Deprecate StateLog model, to instead bring your own model.

This is an implementation that support the idea exposed in
#133

It's still a Draft, I'm open for any feedback more specifically around the names.
Not tested yet with a real project.

It's meant to be completely backward compatible.

Author: ticosax

README.md

@@ -17,6 +17,9 @@ by enabling a cached backend. See [Advanced Usage](#advanced-usage)
 ## 4.0.0 (not released)
 
 - remove support for django 2.2 & 4.0
+- Bring your own PersistedTransition model:
+  From this relase, django-fsm-log is deprecating StateLog and instead encourages you
+  to define for your own application the concrete model that will persist the transition
 
 ## 3.1.0 (2023-03-23)
 
@@ -99,14 +102,29 @@ python manage.py migrate django_fsm_log
 
 ## Usage
 
+### Define you own model
+
+```python
+from django_fsm_log.models import PersistedTransitionMixin
+
+
+class TransitionLog(PersistedTransitionMixin):
+    pass
+```
+
+### Register the model
+
+```python
+DJANGO_FSM_LOG_CONCRETE_MODEL = 'poll.models.TransitionLog'  # This model must inherit from django_fsm_log.models.PersistedTransition
+```
+
 The app listens for the `django_fsm.signals.post_transition` signal and
 creates a new record for each transition.
 
 To query the log:
 
 ```python
-from django_fsm_log.models import StateLog
-StateLog.objects.all()
+TransitionLog.objects.all()
 # ...all recorded logs...
 ```
 
@@ -125,11 +143,10 @@ For convenience there is a custom `for_` manager method to easily filter on the
 
 ```python
 from my_app.models import Article
-from django_fsm_log.models import StateLog
 
 article = Article.objects.all()[0]
 
-StateLog.objects.for_(article)
+TransitionLog.objects.for_(article)
 # ...logs for article...
 ```
 
@@ -157,7 +174,7 @@ With this the transition gets logged when the `by` kwarg is present.
 
 ```python
 article = Article.objects.create()
-article.submit(by=some_user) # StateLog.by will be some_user
+article.submit(by=some_user)  # TransitionLog.by will be some_user
 ```
 
 ### `description` Decorator
@@ -210,21 +227,31 @@ article.submit()  # logged with "Article submitted" description
 
 There is an InlineForm available that can be used to display the history of changes.
 
-To use it expand your own `AdminModel` by adding `StateLogInline` to its inlines:
+To use it expand your own `AdminModel` by adding `PersistedTransitionInline` to its inlines:
 
 ```python
 from django.contrib import admin
-from django_fsm_log.admin import StateLogInline
+from django_fsm_log.admin import PersistedTransitionInline
 
 
 @admin.register(FSMModel)
 class FSMModelAdmin(admin.ModelAdmin):
-    inlines = [StateLogInline]
+    inlines = [PersistedTransitionInline]
+```
+
+### Migration to Abstract model PersistedTransitionMixin
+
+Once you defined your own model, you'll have to create the relevant migration to create the table.
+
+```sh
+python manage.py makemigrations
 ```
 
+Additionally you'd want to migrate the data from django_fsm_log.models.StateLog to your new table.
+
 ### Advanced Usage
 
-You can change the behaviour of this app by turning on caching for StateLog records.
+You can change the behaviour of this app by turning on caching for PersistedTransition records.
 Simply add `DJANGO_FSM_LOG_STORAGE_METHOD = 'django_fsm_log.backends.CachedBackend'` to your project's settings file.
 It will use your project's default cache backend by default. If you wish to use a specific cache backend, you can add to
 your project's settings:
@@ -233,22 +260,23 @@ your project's settings:
 DJANGO_FSM_LOG_CACHE_BACKEND = 'some_other_cache_backend'
 ```
 
-The StateLog object is now available after the `django_fsm.signals.pre_transition`
+The PersistedTransition object is now available after the `django_fsm.signals.pre_transition`
 signal is fired, but is deleted from the cache and persisted to the database after `django_fsm.signals.post_transition`
 is fired.
 
 This is useful if:
 
-- you need immediate access to StateLog details, and cannot wait until `django_fsm.signals.post_transition`
+- you need immediate access to PersistedTransition details, and cannot wait until `django_fsm.signals.post_transition`
 has been fired
-- at any stage, you need to verify whether or not the StateLog has been written to the database
+- at any stage, you need to verify whether or not the PersistedTransition has been written to the database
 
-Access to the pending StateLog record is available via the `pending_objects` manager
+Access to the pending PersistedTransition record is available via the `pending_objects` manager
 
