271 lines
8.2 KiB
Python
271 lines
8.2 KiB
Python
# based on aiopg pool
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# https://github.com/aio-libs/aiopg/blob/master/aiopg/pool.py
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import asyncio
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import collections
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import warnings
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from .connection import connect
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from .utils import (_PoolContextManager, _PoolConnectionContextManager,
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_PoolAcquireContextManager)
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def create_pool(minsize=1, maxsize=10, echo=False, pool_recycle=-1,
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loop=None, **kwargs):
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coro = _create_pool(minsize=minsize, maxsize=maxsize, echo=echo,
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pool_recycle=pool_recycle, loop=loop, **kwargs)
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return _PoolContextManager(coro)
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async def _create_pool(minsize=1, maxsize=10, echo=False, pool_recycle=-1,
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loop=None, **kwargs):
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if loop is None:
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loop = asyncio.get_event_loop()
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pool = Pool(minsize=minsize, maxsize=maxsize, echo=echo,
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pool_recycle=pool_recycle, loop=loop, **kwargs)
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if minsize > 0:
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async with pool._cond:
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await pool._fill_free_pool(False)
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return pool
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class Pool(asyncio.AbstractServer):
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"""Connection pool"""
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def __init__(self, minsize, maxsize, echo, pool_recycle, loop, **kwargs):
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if minsize < 0:
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raise ValueError("minsize should be zero or greater")
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if maxsize < minsize and maxsize != 0:
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raise ValueError("maxsize should be not less than minsize")
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self._minsize = minsize
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self._loop = loop
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self._conn_kwargs = kwargs
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self._acquiring = 0
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self._free = collections.deque(maxlen=maxsize or None)
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self._cond = asyncio.Condition()
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self._used = set()
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self._terminated = set()
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self._closing = False
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self._closed = False
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self._echo = echo
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self._recycle = pool_recycle
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@property
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def echo(self):
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return self._echo
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@property
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def minsize(self):
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return self._minsize
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@property
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def maxsize(self):
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return self._free.maxlen
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@property
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def size(self):
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return self.freesize + len(self._used) + self._acquiring
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@property
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def freesize(self):
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return len(self._free)
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async def clear(self):
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"""Close all free connections in pool."""
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async with self._cond:
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while self._free:
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conn = self._free.popleft()
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await conn.ensure_closed()
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self._cond.notify()
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@property
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def closed(self):
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"""
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The readonly property that returns ``True`` if connections is closed.
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"""
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return self._closed
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def close(self):
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"""Close pool.
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Mark all pool connections to be closed on getting back to pool.
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Closed pool doesn't allow to acquire new connections.
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"""
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if self._closed:
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return
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self._closing = True
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def terminate(self):
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"""Terminate pool.
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Close pool with instantly closing all acquired connections also.
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"""
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self.close()
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for conn in list(self._used):
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conn.close()
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self._terminated.add(conn)
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self._used.clear()
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async def wait_closed(self):
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"""Wait for closing all pool's connections."""
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if self._closed:
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return
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if not self._closing:
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raise RuntimeError(".wait_closed() should be called "
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"after .close()")
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while self._free:
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conn = self._free.popleft()
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conn.close()
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async with self._cond:
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while self.size > self.freesize:
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await self._cond.wait()
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self._closed = True
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def acquire(self):
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"""Acquire free connection from the pool."""
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coro = self._acquire()
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return _PoolAcquireContextManager(coro, self)
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async def _acquire(self):
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if self._closing:
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raise RuntimeError("Cannot acquire connection after closing pool")
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async with self._cond:
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while True:
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await self._fill_free_pool(True)
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if self._free:
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conn = self._free.popleft()
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assert not conn.closed, conn
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assert conn not in self._used, (conn, self._used)
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self._used.add(conn)
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return conn
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else:
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await self._cond.wait()
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async def _fill_free_pool(self, override_min):
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# iterate over free connections and remove timed out ones
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free_size = len(self._free)
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n = 0
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while n < free_size:
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conn = self._free[-1]
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if conn._reader.at_eof() or conn._reader.exception():
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self._free.pop()
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conn.close()
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# On MySQL 8.0 a timed out connection sends an error packet before
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# closing the connection, preventing us from relying on at_eof().
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# This relies on our custom StreamReader, as eof_received is not
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# present in asyncio.StreamReader.
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elif conn._reader.eof_received:
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self._free.pop()
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conn.close()
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elif (self._recycle > -1 and
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self._loop.time() - conn.last_usage > self._recycle):
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self._free.pop()
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conn.close()
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else:
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self._free.rotate()
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n += 1
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while self.size < self.minsize:
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self._acquiring += 1
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try:
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conn = await connect(echo=self._echo, loop=self._loop,
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**self._conn_kwargs)
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# raise exception if pool is closing
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self._free.append(conn)
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self._cond.notify()
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finally:
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self._acquiring -= 1
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if self._free:
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return
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if override_min and (not self.maxsize or self.size < self.maxsize):
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self._acquiring += 1
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try:
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conn = await connect(echo=self._echo, loop=self._loop,
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**self._conn_kwargs)
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# raise exception if pool is closing
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self._free.append(conn)
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self._cond.notify()
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finally:
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self._acquiring -= 1
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async def _wakeup(self):
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async with self._cond:
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self._cond.notify()
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def release(self, conn):
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"""Release free connection back to the connection pool.
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This is **NOT** a coroutine.
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"""
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fut = self._loop.create_future()
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fut.set_result(None)
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if conn in self._terminated:
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assert conn.closed, conn
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self._terminated.remove(conn)
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return fut
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assert conn in self._used, (conn, self._used)
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self._used.remove(conn)
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if not conn.closed:
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in_trans = conn.get_transaction_status()
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if in_trans:
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conn.close()
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return fut
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if self._closing:
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conn.close()
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else:
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self._free.append(conn)
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fut = self._loop.create_task(self._wakeup())
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return fut
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def __enter__(self):
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raise RuntimeError(
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'"yield from" should be used as context manager expression')
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def __exit__(self, *args):
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# This must exist because __enter__ exists, even though that
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# always raises; that's how the with-statement works.
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pass # pragma: nocover
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def __iter__(self):
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# This is not a coroutine. It is meant to enable the idiom:
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#
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# with (yield from pool) as conn:
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# <block>
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#
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# as an alternative to:
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#
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# conn = yield from pool.acquire()
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# try:
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# <block>
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# finally:
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# conn.release()
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conn = yield from self.acquire()
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return _PoolConnectionContextManager(self, conn)
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def __await__(self):
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msg = "with await pool as conn deprecated, use" \
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"async with pool.acquire() as conn instead"
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warnings.warn(msg, DeprecationWarning, stacklevel=2)
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conn = yield from self.acquire()
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return _PoolConnectionContextManager(self, conn)
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async def __aenter__(self):
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return self
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async def __aexit__(self, exc_type, exc_val, exc_tb):
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self.close()
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await self.wait_closed()
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