~james-page/charms/trusty/swift-proxy/trunk

# Copyright 2014-2015 Canonical Limited.

#

# This file is part of charm-helpers.

#

# charm-helpers is free software: you can redistribute it and/or modify

# it under the terms of the GNU Lesser General Public License version 3 as

# published by the Free Software Foundation.

#

# charm-helpers 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 charm-helpers.  If not, see <http://www.gnu.org/licenses/>.

"""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,

    local_unit,

    log,

    relation_ids,

    relation_set,

    relations_of_type,

)

from charmhelpers.core.host import service

# 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()

#

# 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))

            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'

    def __init__(self, hostname=None):

        super(NRPE, self).__init__()

        self.config = config()

        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 = []

    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:

            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,

            }

        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):

    """

    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

    """

    for svc in services:

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

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

        if os.path.exists(upstart_init):

            # Don't add a check for these services from neutron-gateway

            if svc not in ['ext-port', 'os-charm-phy-nic-mtu']:

                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

            cron_file = ('*/5 * * * * root '

                         '/usr/local/lib/nagios/plugins/check_exit_status.pl '

                         '-s /etc/init.d/%s status > '

                         '/var/lib/nagios/service-check-%s.txt\n' % (svc,

                                                                     svc)

                         )

            f = open(cronpath, 'w')

            f.write(cron_file)

            f.close()

            nrpe.add_check(

                shortname=svc,

                description='process check {%s}' % unit_name,

                check_cmd='check_status_file.py -f '

                          '/var/lib/nagios/service-check-%s.txt' % svc,

            )

def copy_nrpe_checks():

    """

    Copy the nrpe checks into place

    """

    NAGIOS_PLUGINS = '/usr/local/lib/nagios/plugins'

    nrpe_files_dir = os.path.join(os.getenv('CHARM_DIR'), 'hooks',

                                  'charmhelpers', 'contrib', 'openstack',

                                  'files')

    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')