#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
#  Copyright (c) 2013 Catalyst IT http://www.catalyst.net.nz
#  Copyright (c) 2015 SWITCH http://www.switch.ch
#
#  Licensed under the Apache License, Version 2.0 (the "License");
#  you may not use this file except in compliance with the License.
#  You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#  See the License for the specific language governing permissions and
#  limitations under the License.


from __future__ import print_function
import argparse
import socket
import os
import re
import subprocess
import sys
import json

__version__ = '1.6.0'

# default ceph values
CEPH_EXEC = '/usr/bin/ceph'
CEPH_COMMAND = 'mds stat -f json'

# nagios exit code
STATUS_OK = 0
STATUS_WARNING = 1
STATUS_ERROR = 2
STATUS_UNKNOWN = 3

def main():
    # parse args
    parser = argparse.ArgumentParser(description="'ceph mds stat' nagios plugin.")
    parser.add_argument('-e','--exe', help='ceph executable [%s]' % CEPH_EXEC)
    parser.add_argument('-c','--conf', help='alternative ceph conf file')
    parser.add_argument('-m','--monaddress', help='ceph monitor to use for queries (address[:port])')
    parser.add_argument('-i','--id', help='ceph client id')
    parser.add_argument('-k','--keyring', help='ceph client keyring file')
    parser.add_argument('-V','--version', help='show version and exit', action='store_true')
    parser.add_argument('-n','--name', help='mds daemon name', required=True)
    parser.add_argument('-f','--filesystem', help='mds filesystem name', required=True)
    args = parser.parse_args()

    if args.version:
        print('version %s' % __version__)
        return STATUS_OK

    # validate args
    ceph_exec = args.exe if args.exe else CEPH_EXEC
    if not os.path.exists(ceph_exec):
        print("MDS ERROR: ceph executable '%s' doesn't exist" % ceph_exec)
        return STATUS_UNKNOWN

    if args.conf and not os.path.exists(args.conf):
        print("MDS ERROR: ceph conf file '%s' doesn't exist" % args.conf)
        return STATUS_UNKNOWN

    if args.keyring and not os.path.exists(args.keyring):
        print("MDS ERROR: keyring file '%s' doesn't exist" % args.keyring)
        return STATUS_UNKNOWN

    # build command
    ceph_cmd = [ceph_exec]
    if args.monaddress:
        ceph_cmd.append('-m')
        ceph_cmd.append(args.monaddress)
    if args.conf:
        ceph_cmd.append('-c')
        ceph_cmd.append(args.conf)
    if args.id:
        ceph_cmd.append('--id')
        ceph_cmd.append(args.id)
    if args.keyring:
        ceph_cmd.append('--keyring')
        ceph_cmd.append(args.keyring)
    ceph_cmd.extend(CEPH_COMMAND.split(' '))

    # exec command
    p = subprocess.Popen(ceph_cmd,stdout=subprocess.PIPE,stderr=subprocess.PIPE)
    output, err = p.communicate()

    if p.returncode != 0 or not output:
        print("MDS ERROR: %s" % err)
        return STATUS_ERROR

    # load json output and parse
    mds_stat = None
    try:
        mds_stat = json.loads(output)
    except Exception as e:
        print("MDS ERROR: could not parse '%s' output: %s: %s" % (CEPH_COMMAND,output,e))
        return STATUS_UNKNOWN

    return check_target_mds(mds_stat, args.filesystem, args.name)

def check_target_mds(mds_stat, fs_name, name):
    # find mds from standby list
    standby_mdss = _get_standby_mds(mds_stat)
    for mds in standby_mdss:
        if mds.get_name() == name:
            print("MDS OK: %s" % (mds))
            return STATUS_OK

    # find mds from active list
    active_mdss = _get_active_mds(mds_stat, fs_name)

    if active_mdss:
        for mds in active_mdss:
            if mds.get_name() != name:
                continue
            # target mds in active list
            print("MDS %s: %s" % ("WARN" if mds.is_laggy() else "OK", mds))
            return STATUS_WARNING if mds.is_laggy() else STATUS_OK

        # mds not found
        print("MDS ERROR: MDS '%s' is not found (offline?)" % (name))
        return STATUS_ERROR
    else:
        # fs not found in map, perhaps user input error
        print("MDS ERROR: FS '%s' is not found in fsmap" % (fs_name))
        return STATUS_ERROR

def _get_standby_mds(mds_stat):
    mds_array = []
    for mds in mds_stat['fsmap']['standbys']:
        name = mds['name']
        state = mds['state']
        laggy_since = mds['laggy_since'] if 'laggy_since' in mds else None
        mds_array.append(MDS(name, state))

    return mds_array

def _get_active_mds(mds_stat, fs_name):
    mds_fs = mds_stat['fsmap']['filesystems']

    # find filesystem in stat
    for i in range(len(mds_fs)):
        mdsmap = mds_fs[i]['mdsmap']
        if mdsmap['fs_name'] != fs_name:
            continue
        # put mds to array
        mds_array = []
        infos = mds_stat['fsmap']['filesystems'][i]['mdsmap']['info']
        for gid in infos:
            name = infos[gid]['name']
            state = infos[gid]['state']
            laggy_since = infos[gid]['laggy_since'] if 'laggy_since' in infos[gid] else None
            mds_array.append(MDS(name, state, laggy_since))

        return mds_array

    # no fs found
    return None

class MDS(object):
    def __init__(self, name, state, laggy_since=None):
        self.name = name
        self.state = state
        self.laggy_since = laggy_since

    def get_name(self):
        return self.name

    def get_state(self):
        return self.state

    def is_laggy(self):
        return self.laggy_since is not None

    def __str__(self):
        msg = "MDS '%s' is %s" % (self.name, self.state)
        if self.laggy_since is not None:
            msg += " (laggy or crashed)"
        return msg

# main
if __name__ == "__main__":
  sys.exit(main())