#!/usr/bin/env python3

"""Munin plugin to monitor process group process count, memory, cpu and age.

=head1 NAME

process_group - monitor process group process count, memory, cpu and age

=head1 APPLICABLE SYSTEMS

Linux systems.

=head1 CONFIGURATION

List of monitored process groups must be configured as regexps. Example:

  [process_group]
  env.group1 php-fpm: pool
  env.group2 nginx

This will monitor two process groups: "php-fpm: pool" PHP application server
running any pool and "nginx" web server. Regexps must match "ps -eo command"
output.

=head1 AUTHOR

Kim B. Heino <b@bbbs.net>

=head1 LICENSE

GPLv2

=head1 MAGIC MARKERS

 #%# family=auto
 #%# capabilities=autoconf

=cut
"""

import os
import re
import subprocess
import sys
import unicodedata


def safename(name):
    """Return safe variable name."""
    # Convert ä->a as isalpha('ä') is true
    value = unicodedata.normalize('NFKD', name)
    value = value.encode('ASCII', 'ignore').decode('utf-8')

    # Remove non-alphanumeric chars
    return ''.join(char.lower() if char.isalnum() else '_' for char in value)


def run_binary(arg):
    """Run binary and return output."""
    try:
        return subprocess.run(arg, stdout=subprocess.PIPE, check=False,
                              encoding='utf-8', errors='ignore').stdout
    except FileNotFoundError:
        return ''


def parse_config():
    """Get groups from environment variables / munin plugin config."""
    groups = []
    counter = 1
    while True:
        group = os.getenv(f'group{counter}')
        if not group:
            break
        groups.append(group)
        counter += 1
    return groups


def parse_elapsed(text):
    """Parse ps's elapsed field to seconds.

    8-23:05:27   day, hour, min, sec
    21:16:53     hour, min, sec
    04:29        min, sec
    """
    days = hours = minutes = seconds = '0'
    if '-' in text:
        days, text = text.split('-', 1)
    if text.count(':') == 2:
        hours, text = text.split(':', 1)
    minutes, seconds = text.split(':')
    return (int(days) * 86400 +
            int(hours) * 3600 +
            int(minutes) * 60 +
            int(seconds))


def collect_data():
    """Run ps and parse its output."""
    groups = parse_config()
    values = {}
    for group in groups:
        values[group] = {
            'count': 0,
            'cpu': 0,
            'elapsed': 0,
            'rss': 0,
        }

    lines = run_binary(['ps', '-eo', '%cpu,etime,rss,command'])
    for line in lines.splitlines():
        cpu, elapsed, rss, command = line.split(None, 3)
        for group in groups:
            if re.search(group, command):
                values[group]['count'] += 1
                values[group]['cpu'] += float(cpu)
                values[group]['elapsed'] += parse_elapsed(elapsed)
                values[group]['rss'] += int(rss) * 1024
    return values


def config():
    """Print plugin config."""
    groups = parse_config()
    if not groups:
        return

    print('multigraph process_group_age')
    print('graph_title Process group average age')
    print('graph_category processes')
    print('graph_vlabel seconds')
    print('graph_args --base 1000')
    print('graph_scale no')
    for group in groups:
        print(f'{safename(group)}.label {group}')

    print('multigraph process_group_memory')
    print('graph_title Process group average memory')
    print('graph_category processes')
    print('graph_vlabel bytes')
    print('graph_args --base 1024')
    for group in groups:
        print(f'{safename(group)}.label {group}')

    print('multigraph process_group_cpu')
    print('graph_title Process group CPU usage')
    print('graph_category processes')
    print('graph_vlabel %')
    print('graph_args --base 1000')
    print('graph_scale no')
    for group in groups:
        print(f'{safename(group)}.label {group}')

    print('multigraph process_group_count')
    print('graph_title Process group process count')
    print('graph_category processes')
    print('graph_vlabel processes')
    print('graph_args --base 1000')
    print('graph_scale no')
    for group in groups:
        print(f'{safename(group)}.label {group}')

    if os.environ.get('MUNIN_CAP_DIRTYCONFIG') == '1':
        fetch()


def fetch():
    """Print values."""
    data = collect_data()
    if not data:
        return

    print('multigraph process_group_age')
    for group, values in data.items():
        if not values['count']:
            value = 0
        else:
            value = values['elapsed'] / values['count']
        print(f'{safename(group)}.value {value}')

    print('multigraph process_group_memory')
    for group, values in data.items():
        if not values['count']:
            value = 0
        else:
            value = values['rss'] / values['count']
        print(f'{safename(group)}.value {value}')

    print('multigraph process_group_cpu')
    for group, values in data.items():
        print(f'{safename(group)}.value {values["cpu"]}')

    print('multigraph process_group_count')
    for group, values in data.items():
        print(f'{safename(group)}.value {values["count"]}')


if __name__ == '__main__':
    if len(sys.argv) > 1 and sys.argv[1] == 'autoconf':
        print('yes' if parse_config() else 'no (no groups configured)')
    elif len(sys.argv) > 1 and sys.argv[1] == 'config':
        config()
    else:
        fetch()