#!/usr/bin/python

"""
=head1 NAME

monit_parser -  Monit status parser plugin for munin.


=head1 APPLICABLE SYSTEMS

Any system running monit.

Monit needs to be configured with the httpd port enabled, e.g.:

    set httpd port 2812

The configured port is not important, since this plugin uses "monit status"
for retrieving data. Thus the monit configuration is parsed implicitly.


=head1 CONFIGURATION

This plugin requires read access for the monit configuration.
Thus it needs to run as root:

  [monit_parser]
  user root


=head1 AUTHOR

  Todd Troxell <ttroxell@debian.org>
  Lars Kruse <devel@sumpfralle.de>


=head1 MAGIC MARKERS

  family=auto
  capabilities=autoconf

=cut
"""

import re
import subprocess
import sys


def sanitize(s):
    OK_CHARS = "abcdefghijklmnopqrstuvwxyz0123456789"
    return "".join([char for char in s if char in OK_CHARS])


def get_monit_status_lines():
    # retrieve output
    try:
        output = subprocess.check_output(["monit", "status"])
        error_message = None
    except (OSError, subprocess.CalledProcessError) as exc:
        error_message = "Error running monit status command: %s" % str(exc)
    if error_message is not None:
        raise OSError(error_message)
    # python3: the result of command execution is bytes and needs to be converted
    if not isinstance(output, str):
        output = output.decode("ascii", "ignore")
    return output.splitlines()


def parse_processes():
    cur_proc = None
    procs = {}
    for line in get_monit_status_lines():
        m = re.match("^Process '(.*)'.*$", line)
        if m:
            cur_proc = sanitize(m.group(1))
            try:
                procs[cur_proc]
            except KeyError:
                procs[cur_proc] = {}
            continue
        m = re.match("  memory kilobytes total\s+([0-9.]+)(.*)$", line)
        if m:
            size, suffix = m.groups()
            # we store memory consumption as megabytes
            factor = {
                "": 1024 ** -1,
                "KB": 1024 ** -1,
                "MB": 1024 ** 0,
                "GB": 1024 ** 1,
                "TB": 1024 ** 2,
            }[suffix.strip().upper()]
            try:
                procs[cur_proc]["total_memory"] = float(size) * factor
            except ValueError:
                procs[cur_proc]["total_memory"] = "U"
            continue
        m = re.match("  cpu percent total\s+([.0-9]+)%.*$", line)
        if m:
            procs[cur_proc]["total_cpu"] = m.group(1)
            continue
    return procs


action = sys.argv[1] if (len(sys.argv) > 1) else None

if action == 'autoconf':
    try:
        get_monit_status_lines()
        print("yes")
    except OSError:
        print("no (failed to request monit status)")
elif action == 'config':
    procs = parse_processes()
    print('graph_title Per process stats from Monit')
    print('graph_vlabel usage of memory [MB] or cpu [%]')
    print('graph_category monit')
    for process in procs:
        for stat in procs[process]:
            print("monit_%s_%s.label %s.%s" % (process, stat, process, stat))
            if stat == 'total_memory':
                # the allocated memory may never be zero
                print("monit_%s_%s.warning 1:" % (process, stat))
else:
    for process, stats in parse_processes().items():
        for stat_key, stat_value in stats.items():
            print("monit_%s_%s.value %s" % (process, stat_key, stat_value))