summaryrefslogtreecommitdiff
path: root/hooks/charmhelpers/contrib/charmsupport/nrpe.py
blob: e3d10c1ca08fc1191449796dea771779fd9f5adc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
# Copyright 2014-2015 Canonical Limited.
#
# 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.

"""Compatibility with the nrpe-external-master charm"""
# Copyright 2012 Canonical Ltd.
#
# Authors:
#  Matthew Wedgwood <matthew.wedgwood@canonical.com>

import subprocess
import pwd
import grp
import os
import glob
import shutil
import re
import shlex
import yaml

from charmhelpers.core.hookenv import (
    config,
    hook_name,
    local_unit,
    log,
    relation_ids,
    relation_set,
    relations_of_type,
)

from charmhelpers.core.host import service
from charmhelpers.core import host

# This module adds compatibility with the nrpe-external-master and plain nrpe
# subordinate charms. To use it in your charm:
#
# 1. Update metadata.yaml
#
#   provides:
#     (...)
#     nrpe-external-master:
#       interface: nrpe-external-master
#       scope: container
#
#   and/or
#
#   provides:
#     (...)
#     local-monitors:
#       interface: local-monitors
#       scope: container

#
# 2. Add the following to config.yaml
#
#    nagios_context:
#      default: "juju"
#      type: string
#      description: |
#        Used by the nrpe subordinate charms.
#        A string that will be prepended to instance name to set the host name
#        in nagios. So for instance the hostname would be something like:
#            juju-myservice-0
#        If you're running multiple environments with the same services in them
#        this allows you to differentiate between them.
#    nagios_servicegroups:
#      default: ""
#      type: string
#      description: |
#        A comma-separated list of nagios servicegroups.
#        If left empty, the nagios_context will be used as the servicegroup
#
# 3. Add custom checks (Nagios plugins) to files/nrpe-external-master
#
# 4. Update your hooks.py with something like this:
#
#    from charmsupport.nrpe import NRPE
#    (...)
#    def update_nrpe_config():
#        nrpe_compat = NRPE()
#        nrpe_compat.add_check(
#            shortname = "myservice",
#            description = "Check MyService",
#            check_cmd = "check_http -w 2 -c 10 http://localhost"
#            )
#        nrpe_compat.add_check(
#            "myservice_other",
#            "Check for widget failures",
#            check_cmd = "/srv/myapp/scripts/widget_check"
#            )
#        nrpe_compat.write()
#
#    def config_changed():
#        (...)
#        update_nrpe_config()
#
#    def nrpe_external_master_relation_changed():
#        update_nrpe_config()
#
#    def local_monitors_relation_changed():
#        update_nrpe_config()
#
# 4.a If your charm is a subordinate charm set primary=False
#
#    from charmsupport.nrpe import NRPE
#    (...)
#    def update_nrpe_config():
#        nrpe_compat = NRPE(primary=False)
#
# 5. ln -s hooks.py nrpe-external-master-relation-changed
#    ln -s hooks.py local-monitors-relation-changed


class CheckException(Exception):
    pass


class Check(object):
    shortname_re = '[A-Za-z0-9-_.]+$'
    service_template = ("""
#---------------------------------------------------
# This file is Juju managed
#---------------------------------------------------
define service {{
    use                             active-service
    host_name                       {nagios_hostname}
    service_description             {nagios_hostname}[{shortname}] """
                        """{description}
    check_command                   check_nrpe!{command}
    servicegroups                   {nagios_servicegroup}
}}
""")

    def __init__(self, shortname, description, check_cmd):
        super(Check, self).__init__()
        # XXX: could be better to calculate this from the service name
        if not re.match(self.shortname_re, shortname):
            raise CheckException("shortname must match {}".format(
                Check.shortname_re))
        self.shortname = shortname
        self.command = "check_{}".format(shortname)
        # Note: a set of invalid characters is defined by the
        # Nagios server config
        # The default is: illegal_object_name_chars=`~!$%^&*"|'<>?,()=
        self.description = description
        self.check_cmd = self._locate_cmd(check_cmd)

    def _get_check_filename(self):
        return os.path.join(NRPE.nrpe_confdir, '{}.cfg'.format(self.command))

    def _get_service_filename(self, hostname):
        return os.path.join(NRPE.nagios_exportdir,
                            'service__{}_{}.cfg'.format(hostname, self.command))

    def _locate_cmd(self, check_cmd):
        search_path = (
            '/usr/lib/nagios/plugins',
            '/usr/local/lib/nagios/plugins',
        )
        parts = shlex.split(check_cmd)
        for path in search_path:
            if os.path.exists(os.path.join(path, parts[0])):
                command = os.path.join(path, parts[0])
                if len(parts) > 1:
                    command += " " + " ".join(parts[1:])
                return command
        log('Check command not found: {}'.format(parts[0]))
        return ''

