#!/usr/bin/env python3

"""Munin plugin to monitor NGINX Unit applications.

=head1 NAME

nginx_unit - monitor NGINX Unit applications

=head1 APPLICABLE SYSTEMS

Systems with NGINX Unit running. See https://unit.nginx.org/ for more
information.

=head1 CONFIGURATION

No configuration is required for this plugin.

=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_time(value):
    """Parse "dd-hh:mm:ss", "hh:mm:ss" and "mm:ss" to seconds."""
    days = hours = '0'
    if '-' in value:
        days, value = value.split('-', 1)
    if value.count(':') == 2:
        hours, value = value.split(':', 1)
    minutes, seconds = value.split(':')
    return (int(days) * 86400 + int(hours) * 3600 + int(minutes) * 60 +
            int(seconds))


def find_apps():
    """Return dict of found applications."""
    apps = {}
    ps_lines = run_binary(['ps', '-eo', '%cpu,etime,rss,command']).splitlines()
    for line in ps_lines:
        appmatch = re.match(r' *([.0-9]+) +([-:0-9]+) +([0-9]+) '
                            r'unit: "(.*)" application', line)
        if not appmatch:
            continue
        cpu = float(appmatch.group(1))
        age = parse_time(appmatch.group(2))
        memory = int(appmatch.group(3)) * 1024
        appname = appmatch.group(4)
        if appname in apps:
            apps[appname]['count'] += 1
            apps[appname]['cpu'] += cpu
            apps[appname]['age'] += age
            apps[appname]['memory'] += memory
        else:
            apps[appname] = {
                'count': 1,
                'cpu': cpu,
                'age': age,
                'memory': memory,
            }
    return apps


def config(apps):
    """Print plugin config."""
    print('multigraph nginx_unit_process')
    print('graph_title Unit application processes')
    print('graph_info NGINX Unit application process counts.')
    print('graph_category appserver')
    print('graph_vlabel processes')
    print('graph_args --lower-limit 0')
    print('graph_scale no')
    for app in sorted(apps):
        safe = safename(app)
        print(f'{safe}.label {app} processes')
        print(f'{safe}.draw AREASTACK')

    print('multigraph nginx_unit_cpu')
    print('graph_title Unit application average CPU usage')
    print('graph_info NGINX Unit application average CPU usage per process.')
    print('graph_category appserver')
    print('graph_vlabel %')
    print('graph_args --lower-limit 0')
    print('graph_scale no')
    for app in sorted(apps):
        safe = safename(app)
        print(f'{safe}.label {app} CPU')

    print('multigraph nginx_unit_age')
    print('graph_title Unit application average age')
    print('graph_info NGINX Unit application average age per process.')
    print('graph_category appserver')
    print('graph_vlabel days')
    print('graph_args --lower-limit 0')
    for app in sorted(apps):
        safe = safename(app)
        print(f'{safe}.label {app} age')

    print('multigraph nginx_unit_memory')
    print('graph_title Unit application average memory')
    print('graph_info NGINX Unit application average memory per process.')
    print('graph_category appserver')
    print('graph_vlabel bytes')
    print('graph_args --lower-limit 0 --base 1024')
    for app in sorted(apps):
        safe = safename(app)
        print(f'{safe}.label {app} memory')

    print('multigraph nginx_unit_total_memory')
    print('graph_title Unit application total memory')
    print('graph_info NGINX Unit application total memory.')
    print('graph_category appserver')
    print('graph_vlabel bytes')
    print('graph_args --lower-limit 0 --base 1024')
    for app in sorted(apps):
        safe = safename(app)
        print(f'{safe}.label {app} memory')
        print(f'{safe}.draw AREASTACK')

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


def fetch(apps):
    """Print values."""
    print('multigraph nginx_unit_process')
    for app, values in apps.items():
        safe = safename(app)
        print(f'{safe}.value {values["count"]}')

    print('multigraph nginx_unit_cpu')
    for app, values in apps.items():
        safe = safename(app)
        print(f'{safe}.value {values["cpu"] / values["count"]}')

    print('multigraph nginx_unit_age')
    for app, values in apps.items():
        safe = safename(app)
        print(f'{safe}.value {values["age"] / values["count"] / 86400}')

    print('multigraph nginx_unit_memory')
    for app, values in apps.items():
        safe = safename(app)
        print(f'{safe}.value {values["memory"] / values["count"]}')

    print('multigraph nginx_unit_total_memory')
    for app, values in apps.items():
        safe = safename(app)
        print(f'{safe}.value {values["memory"]}')


if __name__ == '__main__':
    if len(sys.argv) > 1 and sys.argv[1] == 'autoconf':
        print('yes' if find_apps() else 'no (NGINX Unit is not running)')
    elif len(sys.argv) > 1 and sys.argv[1] == 'config':
        config(find_apps())
    else:
        fetch(find_apps())