53 lines
1.3 KiB
Python
53 lines
1.3 KiB
Python
# Test that locks work when cancelling multiple waiters on the lock
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try:
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import asyncio
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except ImportError:
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print("SKIP")
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raise SystemExit
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async def task(i, lock, lock_flag):
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print("task", i, "start")
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try:
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await lock.acquire()
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except asyncio.CancelledError:
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print("task", i, "cancel")
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return
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print("task", i, "lock_flag", lock_flag[0])
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lock_flag[0] = True
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await asyncio.sleep(0)
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lock.release()
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lock_flag[0] = False
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print("task", i, "done")
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async def main():
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# Create a lock and acquire it so the tasks below must wait
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lock = asyncio.Lock()
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await lock.acquire()
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lock_flag = [True]
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# Create 4 tasks and let them all run
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t0 = asyncio.create_task(task(0, lock, lock_flag))
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t1 = asyncio.create_task(task(1, lock, lock_flag))
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t2 = asyncio.create_task(task(2, lock, lock_flag))
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t3 = asyncio.create_task(task(3, lock, lock_flag))
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await asyncio.sleep(0)
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# Cancel 2 of the tasks (which are waiting on the lock) and release the lock
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t1.cancel()
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t2.cancel()
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lock.release()
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lock_flag[0] = False
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# Let the tasks run to completion
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for _ in range(4):
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await asyncio.sleep(0)
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# The locke should be unlocked
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print(lock.locked())
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asyncio.run(main())
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