Add salt-ssh roster for the minons cache on the master

salt/roster/cache.py

@@ -0,0 +1,75 @@
+# -*- coding: utf-8 -*-
+'''
+Use the minion cache on the master to derive IP addresses based on minion ID.
+
+Currently only contains logic to return an IPv4 address; does not handle IPv6,
+or authentication (passwords, keys, etc).
+
+It is possible to configure this roster to prefer a particular type of IP over
+another. To configure the order, set the roster_order in the master config
+file. The default for this is:
+
+.. code-block:: yaml
+
+    roster_order:
+      - public
+      - private
+      - local
+'''
+
+# Import python libs
+import os.path
+import msgpack
+
+# Import Salt libs
+import salt.loader
+import salt.utils
+import salt.utils.cloud
+import salt.utils.validate.net
+from salt import syspaths
+
+
+def targets(tgt, tgt_type='glob', **kwargs):  # pylint: disable=W0613
+    '''
+    Return the targets from the flat yaml file, checks opts for location but
+    defaults to /etc/salt/roster
+    '''
+    cache = os.path.join(syspaths.CACHE_DIR, 'master', 'minions', tgt, 'data.p')
+
+    if not os.path.exists(cache):
+        return {}
+
+    roster_order = __opts__.get('roster_order', (
+        'public', 'private', 'local'
+    ))
+
+    with salt.utils.fopen(cache, 'r') as fh_:
+        cache_data = msgpack.load(fh_)
+
+    ipv4 = cache_data.get('grains', {}).get('ipv4', [])
+    preferred_ip = extract_ipv4(roster_order, ipv4)
+    if preferred_ip is None:
+        return {}
+
+    return {
+        tgt: {
+            'host': preferred_ip,
+        }
+    }
+
+
+def extract_ipv4(roster_order, ipv4):
+    '''
+    Extract the preferred IP address from the ipv4 grain
+    '''
+    for ip_type in roster_order:
+        for ip_ in ipv4:
+            if not salt.utils.validate.net.ipv4_addr(ip_):
+                continue
+            if ip_type == 'local' and ip_.startswith('127.'):
+                return ip_
+            elif ip_type == 'private' and not salt.utils.cloud.is_public_ip(ip_):
+                return ip_
+            elif ip_type == 'public' and salt.utils.cloud.is_public_ip(ip_):
+                return ip_
+    return None