 ```python
-from django_fsm_log.models import StateLog
+from my_app.models import TransitionLog
+
 article = Article.objects.get(...)
-pending_state_log = StateLog.pending_objects.get_for_object(article)
+pending_transition_logs = TransitionLog.pending_objects.get_for_object(article)
 ```
 
 ## Contributing

django_fsm_log/admin.py

@@ -1,13 +1,15 @@
+from warnings import warn
+
 from django.contrib.contenttypes.admin import GenericTabularInline
 from django.db.models import F
 
-from .models import StateLog
+from .backends import _get_concrete_model
 
-__all__ = ("StateLogInline",)
+__all__ = ("PersistedTransitionInline",)
 
 
-class StateLogInline(GenericTabularInline):
-    model = StateLog
+class PersistedTransitionInline(GenericTabularInline):
+    model = _get_concrete_model()
     can_delete = False
 
     def has_add_permission(self, request, obj=None):
@@ -30,3 +32,12 @@ def get_readonly_fields(self, request, obj=None):
 
     def get_queryset(self, request):
         return super().get_queryset(request).order_by(F("timestamp").desc())
+
+
+def StateLogInline(*args, **kwargs):
+    warn(
+        "StateLogInLine has been deprecated by PersistedTransitionInline.",
+        DeprecationWarning,
+        stacklevel=2,
+    )
+    return PersistedTransitionInline(*args, **kwargs)

django_fsm_log/apps.py

@@ -10,9 +10,9 @@ class DjangoFSMLogAppConfig(AppConfig):
 
     def ready(self):
         backend = import_string(settings.DJANGO_FSM_LOG_STORAGE_METHOD)
-        StateLog = self.get_model("StateLog")
+        ConcreteModel = import_string(settings.DJANGO_FSM_LOG_CONCRETE_MODEL)
 
-        backend.setup_model(StateLog)
+        backend.setup_model(ConcreteModel)
 
         pre_transition.connect(backend.pre_transition_callback)
         post_transition.connect(backend.post_transition_callback)

django_fsm_log/backends.py

@@ -1,7 +1,18 @@
+import typing
+
+from django.utils.module_loading import import_string
+
 from django_fsm_log.conf import settings
 
 from .helpers import FSMLogDescriptor
 
+if typing.TYPE_CHECKING:
+    import django_fsm_log.models
+
+
+def _get_concrete_model() -> typing.Type["django_fsm_log.models.PersistedTransitionMixin"]:
+    return import_string(settings.DJANGO_FSM_LOG_CONCRETE_MODEL)
+
 
 def _pre_transition_callback(sender, instance, name, source, target, manager, **kwargs):
     if BaseBackend._get_model_qualified_name__(sender) in settings.DJANGO_FSM_LOG_IGNORED_MODELS:
@@ -49,21 +60,21 @@ def _get_model_qualified_name__(sender):
 class CachedBackend(BaseBackend):
     @staticmethod
     def setup_model(model):
-        from .managers import PendingStateLogManager
+        from .managers import PendingPersistedTransitionManager
 
-        model.add_to_class("pending_objects", PendingStateLogManager())
+        model.add_to_class("pending_objects", PendingPersistedTransitionManager())
 
     @staticmethod
     def pre_transition_callback(sender, instance, name, source, target, **kwargs):
-        from .models import StateLog
+        klass = _get_concrete_model()
 
-        return _pre_transition_callback(sender, instance, name, source, target, StateLog.pending_objects, **kwargs)
+        return _pre_transition_callback(sender, instance, name, source, target, klass.pending_objects, **kwargs)
 
     @staticmethod
     def post_transition_callback(sender, instance, name, source, target, **kwargs):
-        from .models import StateLog
+        klass = _get_concrete_model()
 
-        StateLog.pending_objects.commit_for_object(instance)
+        klass.pending_objects.commit_for_object(instance)
 
 
 class SimpleBackend(BaseBackend):
@@ -77,9 +88,9 @@ def pre_transition_callback(sender, **kwargs):
 
     @staticmethod
     def post_transition_callback(sender, instance, name, source, target, **kwargs):
-        from .models import StateLog
+        klass = _get_concrete_model()
 
-        return _pre_transition_callback(sender, instance, name, source, target, StateLog.objects, **kwargs)
+        return _pre_transition_callback(sender, instance, name, source, target, klass.objects, **kwargs)
 
 
 if settings.DJANGO_FSM_LOG_STORAGE_METHOD == "django_fsm_log.backends.CachedBackend":

django_fsm_log/conf.py

@@ -1,8 +1,15 @@
+from typing import List
+
 from appconf import AppConf
 from django.conf import settings  # noqa: F401
 
 
 class DjangoFSMLogConf(AppConf):
     STORAGE_METHOD = "django_fsm_log.backends.SimpleBackend"
     CACHE_BACKEND = "default"
-    IGNORED_MODELS = []
+    IGNORED_MODELS: List[str] = []
+    CONCRETE_MODEL: str = "django_fsm_log.models.StateLog"
+
+    class Meta:
+        prefix = "django_fsm_log"
+        holder = "django_fsm_log.conf.settings"

