use contextvar instead of threadlocal (#581)

* use contextvar instead of threadlocal

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Update auditlog/context.py

* update CHANGELOG.md

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Hasan Ramezani <hasan.r67@gmail.com>

CHANGELOG.md

@@ -3,7 +3,9 @@
 ## Next Release
 
 #### Improvements
+
 - Python: Confirm Python 3.12 support ([#572](https://github.com/jazzband/django-auditlog/pull/572))
+- feat: `thread.local` replaced with `ContextVar` to improve context managers in Django 4.2+
 
 ## 3.0.0-beta.2 (2023-10-05)
 

auditlog/context.py

@@ -1,32 +1,33 @@
 import contextlib
-import threading
 import time
+from contextvars import ContextVar
 from functools import partial
 
+from django.contrib.auth import get_user_model
 from django.db.models.signals import pre_save
 
 from auditlog.models import LogEntry
 
-threadlocal = threading.local()
+auditlog_value = ContextVar("auditlog_value")
+auditlog_disabled = ContextVar("auditlog_disabled", default=False)
 
 
 @contextlib.contextmanager
 def set_actor(actor, remote_addr=None):
     """Connect a signal receiver with current user attached."""
     # Initialize thread local storage
-    threadlocal.auditlog = {
+    context_data = {
         "signal_duid": ("set_actor", time.time()),
         "remote_addr": remote_addr,
     }
+    auditlog_value.set(context_data)
 
     # Connect signal for automatic logging
-    set_actor = partial(
-        _set_actor, user=actor, signal_duid=threadlocal.auditlog["signal_duid"]
-    )
+    set_actor = partial(_set_actor, user=actor, signal_duid=context_data["signal_duid"])
     pre_save.connect(
         set_actor,
         sender=LogEntry,
-        dispatch_uid=threadlocal.auditlog["signal_duid"],
+        dispatch_uid=context_data["signal_duid"],
         weak=False,
     )
 
@@ -34,12 +35,11 @@ def set_actor(actor, remote_addr=None):
         yield
     finally:
         try:
-            auditlog = threadlocal.auditlog
-        except AttributeError:
+            auditlog = auditlog_value.get()
+        except LookupError:
             pass
         else:
             pre_save.disconnect(sender=LogEntry, dispatch_uid=auditlog["signal_duid"])
-            del threadlocal.auditlog
 
 
 def _set_actor(user, sender, instance, signal_duid, **kwargs):
@@ -48,14 +48,18 @@ def _set_actor(user, sender, instance, signal_duid, **kwargs):
     This function becomes a valid signal receiver when it is curried with the actor and a dispatch id.
     """
     try:
-        auditlog = threadlocal.auditlog
-    except AttributeError:
+        auditlog = auditlog_value.get()
+    except LookupError:
         pass
     else:
         if signal_duid != auditlog["signal_duid"]:
             return
-
-        if sender == LogEntry and instance.actor is None:
+        auth_user_model = get_user_model()
+        if (
+            sender == LogEntry
+            and isinstance(user, auth_user_model)
+            and instance.actor is None
+        ):
             instance.actor = user
 
         instance.remote_addr = auditlog["remote_addr"]
@@ -63,11 +67,11 @@ def _set_actor(user, sender, instance, signal_duid, **kwargs):
 
 @contextlib.contextmanager
 def disable_auditlog():
-    threadlocal.auditlog_disabled = True
+    token = auditlog_disabled.set(True)
     try:
         yield
     finally:
         try:
-            del threadlocal.auditlog_disabled
-        except AttributeError:
+            auditlog_disabled.reset(token)
+        except LookupError:
             pass

auditlog/receivers.py

@@ -2,7 +2,7 @@ from functools import wraps
 
 from django.conf import settings
 
-from auditlog.context import threadlocal
+from auditlog.context import auditlog_disabled
 from auditlog.diff import model_instance_diff
 from auditlog.models import LogEntry
 from auditlog.signals import post_log, pre_log
@@ -17,7 +17,11 @@ def check_disable(signal_handler):
 
     @wraps(signal_handler)
     def wrapper(*args, **kwargs):
-        if not getattr(threadlocal, "auditlog_disabled", False) and not (
+        try:
+            auditlog_disabled_value = auditlog_disabled.get()
+        except LookupError:
+            auditlog_disabled_value = False
+        if not auditlog_disabled_value and not (
             kwargs.get("raw") and settings.AUDITLOG_DISABLE_ON_RAW_SAVE
         ):
             signal_handler(*args, **kwargs)