Add validation on 'with-items' input

Partially implements blueprint mistral-with-items

Change-Id: I5c2446133ab6447ffd8f9c6336b11cc8fb340804

mistral/exceptions.py

@@ -89,6 +89,10 @@ class WorkflowInputException(MistralException):
     http_code = 400
 
 
+class InputException(MistralException):
+    http_code = 400
+
+
 class ApplicationContextNotFoundException(MistralException):
     http_code = 400
     message = "Application context not found"

mistral/tests/unit/workflow/test_with_items.py

@@ -15,6 +15,7 @@
 #    limitations under the License.
 
 from mistral.db.v2.sqlalchemy import models
+from mistral import exceptions as exc
 from mistral.tests import base
 from mistral.workbook.v2 import tasks
 from mistral.workflow import utils
@@ -114,4 +115,41 @@ class WithItemsCalculationsTest(base.BaseTest):
                 {'name_info': {'name': 'Mistral'}, 'server_info': 'server3'},
             ],
             action_input_collection
-        )
+        )
+
+    def test_calculate_input_wrong_array_length(self):
+        with_items_input = {
+            'name_info': [
+                {'name': 'John'},
+                {'name': 'Ivan'},
+                {'name': 'Mistral'}
+            ],
+            'server_info': [
+                'server1',
+                'server2'
+            ]
+        }
+        exception = self.assertRaises(
+            exc.InputException,
+            with_items.calc_input,
+            with_items_input
+        )
+
+        self.assertIn("the same length", exception.message)
+
+    def test_calculate_input_not_list(self):
+        with_items_input = {
+            'name_info': [
+                {'name': 'John'},
+                {'name': 'Ivan'},
+                {'name': 'Mistral'}
+            ],
+            'server_info': 'some_string'
+        }
+        exception = self.assertRaises(
+            exc.InputException,
+            with_items.calc_input,
+            with_items_input
+        )
+
+        self.assertIn("List type", exception.message)

mistral/workflow/with_items.py

@@ -14,6 +14,7 @@
 
 import copy
 
+from mistral import exceptions as exc
 from mistral import expressions as expr
 
 
@@ -112,6 +113,8 @@ def calc_input(with_items_input):
     :param with_items_input: Dict containing mapped variables to their arrays.
     :return: list containing dicts of each action input.
     """
+    validate_input(with_items_input)
+
     action_input_collection = []
 
     for key, value in with_items_input.items():
@@ -126,6 +129,22 @@ def calc_input(with_items_input):
     return action_input_collection
 
 
+def validate_input(with_items_input):
+    # Take only mapped values and check them.
+    values = with_items_input.values()
+
+    if not all([isinstance(v, list) for v in values]):
+        raise exc.InputException(
+            "Wrong input format for: %s. List type is"
+            " expected for each value." % with_items_input)
+
+    required_len = len(values[0])
+    if not all(len(v) == required_len for v in values):
+        raise exc.InputException(
+            "Wrong input format for: %s. All arrays must"
+            " have the same length." % with_items_input)
+
+
 def _get_output_key(task_spec):
     return (task_spec.get_publish().keys()[0]
             if task_spec.get_publish() else None)