django_fsm_log/managers.py

@@ -1,23 +1,30 @@
+from warnings import warn
+
 from django.contrib.contenttypes.models import ContentType
 from django.db import models
 from django.db.models.query import QuerySet
 
 from django_fsm_log.backends import cache
 
 
-class StateLogQuerySet(QuerySet):
+class PersistedTransitionQuerySet(QuerySet):
     def _get_content_type(self, obj):
         return ContentType.objects.get_for_model(obj)
 
     def for_(self, obj):
         return self.filter(content_type=self._get_content_type(obj), object_id=obj.pk)
 
 
-class StateLogManager(models.Manager):
+def StateLogQuerySet(*args, **kwargs):
+    warn("StateLogQuerySet has been renamed PersistedTransitionQuerySet", DeprecationWarning, stacklevel=2)
+    return PersistedTransitionQuerySet(*args, **kwargs)
+
+
+class PersistedTransitionManager(models.Manager):
     use_in_migrations = True
 
     def get_queryset(self):
-        return StateLogQuerySet(self.model)
+        return PersistedTransitionQuerySet(self.model)
 
     def __getattr__(self, attr, *args):
         # see https://code.djangoproject.com/ticket/15062 for details
@@ -26,7 +33,12 @@ def __getattr__(self, attr, *args):
         return getattr(self.get_queryset(), attr, *args)
 
 
-class PendingStateLogManager(models.Manager):
+def StateLogManager(*args, **kwargs):
+    warn("StateLogManager has been renamed PersistedTransitionManager", DeprecationWarning, stacklevel=2)
+    return PersistedTransitionManager(*args, **kwargs)
+
+
+class PendingPersistedTransitionManager(models.Manager):
     def _get_cache_key_for_object(self, obj):
         return f"StateLog:{obj.__class__.__name__}:{obj.pk}"
 
@@ -46,3 +58,8 @@ def commit_for_object(self, obj):
     def get_for_object(self, obj):
         key = self._get_cache_key_for_object(obj)
         return cache.get(key)
+
+
+def PendingStateLogManager(*args, **kwargs):
+    warn("PendingStateLogManager has been renamed PendingPersistedTransitionManager", DeprecationWarning, stacklevel=2)
+    return PendingPersistedTransitionManager(*args, **kwargs)

django_fsm_log/migrations/0001_initial.py

@@ -1,6 +1,6 @@
-from django.db import models, migrations
 import django.utils.timezone
 from django.conf import settings
+from django.db import migrations, models
 
 
 class Migration(migrations.Migration):

django_fsm_log/migrations/0004_auto_20190131_0341.py

@@ -1,6 +1,7 @@
 # Generated by Django 2.1.5 on 2019-01-31 03:41
 
 from django.db import migrations
+
 import django_fsm_log.managers
 
 

django_fsm_log/models.py

@@ -1,14 +1,22 @@
+from warnings import warn
+
+from django.conf import settings
 from django.contrib.contenttypes.fields import GenericForeignKey
 from django.contrib.contenttypes.models import ContentType
 from django.db import models
 from django.utils.timezone import now
 from django_fsm import FSMFieldMixin, FSMIntegerField
 
-from .conf import settings
-from .managers import StateLogManager
+from .managers import PersistedTransitionManager
+
 
+class PersistedTransitionMixin(models.Model):
+    """
+    Abstract Class that should be subclassed by the host application.
+    Host projects should own the migrations and
+    can decide on their own primary key type.
+    """
 
-class StateLog(models.Model):
     timestamp = models.DateTimeField(default=now)
     by = models.ForeignKey(
         getattr(settings, "AUTH_USER_MODEL", "auth.User"),
@@ -26,9 +34,10 @@ class StateLog(models.Model):
 
     description = models.TextField(blank=True, null=True)
 
-    objects = StateLogManager()
+    objects = PersistedTransitionManager()
 
     class Meta:
+        abstract = True
         get_latest_by = "timestamp"
 
     def __str__(self):
@@ -47,3 +56,15 @@ def get_state_display(self, field_name="state"):
 
     def get_source_state_display(self):
         return self.get_state_display("source_state")
+
+
+class StateLog(PersistedTransitionMixin):
+    def __init__(self, *args, **kwargs):
+        warn(
+            "StateLog model has been deprecated, you should now bring your own Model."
+            "\nPlease check the documentation at https://django-fsm-log.readthedocs.io/en/latest/"
+            "\nto know how to.",
+            DeprecationWarning,
+            stacklevel=2,
+        )
+        return super().__init__(*args, **kwargs)

tests/admin.py

@@ -1,12 +1,12 @@
 from django.contrib import admin
 
-from django_fsm_log.admin import StateLogInline
+from django_fsm_log.admin import PersistedTransitionInline
 
 from .models import Article
 
 
 class ArticleAdmin(admin.ModelAdmin):
-    inlines = [StateLogInline]
+    inlines = [PersistedTransitionInline]
 
 
 admin.site.register(Article, ArticleAdmin)