check_docker

#! /usr/bin/env python

import argparse
import docker
import nagiosplugin


class Docker(nagiosplugin.Resource):

    def __init__(self, url, api_version):
        self.url = url
        self.api_version = api_version

    def probe(self):
        '''Checks docker stats.

        This method returns the following metrics: 

        `images` is total number of docker images
        on the Docker system. 

        `go_routines` are the number of go threads.

        `file_descriptors` are the number of open file descriptors.

        `events_listeners` are the number of events listener processes.
        '''

        conn = docker.Client(base_url=self.url, version=self.api_version, timeout=20)

        # try to connect the docker service, and catch an exception if we
        # can't.
        try:
            docker_info = conn.info()
            self.docker_running = True
        except:
            self.docker_running = False

        if self.docker_running == True:
            self.images = docker_info['Images']
            self.go_routines = docker_info['NGoroutines']
            self.file_descriptors = docker_info['NFd']
            self.events_listeners = docker_info['NEventsListener']

            metrics = [
                nagiosplugin.Metric(
                    'service', self.docker_running),
                nagiosplugin.Metric('images', self.images, context='default'),
                nagiosplugin.Metric(
                    'go_routines', self.go_routines, context='default'),
                nagiosplugin.Metric(
                    'file_descriptors', self.file_descriptors, context='default'),
                nagiosplugin.Metric(
                    'events_listeners', self.events_listeners, context='default')
            ]

        else:
            metrics = [nagiosplugin.Metric('service', self.docker_running)]

        return metrics


class DockerSummary(nagiosplugin.Summary):

    def verbose(self, results):
        ''' Super-classes summary so we can get verbose results '''
        super(DockerSummary, self).verbose(results)

# If the nagios plugin aborts with an uncaught exception or timeout, it exits with 
# an unknown exit code and prints a traceback in a format acceptable by Nagios.
@nagiosplugin.guarded

def main():

    argp = argparse.ArgumentParser()
    argp.add_argument('-u', '--url', metavar='URL',
                      help='URL string for Docker service.',
                      default='unix://var/run/docker.sock'),
    argp.add_argument('-a', '--api_version', default='1.16',
                      help='client API version (default 1.16)')
    argp.add_argument('-t', '--timeout', default=10,
                      help='abort execution after TIMEOUT seconds')
    argp.add_argument('-v', '--verbose', action='count', default=0,
                      help='increase output verbosity (use up to 3 times)')

    args = argp.parse_args()

    # create our check object, if service metric !=0, consider that critical.
    check = nagiosplugin.Check(Docker(args.url, args.api_version),
                               nagiosplugin.ScalarContext('service', '0', '0', fmt_metric=''),
                               DockerSummary())

    check.main(args.verbose, args.timeout)


if __name__ == '__main__':
    main()