183 lines
5.8 KiB
Python
183 lines
5.8 KiB
Python
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"""pyzmq logging handlers.
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This mainly defines the PUBHandler object for publishing logging messages over
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a zmq.PUB socket.
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The PUBHandler can be used with the regular logging module, as in::
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>>> import logging
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>>> handler = PUBHandler('tcp://127.0.0.1:12345')
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>>> handler.root_topic = 'foo'
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>>> logger = logging.getLogger('foobar')
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>>> logger.setLevel(logging.DEBUG)
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>>> logger.addHandler(handler)
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After this point, all messages logged by ``logger`` will be published on the
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PUB socket.
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Code adapted from StarCluster:
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http://github.com/jtriley/StarCluster/blob/master/starcluster/logger.py
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"""
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# Copyright (C) PyZMQ Developers
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# Distributed under the terms of the Modified BSD License.
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import logging
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from logging import INFO, DEBUG, WARN, ERROR, FATAL
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import zmq
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from zmq.utils.strtypes import bytes, unicode, cast_bytes
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TOPIC_DELIM="::" # delimiter for splitting topics on the receiving end.
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class PUBHandler(logging.Handler):
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"""A basic logging handler that emits log messages through a PUB socket.
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Takes a PUB socket already bound to interfaces or an interface to bind to.
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Example::
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sock = context.socket(zmq.PUB)
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sock.bind('inproc://log')
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handler = PUBHandler(sock)
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Or::
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handler = PUBHandler('inproc://loc')
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These are equivalent.
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Log messages handled by this handler are broadcast with ZMQ topics
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``this.root_topic`` comes first, followed by the log level
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(DEBUG,INFO,etc.), followed by any additional subtopics specified in the
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message by: log.debug("subtopic.subsub::the real message")
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"""
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socket = None
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def __init__(self, interface_or_socket, context=None, root_topic=''):
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logging.Handler.__init__(self)
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self._root_topic = root_topic
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self.formatters = {
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logging.DEBUG: logging.Formatter(
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"%(levelname)s %(filename)s:%(lineno)d - %(message)s\n"),
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logging.INFO: logging.Formatter("%(message)s\n"),
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logging.WARN: logging.Formatter(
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"%(levelname)s %(filename)s:%(lineno)d - %(message)s\n"),
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logging.ERROR: logging.Formatter(
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"%(levelname)s %(filename)s:%(lineno)d - %(message)s - %(exc_info)s\n"),
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logging.CRITICAL: logging.Formatter(
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"%(levelname)s %(filename)s:%(lineno)d - %(message)s\n")}
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if isinstance(interface_or_socket, zmq.Socket):
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self.socket = interface_or_socket
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self.ctx = self.socket.context
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else:
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self.ctx = context or zmq.Context()
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self.socket = self.ctx.socket(zmq.PUB)
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self.socket.bind(interface_or_socket)
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@property
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def root_topic(self):
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return self._root_topic
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@root_topic.setter
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def root_topic(self, value):
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self.setRootTopic(value)
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def setRootTopic(self, root_topic):
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"""Set the root topic for this handler.
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This value is prepended to all messages published by this handler, and it
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defaults to the empty string ''. When you subscribe to this socket, you must
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set your subscription to an empty string, or to at least the first letter of
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the binary representation of this string to ensure you receive any messages
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from this handler.
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If you use the default empty string root topic, messages will begin with
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the binary representation of the log level string (INFO, WARN, etc.).
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Note that ZMQ SUB sockets can have multiple subscriptions.
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"""
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self._root_topic = root_topic
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def setFormatter(self, fmt, level=logging.NOTSET):
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"""Set the Formatter for this handler.
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If no level is provided, the same format is used for all levels. This
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will overwrite all selective formatters set in the object constructor.
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"""
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if level==logging.NOTSET:
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for fmt_level in self.formatters.keys():
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self.formatters[fmt_level] = fmt
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else:
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self.formatters[level] = fmt
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def format(self,record):
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"""Format a record."""
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return self.formatters[record.levelno].format(record)
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def emit(self, record):
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"""Emit a log message on my socket."""
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try:
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topic, record.msg = record.msg.split(TOPIC_DELIM,1)
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except Exception:
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topic = ""
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try:
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bmsg = cast_bytes(self.format(record))
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except Exception:
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self.handleError(record)
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return
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topic_list = []
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if self.root_topic:
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topic_list.append(self.root_topic)
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topic_list.append(record.levelname)
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if topic:
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topic_list.append(topic)
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btopic = b'.'.join(cast_bytes(t) for t in topic_list)
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self.socket.send_multipart([btopic, bmsg])
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class TopicLogger(logging.Logger):
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"""A simple wrapper that takes an additional argument to log methods.
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All the regular methods exist, but instead of one msg argument, two
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arguments: topic, msg are passed.
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That is::
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logger.debug('msg')
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Would become::
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logger.debug('topic.sub', 'msg')
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"""
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def log(self, level, topic, msg, *args, **kwargs):
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"""Log 'msg % args' with level and topic.
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To pass exception information, use the keyword argument exc_info
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with a True value::
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logger.log(level, "zmq.fun", "We have a %s",
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"mysterious problem", exc_info=1)
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"""
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logging.Logger.log(self, level, '%s::%s'%(topic,msg), *args, **kwargs)
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# Generate the methods of TopicLogger, since they are just adding a
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# topic prefix to a message.
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for name in "debug warn warning error critical fatal".split():
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meth = getattr(logging.Logger,name)
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setattr(TopicLogger, name,
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lambda self, level, topic, msg, *args, **kwargs:
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meth(self, level, topic+TOPIC_DELIM+msg,*args, **kwargs))
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