#!/usr/bin/env python3

# This plugin graphs the following values of the Motorola SB6141 cable
# modem:
#
# * upstream and downstream power levels
# * downstream signal to noise ratio
# * downstream signal statistics (codeword counts)
#
# The values are retrieved from the cable modem's status web pages at
# 192.168.100.1. So, this plugin must be installed on a munin node
# which can access those pages.
#
# To install, place this plugin in the node's plugins directory,
# /etc/munin/plugins and restart munin-node.
#
# Developed and tested with firmware SB_KOMODO-1.0.6.16-SCM00-NOSH
# (build time Feb 16 2016 11:28:04), hardware version 7.0, boot
# version PSPU-Boot(25CLK) 1.0.12.18m3.
#
# Requires the multigraph and dirtyconfig capabilities available in
# munin 2.0 and newer.
#
# Copyright © 2016 Kenyon Ralph <kenyon@kenyonralph.com>
#
# This program is free software. It comes without any warranty, to the
# extent permitted by applicable law. You can redistribute it and/or
# modify it under the terms of the Do What The Fuck You Want To Public
# License, Version 2, as published by Sam Hocevar. See
# http://www.wtfpl.net/ for more details.
#
# The latest version of this plugin can be found in the munin contrib
# repository at https://github.com/munin-monitoring/contrib. Issues
# with this plugin may be reported there. Patches accepted through the
# normal github process of forking the repository and submitting a
# pull request with your commits.

import html.parser
import urllib.request
import sys

class MotorolaHTMLParser(html.parser.HTMLParser):
    def __init__(self):
        html.parser.HTMLParser.__init__(self)
        self.signaldatapage = list()
        self.downstream_channels = list()
        self.downstream_SNRs = list()
        self.downstream_powers = list()
        self.upstream_channels = list()
        self.upstream_powers = list()
        self.unerrored_codewords = list()
        self.correctable_codewords = list()
        self.uncorrectable_codewords = list()

    def handle_data(self, data):
        data = data.strip()
        if data != '': self.signaldatapage.append(data)

    def process(self):
        # first and last elements are just javascript
        del self.signaldatapage[0]
        del self.signaldatapage[-1]

        di = iter(self.signaldatapage)

        element = next(di)
        while element != 'Channel ID': element = next(di)

        while element != 'Frequency':
            element = next(di)
            if element != 'Frequency': self.downstream_channels.append(element)

        while element != 'Signal to Noise Ratio': element = next(di)

        while element != 'Downstream Modulation':
            element = next(di)
            if element != 'Downstream Modulation': self.downstream_SNRs.append(element.split()[0])

        while element != 'The Downstream Power Level reading is a             snapshot taken at the time this page was requested. Please             Reload/Refresh this Page for a new reading': element = next(di)

        while element != 'Upstream':
            element = next(di)
            if element != 'Upstream': self.downstream_powers.append(element.split()[0])

        while element != 'Channel ID': element = next(di)

        while element != 'Frequency':
            element = next(di)
            if element != 'Frequency': self.upstream_channels.append(element)

        while element != 'Power Level': element = next(di)

        while element != 'Upstream Modulation':
            element = next(di)
            if element != 'Upstream Modulation': self.upstream_powers.append(element.split()[0])

        while element != 'Total Unerrored Codewords': element = next(di)

        while element != 'Total Correctable Codewords':
            element = next(di)
            if element != 'Total Correctable Codewords': self.unerrored_codewords.append(element)

        while element != 'Total Uncorrectable Codewords':
            element = next(di)
            if element != 'Total Uncorrectable Codewords': self.correctable_codewords.append(element)

        while True:
            try:
                element = next(di)
                self.uncorrectable_codewords.append(element)
            except StopIteration:
                break

def main():
    if len(sys.argv) != 2 or sys.argv[1] != 'config':
        print('Error: plugin designed for the dirtyconfig protocol, must be run with the config argument')
        sys.exit(1)

    parser = MotorolaHTMLParser()
    for line in urllib.request.urlopen("http://192.168.100.1/cmSignalData.htm"):
        parser.feed(line.decode())
    parser.process()

    print('multigraph motorola_sb6141_power')
    print('graph_title Motorola SB6141 Cable Modem Power')
    print('graph_vlabel Signal Strength (dBmV)')
    print('graph_info This graph shows the downstream and upstream power reported by a Motorola SB6141 cable modem.')
    print('graph_category network')
    for c, p in zip(parser.downstream_channels, parser.downstream_powers):
        print('ds_power_{0}.label Channel {0} Downstream Power'.format(c))
        print('ds_power_{0}.type GAUGE'.format(c))
        print('ds_power_{0}.value {1}'.format(c, p))
    for c, p in zip(parser.upstream_channels, parser.upstream_powers):
        print('us_power_{0}.label Channel {0} Upstream Power'.format(c))
        print('us_power_{0}.type GAUGE'.format(c))
        print('us_power_{0}.value {1}'.format(c, p))

    print('multigraph motorola_sb6141_snr')
    print('graph_title Motorola SB6141 Cable Modem SNR')
    print('graph_vlabel Signal-to-Noise Ratio (dB)')
    print('graph_info This graph shows the downstream signal-to-noise ratio reported by a Motorola SB6141 cable modem.')
    print('graph_category network')
    for c, snr in zip(parser.downstream_channels, parser.downstream_SNRs):
        print('snr_chan_{0}.label Channel {0} SNR'.format(c))
        print('snr_chan_{0}.type GAUGE'.format(c))
        print('snr_chan_{0}.value {1}'.format(c, snr))

    print('multigraph motorola_sb6141_codewords')
    print('graph_title Motorola SB6141 Cable Modem Codewords')
    print('graph_vlabel Codewords/${graph_period}')
    print('graph_info This graph shows the downstream codeword rates reported by a Motorola SB6141 cable modem.')
    print('graph_category network')
    for c, unerr in zip(parser.downstream_channels, parser.unerrored_codewords):
        print('unerr_chan_{0}.label Channel {0} Unerrored Codewords'.format(c))
        print('unerr_chan_{0}.type DERIVE'.format(c))
        print('unerr_chan_{0}.min 0'.format(c))
        print('unerr_chan_{0}.value {1}'.format(c, unerr))
    for c, corr in zip(parser.downstream_channels, parser.correctable_codewords):
        print('corr_chan_{0}.label Channel {0} Correctable Codewords'.format(c))
        print('corr_chan_{0}.type DERIVE'.format(c))
        print('corr_chan_{0}.min 0'.format(c))
        print('corr_chan_{0}.value {1}'.format(c, corr))
    for c, uncorr in zip(parser.downstream_channels, parser.uncorrectable_codewords):
        print('uncorr_chan_{0}.label Channel {0} Uncorrectable Codewords'.format(c))
        print('uncorr_chan_{0}.type DERIVE'.format(c))
        print('uncorr_chan_{0}.min 0'.format(c))
        print('uncorr_chan_{0}.value {1}'.format(c, uncorr))

if __name__ == "__main__":
    main()