create historical instance with respect to using() for multidb enviro… (#507)

* create historical instance with respect to using() for multidb environment.

* add name to authors

* add name to authors

* code formatting

* update CHANGES

* revert post delete method to current version, add using

* rename second DB to other to be consistent with Django docs

* add section on multiple databases to documentation.

* minor edit to Multiple Databases section in documents

* minor edit to Multiple Databases section in documents

Author: erikvw

AUTHORS.rst

@@ -28,6 +28,7 @@ Authors
 - David Grochowski (`ThePumpingLemma <https://github.com/ThePumpingLemma>`_)
 - David Hite
 - Eduardo Cuducos
+- Erik van Widenfelt (`erikvw <https://github.com/erikvw>`_)
 - Filipe Pina (@fopina)
 - Florian Eßer
 - Frank Sachsenheim

CHANGES.rst

@@ -1,6 +1,10 @@
 Changes
 =======
 
+Unreleased
+----------
+- Add support for `using` chained manager method and save/delete keyword argument (gh-507)
+
 2.6.0 (2018-12-12)
 ------------------
 - Add `app` parameter to the constructor of `HistoricalRecords` (gh-486)

docs/advanced.rst

@@ -486,6 +486,36 @@ be accomplished by setting ``cascade_delete_history=True``.
         history = HistoricalRecords(cascade_delete_history=True)
 
 
+Multiple databases
+------------------
+`django-simple-history` follows the Django conventions for interacting with multiple databases.
+
+.. code-block:: python
+
+    >>> # This will create a new historical record on the 'other' database.
+    >>> poll = Poll.objects.using('other').create(question='Question 1')
+
+    >>> # This will also create a new historical record on the 'other' database.
+    >>> poll.save(using='other')
+
+
+When interacting with ``QuerySets``, use ``using()``:
+
+.. code-block:: python
+
+    >>> # This will return a QuerySet from the 'other' database.
+    Poll.history.using('other').all()
+
+When interacting with manager methods, use ``db_manager()``:
+
+.. code-block:: python
+
+    >>> # This will call a manager method on the 'other' database.
+    >>> poll.history.db_manager('other').as_of(datetime(2010, 10, 25, 18, 4, 0))
+
+See the Django documentation for more information on how to interact with multiple databases.
+
+
 History Diffing
 -------------------
 
@@ -523,6 +553,8 @@ history_change_reason
     Freetext description of the reason for the change
 history_user
     The user that instigated the change
+using
+    The database alias being used
 
 To connect the signals to your callbacks, you can use the @receiver decorator:
 

runtests.py

@@ -38,6 +38,9 @@
     DATABASES={
         'default': {
             'ENGINE': 'django.db.backends.sqlite3',
+        },
+        'other': {
+            'ENGINE': 'django.db.backends.sqlite3',
         }
     },
     TEMPLATES=[{

simple_history/models.py

@@ -349,20 +349,20 @@ def get_meta_options(self, model):
             meta_fields["app_label"] = self.app
         return meta_fields
 
-    def post_save(self, instance, created, **kwargs):
+    def post_save(self, instance, created, using=None, **kwargs):
         if not created and hasattr(instance, "skip_history_when_saving"):
             return
         if not kwargs.get("raw", False):
-            self.create_historical_record(instance, created and "+" or "~")
+            self.create_historical_record(instance, created and "+" or "~", using=using)
 
-    def post_delete(self, instance, **kwargs):
+    def post_delete(self, instance, using=None, **kwargs):
         if self.cascade_delete_history:
             manager = getattr(instance, self.manager_name)
-            manager.all().delete()
+            manager.using(using).all().delete()
         else:
-            self.create_historical_record(instance, "-")
+            self.create_historical_record(instance, "-", using=using)
 
-    def create_historical_record(self, instance, history_type):
+    def create_historical_record(self, instance, history_type, using=None):
         history_date = getattr(instance, "_history_date", now())
         history_user = self.get_history_user(instance)
         history_change_reason = getattr(instance, "changeReason", None)
@@ -387,9 +387,10 @@ def create_historical_record(self, instance, history_type):
             history_user=history_user,
             history_change_reason=history_change_reason,
             history_instance=history_instance,
+            using=using,
         )
 
