improve creation order to preserve primary key order respective to de…

…claration order in yaml

py_yaml_fixtures/fixtures_loader.py

@@ -82,12 +82,19 @@ def create_all(
         # build up a directed acyclic graph to determine the model instantiation order
         dag = nx.DiGraph()
         for model_class_name, dependencies in self.relationships.items():
+            dag.add_node(model_class_name)
+            if model_class_name not in dependencies:
+                for dep in dependencies:
+                    dag.add_edge(model_class_name, dep)
+                continue
+
             for dep in dependencies:
                 associated_col_name = dependencies[dep]
                 for id_key, instance_data in self.model_fixtures[model_class_name].items():
                     identifier = Identifier(model_class_name, id_key)
-                    dag.add_node(identifier)
+                    dag.add_edge(model_class_name, identifier)
 
+                    dag.add_node(identifier)
                     associated_identifiers = instance_data.get(associated_col_name)
                     if associated_identifiers is None:
                         continue
@@ -98,30 +105,42 @@ def create_all(
                         dag.add_edge(identifier, associated_identifier)
 
         try:
-            creation_order = reversed(list(nx.topological_sort(dag)))
+            creation_order = list(reversed(list(nx.topological_sort(dag))))
         except nx.NetworkXUnfeasible:
             raise Exception('Circular dependency detected between models: ' +
                             ', '.join('{a} -> {b}'.format(a=a, b=b)
                                       for a, b in nx.find_cycle(dag)))
 
         # create or update the models in the determined order
-        rv = []
+        rv = {}
         for identifier in creation_order:
-            data = self.factory.maybe_convert_values(
-                identifier,
-                data=self.model_fixtures[identifier.class_name][identifier.key],
-            )
-            self._data_cache[identifier.class_name][identifier.key] = data
+            if isinstance(identifier, str):
+                model_class_name = identifier
+                keys = list(self.model_fixtures[model_class_name].keys())
+            else:
+                model_class_name = identifier.class_name
+                keys = [identifier.key]
+
+            for key in keys:
+                identifier = Identifier(model_class_name, key)
+                if identifier in rv:
+                    continue
+
+                data = self.factory.maybe_convert_values(
+                    identifier,
+                    data=self.model_fixtures[identifier.class_name][identifier.key],
+                )
+                self._data_cache[identifier.class_name][identifier.key] = data
 
-            model_instance, created = self.factory.create_or_update(identifier, data)
-            if progress_callback:
-                progress_callback(identifier, model_instance, created)
-            rv.append(model_instance)
+                model_instance, created = self.factory.create_or_update(identifier, data)
+                if progress_callback:
+                    progress_callback(identifier, model_instance, created)
+                rv[identifier] = model_instance
 
         # FIXME if there are any model names in the seed files but not in creation_order
 
         self.factory.commit()
-        return rv
+        return list(rv.values())
 
     def convert_identifiers(self, identifiers: Union[Identifier, List[Identifier]]):
         """
@@ -272,6 +291,7 @@ def _ensure_env(self, env: Union[jinja2.Environment, None]):
             env.globals['faker'] = faker
 
         env.globals.setdefault('hash_password', hash_password)
+        env.filters.setdefault('isoformat', lambda dt: dt.isoformat())
         if hasattr(jinja2, 'pass_context'):
             env.globals.setdefault('random_model', jinja2.pass_context(random_model))
             env.globals.setdefault('random_models', jinja2.pass_context(random_models))