    def _remove_service_files(self):
        if not os.path.exists(NRPE.nagios_exportdir):
            return
        for f in os.listdir(NRPE.nagios_exportdir):
            if f.endswith('_{}.cfg'.format(self.command)):
                os.remove(os.path.join(NRPE.nagios_exportdir, f))

    def remove(self, hostname):
        nrpe_check_file = self._get_check_filename()
        if os.path.exists(nrpe_check_file):
            os.remove(nrpe_check_file)
        self._remove_service_files()

    def write(self, nagios_context, hostname, nagios_servicegroups):
        nrpe_check_file = self._get_check_filename()
        with open(nrpe_check_file, 'w') as nrpe_check_config:
            nrpe_check_config.write("# check {}\n".format(self.shortname))
            if nagios_servicegroups:
                nrpe_check_config.write(
                    "# The following header was added automatically by juju\n")
                nrpe_check_config.write(
                    "# Modifying it will affect nagios monitoring and alerting\n")
                nrpe_check_config.write(
                    "# servicegroups: {}\n".format(nagios_servicegroups))
            nrpe_check_config.write("command[{}]={}\n".format(
                self.command, self.check_cmd))

        if not os.path.exists(NRPE.nagios_exportdir):
            log('Not writing service config as {} is not accessible'.format(
                NRPE.nagios_exportdir))
        else:
            self.write_service_config(nagios_context, hostname,
                                      nagios_servicegroups)

    def write_service_config(self, nagios_context, hostname,
                             nagios_servicegroups):
        self._remove_service_files()

        templ_vars = {
            'nagios_hostname': hostname,
            'nagios_servicegroup': nagios_servicegroups,
            'description': self.description,
            'shortname': self.shortname,
            'command': self.command,
        }
        nrpe_service_text = Check.service_template.format(**templ_vars)
        nrpe_service_file = self._get_service_filename(hostname)
        with open(nrpe_service_file, 'w') as nrpe_service_config:
            nrpe_service_config.write(str(nrpe_service_text))

    def run(self):
        subprocess.call(self.check_cmd)


class NRPE(object):
    nagios_logdir = '/var/log/nagios'
    nagios_exportdir = '/var/lib/nagios/export'
    nrpe_confdir = '/etc/nagios/nrpe.d'
    homedir = '/var/lib/nagios'  # home dir provided by nagios-nrpe-server

    def __init__(self, hostname=None, primary=True):
        super(NRPE, self).__init__()
        self.config = config()
        self.primary = primary
        self.nagios_context = self.config['nagios_context']
        if 'nagios_servicegroups' in self.config and self.config['nagios_servicegroups']:
            self.nagios_servicegroups = self.config['nagios_servicegroups']
        else:
            self.nagios_servicegroups = self.nagios_context
        self.unit_name = local_unit().replace('/', '-')
        if hostname:
            self.hostname = hostname
        else:
            nagios_hostname = get_nagios_hostname()
            if nagios_hostname:
                self.hostname = nagios_hostname
            else:
                self.hostname = "{}-{}".format(self.nagios_context, self.unit_name)
        self.checks = []
        # Iff in an nrpe-external-master relation hook, set primary status
        relation = relation_ids('nrpe-external-master')
        if relation:
            log("Setting charm primary status {}".format(primary))
            for rid in relation_ids('nrpe-external-master'):
                relation_set(relation_id=rid, relation_settings={'primary': self.primary})

    def add_check(self, *args, **kwargs):
        self.checks.append(Check(*args, **kwargs))

    def remove_check(self, *args, **kwargs):
        if kwargs.get('shortname') is None:
            raise ValueError('shortname of check must be specified')

        # Use sensible defaults if they're not specified - these are not
        # actually used during removal, but they're required for constructing
        # the Check object; check_disk is chosen because it's part of the
        # nagios-plugins-basic package.
        if kwargs.get('check_cmd') is None:
            kwargs['check_cmd'] = 'check_disk'
        if kwargs.get('description') is None:
            kwargs['description'] = ''

        check = Check(*args, **kwargs)
        check.remove(self.hostname)

    def write(self):
        try:
            nagios_uid = pwd.getpwnam('nagios').pw_uid
            nagios_gid = grp.getgrnam('nagios').gr_gid
        except Exception:
            log("Nagios user not set up, nrpe checks not updated")
            return

        if not os.path.exists(NRPE.nagios_logdir):
            os.mkdir(NRPE.nagios_logdir)
            os.chown(NRPE.nagios_logdir, nagios_uid, nagios_gid)

        nrpe_monitors = {}
        monitors = {"monitors": {"remote": {"nrpe": nrpe_monitors}}}
        for nrpecheck in self.checks:
            nrpecheck.write(self.nagios_context, self.hostname,
                            self.nagios_servicegroups)
            nrpe_monitors[nrpecheck.shortname] = {
                "command": nrpecheck.command,
            }

