119 lines
3.8 KiB
Python
119 lines
3.8 KiB
Python
#
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# Copyright 2013, Martin Owens <doctormo@gmail.com>
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#
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# This library is free software; you can redistribute it and/or
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# modify it under the terms of the GNU Lesser General Public
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# License as published by the Free Software Foundation; either
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# version 3.0 of the License, or (at your option) any later version.
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#
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# This library is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# Lesser General Public License for more details.
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#
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# You should have received a copy of the GNU Lesser General Public
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# License along with this library.
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#
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"""
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Access logs in known locations to find information about them.
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"""
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import os
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import re
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import codecs
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from datetime import datetime
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MATCHER = r'(?P<date>\w+ +\d+ +\d\d:\d\d:\d\d) (?P<host>\w+) ' + \
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r'CRON\[(?P<pid>\d+)\]: \((?P<user>\w+)\) CMD \((?P<cmd>.*)\)'
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class LogReader(object):
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"""Opens a Log file, reading backwards and watching for changes"""
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def __init__(self, filename, mass=4096):
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self.filename = filename
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self.mass = mass
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self.size = -1
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self.read = -1
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self.pipe = None
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def __enter__(self):
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self.size = os.stat(self.filename)[6]
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self.pipe = codecs.open(self.filename, 'r', encoding='utf-8')
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return self
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def __exit__(self, error_type, value, traceback):
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self.pipe.close()
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def __iter__(self):
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if self.pipe is None:
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with self as reader:
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for (offset, line) in reader.readlines():
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yield line
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else:
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for (offset, line) in self.readlines():
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yield line
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def readlines(self, until=0):
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"""Iterator for reading lines from a file backwards"""
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if not self.pipe or self.pipe.closed:
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raise IOError("Can't readline, no opened file.")
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# Always seek to the end of the file, this accounts for file updates
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# that happen during our running process.
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location = self.size
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halfline = ''
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while location > until:
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location -= self.mass
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mass = self.mass
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if location < 0:
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mass = self.mass + location
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location = 0
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self.pipe.seek(location)
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line = self.pipe.read(mass) + halfline
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data = line.split('\n')
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if location != 0:
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halfline = data.pop(0)
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loc = location + mass
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data.reverse()
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for line in data:
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if line.strip() == '':
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continue
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yield (loc, line)
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loc -= len(line)
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def cron_date_to_datetime(cron_str):
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with_year = f"{cron_str} {datetime.now().year}"
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return datetime.strptime(with_year, "%b %d %H:%M:%S %Y")
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class CronLog(LogReader):
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"""Use the LogReader to make a Cron specific log reader"""
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def __init__(self, filename='/var/log/syslog', user=None):
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LogReader.__init__(self, filename)
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self.user = user
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def for_program(self, command):
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"""Return log entries for this specific command name"""
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return ProgramLog(self, command)
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def __iter__(self):
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for line in super(CronLog, self).__iter__():
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match = re.match(MATCHER, str(line))
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datum = match and match.groupdict()
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if datum and (not self.user or datum['user'] == self.user):
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datum['date'] = cron_date_to_datetime(datum['date'])
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yield datum
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class ProgramLog(object):
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"""Specific log control for a single command/program"""
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def __init__(self, log, command):
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self.log = log
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self.command = command
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def __iter__(self):
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for entry in self.log:
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if entry['cmd'] == str(self.command):
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yield entry
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