#!/usr/bin/env python
"""
# Cycle on the list of Xen hypervisors
# Get the list of the online hosts
# Build the hosts file in a format that prometheus likes (json better than yaml)
# One file for hypervisor?

# Input example (one node on one hypervisor):
<map>
 <dom online="yes" domain="parthenos.d4science.org">
  <name>themas.parthenos.d4science.org</name>
  <mem>6000</mem>
  <uptime>136d</uptime>
  <fulluptime>136d22h5m</fulluptime>
  <cpus>2</cpus>
  <san>no</san>
  <uuid>no</uuid>
  <badconf>no</badconf>
  <avgXenCpu>0</avgXenCpu>
 </dom>
 </map>

# Output example:

[
  {
    "targets": ["127.0.0.1:9100"],
    "labels": {
      "instance": "localhost"
    }
  }
]
 """


import requests
import lxml
from lxml import etree
import json

# hypervisors with hostname under 20 are either dismissed or do not export a xenmap
# The latest available Xen hypervisor is 35
hy_lower = 20
hy_upper = 36
prometheus_node_port = 9100
dest_path_prefix = '/opt/prometheus/conf/sd_nodes'
dest_path_prefix = '/tmp'
host_data = {}

def get_hosts(xenmap_url):
        hosts_list = []
        xenmap = requests.get(xenmap_url)
        hostmap = etree.fromstring(xenmap.text)

        for dom in hostmap.findall('dom'):
                host = dom.find('name').text
                status = dom.get('online')
                if status == 'yes':
                        prometheus_target = host + ':' + str(prometheus_node_port)
                        hosts_list.append(prometheus_target)
        return hosts_list


hypervisors = range(hy_lower, hy_upper)
for i in 5, 7, 11:
        hypervisors.append(i)
for hyper_num in hypervisors:
        hypervisor_host = 'dlib' + str(hyper_num) + 'x.dom0.research-infrastructures.eu'
        xenmap_url = 'http://' + hypervisor_host + '/xen/map.xml'
        dest_file = dest_path_prefix + '/' + hypervisor_host + '.json'
        host_data['labels'] = dict(group='node')
        host_data['targets'] = get_hosts(xenmap_url)
        if host_data['targets']:
                json_data = json.dumps(host_data, ensure_ascii=False, sort_keys=False, indent=4)
                write_file = open(dest_file, 'w')
                write_file.write(json_data)
                write_file.close()

                print hypervisor_host + (' VMs ') + json_data