#!/usr/bin/env python3
"""

=head1 NAME

nova_instance_ - monitor status of Floating IPs in Nova


=head1 CONFIGURATION


To monitor instance states, link instance_states to this file.
E.g.

 ln -s /usr/share/munin/plugins/nova_instance_states /etc/munin/plugins/

Needs following minimal configuration in plugin-conf.d/nova:

 [nova_*]
 user nova


=head1 AUTHORS

Copyright 2012 Mehdi Abaakouk <sileht@sileht.net>


=head1 MAGIC MARKERS

 #%# capabilities=autoconf suggest
 #%# family=auto

=cut
"""

import os
import sys


try:
    from nova import context
    from nova import db
    from nova import flags
    from nova import utils
    from nova.compute import power_state
except ImportError:
    successful_import = False
else:
    successful_import = True


class InstanceState:
    instance_counts = None
    states = None

    @classmethod
    def init(cls, metric):
        if cls.states and cls.instance_counts:
            return
        ctxt = context.get_admin_context()
        instances = db.instance_get_all(ctxt)
        cls.instance_counts = {}
        instance_types = {}
        for it in db.instance_type_get_all(ctxt, True):
            instance_types[it['id']] = it['name']

        for instance in instances:
            i = dict(instance)
            i['type'] = instance_types.get(instance.instance_type_id, '(unknown')
            i['instance_type'] = i['type']
            val = cls.instance_counts.get(i[metric], 0)
            cls.instance_counts[i[metric]] = val + 1
        cls.states = cls.instance_counts.keys()

    @classmethod
    def get_states(cls, metric):
        InstanceState.init(metric)
        return cls.states

    @classmethod
    def get_instance_counts(cls, metric):
        InstanceState.init(metric)
        return cls.instance_counts


def get_name(metric, code):
    if metric == "power_state":
        return power_state.name(code)
    elif metric in ["root_gb", "ephemeral_gb"]:
        return "%d gb" % code
    else:
        return code


def print_config(metric):
    states = InstanceState.get_states(metric)
    print('graph_title Nova Instance %s' % metric)
    print('graph_vlabel instances')
    print('graph_args --base 1000 --lower-limit 0')
    print('graph_category cloud')
    print('graph_scale no')
    print('graph_info This graph shows the number of instances by %s' % metric)
    for state in states:
        print('%s.label %s' % (state, get_name(metric, state)))
        print('%s.draw LINE2' % state)
        print('%s.info %s IPs' % (state, state))


def print_values(metric):
    status = InstanceState.get_instance_counts(metric)
    for (state, value) in status.items():
        print('%s.value %s' % (state, value))


def print_suggest():
    suggest = [
        "vm_state",
        "vcpus",
        "task_state",
        "root_gb",
        "ephemeral_gb",
        "power_state",
        "memory_mb",
        "instance_type_id",
    ]
    print(os.linesep.join(suggest))


if __name__ == '__main__':
    argv = sys.argv[:]
    utils.default_flagfile()
    flags.FLAGS(sys.argv)
    metric = argv[0].split('nova_instance_').pop() or 'vm_state'

    if len(argv) > 1:
        if argv[1] == 'config':
            print_config(metric)
        elif argv[1] == 'suggest':
            print_suggest()
        elif argv[1] == 'autoconf':
            if not successful_import:
                print('no (failed import nova module)')
            else:
                print('yes')
            sys.exit(0)
    elif successful_import:
        print_values(metric)