#!/usr/bin/env python

#
# check_varnishbackends.py
# Varnish Backend Checker for Icinga/Nagios

# Author
#  - Scott Mcintyre <me@scott.cm>
#  - http://scott.cm
# Usage
#  -h, --help            	Show help message and exit
#  -H HOST, --host=HOST  	The ip varnishadm is listening on (Default: 127.0.0.1)
#  -P PORT, --port=PORT  	The port varnishadm is listening on (Default: 6082)
#  -s SECRET, --secret=SECRET 	The path to the secret file (Default: /etc/varnish/secret)
#  -p PATH, --path=PATH  	The path to the varnishadm binary (Default: /usr/bin/varnishadm
# Example: ./check_varnishbackends.py -H 127.0.0.1 -P 6082 -S /etc/varnish/secret -p /usr/bin/varnishadm
# 

import sys
import optparse
import subprocess

def runcommand(command, exit_on_fail=True):
    try:
      process = subprocess.Popen(command.split(" "), stdout=subprocess.PIPE)
      output, unused_err = process.communicate()
      retcode = process.poll()
      return output

    except OSError, e:
      print "Error: Executing command failed,  does it exist?"
      sys.exit(2)


def main(argv):
  o = optparse.OptionParser(conflict_handler="resolve", description="Nagios plugin to check varnish backend health.")
  o.add_option('-H', '--host', action='store', type='string', dest='host', default='127.0.0.1', help='The ip varnishadm is listening on')
  o.add_option('-P', '--port', action='store', type='int', dest='port', default=6082, help='The port varnishadm is listening on')
  o.add_option('-s', '--secret', action='store', type='string', dest='secret', default='/etc/varnish/secret', help='The path to the secret file')
  o.add_option('-p', '--path', action='store', type='string', dest='path', default='/usr/bin/varnishadm', help='The path to the varnishadm binary')

  options=o.parse_args()[0]
  command = runcommand("%(path)s -S %(secret)s -T %(host)s:%(port)s debug.health" % options.__dict__)
  backends = command.split("\n")
  backends_healthy, backends_sick = [], []
  for line in backends:
    if line.startswith("Backend") and line.find("test")==-1:
      if line.endswith("Healthy"):
        backends_healthy.append(line.split(" ")[1])
      else:
        backends_sick.append(line.split(" ")[1])
 
  if backends_sick:
    print "%s backends are down.  %s" % (len(backends_sick), "".join(backends_sick))
    sys.exit(2)

  if not backends_sick and not backends_healthy:
    print "No backends found"
    sys.exit(1)

  print "All %s backends are healthy" % (len(backends_healthy))
  sys.exit(0)


if __name__ == "__main__":
    main(sys.argv[1:])