examine-syslog

#!/usr/bin/env python3

# Copyright 2019 Joseph Lorimer <joseph@lorimer.me>
#
# Permission to use, copy, modify, and distribute this software for any purpose
# with or without fee is hereby granted, provided that the above copyright
# notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
# REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
# AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
# INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
# LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
# OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
# PERFORMANCE OF THIS SOFTWARE.

from collections import defaultdict
from operator import itemgetter
from re import compile, split, sub
from statistics import mean
from subprocess import check_output

from dateparser import parse
from tabulate import tabulate

LOG_PATH = '/var/log/messages'
FIRST_LINE = 'syslogd: kernel boot file is /boot/kernel/kernel'


def get_hostname():
    return (
        check_output(['sysctl', 'kern.hostname'])
        .decode('utf-8')
        .split(':')[1]
        .strip()
    )


def get_times(hostname, exclude=[]):
    regex = compile('({})'.format('|'.join(exclude)))
    times = defaultdict(list)
    with open(LOG_PATH, encoding='utf-8') as log:
        prev = None
        for line in log:
            if line.count(hostname) != 1:
                continue
            timestamp, desc = split(hostname, line)
            desc = sub(r'\[[0-9]+\]', '', desc.strip())
            if line.find(FIRST_LINE) != -1 or regex.match(desc):
                prev = None
                continue
            if prev:
                prev_timestamp, prev_desc = prev
                seconds = int(
                    (parse(timestamp) - prev_timestamp).total_seconds()
                )
                times[desc].append(seconds)
            prev = (parse(timestamp), desc)
    return times


def show(times, max_width=79):
    data = []
    for desc in times:
        seconds = int(mean(times[desc]))
        if seconds > 1:
            data.append((seconds, desc[:max_width]))
        data.sort(key=itemgetter(0), reverse=True)
    print(tabulate(data, tablefmt='fancy_grid'))


if __name__ == '__main__':
    show(get_times(get_hostname(), ['pkg']))