Don't lock read session from the main database

platypush/entities/_engine.py

@@ -32,10 +32,10 @@ class EntitiesEngine(Thread):
             'by_name_and_plugin': {},
         }
 
-    def _get_session(self):
+    def _get_session(self, *args, **kwargs):
         db = get_plugin('db')
         assert db
-        return db.get_session()
+        return db.get_session(*args, **kwargs)
 
     def _get_cached_entity(self, entity: Entity) -> Optional[dict]:
         if entity.id:
@@ -247,7 +247,7 @@ class EntitiesEngine(Thread):
         return list(new_entities.values())
 
     def _process_entities(self, *entities: Entity):
-        with self._get_session() as session:
+        with self._get_session(locked=True) as session:
             # Ensure that the internal IDs are set to null before the merge
             for e in entities:
                 e.id = None  # type: ignore

platypush/plugins/db/__init__.py

@@ -509,17 +509,21 @@ class DbPlugin(Plugin):
                 connection.execute(delete)
 
     def create_all(self, engine, base):
-        with (self.get_session(engine) as session, session.begin()):
+        with (self.get_session(engine, locked=True) as session, session.begin()):
             base.metadata.create_all(session.connection())
 
     @contextmanager
     def get_session(
-        self, engine=None, *args, **kwargs
+        self, engine=None, locked=False, *args, **kwargs
     ) -> Generator[Session, None, None]:
         engine = self.get_engine(engine, *args, **kwargs)
-        session_locks[engine.url] = session_locks.get(engine.url, RLock())
+        if locked:
+            lock = session_locks[engine.url] = session_locks.get(engine.url, RLock())
+        else:
+            # Mock lock
+            lock = RLock()
 
-        with (session_locks[engine.url], engine.connect() as conn, conn.begin()):
+        with (lock, engine.connect() as conn, conn.begin()):
             session = scoped_session(
                 sessionmaker(
                     expire_on_commit=False,

platypush/plugins/entities/__init__.py

@@ -26,10 +26,10 @@ class EntitiesPlugin(Plugin):
     def __init__(self, **kwargs):
         super().__init__(**kwargs)
 
-    def _get_session(self):
+    def _get_session(self, *args, **kwargs):
         db = get_plugin('db')
         assert db
-        return db.get_session()
+        return db.get_session(*args, **kwargs)
 
     @action
     def get(
@@ -194,7 +194,7 @@ class EntitiesPlugin(Plugin):
         :param entities: IDs of the entities to be removed.
         :return: The payload of the deleted entities.
         """
-        with self._get_session() as session:
+        with self._get_session(locked=True) as session:
             entities: Collection[Entity] = (
                 session.query(Entity).filter(Entity.id.in_(entities)).all()
             )
@@ -235,7 +235,7 @@ class EntitiesPlugin(Plugin):
         :return: The updated entities.
         """
         entities = {str(k): v for k, v in entities.items()}
-        with self._get_session() as session:
+        with self._get_session(locked=True) as session:
             objs = session.query(Entity).filter(Entity.id.in_(entities.keys())).all()
             for obj in objs:
                 obj.meta = {**(obj.meta or {}), **(entities.get(str(obj.id), {}))}

platypush/user/__init__.py

@@ -67,7 +67,7 @@ class UserManager:
         if not password:
             raise ValueError('Please provide a password for the user')
 
-        with self._get_session() as session:
+        with self._get_session(locked=True) as session:
             user = self._get_user(session, username)
             if user:
                 raise NameError('The user {} already exists'.format(username))
@@ -86,7 +86,7 @@ class UserManager:
         return self._mask_password(user)
 
     def update_password(self, username, old_password, new_password):
-        with self._get_session() as session:
+        with self._get_session(locked=True) as session:
             if not self._authenticate_user(session, username, old_password):
                 return False
 
@@ -117,7 +117,7 @@ class UserManager:
             return self._mask_password(user), user_session
 
     def delete_user(self, username):
-        with self._get_session() as session:
+        with self._get_session(locked=True) as session:
             user = self._get_user(session, username)
             if not user:
                 raise NameError('No such user: {}'.format(username))
@@ -133,7 +133,7 @@ class UserManager:
             return True
 
     def delete_user_session(self, session_token):
-        with self._get_session() as session:
+        with self._get_session(locked=True) as session:
             user_session = (
                 session.query(UserSession)
                 .filter_by(session_token=session_token)
@@ -148,7 +148,7 @@ class UserManager:
             return True
 
     def create_user_session(self, username, password, expires_at=None):
-        with self._get_session() as session:
+        with self._get_session(locked=True) as session:
             user = self._authenticate_user(session, username, password)
             if not user:
                 return None