fix select_related usage (#24)

* fix select_related usage

In order to optimize the query, we need to select foreign key references
as well from the database. So all foreign keys in the query are passed
as parameters of select_related function

* remove extra logging statement

Signed-off-by: Priyank Singh <[email protected]>

Author: preyunk

bridgeql/__init__.py

@@ -14,7 +14,7 @@
 """
 
 __title__ = 'BridgeQL'
-__version__ = '0.1.15'
+__version__ = '0.1.16'
 __license__ = 'BSD 2-Clause'
 __copyright__ = 'Copyright © 2023 VMware, Inc.  All rights reserved.'
 

bridgeql/django/models.py

@@ -47,6 +47,14 @@ def _inject_params(self):
         if not any((self.app_name, self.model_name)):
             raise InvalidRequest('app_name or model_name missing')
 
+    @property
+    def fk_refs_in_fields(self):
+        refs = []
+        for field in self.fields:
+            if '__' in field:
+                refs.append(field.rsplit('__', 1)[0])
+        return refs
+
 
 class ModelConfig(object):
     def __init__(self, app_name, model_name):
@@ -175,23 +183,10 @@ def _apply_opts(self):
             elif qset_opt == 'limit':
                 self.qset = self.qset[:self.params.limit]
             elif isinstance(value, list):
-                # handle values case separately
-                if qset_opt == 'values':
-                    # list of parameters passed in values function
-                    values_params = set(value) - \
-                        self.model_config.get_properties()
-                    # list of properties handled separately
-                    properties = set(value) - values_params
-                    try:
-                        # qset.values(*fields) is called but not yet evaluated
-                        qset_values = func(*values_params)
-                    except FieldError as e:
-                        raise InvalidModelFieldName(str(e))
-                    if self.query_has_properties():
-                        # queryset evaluated
-                        qset_values = self._add_properties(
-                            qset_values, properties)
-                    self.qset = qset_values
+                # handle values case where property is passed in fields
+                if qset_opt == 'values' and self.query_has_properties():
+                    # returns DBRows instance
+                    self.qset = self._add_fields()
                 else:
                     try:
                         self.qset = func(*value)
@@ -207,24 +202,25 @@ def query_has_properties(self):
         return bool(set(self.params.fields).intersection(
             self.model_config.get_properties()))
 
-    def _add_properties(self, db_rows, query_properties):
-        # evaluate queryset values
-        db_rows = list(db_rows)
+    def _add_fields(self):
         qset_values = DBRows()
-        # skipping select_related call, expecting
-        # properties will not have references call
-        # like machine.os.arch in any of the machine's property
-        logger.debug('Request parameters: %s \nQuery (2nd call): %s\n',
+        self.qset = self.qset.select_related(*self.params.fk_refs_in_fields)
+        logger.debug('Request parameters: %s \nQuery: %s\n',
                      self.params.params, self.qset.query)
-        for i, row in enumerate(self.qset):
-            for field in query_properties:
-                try:
-                    model_property = getattr(row, field)
-                except AttributeError:
-                    raise InvalidModelFieldName(
-                        'Query field "%s" does not exists.' % field)
-                db_rows[i][field] = model_property
-            qset_values.append(db_rows[i])
+        for row in self.qset:
+            model_fields = {}
+            for field in self.params.fields:
+                attr = row
+                for ref in field.split('__'):
+                    try:
+                        attr = getattr(attr, ref)
+                        if attr is None:
+                            break
+                    except AttributeError:
+                        raise InvalidModelFieldName(
+                            'Invalid query for field %s in %s.' % (ref, attr))
+                model_fields[field] = attr
+            qset_values.append(model_fields)
         return qset_values
 
     def queryset(self):

tests/server/machine/tests/test_api_reader.py

@@ -27,7 +27,7 @@ def test_get_machine(self):
             'filter': {
                 'name': 'machine-name-1'
             },
-            'fields': ['ip', 'name', 'created_at', 'stats']
+            'fields': ['ip', 'name', 'created_at', 'stats', 'os__name']
         }
         resp = self.client.get(self.url, {'payload': json.dumps(self.params)})
         self.assertEqual(resp.status_code, 200)