Fun with salt, basically running scripts on master when events are fired via the Reactor system. The names of the files are paths with - replacing /

etc-salt-reactor

<contents of normal file>
 
# Add any additional locations to look for master runners
runner_dirs: [/srv/runners]
 
# Register a reactor whenever a cloud provider emits 'created'
# the * is the name of the VM, we want any, but you could
# do something like salt/cloud/Webservers-*/created if you only
# wanted your webservers
reactor:
  - 'salt/cloud/*/created':
    - /srv/reactor/subdomain.sls

srv-reactor-subdomain.sls

# `runner.subdomain.add` is literally
# run subdomain.py's add method and the first argument to that function is vm_name
# and set vm_name to the name of the vm just created
subdomain:
  runner.subdomain.add:
    - vm_name: {{ data['name'] }}

srv-runners-subdomain.py

import sys
import salt.client
import json
import urllib2
 
from urllib2 import HTTPError
 
client_id = DIGITALOCEAN_CLIENT_ID 
api_key = DIGITALOCEAN_API_KEY
 
base_url = "https://api.digitalocean.com/domains/$DOMAIN_NAME/records"
list_url = base_url + "?client_id=%s&api_key=%s"
remove_url = base_url + "/%s/destroy?client_id=%s&api_key=%s"
add_url = base_url + "/new?client_id=%s&api_key=%s&record_type=A&data=%s&name=%s"
 
def pretty_json(j):
  return json.dumps(j, indent=2, separators=(',',':'))
 
def request(url):
  return json.load(urllib2.urlopen(url))
  
def remove(vm_name):
  '''
  Remove a vm's subdomain if it already exists
  '''
  # First get a list of existing records
  url = list_url % (client_id, api_key)
  try:
    res = request(url)
 
    # Try and find a duplicate
    records = res['records']
    remove = None
    for record in records:
      if record['name'] == vm_name:
        remove = record;
        break;
 
    if remove:
      print "Removing %s" % pretty_json(remove)
      url = remove_url % (remove['id'], client_id, api_key)
      res = request(url)
      print pretty_json(res)
    else:
      print "No existing record found"
  
  except HTTPError, e:
    print "Unable to list existing records: %s" % e
 
 
# vm_name is coming from salt directly, see the .sls file above
def add(vm_name):
  '''
  Add a new vm to the our cloud domain
  '''
  client = salt.client.LocalClient(__opts__['conf_file'])
  ip = client.cmd(vm_name, 'network.ip_addrs', interface='eth0', timeout=5)[vm_name][0]
 
  remove(vm_name)
 
  print 'Adding %s (%s) to subdomain list' % (vm_name,  ip)
  url = add_url % (client_id, api_key, ip, vm_name)
  
  try:
    res = request(url)
    print res
   
  except HTTPError, e:
    print "Unable to add record: %s" % e