Simple nagios check that reads a json via http and converts it's output to a nagios check result

check_http_json

#!/usr/bin/python
#
'''
 This script reads a JSON from an URL and converts it to nagios-plugin output.
 The JSON must be in the following format (See https://nagios-plugins.org/doc/guidelines.html#AEN78
 for Details about min/max/warn/crit values and units:
 {
   status: 'OK'|'WARNING'|'CRITICAL',
   message: 'any text not containing single quote',
   metrics: [ // optional
     {
       name: 'MetricName',
       value: 12345.67,
       unit: optional unit,
       min: optional min value,
       max: optional max value,
       warn: optional warning threshold,
       crit: optional critical threshold,
     },
     { ... }
   ]
 }
'''


import sys
import urllib3
import simplejson

ST_OK=0
ST_WARN=1
ST_CRIT=2

def main():
	args=sys.argv
#	args=["","http://crawler1.jenkins.evermind.de:8080/service/status/DE_IMMOSCOUT24"]
	if (len(args)!=2):
		print("CRITICAL: Missing argument: URL")
		sys.exit(ST_CRIT)
	url=args[1]
	http = urllib3.PoolManager()
	try:
		req = http.request("GET",url)
	except (ConnectionRefusedError,urllib3.exceptions.MaxRetryError):
		print("CRITICAL: Unable to connect to "+url)
		sys.exit(ST_CRIT)

	if (req.status!=200):
		print("CRITICAL: Got HTTP-Status "+str(req.status))
		sys.exit(ST_CRIT)

	try:
		json=simplejson.loads(req.data)
	except (TypeError,UnicodeDecodeError):
		print("CRITICAL: Unable to parse json: "+str(req.data))
		sys.exit(ST_CRIT)

	metrics=""

	if ('metrics' in json and hasattr(json['metrics'], '__iter__')):
		metrics+=" |"
		for metric in json['metrics']:
			metrics+=" '"+metric['name']+"'"
			metrics+="="+str(metric['value'])
			if ('unit' in json):
				metrics+=metric['unit']
			metrics+=';'
			if ('warn' in json):
				metrics+=int(metric['warn'])
			metrics+=';'
			if ('crit' in json):
				metrics+=int(metric['crit'])
			metrics+=';'
			if ('min' in json):
				metrics+=int(metric['min'])
			metrics+=';'
			if ('max' in json):
				metrics+=int(metric['max'])

	if ('status' not in json):
		print("CRITICAL: Invalid json: "+simplejson.dumps(json))
		sys.exit(ST_CRIT)

	print(json['message']+metrics)
	if (json['status']=='OK'):
		sys.exit(ST_OK)
	if (json['status']=='WARNING'):
		sys.exit(ST_WARN)
	sys.exit(ST_CRIT)






if __name__ == "__main__":
	main()