Read write lock for asyncio.
Read write lock for asyncio . A RWLock maintains a pair of associated locks, one for read-only operations and one for writing. The read lock may be held simultaneously by multiple reader tasks, so long as there are no writers. The write lock is exclusive.
Whether or not a read-write lock will improve performance over the use of a mutual exclusion lock depends on the frequency that the data is read compared to being modified. For example, a collection that is initially populated with data and thereafter infrequently modified, while being frequently searched is an ideal candidate for the use of a read-write lock. However, if updates become frequent then the data spends most of its time being exclusively locked and there is little, if any increase in concurrency.
Implementation is almost direct port from this patch.
Example with async def
Requires Python 3.5+
import asyncio import aiorwlock loop = asyncio.get_event_loop() async def go(): rwlock = aiorwlock.RWLock(loop=loop) async with rwlock.writer: # or same way you can acquire reader lock # async with rwlock.reader: pass print("inside writer") await asyncio.sleep(0.1, loop=loop) loop.run_until_complete(go())
Requires Python 3.3+
import asyncio import aiorwlock loop = asyncio.get_event_loop() @asyncio.coroutine def go(): rwlock = aiorwlock.RWLock(loop=loop) with (yield from rwlock.writer): # or same way you can acquire reader lock # with (yield from rwlock.reader): pass print("inside writer") yield from asyncio.sleep(0.1, loop=loop) loop.run_until_complete(go())
RWLock switches context on lock acquiring. That allows to
other waiting tasks get the lock even if task that holds the lock
doesn’t contain context switches (
await fut statements).
The default behavior can be switched off by
Long story short: lock is safe by default, but if you sure you have
context switches (
async for or
statements) inside locked code you may want to use
aiorwlock is offered under the Apache 2 license.
- Fix corner cases and deadlock when we upgrade lock from write to read #39
- Use loop.create_future instead asyncio.Future if possible
- Support Python 3.5 and
.writer. Backward compatibility is preserved.
- Initial release
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|aiorwlock-0.5.0-py3-none-any.whl (7.3 kB) Copy SHA256 Checksum SHA256||py3||Wheel||Dec 3, 2017|
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