Apply input schema to workflow/action input

* apply the schema introduced in previous
  patch(https://review.openstack.org/#/c/172438/).
* add some unit tests accordingly.

things need to be done in the subsequent patches:
- consider the input default value when validating inputs of
  workflow/action.
- add some unit tests for input default value.
- add some samples in mistral-extra repository if needed.

Partially Implements: blueprint mistral-default-input-values

Change-Id: I9737dbffe0e6913d976990fbdc31086539b5956e

mistral/tests/unit/workbook/v2/test_actions.py

@@ -73,7 +73,12 @@ class ActionSpecValidation(base.WorkbookSpecValidationTestCase):
             ({'input': ['']}, True),
             ({'input': None}, True),
             ({'input': ['k1', 'k2']}, False),
-            ({'input': ['k1', 12345]}, True)
+            ({'input': ['k1', 12345]}, True),
+            ({'input': ['k1', {'k2': 2}]}, False),
+            ({'input': [{'k1': 1}, {'k2': 2}]}, False),
+            ({'input': [{'k1': None}]}, False),
+            ({'input': [{'k1': 1}, {'k1': 1}]}, True),
+            ({'input': [{'k1': 1, 'k2': 2}]}, True)
         ]
 
         actions = {

mistral/tests/unit/workbook/v2/test_workflows.py

@@ -132,7 +132,12 @@ class WorkflowSpecValidation(base.WorkflowSpecValidationTestCase):
             ({'input': [None]}, True),
             ({'input': ['']}, True),
             ({'input': None}, True),
-            ({'input': []}, True)
+            ({'input': []}, True),
+            ({'input': ['var1', {'var2': 2}]}, False),
+            ({'input': [{'var1': 1}, {'var2': 2}]}, False),
+            ({'input': [{'var1': None}]}, False),
+            ({'input': [{'var1': 1}, {'var1': 1}]}, True),
+            ({'input': [{'var1': 1, 'var2': 2}]}, True)
         ]
 
         for wf_input, expect_error in tests:

mistral/workbook/v2/actions.py

@@ -25,7 +25,7 @@ class ActionSpec(base.BaseSpec):
         "properties": {
             "base": types.NONEMPTY_STRING,
             "base-input": types.NONEMPTY_DICT,
-            "input": types.UNIQUE_STRING_LIST,
+            "input": types.UNIQUE_STRING_OR_ONE_KEY_DICT_LIST,
             "output": types.ANY_NULLABLE,
         },
         "required": ["base"],

mistral/workbook/v2/workflows.py

@@ -37,7 +37,7 @@ class WorkflowSpec(base.BaseSpec):
         "properties": {
             "type": types.WORKFLOW_TYPE,
             "task-defaults": _task_defaults_schema,
-            "input": types.UNIQUE_STRING_LIST,
+            "input": types.UNIQUE_STRING_OR_ONE_KEY_DICT_LIST,
             "output": types.NONEMPTY_DICT,
             "tasks": {
                 "type": "object",