Remove keys of disconnected Saltstack minions

master

# Enable "presence" events
# - http://docs.saltstack.com/en/latest/ref/configuration/master.html#presence-events
# - http://docs.saltstack.com/en/latest/topics/event/master_events.html#presence-events
presence_events: True

reactor:
 # Note: This tag has a typo in it (version 2014.1.5), subject to change!
 - 'salt/presense/change':
   - /srv/reactor/presence.sls

presence.sls

{% for minion_id in data['lost'] %}
remove_unused_keys:
  wheel.key.delete:
    - match: {{ minion_id }}
{% endfor %}

to those that find this using google, here's an updated version without the typo from version 2014.1.5
the following is confirmed working in 2016.11.3:

reactor:
  - 'salt/presence/change':
    - /srv/reactor/presence.sls

{% for minion_id in data['lost'] %}
remove_unused_keys_{{ minion_id }}: # avoid duplicate key error
  wheel.key.delete:
    - match: {{ minion_id }}
{% endfor %}