Read specific multipath events from systemd-udevd.service via systemd-journal

read-udev-multipath-events.py

#!/usr/bin/env python3
#
# use with:
# udevadm control --log-level=debug
#
# example output:
#
#    ACTIVE: 0, STARTED: 142, SUCCEEDED: 142, BURSTS: 0, LONGEST: 0.366994 secs (device: dm-18, start: 11:22:09.099568, end: 11:22:09.466562)
#    Burst detected. Resetting.

import select
from systemd import journal
import datetime

j = journal.Reader()
j.add_match(_SYSTEMD_UNIT="systemd-udevd.service")
j.add_match(_SYSTEMD_UNIT="multipathd.service")
j.seek_tail()
j.get_previous()
j.get_next()

p = select.poll()
p.register(j, j.get_events())

active_multipaths = {}
succeeded_but_not_in_list = []
counter_starting = 0
counter_succeeded = 0
max_start = None
max_end = None
max_duration = 0
max_dev = 'none'
counter_bursts = 0

while p.poll():
    if j.process() != journal.APPEND:
        continue

    for entry in j:
        # print(str(entry['__REALTIME_TIMESTAMP'] )+ ' ' + entry['MESSAGE'])
        # print(entry)

        if '/sbin/multipath -U' in entry['MESSAGE']:
            if 'Starting' in entry['MESSAGE']: # or 'Running' in entry['MESSAGE']:
                active_multipaths[entry['DEVICE']] = entry['_SOURCE_REALTIME_TIMESTAMP']
                counter_starting = counter_starting + 1

            if 'succeeded' in entry['MESSAGE']:
                try:
                    diff = (entry['_SOURCE_REALTIME_TIMESTAMP'] - active_multipaths[entry['DEVICE']]).total_seconds()
                    if diff > max_duration:
                        max_start = active_multipaths[entry['DEVICE']]
                        max_end = entry['_SOURCE_REALTIME_TIMESTAMP']
                        max_duration = diff
                        max_dev = entry['DEVICE']
                    del(active_multipaths[entry['DEVICE']])
                except (KeyError, ValueError):
                    succeeded_but_not_in_list.append(entry['DEVICE'])
                counter_succeeded = counter_succeeded + 1

        if 'burst' in entry['MESSAGE']:
            counter_bursts = counter_bursts + 1
            print('\r\nBurst detected. Resetting.')
            active_multipaths = {}
            succeeded_but_not_in_list = []
            counter_starting = 0
            counter_succeeded = 0
            max_start = None
            max_end = None
            max_duration = 0
            max_dev = 'none'
            continue

        current_str = ' '.join(active_multipaths)
        current_str = (current_str[:30] + '...') if len(current_str) > 30 else current_str

        output_str = "ACTIVE: " + str(len(active_multipaths))

        if counter_bursts < 1:
            output_str+= ', STARTED: ' + str(counter_starting) + ', SUCCEEDED: ' + str(counter_succeeded)

        output_str+= ', BURSTS: ' + str(counter_bursts)
        output_str+= ', LONGEST: ' + str(max_duration) + ' secs (device: ' + max_dev

        if max_duration > 0:
            output_str+= ', start: ' + max_start.strftime("%H:%M:%S.%f")
            output_str+= ', end: ' + max_end.strftime("%H:%M:%S.%f")

        output_str+= ')'

        if current_str:
            output_str+= ' (current: ' + current_str + ')'

        print(end='\x1b[2K')
        print(output_str, end='\r')