60 lines
1.4 KiB
Python
60 lines
1.4 KiB
Python
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# -*- test-case-name: twisted.logger.test.test_buffer -*-
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# Copyright (c) Twisted Matrix Laboratories.
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# See LICENSE for details.
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"""
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Log observer that maintains a buffer.
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"""
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from collections import deque
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from zope.interface import implementer
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from ._observer import ILogObserver
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_DEFAULT_BUFFER_MAXIMUM = 64 * 1024
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@implementer(ILogObserver)
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class LimitedHistoryLogObserver(object):
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"""
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L{ILogObserver} that stores events in a buffer of a fixed size::
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>>> from twisted.logger import LimitedHistoryLogObserver
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>>> history = LimitedHistoryLogObserver(5)
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>>> for n in range(10): history({'n': n})
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...
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>>> repeats = []
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>>> history.replayTo(repeats.append)
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>>> len(repeats)
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5
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>>> repeats
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[{'n': 5}, {'n': 6}, {'n': 7}, {'n': 8}, {'n': 9}]
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>>>
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"""
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def __init__(self, size=_DEFAULT_BUFFER_MAXIMUM):
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"""
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@param size: The maximum number of events to buffer. If L{None}, the
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buffer is unbounded.
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@type size: L{int}
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"""
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self._buffer = deque(maxlen=size)
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def __call__(self, event):
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self._buffer.append(event)
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def replayTo(self, otherObserver):
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"""
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Re-play the buffered events to another log observer.
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@param otherObserver: An observer to replay events to.
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@type otherObserver: L{ILogObserver}
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"""
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for event in self._buffer:
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otherObserver(event)
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