#!/usr/bin/env python3
"""
=head1 NAME

docker_ - Docker wildcard-plugin to monitor a L<Docker|https://www.docker.com> host.

This wildcard plugin provides at the moment only the suffixes C<containers>, C<images>, C<status>,
C<volumes>, C<cpu> and C<memory>.

=head1 INSTALLATION

- Copy this plugin in your munin plugins directory
- Install Python3 "docker" package

=over 2

    ln -s /usr/share/munin/plugins/docker_ /etc/munin/plugins/docker_containers
    ln -s /usr/share/munin/plugins/docker_ /etc/munin/plugins/docker_cpu
    ln -s /usr/share/munin/plugins/docker_ /etc/munin/plugins/docker_images
    ln -s /usr/share/munin/plugins/docker_ /etc/munin/plugins/docker_memory
    ln -s /usr/share/munin/plugins/docker_ /etc/munin/plugins/docker_status
    ln -s /usr/share/munin/plugins/docker_ /etc/munin/plugins/docker_volumes

=back

After the installation you need to restart your munin-node:

=over 2

    systemctl restart munin-node

=back

=head1 CONFIGURATION

This plugin need to run as root, you need to create a file named docker placed in the
directory /etc/munin/plugin-conf.d/ with the following config (you can also use
Docker environment variables here as described in
https://docs.docker.com/compose/reference/envvars/):

=over 2

    [docker_*]
    user root
    env.DOCKER_HOST unix://var/run/docker.sock

=back
"""

import os
import sys
import docker


def print_containers_status(client):
    running = 0
    paused = 0
    created = 0
    restarting = 0
    removing = 0
    exited = 0
    dead = 0
    for container in client.containers.list():
        if container.status == 'running':
            running += 1
        elif container.status == 'paused':
            paused += 1
        elif container.status == 'created':
            created += 1
        elif container.status == 'restarting':
            restarting += 1
        elif container.status == 'removing':
            removing += 1
        elif container.status == 'exited':
            exited += 1
        elif container.status == 'dead':
            dead += 1
    print('running.value', running)
    print('paused.value', paused)
    print('created.value', created)
    print('restarting.value', restarting)
    print('removing.value', removing)
    print('exited.value', exited)
    print('dead.value', dead)


def print_containers_cpu(client):
    for container in client.containers.list():
        stats = container.stats(stream=False)
        cpu_count = len(stats["cpu_stats"]["cpu_usage"]["percpu_usage"])
        cpu_percent = 0.0
        cpu_delta = float(stats["cpu_stats"]["cpu_usage"]["total_usage"]) \
            - float(stats["precpu_stats"]["cpu_usage"]["total_usage"])
        system_delta = float(stats["cpu_stats"]["system_cpu_usage"]) \
            - float(stats["precpu_stats"]["system_cpu_usage"])
        if system_delta > 0.0:
            cpu_percent = cpu_delta / system_delta * 100.0 * cpu_count
        print(container.name + '.value', cpu_percent)


def print_containers_memory(client):
    for container in client.containers.list():
        stats = container.stats(stream=False)['memory_stats']
        print(container.name + '.value', stats['stats']['total_rss'])


def main():
    try:
        mode = sys.argv[1]
    except IndexError:
        mode = ""
    wildcard = sys.argv[0].split("docker_")[1].split("_")[0]

    if mode == "suggest":
        print("containers")
        print("cpu")
        print("images")
        print("memory")
        print("status")
        print("volumes")

    client = docker.from_env()

    if wildcard == "status":
        if mode == "config":
            print("graph_title Docker status")
            print("graph_vlabel containers")
            print("graph_category virtualization")
            print("running.label RUNNING")
            print("paused.label PAUSED")
            print("created.label CREATED")
            print("restarting.label RESTARTING")
            print("removing.label REMOVING")
            print("exited.label EXITED")
            print("dead.label DEAD")
        else:
            print_containers_status(client)
    elif wildcard == "containers":
        if mode == "config":
            print("graph_title Docker containers")
            print("graph_vlabel containers")
            print("graph_category virtualization")
            print("containers_quantity.label Containers")
        else:
            print('containers_quantity.value', len(client.containers.list()))
    elif wildcard == "images":
        if mode == "config":
            print("graph_title Docker images")
            print("graph_vlabel images")
            print("graph_category virtualization")
            print("images_quantity.label Images")
        else:
            print('images_quantity.value', len(client.images.list()))
    elif wildcard == "volumes":
        if mode == "config":
            print("graph_title Docker volumes")
            print("graph_vlabel volumes")
            print("graph_category virtualization")
            print("volumes_quantity.label Volumes")
        else:
            print('volumes_quantity.value', len(client.volumes.list()))
    elif wildcard == "cpu":
        if mode == "config":
            graphlimit = str(os.cpu_count() * 100)
            print("graph_title Docker containers CPU usage")
            print("graph_args --base 1000 -r --lower-limit 0 --upper-limit " + graphlimit)
            print("graph_scale no")
            print("graph_period second")
            print("graph_vlabel CPU usage (%)")
            print("graph_category virtualization")
            print("graph_info This graph shows docker container CPU usage.")
            for container in client.containers.list():
                print("{}.label {}".format(container.name, container.name))
        else:
            print_containers_cpu(client)
    elif wildcard == "memory":
        if mode == "config":
            print("graph_title Docker containers memory usage")
            print("graph_args --base 1024 -l 0")
            print("graph_vlabel Bytes")
            print("graph_category virtualization")
            print("graph_info This graph shows docker container memory usage.")
            for container in client.containers.list():
                print("{}.label {}".format(container.name, container.name))
        else:
            print_containers_memory(client)


if __name__ == '__main__':
    main()