default, use the "insertmanyvalues" + execution style for INSERT..RETURNING statements by default. + + .. versionadded:: 2.0 + + .. seealso:: + + :ref:`engine_insertmanyvalues` + + """ # noqa + + if "strategy" in kwargs: + strat = kwargs.pop("strategy") + if strat == "mock": + # this case is deprecated + return create_mock_engine(url, **kwargs) # type: ignore + else: + raise exc.ArgumentError("unknown strategy: %r" % strat) + + kwargs.pop("empty_in_strategy", None) + + # create url.URL object + u = _url.make_url(url) + + u, plugins, kwargs = u._instantiate_plugins(kwargs) + + entrypoint = u._get_entrypoint() + _is_async = kwargs.pop("_is_async", False) + if _is_async: + dialect_cls = entrypoint.get_async_dialect_cls(u) + else: + dialect_cls = entrypoint.get_dialect_cls(u) + + if kwargs.pop("_coerce_config", False): + + def pop_kwarg(key: str, default: Optional[Any] = None) -> Any: + value = kwargs.pop(key, default) + if key in dialect_cls.engine_config_types: + value = dialect_cls.engine_config_types[key](value) + return value + + else: + pop_kwarg = kwargs.pop # type: ignore + + dialect_args = {} + # consume dialect arguments from kwargs + for k in util.get_cls_kwargs(dialect_cls): + if k in kwargs: + dialect_args[k] = pop_kwarg(k) + + dbapi = kwargs.pop("module", None) + if dbapi is None: + dbapi_args = {} + + if "import_dbapi" in dialect_cls.__dict__: + dbapi_meth = dialect_cls.import_dbapi + + elif hasattr(dialect_cls, "dbapi") and inspect.ismethod( + dialect_cls.dbapi + ): + util.warn_deprecated( + "The dbapi() classmethod on dialect classes has been " + "renamed to import_dbapi(). Implement an import_dbapi() " + f"classmethod directly on class {dialect_cls} to remove this " + "warning; the old .dbapi() classmethod may be maintained for " + "backwards compatibility.", + "2.0", + ) + dbapi_meth = dialect_cls.dbapi + else: + dbapi_meth = dialect_cls.import_dbapi + + for k in util.get_func_kwargs(dbapi_meth): + if k in kwargs: + dbapi_args[k] = pop_kwarg(k) + dbapi = dbapi_meth(**dbapi_args) + + dialect_args["dbapi"] = dbapi + + dialect_args.setdefault("compiler_linting", compiler.NO_LINTING) + enable_from_linting = kwargs.pop("enable_from_linting", True) + if enable_from_linting: + dialect_args["compiler_linting"] ^= compiler.COLLECT_CARTESIAN_PRODUCTS + + for plugin in plugins: + plugin.handle_dialect_kwargs(dialect_cls, dialect_args) + + # create dialect + dialect = dialect_cls(**dialect_args) + + # assemble connection arguments + (cargs_tup, cparams) = dialect.create_connect_args(u) + cparams.update(pop_kwarg("connect_args", {})) + + if "async_fallback" in cparams and util.asbool(cparams["async_fallback"]): + util.warn_deprecated( + "The async_fallback dialect argument is deprecated and will be " + "removed in SQLAlchemy 2.1.", + "2.0", + ) + + cargs = list(cargs_tup) # allow mutability + + # look for existing pool or create + pool = pop_kwarg("pool", None) + if pool is None: + + def connect( + connection_record: Optional[ConnectionPoolEntry] = None, + ) -> DBAPIConnection: + if dialect._has_events: + for fn in dialect.dispatch.do_connect: + connection = cast( + DBAPIConnection, + fn(dialect, connection_record, cargs, cparams), + ) + if connection is not None: + return connection + + return dialect.connect(*cargs, **cparams) + + creator = pop_kwarg("creator", connect) + + poolclass = pop_kwarg("poolclass", None) + if poolclass is None: + poolclass = dialect.get_dialect_pool_class(u) + pool_args = {"dialect": dialect} + + # consume pool arguments from kwargs, translating a few of + # the arguments + for k in util.get_cls_kwargs(poolclass): + tk = _pool_translate_kwargs.get(k, k) + if tk in kwargs: + pool_args[k] = pop_kwarg(tk) + + for plugin in plugins: + plugin.handle_pool_kwargs(poolclass, pool_args) + + pool = poolclass(creator, **pool_args) + else: + pool._dialect = dialect + + if ( + hasattr(pool, "_is_asyncio") + and pool._is_asyncio is not dialect.is_async + ): + raise exc.ArgumentError( + f"Pool class {pool.__class__.__name__} cannot be " + f"used with {'non-' if not dialect.is_async else ''}" + "asyncio engine", + code="pcls", + ) + + # create engine. + if not pop_kwarg("future", True): + raise exc.ArgumentError( + "The 'future' parameter passed to " + "create_engine() may only be set to True." + ) + + engineclass = base.Engine + + engine_args = {} + for k in util.get_cls_kwargs(engineclass): + if k in kwargs: + engine_args[k] = pop_kwarg(k) + + # internal flags used by the test suite for instrumenting / proxying + # engines with mocks etc. + _initialize = kwargs.pop("_initialize", True) + + # all kwargs should be consumed + if kwargs: + raise TypeError( + "Invalid argument(s) %s sent to create_engine(), " + "using configuration %s/%s/%s. Please check that the " + "keyword arguments are appropriate for this combination " + "of components." + % ( + ",".join("'%s'" % k for k in kwargs), + dialect.__class__.__name__, + pool.__class__.__name__, + engineclass.