added check_temperature plugin to monitor temperatures on a RaspberryPi

Frederik Lindenaar
1 parent 4a52b302
Showing 2 changed files with 331 additions and 0 deletions
README.md
plugins/check_temperature
@@ -24,6 +24,8 @@ This repository contains the following scripts:
     monitor multi-home and dual-stack (i.e. ipv4 and ipv6) servers.
   * [check_otp](#check_otp)
     plugin to monitor PrivacyIDEA (and LinOTP) OTP validation
+  * [check_temperature](#check_temperature)
+    plugin to monitor the temperature of a 1-wire sensor on a RaspberryPi
   * [nagiosstatus](#nagiosstatus)
     CGI-BIN script to report the status of nagios (to monitor nagios itself)
@@ -233,6 +235,63 @@ define service {
 ~~~
+<a name=check_temperature>plugins/check_temperature</a>
+-------------------------------------------------------
+Plugin (check) to monitor monitor the temperature using a sensor connected to a
+RaspberryPi. This implementation is specifically for the DS18B20 1-wire
+temperature sensor. Other methods and interfaces can be plugged in easily (just
+raise a request or provide a patch). For information on how to connect sensor
+to the RaspberryPi and to get it working please see [this Adafruit tutorial](
+https://learn.adafruit.com/adafruits-raspberry-pi-lesson-11-ds18b20-temperature-sensing).
+
+To enable the 1-wire interface support on the RaspberryPi one can use the
+command:
+~~~
+   sudo raspi-config nonint do_onewire 0
+~~~
+or use `raspi-config` in interactive mode (9. Advanced Options --> A9. 1-Wire).
+Please note that changing this requires a reboot.
+
+Installation for is straightforward, after installing the script on the server
+add the following to your Nagios `commands.cmd` configuration file:
+
+~~~
+# 'check_temperature' command definition to monitor a single temperature in C
+# parameters: warning (ARG1) and critical (ARG2) temperature in Celcius
+define command {
+        command_name    check_temperature
+        command_line    [install_path]/plugins/check_temperature -w $ARG1$ -c $ARG2$
+}
+
+# 'check_ftemperature' command definition to monitor a single temperature in F
+# parameters: warning (ARG1) and critical (ARG2) temperature in Farenheit
+define command {
+        command_name    check_ftemperature
+        command_line    [install_path]/plugins/check_temperature -F -w $ARG1$ -c $ARG2$
+}
+
+# 'check_temperature_sensor' command definition to monitor a single temperature in C
+# parameters: sensor serial (ARG1), warning (ARG2) and critical (ARG3) temperature in Celcius
+define command {
+        command_name    check_temperature_sensor
+        command_line    [install_path]/plugins/check_temperature -s $ARG1$ -w $ARG2$ -c $ARG3$
+}
+
+# 'check_ftemperature_sensor' command definition to monitor a single temperature in F
+# parameters: sensor serial (ARG1), warning (ARG2) and critical (ARG3) temperature in Farenheit
+define command {
+        command_name    check_ftemperature_sensor
+        command_line    [install_path]/plugins/check_temperature -F -s $ARG1$ -w $ARG2$ -c $ARG3$
+}
+
+~~~
+
+Make sure to replace `[install_path]/plugins` with the location of the script.
+
+Please run `check_temperature -h` after installation for an overview of the
+available command line options (e.g. to enable logging to a file).
+
+
 <a name=nagiosstatus>cgi-bin/nagiosstatus.sh</a>
 ------------------------------------------------
 Very simplistic CGI-BIN script that checkes whether nagios is still running and
+#! /usr/bin/env python
+#
+# check_temperature - Nagios temperature check for DS18B20 sensor on RaspberryPi
+#
+# Version 1.0, latest version, documentation and bugtracker available at:
+#              https://gitlab.lindenaar.net/scripts/nagios-plugins
+#
+# Copyright (c) 2016 Frederik Lindenaar
+#
+# This script is free software: you can redistribute and/or modify it under the
+# terms of version 3 of the GNU General Public License as published by the Free
+# Software Foundation, or (at your option) any later version of the license.
