76 lines
2.6 KiB
Python
76 lines
2.6 KiB
Python
# Code to implement asynchronous logging from a background thread
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#
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# Copyright (C) 2016-2019 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, logging.handlers, threading, queue, time
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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(logging.handlers.TimedRotatingFileHandler):
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def __init__(self, filename):
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logging.handlers.TimedRotatingFileHandler.__init__(
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self, filename, when='midnight', backupCount=5)
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self.bg_queue = queue.Queue()
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self.bg_thread = threading.Thread(target=self._bg_thread)
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self.bg_thread.start()
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self.rollover_info = {}
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def _bg_thread(self):
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while 1:
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record = self.bg_queue.get(True)
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if record is None:
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break
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self.handle(record)
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def stop(self):
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self.bg_queue.put_nowait(None)
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self.bg_thread.join()
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def set_rollover_info(self, name, info):
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if info is None:
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self.rollover_info.pop(name, None)
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return
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self.rollover_info[name] = info
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def clear_rollover_info(self):
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self.rollover_info.clear()
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def doRollover(self):
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logging.handlers.TimedRotatingFileHandler.doRollover(self)
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lines = [self.rollover_info[name]
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for name in sorted(self.rollover_info)]
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lines.append(
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"=============== Log rollover at %s ===============" % (
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time.asctime(),))
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self.emit(logging.makeLogRecord(
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{'msg': "\n".join(lines), 'level': logging.INFO}))
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MainQueueHandler = None
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def setup_bg_logging(filename, debuglevel):
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global MainQueueHandler
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ql = QueueListener(filename)
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MainQueueHandler = QueueHandler(ql.bg_queue)
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root = logging.getLogger()
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root.addHandler(MainQueueHandler)
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root.setLevel(debuglevel)
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return ql
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def clear_bg_logging():
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global MainQueueHandler
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if MainQueueHandler is not None:
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root = logging.getLogger()
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root.removeHandler(MainQueueHandler)
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root.setLevel(logging.WARNING)
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MainQueueHandler = None
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