use the cache runner in the cache roster file to get grains

Instead of having to query each file individitually.

.testing.pylintrc

@@ -227,6 +227,7 @@ additional-builtins=__opts__,
   __pillar__,
   __grains__,
   __context__,
+  __runner__,
   __ret__,
   __env__,
   __low__,

salt/loader.py

@@ -432,7 +432,7 @@ def fileserver(opts, backends):
                       pack={'__utils__': utils(opts)})
 
 
-def roster(opts, whitelist=None):
+def roster(opts, runner, whitelist=None):
     '''
     Returns the roster modules
     '''
@@ -441,6 +441,7 @@ def roster(opts, whitelist=None):
         opts,
         tag='roster',
         whitelist=whitelist,
+        pack={'__runner__': runner},
     )
 
 

salt/roster/__init__.py

@@ -50,7 +50,7 @@ def __init__(self, opts, backends='flat'):
             self.backends = backends
         if not backends:
             self.backends = ['flat']
-        self.rosters = salt.loader.roster(opts)
+        self.rosters = salt.loader.roster(opts, runner=salt.loader.runner(self.opts))
 
     def _gen_back(self):
         '''

salt/roster/cache.py

@@ -18,45 +18,28 @@
 '''
 from __future__ import absolute_import
 
-# 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,
-        }
-    }
+    cached_data = __runner__['cache.grains'](tgt=tgt, expr_form=tgt_type)
+    ret = {}
+    for server, grains in cached_data.items():
+        ret[server] = {'host': extract_ipv4(roster_order, grains.get('ipv4', []))}
+    return ret
 
 
 def extract_ipv4(roster_order, ipv4):