__name__, + ) + ) + + engine = engineclass(pool, dialect, u, **engine_args) + + if _initialize: + do_on_connect = dialect.on_connect_url(u) + if do_on_connect: + + def on_connect( + dbapi_connection: DBAPIConnection, + connection_record: ConnectionPoolEntry, + ) -> None: + assert do_on_connect is not None + do_on_connect(dbapi_connection) + + event.listen(pool, "connect", on_connect) + + builtin_on_connect = dialect._builtin_onconnect() + if builtin_on_connect: + event.listen(pool, "connect", builtin_on_connect) + + def first_connect( + dbapi_connection: DBAPIConnection, + connection_record: ConnectionPoolEntry, + ) -> None: + c = base.Connection( + engine, + connection=_AdhocProxiedConnection( + dbapi_connection, connection_record + ), + _has_events=False, + # reconnecting will be a reentrant condition, so if the + # connection goes away, Connection is then closed + _allow_revalidate=False, + # dont trigger the autobegin sequence + # within the up front dialect checks + _allow_autobegin=False, + ) + c._execution_options = util.EMPTY_DICT + + try: + dialect.initialize(c) + finally: + # note that "invalidated" and "closed" are mutually + # exclusive in 1.4 Connection. + if not c.invalidated and not c.closed: + # transaction is rolled back otherwise, tested by + # test/dialect/postgresql/test_dialect.py + # ::MiscBackendTest::test_initial_transaction_state + dialect.do_rollback(c.connection) + + # previously, the "first_connect" event was used here, which was then + # scaled back if the "on_connect" handler were present. now, + # since "on_connect" is virtually always present, just use + # "connect" event with once_unless_exception in all cases so that + # the connection event flow is consistent in all cases. + event.listen( + pool, "connect", first_connect, _once_unless_exception=True + ) + + dialect_cls.engine_created(engine) + if entrypoint is not dialect_cls: + entrypoint.engine_created(engine) + + for plugin in plugins: + plugin.engine_created(engine) + + return engine + + +def engine_from_config( + configuration: Dict[str, Any], prefix: str = "sqlalchemy.", **kwargs: Any +) -> Engine: + """Create a new Engine instance using a configuration dictionary. + + The dictionary is typically produced from a config file. + + The keys of interest to ``engine_from_config()`` should be prefixed, e.g. + ``sqlalchemy.url``, ``sqlalchemy.echo``, etc. The 'prefix' argument + indicates the prefix to be searched for. Each matching key (after the + prefix is stripped) is treated as though it were the corresponding keyword + argument to a :func:`_sa.create_engine` call. + + The only required key is (assuming the default prefix) ``sqlalchemy.url``, + which provides the :ref:`database URL <database_urls>`. + + A select set of keyword arguments will be "coerced" to their + expected type based on string values. The set of arguments + is extensible per-dialect using the ``engine_config_types`` accessor. + + :param configuration: A dictionary (typically produced from a config file, + but this is not a requirement). Items whose keys start with the value + of 'prefix' will have that prefix stripped, and will then be passed to + :func:`_sa.create_engine`. + + :param prefix: Prefix to match and then strip from keys + in 'configuration'. + + :param kwargs: Each keyword argument to ``engine_from_config()`` itself + overrides the corresponding item taken from the 'configuration' + dictionary. Keyword arguments should *not* be prefixed. + + """ + + options = { + key[len(prefix) :]: configuration[key] + for key in configuration + if key.startswith(prefix) + } + options["_coerce_config"] = True + options.update(kwargs) + url = options.pop("url") + return create_engine(url, **options) + + +@overload +def create_pool_from_url( + url: Union[str, URL], + *, + poolclass: Optional[Type[Pool]] = ..., + logging_name: str = ..., + pre_ping: bool = ..., + size: int = ..., + recycle: int = ..., + reset_on_return: Optional[_ResetStyleArgType] = ..., + timeout: float = ..., + use_lifo: bool = ..., + **kwargs: Any, +) -> Pool: ... + + +@overload +def create_pool_from_url(url: Union[str, URL], **kwargs: Any) -> Pool: ... + + +def create_pool_from_url(url: Union[str, URL], **kwargs: Any) -> Pool: + """Create a pool instance from the given url. + + If ``poolclass`` is not provided the pool class used + is selected using the dialect specified in the URL. + + The arguments passed to :func:`_sa.create_pool_from_url` are + identical to the pool argument passed to the :func:`_sa.create_engine` + function. + + .. versionadded:: 2.0.10 + """ + + for key in _pool_translate_kwargs: + if key in kwargs: + kwargs[_pool_translate_kwargs[key]] = kwargs.pop(key) + + engine = create_engine(url, **kwargs, _initialize=False) + return engine.pool + + +_pool_translate_kwargs = immutabledict( + { + "logging_name": "pool_logging_name", + "echo": "echo_pool", + "timeout": "pool_timeout", + "recycle": "pool_recycle", + "events": "pool_events", # deprecated + "reset_on_return": "pool_reset_on_return", + "pre_ping": "pool_pre_ping", + "use_lifo": "pool_use_lifo", + } +) |