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# Copyright 2015, 2016 OpenMarket Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from typing import Any, Mapping, NoReturn
from ._base import BaseDatabaseEngine, IncorrectDatabaseSetup
# The classes `PostgresEngine` and `Sqlite3Engine` must always be importable, because
# we use `isinstance(engine, PostgresEngine)` to write different queries for postgres
# and sqlite. But the database driver modules are both optional: they may not be
# installed. To account for this, create dummy classes on import failure so we can
# still run `isinstance()` checks.
try:
from .postgres import PostgresEngine
except ImportError:
class PostgresEngine(BaseDatabaseEngine): # type: ignore[no-redef]
def __new__(cls, *args: object, **kwargs: object) -> NoReturn:
raise RuntimeError(
f"Cannot create {cls.__name__} -- psycopg2 module is not installed"
)
try:
from .sqlite import Sqlite3Engine
except ImportError:
class Sqlite3Engine(BaseDatabaseEngine): # type: ignore[no-redef]
def __new__(cls, *args: object, **kwargs: object) -> NoReturn:
raise RuntimeError(
f"Cannot create {cls.__name__} -- sqlite3 module is not installed"
)
def create_engine(database_config: Mapping[str, Any]) -> BaseDatabaseEngine:
name = database_config["name"]
if name == "sqlite3":
return Sqlite3Engine(database_config)
if name == "psycopg2":
return PostgresEngine(database_config)
raise RuntimeError("Unsupported database engine '%s'" % (name,))
__all__ = [
"create_engine",
"BaseDatabaseEngine",
"PostgresEngine",
"Sqlite3Engine",
"IncorrectDatabaseSetup",
]
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