+#
+# This script 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along with
+# this program.  If not, visit <http://www.gnu.org/licenses/> to download it.
+
+from sys import exit
+from os.path import basename, splitext
+from glob import glob
+from time import time, sleep
+from argparse import ArgumentParser as StandardArgumentParser, FileType, \
+              _StoreAction as StoreAction, _StoreConstAction as StoreConstAction
+import logging
+
+# Constants (no need to change but allows for easy customization)
+VERSION="1.0"
+PROG_NAME=splitext(basename(__file__))[0]
+PROG_VERSION=PROG_NAME + ' ' + VERSION
+SENSOR_SCALE=1000
+SENSOR_DEV_DIR =  '/sys/bus/w1/devices/'
+SENSOR_DEV_PREFIX = '28-'
+SENSOR_DEV_SUFFIX = '/w1_slave'
+SENSOR_READ_RETRIES=10
+
+LOG_FORMAT='%(levelname)s - %(message)s'
+LOG_FORMAT_FILE='%(asctime)s - ' + LOG_FORMAT
+LOGGING_NONE=logging.CRITICAL + 10
+NAGIOS_OK = ( 'OK', 0)
+NAGIOS_WARN = ( 'WARNING', 1)
+NAGIOS_CRITICAL = ( 'CRITICAL', 2 )
+NAGIOS_UNKNOWN = ( 'UNKNOWN', 3 )
+
+# Setup logging
+logging.basicConfig(format=LOG_FORMAT)
+logging.addLevelName(LOGGING_NONE, 'NONE')
+logger = logging.getLogger(PROG_NAME)
+logger.setLevel(logging.CRITICAL)
+
+################[ wrapper to stop ArgumentParser from exiting ]################
+# based on http://stackoverflow.com/questions/14728376/i-want-python-argparse-to-throw-an-exception-rather-than-usage/14728477#14728477
+# the only way to do this is overriding the error method and throw and Exception
+class ArgumentParserError(Exception): pass
+
+class ArgumentParser(StandardArgumentParser):
+    """ArgumentParser not exiting with non-Nagios format message upon errors"""
+    def error(self, message):
+        raise ArgumentParserError(message)
+
+##################[ Action to immediately set the log level ]##################
+class SetLogLevel(StoreConstAction):
+    """ArgumentParser action to set log level to provided const value"""
+    def __call__(self, parser, namespace, values, option_string=None):
+        logging.getLogger(PROG_NAME).setLevel(self.const)
+
+####################[ Action to immediately log to a file ]####################
+class SetLogFile(StoreAction):
+    """ArgumentParser action to log to file (sets up FileHandler accordingly)"""
+    def __call__(self, parser, namespace, values, option_string=None):
+        super(SetLogFile, self).__call__(parser,namespace,values,option_string)
+        formatter = logging.Formatter(LOG_FORMAT_FILE)
+        handler = logging.FileHandler(values)
+        handler.setFormatter(formatter)
+        logger = logging.getLogger(PROG_NAME)
+        logger.propagate = False
+        logger.addHandler(handler)
+
+###############################################################################
+
+def convert_celcius(temp_read):
+    """Converts raw temperature sensore value to degrees Celcius"""
+    return float(temp_read) / float(SENSOR_SCALE)
+CONVERT_CELCIUS = ( convert_celcius, 'C', 'Celcius' )
+
+
+def convert_farenheit(temp_read):
+    """Converts raw temperature sensore value to degrees Farenheit"""
+    return float(temp_read * 9) / float(5 * SENSOR_SCALE) + 32.0
+CONVERT_FARENHEIT = ( convert_farenheit, 'F', 'Farenheit' )
+
+
+def isempty(string):
+    """Checks whether string 'str' provided is unset or empty"""
+    return string is None or len(string) == 0
+
+
+def parse_args():
+    """Parse command line and get parameters from environment, if present"""
+
+    # Setup argument parser, the workhorse gluing it all together
+    parser = ArgumentParser(
+        epilog='(*) by default the script will look for the first device that '
+               'matches %s* in %s, if multiple entries are found -s or -f must '
