Optimize permissions, use memoization

This commit is contained in:
Yohann D'ANELLO 2020-04-02 00:30:22 +02:00
parent 3f5faa0b05
commit 5c9c0bbc2a
6 changed files with 101 additions and 25 deletions

View File

@ -50,7 +50,7 @@ def save_object(sender, instance, **kwargs):
if instance._meta.label_lower in EXCLUDED:
return
if hasattr(instance, "_force_save"):
if hasattr(instance, "_no_log"):
return
# noinspection PyProtectedMember
@ -109,7 +109,7 @@ def delete_object(sender, instance, **kwargs):
if instance._meta.label_lower in EXCLUDED:
return
if hasattr(instance, "_force_delete"):
if hasattr(instance, "_no_log"):
return
# Si un utilisateur est connecté, on récupère l'utilisateur courant ainsi que son adresse IP

View File

@ -10,6 +10,7 @@ from django.db.models import Q, F
from note.models import Note, NoteUser, NoteClub, NoteSpecial
from note_kfet.middlewares import get_current_session
from member.models import Membership, Club
from .decorators import memoize
from .models import Permission
@ -22,6 +23,28 @@ class PermissionBackend(ModelBackend):
supports_anonymous_user = False
supports_inactive_user = False
@staticmethod
@memoize
def get_raw_permissions(user, t):
"""
Query permissions of a certain type for a user, then memoize it.
:param user: The owner of the permissions
:param t: The type of the permissions: view, change, add or delete
:return: The queryset of the permissions of the user (memoized) grouped by clubs
"""
if isinstance(user, AnonymousUser):
# Unauthenticated users have no permissions
return Permission.objects.none()
return Permission.objects.annotate(club=F("rolepermissions__role__membership__club")) \
.filter(
rolepermissions__role__membership__user=user,
rolepermissions__role__membership__date_start__lte=datetime.date.today(),
rolepermissions__role__membership__date_end__gte=datetime.date.today(),
type=t,
mask__rank__lte=get_current_session().get("permission_mask", 0),
).distinct('club', 'pk')
@staticmethod
def permissions(user, model, type):
"""
@ -31,18 +54,16 @@ class PermissionBackend(ModelBackend):
:param type: The type of the permissions: view, change, add or delete
:return: A generator of the requested permissions
"""
for permission in Permission.objects.annotate(club=F("rolepermissions__role__membership__club")) \
.filter(
rolepermissions__role__membership__user=user,
rolepermissions__role__membership__date_start__lte=datetime.date.today(),
rolepermissions__role__membership__date_end__gte=datetime.date.today(),
model__app_label=model.app_label, # For polymorphic models, we don't filter on model type
type=type,
).all():
if not isinstance(model, permission.model.__class__) or not permission.club:
clubs = {}
for permission in PermissionBackend.get_raw_permissions(user, type):
if not isinstance(model.model_class()(), permission.model.model_class()) or not permission.club:
continue
club = Club.objects.get(pk=permission.club)
if permission.club not in clubs:
clubs[permission.club] = club = Club.objects.get(pk=permission.club)
else:
club = clubs[permission.club]
permission = permission.about(
user=user,
club=club,
@ -56,10 +77,10 @@ class PermissionBackend(ModelBackend):
F=F,
Q=Q
)
if permission.mask.rank <= get_current_session().get("permission_mask", 0):
yield permission
yield permission
@staticmethod
@memoize
def filter_queryset(user, model, t, field=None):
"""
Filter a queryset by considering the permissions of a given user.
@ -93,10 +114,15 @@ class PermissionBackend(ModelBackend):
query = query | perm.query
return query
@memoize
def has_perm(self, user_obj, perm, obj=None):
if user_obj is None or isinstance(user_obj, AnonymousUser):
return False
sess = get_current_session()
if sess is not None and sess.session_key is None:
return Permission.objects.none()
if user_obj.is_superuser and get_current_session().get("permission_mask", 0) >= 42:
return True

View File

@ -0,0 +1,56 @@
# Copyright (C) 2018-2020 by BDE ENS Paris-Saclay
# SPDX-License-Identifier: GPL-3.0-or-later
from functools import lru_cache
from time import time
from django.contrib.sessions.models import Session
from note_kfet.middlewares import get_current_session
def memoize(f):
"""
Memoize results and store in sessions
This decorator is useful for permissions: they are loaded once needed, then stored for next calls.
The storage is contained with sessions since it depends on the selected mask.
"""
sess_funs = {}
last_collect = time()
def collect():
"""
Clear cache of results when sessions are invalid, to flush useless data.
This function is called every minute.
"""
nonlocal sess_funs
new_sess_funs = {}
for sess_key in sess_funs:
if Session.objects.filter(session_key=sess_key).exists():
new_sess_funs[sess_key] = sess_funs[sess_key]
sess_funs = new_sess_funs
def func(*args, **kwargs):
nonlocal last_collect
if time() - last_collect > 60:
# Clear cache
collect()
last_collect = time()
# If there is no session, then we don't memoize anything.
sess = get_current_session()
if sess is None or sess.session_key is None:
return f(*args, **kwargs)
sess_key = sess.session_key
if sess_key not in sess_funs:
# lru_cache makes the job of memoization
# We store only the 512 latest data per session. It has to be enough.
sess_funs[sess_key] = lru_cache(512)(f)
return sess_funs[sess_key](*args, **kwargs)
func.func_name = f.__name__
return func

View File

@ -45,7 +45,7 @@ class InstancedPermission:
else:
oldpk = obj.pk
# Ensure previous models are deleted
self.model.model_class().objects.filter(pk=obj.pk).annotate(_force_delete=F("pk") + 1).delete()
self.model.model_class().objects.filter(pk=obj.pk).annotate(_force_delete=F("pk")).delete()
# Force insertion, no data verification, no trigger
obj._force_save = True
Model.save(obj, force_insert=True)

View File

@ -27,7 +27,7 @@ def pre_save_object(sender, instance, **kwargs):
if instance._meta.label_lower in EXCLUDED:
return
if hasattr(instance, "_no_log"):
if hasattr(instance, "_force_save"):
return
user = get_current_authenticated_user()
@ -74,7 +74,7 @@ def pre_delete_object(instance, **kwargs):
if instance._meta.label_lower in EXCLUDED:
return
if hasattr(instance, "_no_log"):
if hasattr(instance, "_force_delete"):
return
user = get_current_authenticated_user()

View File

@ -20,11 +20,8 @@ def not_empty_model_list(model_name):
return False
elif user.is_superuser and session.get("permission_mask", 0) >= 42:
return True
if session.get("not_empty_model_list_" + model_name, None):
return session.get("not_empty_model_list_" + model_name, None) == 1
qs = model_list(model_name)
session["not_empty_model_list_" + model_name] = 1 if qs.exists() else 2
return session.get("not_empty_model_list_" + model_name) == 1
return qs.exists()
@stringfilter
@ -38,11 +35,8 @@ def not_empty_model_change_list(model_name):
return False
elif user.is_superuser and session.get("permission_mask", 0) >= 42:
return True
if session.get("not_empty_model_change_list_" + model_name, None):
return session.get("not_empty_model_change_list_" + model_name, None) == 1
qs = model_list(model_name, "change")
session["not_empty_model_change_list_" + model_name] = 1 if qs.exists() else 2
return session.get("not_empty_model_change_list_" + model_name) == 1
return qs.exists()
@stringfilter