Always read an entity's parent through get_parent when climbing up.

This should avoid the risk of `DetachedInstanceError` by retrieving the
object into the session if it's not available.
This commit is contained in:
Fabio Manganiello 2023-03-22 22:41:09 +01:00
parent 5c23d3aa87
commit e71c312133
Signed by untrusted user: blacklight
GPG key ID: D90FBA7F76362774
4 changed files with 31 additions and 27 deletions

View file

@ -4,9 +4,8 @@ from typing import Dict, Iterable, Optional, Tuple
from sqlalchemy.orm import Session
from platypush.entities._base import Entity, EntityMapping
# pylint: disable=no-name-in-module
from platypush.entities._engine.repo.db import EntitiesDb
from platypush.entities._engine.repo.helpers import get_parent
from platypush.entities._engine.repo.merger import EntitiesMerger
logger = logging.getLogger('entities')
@ -98,7 +97,7 @@ class EntitiesRepository:
"""
parent = entity
while parent:
parent = self._merge.get_parent(session, entity)
parent = get_parent(session, entity)
if parent:
entity = parent

View file

@ -7,6 +7,7 @@ from sqlalchemy.orm import Session
from platypush.context import get_plugin
from platypush.entities._base import Entity
from .helpers import get_parent
@dataclass
@ -69,7 +70,7 @@ class EntitiesDb:
batch.clear()
def _split_entity_batches_for_flush(
self, entities: Iterable[Entity]
self, session: Session, entities: Iterable[Entity]
) -> List[List[Entity]]:
"""
This method retrieves the root entities given a list of entities and
@ -93,9 +94,10 @@ class EntitiesDb:
for entity in entities:
parent_key = None
parent_id = entity.parent_id
if entity.parent:
parent_id = parent_id or entity.parent.id
parent_key = entity.parent.entity_key
parent = get_parent(session, entity)
if parent:
parent_id = parent_id or parent.id
parent_key = parent.entity_key
if parent_id:
children_by_parent_id[parent_id][entity.entity_key] = entity
@ -169,7 +171,7 @@ class EntitiesDb:
Persist a set of entities.
"""
# Get the "unwrapped" batches
batches = self._split_entity_batches_for_flush(entities)
batches = self._split_entity_batches_for_flush(session, entities)
# Flush each batch as we process it
for batch in batches:

View file

@ -0,0 +1,18 @@
from typing import Optional
from sqlalchemy.orm import Session, exc
from platypush.entities import Entity
def get_parent(session: Session, entity: Entity) -> Optional[Entity]:
"""
Gets the parent of an entity, and it fetches if it's not available in
the current session.
"""
try:
return entity.parent
except exc.DetachedInstanceError:
# Dirty fix for `Parent instance <...> is not bound to a Session;
# lazy load operation of attribute 'parent' cannot proceed`
return session.query(Entity).get(entity.parent_id) if entity.parent_id else None

View file

@ -1,9 +1,11 @@
from typing import Iterable, List, Optional
from sqlalchemy.orm import Session, exc
from sqlalchemy.orm import Session
from platypush.entities._base import Entity, EntityMapping
from .helpers import get_parent
# pylint: disable=too-few-public-methods
class EntitiesMerger:
@ -93,7 +95,7 @@ class EntitiesMerger:
appropriately rewired and that all the relevant objects are added to
this session.
"""
parent = cls.get_parent(session, entity)
parent = get_parent(session, entity)
if not parent:
# No parent -> we can terminate the recursive climbing
return entity
@ -140,23 +142,6 @@ class EntitiesMerger:
cls._sync_parent(session, existing_parent, new_entities, existing_entities)
return entity
@staticmethod
def get_parent(session: Session, entity: Entity) -> Optional[Entity]:
"""
Gets the parent of an entity, and it fetches if it's not available in
the current session.
"""
try:
return entity.parent
except exc.DetachedInstanceError:
# Dirty fix for `Parent instance <...> is not bound to a Session;
# lazy load operation of attribute 'parent' cannot proceed`
return (
session.query(Entity).get(entity.parent_id)
if entity.parent_id
else None
)
@staticmethod
def _append_children(entity: Entity, *children: Entity):
"""