+               'be used to specify which sensor to read.' %
+               (SENSOR_DEV_PREFIX, SENSOR_DEV_DIR),
+        description='Nagios check plugin for 1-wire temp. sensor on RaspberryPi'
+    )
+    parser.add_argument('-V', '--version',action="version",version=PROG_VERSION)
+
+    pgroup = parser.add_mutually_exclusive_group(required=False)
+    pgroup.add_argument('-C', '--celcius',  action='store_const',
+                        dest='converter',   const=CONVERT_CELCIUS,
+                        help='measure, critical and warn values in Celcius '
+                             '(default)',   default=CONVERT_CELCIUS)
+    pgroup.add_argument('-F', '--farenheit',action='store_const',
+                        dest='converter',   const=CONVERT_FARENHEIT,
+                        help='measure, critical and warn values in Farenheit')
+
+    parser.add_argument('-w', '--warn',     type=float,
+                        help='temperature for warning status')
+    parser.add_argument('-c','--critical',  type=float,
+                        help='temperature for critical status')
+
+    parser.add_argument('-r', '--retries', type=int,default=SENSOR_READ_RETRIES,
+                        help='number of times to retry reading sensor data when'
+                             ' unstable (defaults to %d)' % SENSOR_READ_RETRIES)
+
+    pgroup = parser.add_mutually_exclusive_group(required=False)
+    pgroup.add_argument('-s', '--serial',
+                        help='(unique part of) temperature sensor serial (*)')
+    pgroup.add_argument('-f', '--file',
+                        help='input file (or device) to obtain data from (*)')
+
+    pgroup = parser.add_mutually_exclusive_group(required=False)
+    pgroup.add_argument('-q', '--quiet',    default=logging.CRITICAL,
+                        action=SetLogLevel, const=LOGGING_NONE,
+                        help='quiet (no output, only exit with exit code)')
+    pgroup.add_argument('-v', '--verbose',  help='more verbose output',
+                        action=SetLogLevel, const=logging.INFO)
+    pgroup.add_argument('-d', '--debug',    help='debug output (more verbose)',
+                        action=SetLogLevel, const=logging.DEBUG)
+
+    parser.add_argument('-l', '--logfile',  action=SetLogFile,
+                        help='send logging output to logfile')
+
+    # parse arguments and post-process command line options
+    args = parser.parse_args()
+
+    # if we got here all seems OK
+    return args
+
+
+def get_sensor_device_filename(args, dev_dir=SENSOR_DEV_DIR,
+                            prefix=SENSOR_DEV_PREFIX, suffix=SENSOR_DEV_SUFFIX):
+    """Auto-determine sensor datafile name (unless args.file is set)"""
+    if isempty(args.file):
+        search_pat = dev_dir + ('/' if dev_dir[-1]!='/' else '')
+        search_pat+= prefix + '*' if isempty(args.serial) else '*' + args.serial
+        logger.debug('looking for sensors with search pattern %s', search_pat)
+
+        device_folders = glob(search_pat)
+        if len(device_folders) == 1:
+            filename = device_folders[0] + suffix
+        else:
+            if len(device_folders) == 0:
+                errmsg = 'no supported temperature sensors in %s' % dev_dir
+            else:
+                serials=map(lambda x: basename(x) if x.find(prefix)<0
+                                 else basename(x)[len(prefix):], device_folders)
+                errmsg = 'found multiple temperature sensors (%s), please '\
+                         'specify which one to use' % ', '.join(serials)
+            logger.critical(errmsg)
+            raise ValueError(errmsg)
+    else:
+        filename = args.file
