Implement watcher datamodel list in watcher-api

1. Add datamodel api and policy_enfoce file.
2. Add related unittest for data_model api and policy.

Partially Implements:blueprint show-datamodel-api

Change-Id: I1654685d8cf04db5dd132d43a8640ddf91893cad

watcher/api/controllers/v1/__init__.py

@@ -35,6 +35,7 @@ from watcher.api.controllers.v1 import action
 from watcher.api.controllers.v1 import action_plan
 from watcher.api.controllers.v1 import audit
 from watcher.api.controllers.v1 import audit_template
+from watcher.api.controllers.v1 import data_model
 from watcher.api.controllers.v1 import goal
 from watcher.api.controllers.v1 import scoring_engine
 from watcher.api.controllers.v1 import service
@@ -114,6 +115,9 @@ class V1(APIBase):
     audits = [link.Link]
     """Links to the audits resource"""
 
+    data_model = [link.Link]
+    """Links to the data model resource"""
+
     actions = [link.Link]
     """Links to the actions resource"""
 
@@ -158,6 +162,13 @@ class V1(APIBase):
                                          'audits', '',
                                          bookmark=True)
                      ]
+        v1.data_model = [link.Link.make_link('self', pecan.request.host_url,
+                                             'data_model', ''),
+                         link.Link.make_link('bookmark',
+                                             pecan.request.host_url,
+                                             'data_model', '',
+                                             bookmark=True)
+                         ]
         v1.actions = [link.Link.make_link('self', pecan.request.host_url,
                                           'actions', ''),
                       link.Link.make_link('bookmark',
@@ -202,6 +213,7 @@ class Controller(rest.RestController):
     scoring_engines = scoring_engine.ScoringEngineController()
     services = service.ServicesController()
     strategies = strategy.StrategiesController()
+    data_model = data_model.DataModelController()
 
     @wsme_pecan.wsexpose(V1)
     def get(self):

watcher/api/controllers/v1/data_model.py

@@ -0,0 +1,68 @@
+# -*- encoding: utf-8 -*-
+# Copyright (c) 2019 ZTE Corporation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""
+An Interface for users and admin to List Data Model.
+"""
+
+import pecan
+from pecan import rest
+from wsme import types as wtypes
+import wsmeext.pecan as wsme_pecan
+
+from watcher.api.controllers.v1 import types
+from watcher.common import exception
+from watcher.common import policy
+from watcher.decision_engine import rpcapi
+
+
+class DataModelController(rest.RestController):
+    """REST controller for data model"""
+    def __init__(self):
+        super(DataModelController, self).__init__()
+
+    from_data_model = False
+    """A flag to indicate if the requests to this controller are coming
+    from the top-level resource DataModel."""
+
+    @wsme_pecan.wsexpose(wtypes.text, wtypes.text, types.uuid)
+    def get_all(self, data_model_type='compute', audit_uuid=None):
+        """Retrieve information about the given data model.
+
+        :param data_model_type: The type of data model user wants to list.
+                                Supported values: compute.
+                                Future support values: storage, baremetal.
+                                The default value is compute.
+        :param audit_uuid: The UUID of the audit,  used to filter data model
+                           by the scope in audit.
+        """
+        if self.from_data_model:
+            raise exception.OperationNotPermitted
+        allowed_data_model_type = [
+            'compute',
+            ]
+        if data_model_type not in allowed_data_model_type:
+            raise exception.DataModelTypeNotFound(
+                data_model_type=data_model_type)
+        context = pecan.request.context
+        de_client = rpcapi.DecisionEngineAPI()
+        policy.enforce(context, 'data_model:get_all',
+                       action='data_model:get_all')
+        rpc_all_data_model = de_client.get_data_model_info(
+            context,
+            data_model_type,
+            audit_uuid)
+        return rpc_all_data_model