49 lines
1.5 KiB
Python
49 lines
1.5 KiB
Python
# Code to implement asynchronous logging from a background thread
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#
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# Copyright (C) 2016 Kevin O'Connor <kevin@koconnor.net>
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#
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# This file may be distributed under the terms of the GNU GPLv3 license.
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import logging, threading, Queue
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# Class to forward all messages through a queue to a background thread
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class QueueHandler(logging.Handler):
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def __init__(self, queue):
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logging.Handler.__init__(self)
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self.queue = queue
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def emit(self, record):
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try:
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self.format(record)
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record.msg = record.message
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record.args = None
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record.exc_info = None
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self.queue.put_nowait(record)
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except Exception:
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self.handleError(record)
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# Class to poll a queue in a background thread and log each message
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class QueueListener(object):
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def __init__(self, handler):
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self.handler = handler
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self.queue = Queue.Queue()
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self.thread = threading.Thread(target=self._bg_thread)
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self.thread.start()
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def _bg_thread(self):
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while 1:
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record = self.queue.get(True)
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if record is None:
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break
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self.handler.handle(record)
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def stop(self):
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self.queue.put_nowait(None)
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self.thread.join()
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def setup_bg_logging(filename, debuglevel):
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logoutput = open(filename, 'wb')
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handler = logging.StreamHandler(logoutput)
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ql = QueueListener(handler)
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qh = QueueHandler(ql.queue)
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root = logging.getLogger()
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root.addHandler(qh)
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root.setLevel(debuglevel)
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return ql
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