Add support for using index and attribute names in the get_attribute function

Change-Id: Ifb9ef61871a22651cb01643996fccebe33184607
Related-Bug: 1539539

toscaparser/functions.py

@@ -120,15 +120,31 @@ class GetAttribute(Function):
 
     * { get_attribute: [ server, private_address ] }
     * { get_attribute: [ HOST, private_address ] }
+    * { get_attribute: [ HOST, private_address, 0 ] }
     """
 
     def validate(self):
-        if len(self.args) != 2:
+        if len(self.args) != 2 and len(self.args) != 3:
             ExceptionCollector.appendException(
                 ValueError(_('Illegal arguments for function "{0}". Expected '
                              'arguments: "node-template-name", '
                              '"attribute-name"').format(GET_ATTRIBUTE)))
-        self._find_node_template_containing_attribute()
+        node_tpl = self._find_node_template_containing_attribute()
+        if len(self.args) > 2:
+            # Currently we only check the first level
+            attrs_def = node_tpl.type_definition.get_attributes_def()
+            attr_def = attrs_def[self.attribute_name]
+            if attr_def.schema['type'] == "list":
+                if not isinstance(self.args[2], int):
+                    ExceptionCollector.appendException(
+                        ValueError(_('Illegal arguments for function "{0}". '
+                                     'Third argument must be a positive'
+                                     ' integer') .format(GET_ATTRIBUTE)))
+            elif attr_def.schema['type'] != "map":
+                ExceptionCollector.appendException(
+                    ValueError(_('Illegal arguments for function "{0}". '
+                                 'Expected arguments: "node-template-name", '
+                                 '"attribute-name"').format(GET_ATTRIBUTE)))
 
     def result(self):
         return self

toscaparser/tests/data/custom_types/compute_with_attribute_list.yaml

@@ -0,0 +1,13 @@
+tosca_definitions_version: tosca_simple_yaml_1_0
+
+description: Compute node type with a list attribute
+
+node_types:
+  tosca.nodes.ComputeWithAttrList:
+    derived_from: tosca.nodes.Compute
+    attributes:
+      attr_list:
+        type: map
+        entry_schema:
+          type: string
+

toscaparser/tests/data/functions/test_get_attribute_with_index.yaml

@@ -0,0 +1,19 @@
+tosca_definitions_version: tosca_simple_yaml_1_0
+
+description: >
+  TOSCA template for testing get_attribute with a list attribute and an index
+
+imports:
+  - ../custom_types/compute_with_attribute_list.yaml
+
+topology_template:
+  node_templates:
+    server:
+      type: tosca.nodes.ComputeWithAttrList
+      interfaces:
+        Standard:
+          configure:
+            implementation: configure.sh
+            inputs:
+              ip_address: { get_attribute: [ SELF, attr_list, 0 ] }
+

toscaparser/tests/data/functions/test_get_attribute_with_index_error.yaml

@@ -0,0 +1,19 @@
+tosca_definitions_version: tosca_simple_yaml_1_0
+
+description: >
+  TOSCA template for testing get_attribute with a list attribute and an index
+
+imports:
+  - ../custom_types/compute_with_attribute_list.yaml
+
+topology_template:
+  node_templates:
+    server:
+      type: tosca.nodes.ComputeWithAttrList
+      interfaces:
+        Standard:
+          configure:
+            implementation: configure.sh
+            inputs:
+              ip_address: { get_attribute: [ SELF, private_address, 0 ] }
+

toscaparser/tests/test_functions.py

@@ -188,7 +188,7 @@ class GetAttributeTest(TestCase):
         self.assertIn(expected_msg, six.text_type(err))
         err = self.assertRaises(ValueError,
                                 functions.get_function, None, None,
-                                {'get_attribute': ['x', 'y', 'z']})
+                                {'get_attribute': ['x', 'y', 'z', 'k']})
         self.assertIn(expected_msg, six.text_type(err))
 
     def test_get_attribute_unknown_node_template_name(self):
@@ -243,3 +243,16 @@ class GetAttributeTest(TestCase):
             ValueError,
             _('"get_attribute: [ HOST, ... ]" is not allowed in "outputs" '
               'section of the TOSCA template.'))
+
+    def test_get_attribute_with_index(self):
+        self._load_template(
+            'functions/test_get_attribute_with_index.yaml')
+
+    def test_get_attribute_with_index_error(self):
+        self.assertRaises(
+            exception.ValidationError, self._load_template,
+            'functions/test_get_attribute_with_index_error.yaml')
+        exception.ExceptionCollector.assertExceptionMessage(
+            ValueError,
+            _('Illegal arguments for function "get_attribute". '
+              'Expected arguments: "node-template-name", "attribute-name"'))