[context] Improved flexibility of configuration variables

Now the form {{var_name}} is allowed too.

Author: nemesifier

docs/source/general/basics.rst

@@ -354,8 +354,7 @@ Let's see the result with:
 .. warning::
     **When using variables, keep in mind the following rules**:
 
-     * variables must be written in the form of ``{{ var_name }}``, including
-       spaces around ``var_name``;
+     * variables must be written in the form of ``{{ var_name }}`` or ``{{var_name}}``;
      * variable names can contain only alphanumeric characters and underscores;
      * unrecognized variables will be ignored;
 

netjsonconfig/utils.py

@@ -37,7 +37,7 @@ def sorted_dict(dictionary):
     return OrderedDict(sorted(dictionary.items()))
 
 
-var_pattern = re.compile(r'\{\{\s(\w*)\s\}\}')
+var_pattern = re.compile(r'\{\{(.*)\}\}')
 
 
 def evaluate_vars(data, context={}):
@@ -58,8 +58,9 @@ def evaluate_vars(data, context={}):
             data[key] = evaluate_vars(value, context)
     elif isinstance(data, six.string_types):
         for var in var_pattern.findall(data):
+            var = var.strip()
             if var in context:
-                data = data.replace('{{ %s }}' % var, context[var])
+                data = re.sub(var_pattern, context[var], data)
     return data
 
 

tests/test_utils.py

@@ -133,3 +133,12 @@ def test_evaluate_vars_list(self):
     def test_evaluate_vars_list_in_dict(self):
         val = evaluate_vars({'l': ['{{ a }}', '{{ b }}']}, {'a': '1', 'b': '2'})
         self.assertEqual(val, {'l': ['1', '2']})
+
+    def test_evaluate_vars_nowhitespace(self):
+        self.assertEqual(evaluate_vars('{{tz}}', {'tz': 'UTC'}), 'UTC')
+
+    def test_evaluate_vars_doublewhitespace(self):
+        self.assertEqual(evaluate_vars('{{  tz  }}', {'tz': 'UTC'}), 'UTC')
+
+    def test_evaluate_vars_strangewhitespace(self):
+        self.assertEqual(evaluate_vars('{{  tz}}', {'tz': 'UTC'}), 'UTC')