        # update-status hooks are configured to firing every 5 minutes by
        # default. When nagios-nrpe-server is restarted, the nagios server
        # reports checks failing causing unneccessary alerts. Let's not restart
        # on update-status hooks.
        if not hook_name() == 'update-status':
            service('restart', 'nagios-nrpe-server')

        monitor_ids = relation_ids("local-monitors") + \
            relation_ids("nrpe-external-master")
        for rid in monitor_ids:
            relation_set(relation_id=rid, monitors=yaml.dump(monitors))


def get_nagios_hostcontext(relation_name='nrpe-external-master'):
    """
    Query relation with nrpe subordinate, return the nagios_host_context

    :param str relation_name: Name of relation nrpe sub joined to
    """
    for rel in relations_of_type(relation_name):
        if 'nagios_host_context' in rel:
            return rel['nagios_host_context']


def get_nagios_hostname(relation_name='nrpe-external-master'):
    """
    Query relation with nrpe subordinate, return the nagios_hostname

    :param str relation_name: Name of relation nrpe sub joined to
    """
    for rel in relations_of_type(relation_name):
        if 'nagios_hostname' in rel:
            return rel['nagios_hostname']


def get_nagios_unit_name(relation_name='nrpe-external-master'):
    """
    Return the nagios unit name prepended with host_context if needed

    :param str relation_name: Name of relation nrpe sub joined to
    """
    host_context = get_nagios_hostcontext(relation_name)
    if host_context:
        unit = "%s:%s" % (host_context, local_unit())
    else:
        unit = local_unit()
    return unit


def add_init_service_checks(nrpe, services, unit_name, immediate_check=True):
    """
    Add checks for each service in list

    :param NRPE nrpe: NRPE object to add check to
    :param list services: List of services to check
    :param str unit_name: Unit name to use in check description
    :param bool immediate_check: For sysv init, run the service check immediately
    """
    for svc in services:
        # Don't add a check for these services from neutron-gateway
        if svc in ['ext-port', 'os-charm-phy-nic-mtu']:
            next

        upstart_init = '/etc/init/%s.conf' % svc
        sysv_init = '/etc/init.d/%s' % svc

        if host.init_is_systemd():
            nrpe.add_check(
                shortname=svc,
                description='process check {%s}' % unit_name,
                check_cmd='check_systemd.py %s' % svc
            )
        elif os.path.exists(upstart_init):
            nrpe.add_check(
                shortname=svc,
                description='process check {%s}' % unit_name,
                check_cmd='check_upstart_job %s' % svc
            )
        elif os.path.exists(sysv_init):
            cronpath = '/etc/cron.d/nagios-service-check-%s' % svc
            checkpath = '%s/service-check-%s.txt' % (nrpe.homedir, svc)
            croncmd = (
                '/usr/local/lib/nagios/plugins/check_exit_status.pl '
                '-e -s /etc/init.d/%s status' % svc
            )
            cron_file = '*/5 * * * * root %s > %s\n' % (croncmd, checkpath)
            f = open(cronpath, 'w')
            f.write(cron_file)
            f.close()
            nrpe.add_check(
                shortname=svc,
                description='service check {%s}' % unit_name,
                check_cmd='check_status_file.py -f %s' % checkpath,
            )
            # if /var/lib/nagios doesn't exist open(checkpath, 'w') will fail
            # (LP: #1670223).
            if immediate_check and os.path.isdir(nrpe.homedir):
                f = open(checkpath, 'w')
                subprocess.call(
                    croncmd.split(),
                    stdout=f,
                    stderr=subprocess.STDOUT
                )
                f.close()
                os.chmod(checkpath, 0o644)


def copy_nrpe_checks(nrpe_files_dir=None):
    """
    Copy the nrpe checks into place

    """
    NAGIOS_PLUGINS = '/usr/local/lib/nagios/plugins'
    default_nrpe_files_dir = os.path.join(
        os.getenv('CHARM_DIR'),
        'hooks',
        'charmhelpers',
        'contrib',
        'openstack',
        'files')
    if not nrpe_files_dir:
        nrpe_files_dir = default_nrpe_files_dir
    if not os.path.exists(NAGIOS_PLUGINS):
        os.makedirs(NAGIOS_PLUGINS)
    for fname in glob.glob(os.path.join(nrpe_files_dir, "check_*")):
        if os.path.isfile(fname):
            shutil.copy2(fname,
                         os.path.join(NAGIOS_PLUGINS, os.path.basename(fname)))


def add_haproxy_checks(nrpe, unit_name):
    """
    Add checks for each service in list

    :param NRPE nrpe: NRPE object to add check to
    :param str unit_name: Unit name to use in check description
    """
    nrpe.add_check(
        shortname='haproxy_servers',
        description='Check HAProxy {%s}' % unit_name,
        check_cmd='check_haproxy.sh')
    nrpe.add_check(
        shortname='haproxy_queue',
        description='Check HAProxy queue depth {%s}' % unit_name,
        check_cmd='check_haproxy_queue_depth.sh')