#!/usr/bin/env python3


"""
=pod

=head1 NAME

btrfs_device_stats - Script to monitor btrfs device statistics

=head1 CONFIGURATION

Simply create a symlink in your plugins directory like with any other plugin.
Must be run as root.

[btrfs_device_stats]
user root

You can optionaly configure the warning and critical limits. By default warning
is set to 1 and critical is not set at all. You can set the limits either for
the entire plugin or per individual metric. The individual values take
precedence over the general ones. See the following example:

[btrfs_device_stats]
user root
env.warning 2
env.critical 4
env.flags_warning 23
env.read_errs_critical 42

=head2 DEFAULT CONFIGURATION

=head1 BUGS

=head1 AUTHOR

2019-2021, HaseHarald

=head1 MAGIC MARKERS

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

=head1 LICENSE

LGPLv3

=cut
"""


# This file contains a munin-plugin to gather btrfs statistics per device.
#
# This is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this plugin.  If not, see <http://www.gnu.org/licenses/>.


import btrfs
import os
import sys


def munin_config(fs):
    fsid = str(fs.fsid).replace('-', '_')
    print("multigraph btrfs_device_stats_" + fsid)
    print("graph_args --base 1000 -l 0")
    print("graph_vlabel total btrfs attribute value")
    print("graph_title btrfs total device stats for " + fs.path)
    print("graph_category disk")
    print("graph_info This graph shows the total stats of devices used by btrfs")

    print("corruption_errs_total.label Corruption Errors")
    print("flush_errs_total.label Flush Errors")
    print("generation_errs_total.label Generation Errors")
    print("read_errs_total.label Read Errors")
    print("write_errs_total.label Write Errors")
    print("nr_items_total.label Nr. of Items")
    print("flags_total.label Nr. of Flags")

    print("")

    devices = fs.devices()
    warning = os.getenv('warning', default = 1)
    critical = os.getenv('critical', default = False)
    for this_device in devices:
        this_dev_info = fs.dev_info(this_device.devid)
        this_dev_name = this_dev_info.path.replace('/dev/', '')
        print("multigraph btrfs_device_stats_" + fsid + "." +
              str(this_device.devid))
        print("graph_args --base 1000 -l 0")
        print("graph_vlabel btrfs attribute value")
        print("graph_title btrfs device stats for " + this_dev_name)
        print("graph_category disk")
        print("graph_info This graph shows stats of devices used by btrfs")

        print("corruption_errs.label Corruption Errors")
        print("corruption_errs.warning " + os.getenv('corruption_errs_warning',
              default = str(warning)))
        if os.getenv('corruption_errs_critical', default = critical):
            print("corruption_errs.critical " +
                  os.getenv('corruption_errs_critical',
                  default = str(critical)))

        print("flush_errs.label Flush Errors")
        print("flush_errs.warning " + os.getenv('flush_errs_warning',
              default = str(warning)))
        if os.getenv('flush_errs_critical', default = critical):
            print("flush_errs.critical " + os.getenv('flush_errs_critical',
                  default = str(critical)))

        print("generation_errs.label Generation Errors")
        print("generation_errs.warning " + os.getenv('generation_errs_warning',
              default = str(warning)))
        if os.getenv('generation_errs_critical', default = critical):
            print("generation_errs.critical " +
                  os.getenv('generation_errs_critical',
                  default = str(critical)))

        print("read_errs.label Read Errors")
        print("read_errs.warning " + os.getenv('read_errs_warning',
              default = str(warning)))
        if os.getenv('read_errs_critical', default = critical):
            print("read_errs.critical " + os.getenv('read_errs_critical',
                  default = str(critical)))

        print("write_errs.label Write Errors")
        print("write_errs.warning " + os.getenv('write_errs_warning',
              default = str(warning)))
        if os.getenv('write_errs_critical', default = critical):
            print("write_errs.critical " + os.getenv('write_errs_critical',
                  default = str(critical)))

        print("nr_items.label Nr. of Items")

        print("flags.label Nr. of Flags")
        print("flags.warning " + os.getenv('flags_warning',
              default = str(warning)))
        if os.getenv('flags_critical', default = critical):
            print("flags.critical " + os.getenv('flags_critical',
                  default = str(critical)))

        print("")


def munin_values(fs):
    corruption_errs_total = 0
    flush_errs_total = 0
    generation_errs_total = 0
    read_errs_total = 0
    write_errs_total = 0
    nr_items_total = 0
    flags_total = 0

    fsid = str(fs.fsid).replace('-', '_')
    devices = fs.devices()

    for this_device in devices:
        this_dev_stat = fs.dev_stats(this_device.devid, False)

        corruption_errs = this_dev_stat.corruption_errs
        flush_errs = this_dev_stat.flush_errs
        generation_errs = this_dev_stat.generation_errs
        read_errs = this_dev_stat.read_errs
        write_errs = this_dev_stat.write_errs
        nr_items = this_dev_stat.nr_items
        flags = this_dev_stat.flags

        corruption_errs_total = corruption_errs_total + corruption_errs
        flush_errs_total = flush_errs_total + flush_errs
        generation_errs_total = generation_errs_total + generation_errs
        read_errs_total = read_errs_total + read_errs
        write_errs_total = write_errs_total + write_errs
        nr_items_total = nr_items_total + nr_items
        flags_total = flags_total + flags

        print("multigraph btrfs_device_stats_" + fsid + "." +
              str(this_device.devid))

        print("corruption_errs.value " + str(corruption_errs))
        print("flush_errs.value " + str(flush_errs))
        print("generation_errs.value " + str(generation_errs))
        print("read_errs.value " + str(read_errs))
        print("write_errs.value " + str(write_errs))
        print("nr_items.value " + str(nr_items))
        print("flags.value " + str(flags))

        print("")

    print("multigraph btrfs_device_stats_" + fsid)

    print("corruption_errs_total.value " + str(corruption_errs_total))
    print("flush_errs_total.value " + str(flush_errs_total))
    print("generation_errs_total.value " + str(generation_errs_total))
    print("read_errs_total.value " + str(read_errs_total))
    print("write_errs_total.value " + str(write_errs_total))
    print("nr_items_total.value " + str(nr_items_total))
    print("flags_total.value " + str(flags_total))

    print("")


def main():
    for path in btrfs.utils.mounted_filesystem_paths():
        with btrfs.FileSystem(path) as fs:
            if len(sys.argv) > 1 and sys.argv[1] == "config":
                munin_config(fs)
            else:
                munin_values(fs)


if __name__ == "__main__":
    main()

exit(0)