pip install critbot

import critbot.plugins.syslog
import critbot.plugins.slack
import critbot.plugins.email
from critbot import crit_defaults
import logging

crit_defaults.subject = 'MyService host:port CRIT'

crit_defaults.plugins = [
    critbot.plugins.syslog.plugin(),
    critbot.plugins.slack.plugin(
        token='Get it from https://my.slack.com/services/new/bot',
        channel='#general', # '@private' or '#channel'
        users='', # '@user1 @user2 @userN'
    ),
    critbot.plugins.email.plugin(
        to='Name1 <[email protected]>, Name2 <[email protected]>',
        user='[email protected]', # Add more config if not GMail.
        password='pa$$word',
    ),
]

crit_defaults.crit_in_crit = logging.getLogger('critbot').critical

from my_project import config
from critbot import crit

try:
    1/0
except Exception:
    crit()
    # More processing if needed.

try:
    1/0
except Exception:
    crit(also='test2')

if True:
    crit('test3')

[eventlistener:critvisor]
command=critvisor /path/to/config.py
events=PROCESS_LOG_STDERR,PROCESS_STATE_EXITED,PROCESS_STATE_FATAL

[program:my_program]
stderr_events_enabled=true

Optional "crit_defaults.skip_stderrs" list allows to avoid some "safe" crits.
Optional "crit_defaults.max_stderr_crit_length" allows to save e.g. Slack from being broken.

stdcrit /path/to/config.py /path/to/script.py arg...

crit_defaults.stop_spam_file.enabled = True
# "crit_defaults.stop_spam_file.path" defaults to "/run/lock/critbot" - RAM, no disk IO.

apt-get install libmemcached-dev zlib1g-dev
pip install pylibmc
crit_defaults.mc.enabled = True

And either "apt-get install memcached"
or update "crit_defaults.mc.servers" list.