adding min() and max() filters for use in Jinja templates

docsite/rst/playbooks_variables.rst

@@ -180,6 +180,20 @@ Jinja2 provides a useful 'default' filter, that is often a better approach to fa
 In the above example, if the variable 'some_variable' is not defined, the value used will be 5, rather than an error
 being raised.
 
+.. _list_filters:
+
+List Filters
+--------------------
+.. versionadded:: 1.7
+
+To get the minimum value from list of numbers::
+
+    {{ list1 | min }}
+
+To get the maximum value from a list of numbers::
+
+    {{ [3, 4, 2] | max }}
+
 .. _set_theory_filters:
 
 Set Theory Filters

lib/ansible/runner/filter_plugins/core.py

@@ -183,6 +183,14 @@ def union(a, b):
         c = unique(a + b)
     return c
 
+def min(a):
+    _min = __builtins__.get('min')
+    return _min(a);
+
+def max(a):
+    _max = __builtins__.get('max')
+    return _max(a);
+
 def version_compare(value, version, operator='eq', strict=False):
     ''' Perform a version comparison on a value '''
     op_map = {
@@ -289,6 +297,8 @@ class FilterModule(object):
             'difference': difference,
             'symmetric_difference': symmetric_difference,
             'union': union,
+            'min' : min,
+            'max' : max,
 
             # version comparison
             'version_compare': version_compare,

test/units/TestFilters.py

@@ -175,3 +175,11 @@ class TestFilters(unittest.TestCase):
         self.assertTrue(ansible.runner.filter_plugins.core.version_compare(1.0, 1.1, '<='))
 
         self.assertTrue(ansible.runner.filter_plugins.core.version_compare('12.04', 12, 'ge'))
+
+    def test_min(self):
+        a = ansible.runner.filter_plugins.core.min([3, 2, 5, 4])
+        assert a == 2
+
+    def test_max(self):
+        a = ansible.runner.filter_plugins.core.max([3, 2, 5, 4])
+        assert a == 5