Add hierarchical dependency to current model

In the case of LogicalRouter and LogicalRouterPort, LogicalRouterPort
has a reference to LogicalSwitch. So LogicalRouter should depend on
LogicalSwitch. But LogicalRouterPort is not a first class db model,
so LogicalRouterPort will not be count in when calculate dependency.

This patch addresses this issue by adding the dependency of non-first
class model to current model.

Change-Id: I37308d1ed70df9b5f5053f2f71cc5c0790af9cec
Partially-Implements: bp refactor-nb-api

dragonflow/db/model_framework.py

@@ -194,7 +194,7 @@ class _CommonBase(models.Base):
 
     @classmethod
     def dependencies(cls):
-        deps = []
+        deps = set()
         for key, field in cls.iterate_over_fields():
             if isinstance(field, fields.ListField):
                 types = field.items_types
@@ -203,11 +203,16 @@ class _CommonBase(models.Base):
 
             for field_type in types:
                 try:
-                    deps.append(field_type.get_proxied_model())
+                    deps.add(field_type.get_proxied_model())
                 except AttributeError:
-                    pass
+                    if issubclass(field_type, ModelBase):
+                        # If the field is not a reference, and it is a df
+                        # model(derived from ModelBase), it is considered as
+                        # non-first class model. And its dependency
+                        # will be treated as current model's dependency.
+                        deps |= field_type.dependencies()
 
-        return set(deps)
+        return deps
 
     @classmethod
     def is_first_class(cls):

dragonflow/tests/unit/test_model_framework.py

@@ -135,6 +135,18 @@ class EmbeddingModel2(mf.ModelBase):
     emb_required = fields.EmbeddedField(EmbeddedModel, required=True)
 
 
+@mf.construct_nb_db_model
+class ReffingNonFirstClassModel(mf.ModelBase):
+    ref1 = df_fields.ReferenceField(ReffedModel)
+
+
+@mf.register_model
+@mf.construct_nb_db_model
+class ReffingModel3(mf.ModelBase):
+    table_name = 'ReffingModel3'
+    ref = fields.ListField(ReffingNonFirstClassModel)
+
+
 class TestModelFramework(tests_base.BaseTestCase):
     def test_lookup(self):
         self.assertEqual(ModelTest, mf.get_model('ModelTest'))
@@ -418,3 +430,11 @@ class TestModelFramework(tests_base.BaseTestCase):
             (emb1, emb2, emb3),
             embedding1.iterate_embedded_model_instances(),
         )
+
+    def test_hierarchical_dependency(self):
+        sorted_models = mf.iter_models_by_dependency_order()
+        self.assertLess(
+            sorted_models.index(ReffedModel),
+            sorted_models.index(ReffingModel3)
+        )
+        self.assertIn(ReffedModel, ReffingModel3.dependencies())