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nagios-plugins/check_cpu.py/okplugin_check_cpu
2014-03-07 11:23:28 +00:00

132 lines
3.8 KiB
Python

#!/usr/bin/python
#
# Copyright 2014, Tomas Edwardsson
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program 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, see <http://www.gnu.org/licenses/>.
"""
Gathers information on cpu usage on a linux machine
It returns performance data for both the last 5 seconds and from last run.
"""
from pynag.Plugins import PluginHelper, ok, unknown
import os
import time
def main():
"""The main logic of the program"""
# See man proc and search for /proc/stat
stat_fields = ['cpu', 'user', 'nice', 'system', 'idle', 'iowait', 'irq',
'softirq', 'steal', 'guest', 'guest_nice']
pyplug = PluginHelper()
# Get the statistics from last run
old_stat = get_saved_stat()
# Get current state
stat = get_stat()
# Resample
time.sleep(5)
stat2 = get_stat()
try:
save_stat(stat)
except IOError, err:
pyplug.exit(unknown, "Unable to save cpu statistics: %s" % err)
# Calculate averages for the last few seconds
current_averages = diff_stats(stat2, stat)
for pos in range(len(current_averages)):
pyplug.add_metric(label=stat_fields[pos+1],
value=current_averages[pos],
uom="%")
# Calculate averages from last run
if old_stat:
last_run_avg = diff_stats(old_stat, stat)
for pos in range(len(current_averages)):
pyplug.add_metric(label=stat_fields[pos+1]+"_avg",
value=last_run_avg[pos],
uom="%")
pyplug.add_status(ok)
pyplug.add_summary("CPU load %.2f%%" % (100.0 - current_averages[3]))
pyplug.exit()
def diff_stats(older, newer):
"""Calculates the percentage between two stat arrays"""
if older:
diff = []
for pos in range(len(newer)):
diff.append(newer[pos] - older[pos])
averages = calc_avg(diff)
else:
averages = calc_avg(newer)
return averages
def remove_stale_state():
"""Removes the last state file if we have rebooted"""
try:
state_mtime = os.stat("/var/lib/nagios-okplugin/check_cpu").st_mtime
boot_time = os.stat("/proc/1").st_mtime
if state_mtime < boot_time:
os.unlink("/var/lib/nagios-okplugin/check_cpu")
except OSError:
return None
return state_mtime
def calc_avg(stat):
"""Calculates the average of each int in array"""
stat_sum = sum(stat)
avg = []
for pos in range(len(stat)):
avg.append(float(stat[pos]) / stat_sum * 100)
return avg
def get_stat():
"""Fetches the first line from /proc/stat and returns the numbers"""
stat_fh = open("/proc/stat")
return [int(pos) for pos in stat_fh.readline().split()[1:]]
def get_saved_stat():
"""Fetches information about the last run to be able to do averages"""
remove_stale_state()
try:
stat_fh = open("/var/lib/nagios-okplugin/check_cpu")
except IOError:
return None
return [int(pos) for pos in stat_fh.readline().split()[1:]]
def save_stat(stat):
"""Save statistics to compare to in next run"""
stat_fh = open("/var/lib/nagios-okplugin/check_cpu", "w")
stat_fh.write("cpu " + " ".join([str(pos) for pos in stat]) + "\n")
stat_fh.close()
if __name__ == "__main__":
main()
# vim: sts=4 expandtab