Merge pull request #9270 from bcoca/do_the_shuffle

added new 'shuffle' filter

docsite/rst/playbooks_variables.rst

@@ -297,6 +297,20 @@ Get a random number from 1 to 100 but in steps of 10::
     {{ 100 |random(start=1, step=10) }}    => 51
 
 
+Shuffle Filter
+--------------
+
+.. versionadded:: 1.8
+
+This filter will randomize an existing list, giving a differnt order every invocation.
+
+To get a random list from an existing  list::
+
+    {{ ['a','b','c']|shuffle }} => ['c','a','b']
+    {{ ['a','b','c']|shuffle }} => ['b','c','a']
+
+note that when used with a non 'listable' item it is a noop, otherwise it always returns a list
+
 .. _other_useful_filters:
 
 Other Useful Filters

lib/ansible/runner/filter_plugins/core.py

@@ -28,7 +28,7 @@ import operator as py_operator
 from ansible import errors
 from ansible.utils import md5s, checksum_s
 from distutils.version import LooseVersion, StrictVersion
-from random import SystemRandom
+from random import SystemRandom, shuffle
 from jinja2.filters import environmentfilter
 
 
@@ -235,6 +235,13 @@ def rand(environment, end, start=None, step=None):
     else:
         raise errors.AnsibleFilterError('random can only be used on sequences and integers')
 
+def randomize_list(mylist):
+    try:
+        mylist = list(mylist)
+        shuffle(mylist)
+    except:
+        pass
+    return mylist
 
 class FilterModule(object):
     ''' Ansible core jinja2 filters '''
@@ -310,6 +317,7 @@ class FilterModule(object):
             # version comparison
             'version_compare': version_compare,
 
-            # random numbers
+            # random stuff
             'random': rand,
+            'shuffle': randomize_list,
         }