41 lines
1.3 KiB
Python
41 lines
1.3 KiB
Python
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import datetime, os
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from src import PollHook, utils
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EXPIRATION = 60 # 1 minute
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class LockFile(PollHook.PollHook):
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def __init__(self, database_location: str):
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self._database_location = database_location
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self._lock_location = "%s.lock" % database_location
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self._next_lock = None
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def available(self):
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now = utils.datetime_utcnow()
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if os.path.exists(self._lock_location):
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with open(self._lock_location, "r") as lock_file:
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timestamp_str = lock_file.read().strip().split(" ", 1)[0]
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timestamp = utils.iso8601_parse(timestamp_str)
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if (now-timestamp).total_seconds() < EXPIRATION:
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return False
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return True
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def lock(self):
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with open(self._lock_location, "w") as lock_file:
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last_lock = utils.datetime_utcnow()
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lock_file.write("%s" % utils.iso8601_format(last_lock))
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self._next_lock = last_lock+datetime.timedelta(
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seconds=EXPIRATION/2)
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def next(self):
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return max(0, (self._next_lock-utils.datetime_utcnow()).total_seconds())
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def call(self):
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if self.next() == 0:
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self.lock()
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def unlock(self):
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if os.path.isfile(self._lock_location):
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os.remove(self._lock_location)
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