Source code for

# ported from:
import asyncio

import aiomysql
from .connection import SAConnection
from .exc import InvalidRequestError, ArgumentError
from ..utils import _PoolContextManager, _PoolAcquireContextManager
from ..cursors import (
    Cursor, DeserializationCursor, DictCursor, SSCursor, SSDictCursor)

    from sqlalchemy.dialects.mysql.pymysql import MySQLDialect_pymysql
    from sqlalchemy.dialects.mysql.mysqldb import MySQLCompiler_mysqldb
except ImportError:  # pragma: no cover
    raise ImportError(' requires sqlalchemy')

class MySQLCompiler_pymysql(MySQLCompiler_mysqldb):
    def construct_params(self, params=None, _group_number=None, _check=True):
        pd = super().construct_params(params, _group_number, _check)

        for column in self.prefetch:
            pd[column.key] = self._exec_default(column.default)

        return pd

    def _exec_default(self, default):
        if default.is_callable:
            return default.arg(self.dialect)
            return default.arg

_dialect = MySQLDialect_pymysql(paramstyle='pyformat')
_dialect.statement_compiler = MySQLCompiler_pymysql
_dialect.default_paramstyle = 'pyformat'

[docs]def create_engine(minsize=1, maxsize=10, loop=None, dialect=_dialect, pool_recycle=-1, compiled_cache=None, **kwargs): """A coroutine for Engine creation. Returns Engine instance with embedded connection pool. The pool has *minsize* opened connections to MySQL server. """ deprecated_cursor_classes = [ DeserializationCursor, DictCursor, SSCursor, SSDictCursor, ] cursorclass = kwargs.get('cursorclass', Cursor) if not issubclass(cursorclass, Cursor) or any( issubclass(cursorclass, cursor_class) for cursor_class in deprecated_cursor_classes ): raise ArgumentError('SQLAlchemy engine does not support ' 'this cursor class') coro = _create_engine(minsize=minsize, maxsize=maxsize, loop=loop, dialect=dialect, pool_recycle=pool_recycle, compiled_cache=compiled_cache, **kwargs) return _EngineContextManager(coro)
async def _create_engine(minsize=1, maxsize=10, loop=None, dialect=_dialect, pool_recycle=-1, compiled_cache=None, **kwargs): if loop is None: loop = asyncio.get_event_loop() pool = await aiomysql.create_pool(minsize=minsize, maxsize=maxsize, loop=loop, pool_recycle=pool_recycle, **kwargs) conn = await pool.acquire() try: return Engine(dialect, pool, compiled_cache=compiled_cache, **kwargs) finally: pool.release(conn)
[docs]class Engine: """Connects a aiomysql.Pool and sqlalchemy.engine.interfaces.Dialect together to provide a source of database connectivity and behavior. An Engine object is instantiated publicly using the create_engine coroutine. """ def __init__(self, dialect, pool, compiled_cache=None, **kwargs): self._dialect = dialect self._pool = pool self._compiled_cache = compiled_cache self._conn_kw = kwargs @property def dialect(self): """An dialect for engine.""" return self._dialect @property def name(self): """A name of the dialect.""" return @property def driver(self): """A driver of the dialect.""" return self._dialect.driver @property def minsize(self): return self._pool.minsize @property def maxsize(self): return self._pool.maxsize @property def size(self): return self._pool.size @property def freesize(self): return self._pool.freesize
[docs] def close(self): """Close engine. Mark all engine connections to be closed on getting back to pool. Closed engine doesn't allow to acquire new connections. """ self._pool.close()
[docs] def terminate(self): """Terminate engine. Terminate engine pool with instantly closing all acquired connections also. """ self._pool.terminate()
[docs] async def wait_closed(self): """Wait for closing all engine's connections.""" await self._pool.wait_closed()
[docs] def acquire(self): """Get a connection from pool.""" coro = self._acquire() return _EngineAcquireContextManager(coro, self)
async def _acquire(self): raw = await self._pool.acquire() conn = SAConnection(raw, self, compiled_cache=self._compiled_cache) return conn
[docs] def release(self, conn): """Revert back connection to pool.""" if conn.in_transaction: raise InvalidRequestError("Cannot release a connection with " "not finished transaction") raw = conn.connection return self._pool.release(raw)
def __enter__(self): raise RuntimeError( '"yield from" should be used as context manager expression') def __exit__(self, *args): # This must exist because __enter__ exists, even though that # always raises; that's how the with-statement works. pass # pragma: nocover def __iter__(self): # This is not a coroutine. It is meant to enable the idiom: # # with (yield from engine) as conn: # <block> # # as an alternative to: # # conn = yield from engine.acquire() # try: # <block> # finally: # engine.release(conn) conn = yield from self.acquire() return _ConnectionContextManager(self, conn) async def __aenter__(self): return self async def __aexit__(self, exc_type, exc_val, exc_tb): self.close() await self.wait_closed()
_EngineContextManager = _PoolContextManager _EngineAcquireContextManager = _PoolAcquireContextManager class _ConnectionContextManager: """Context manager. This enables the following idiom for acquiring and releasing a connection around a block: with (yield from engine) as conn: cur = yield from conn.cursor() while failing loudly when accidentally using: with engine: <block> """ __slots__ = ('_engine', '_conn') def __init__(self, engine, conn): self._engine = engine self._conn = conn def __enter__(self): assert self._conn is not None return self._conn def __exit__(self, *args): try: self._engine.release(self._conn) finally: self._engine = None self._conn = None