+    logger.debug('using temperature sensor at %s', filename)
+    return filename
+
+
+def read_sensor_raw(device_file):
+    """Reads the raw data from the sensor device file, returns array of lines"""
+    with open(device_file, 'r') as f:
+        lines = f.readlines()
+        logger.debug('Temperature sensor data read from %s: %s', f.name, lines)
+    return lines
+
+
+def read_temp(device_file, converter=CONVERT_CELCIUS, maxretries=10):
+    """Reads sensor data and converts it to desired unit, returns temperature"""
+    lines = read_sensor_raw(device_file)
+    tries = 1
+    while lines[0].strip()[-3:] != 'YES' and tries <= maxretries:
+        tries += 1
+        sleep(0.2)
+        logger.warn('Temperature sensor data not stable, reading once more')
+        lines = read_temp_raw(device_file)
+
+    if lines[0].strip()[-3:] != 'YES':
+        errmsg = 'no stable temperature sensor data after %d tries' % tries
+    else:
+        equals_pos = lines[1].find('t=')
+        if equals_pos == -1:
+            errmsg = 'temperature sensor data format is not supported'
+        else:
+            temp_read = int(lines[1][equals_pos+2:])
+            temp = converter[0](temp_read)
+            logger.debug('Temperature sensor value %d is %.2f%s', temp_read,
+                         temp, converter[1])
+            return temp, tries
+
+    logger.critical(errmsg)
+    raise ValueError(errmsg)
+
+
+def nagios_exit(status, message, data=None):
+    """exit 'nagios-style', print status and message followed by perf. data"""
+    if logger.isEnabledFor(logging.CRITICAL):
+        if data is not None and len(data) > 0:
+            perfdata=map(lambda (k,v): "'%s'=%s" %(k,v if not isinstance(v,list)
+                     else ';'.join(map(lambda x:'' if x is None else str(x),v)))
+                         ,data.iteritems())
+            perfstr = ' | ' + ' '.join(perfdata)
+        else:
+            perfstr = ''
+        print 'Temperature %s: %s%s' % (status[0], message, perfstr)
+    exit(status[1])
+
+
+if __name__ == '__main__':
+    try:
+        args = parse_args()
+    except ArgumentParserError as e:
+        nagios_exit(NAGIOS_UNKNOWN,'error with setup: ' + e.message)
+    except (KeyboardInterrupt, EOFError) as e:
+        print
+        nagios_exit(NAGIOS_UNKNOWN,'initialization aborted')
+
+    try:
+        starttime = time()
+        devicefile = get_sensor_device_filename(args)
+        temperature, tries = read_temp(devicefile, args.converter, args.retries)
+        endtime = time()
+
+    except (KeyboardInterrupt) as e:
+        nagios_exit(NAGIOS_UNKNOWN,'temperature sensor read aborted by user')
+
+    except (IOError, ValueError) as e:
+        nagios_exit(NAGIOS_UNKNOWN,'temperature sensor read failed: %s' % e)
+
+    elapse = endtime-starttime
+    logger.info('Got temperature reading of %.2f degrees %s in %fs',
+                temperature, args.converter[2], elapse)
+
+    temp_unit = args.converter[1]
+    message = 'current temperature is %.2f%s' % (temperature, temp_unit)
+    if args.critical is not None and temperature > args.critical:
+        nagiosresult = NAGIOS_CRITICAL
+        message += ', above critical threshold %.2f%s'%(args.critical,temp_unit)
+    elif args.warn is not None and temperature > args.warn:
+        nagiosresult = NAGIOS_WARN
+        message += ', above warning threshold %.2f%s' % (args.warn, temp_unit)
+    else:
+        nagiosresult = NAGIOS_OK
+
+    nagios_exit(nagiosresult, message, {
+          'temperature': [ temperature, args.warn, args.critical, None, None],
+          'retries': [ tries-1, None, args.retries, 0, None ],
+          'time': [ '%f' % elapse, None, None, 0, None]
+    })