-        history_instance.save()
+        history_instance.save(using=using)
 
         post_create_historical_record.send(
             sender=manager.model,
@@ -398,6 +399,7 @@ def create_historical_record(self, instance, history_type):
             history_date=history_date,
             history_user=history_user,
             history_change_reason=history_change_reason,
+            using=using,
         )
 
     def get_history_user(self, instance):

simple_history/signals.py

@@ -8,6 +8,7 @@
         "history_date",
         "history_user",
         "history_change_reason",
+        "using",
     ]
 )
 post_create_historical_record = django.dispatch.Signal(
@@ -17,5 +18,6 @@
         "history_date",
         "history_user",
         "history_change_reason",
+        "using",
     ]
 )

simple_history/tests/tests/test_models.py

@@ -6,6 +6,7 @@
 from datetime import datetime, timedelta
 from django.apps import apps
 from django.contrib.auth import get_user_model
+from django.core.exceptions import ObjectDoesNotExist
 from django.core.files.base import ContentFile
 from django.db import models
 from django.db.models.fields.proxy import OrderWrt
@@ -15,6 +16,7 @@
 from simple_history.models import HistoricalRecords, ModelChange
 from simple_history.signals import pre_create_historical_record
 from simple_history.tests.tests.utils import middleware_override_settings
+from simple_history.utils import get_history_model_for_model
 from simple_history.utils import update_change_reason
 from ..external.models import ExternalModel2, ExternalModel4
 from ..models import (
@@ -1219,3 +1221,91 @@ class Meta:
                 "(AbstractModelWithInheritFalse) without "
                 "inherit=True",
             )
+
+
+class MultiDBWithUsingTest(TestCase):
+
+    """Asserts historical manager respects `using()` and the `using`
+    keyword argument in `save()`.
+    """
+
+    multi_db = True
+    db_name = "other"
+
+    def test_multidb_with_using_not_on_default(self):
+        book = Book.objects.using(self.db_name).create(isbn="1-84356-028-1")
+        self.assertRaises(ObjectDoesNotExist, book.history.get, isbn="1-84356-028-1")
+
+    def test_multidb_with_using_is_on_dbtwo(self):
+        book = Book.objects.using(self.db_name).create(isbn="1-84356-028-1")
+        try:
+            book.history.using(self.db_name).get(isbn="1-84356-028-1")
+        except ObjectDoesNotExist:
+            self.fail("ObjectDoesNotExist unexpectedly raised.")
+
+    def test_multidb_with_using_and_fk_not_on_default(self):
+        book = Book.objects.using(self.db_name).create(isbn="1-84356-028-1")
+        library = Library.objects.using(self.db_name).create(book=book)
+        self.assertRaises(ObjectDoesNotExist, library.history.get, book=book)
+
+    def test_multidb_with_using_and_fk_on_dbtwo(self):
+        book = Book.objects.using(self.db_name).create(isbn="1-84356-028-1")
+        library = Library.objects.using(self.db_name).create(book=book)
+        try:
+            library.history.using(self.db_name).get(book=book)
+        except ObjectDoesNotExist:
+            self.fail("ObjectDoesNotExist unexpectedly raised.")
+
+    def test_multidb_with_using_keyword_in_save_not_on_default(self):
+        book = Book(isbn="1-84356-028-1")
+        book.save(using=self.db_name)
+        self.assertRaises(ObjectDoesNotExist, book.history.get, isbn="1-84356-028-1")
+
+    def test_multidb_with_using_keyword_in_save_on_dbtwo(self):
+        book = Book(isbn="1-84356-028-1")
+        book.save(using=self.db_name)
+        try:
+            book.history.using(self.db_name).get(isbn="1-84356-028-1")
+        except ObjectDoesNotExist:
+            self.fail("ObjectDoesNotExist unexpectedly raised.")
+
+    def test_multidb_with_using_keyword_in_save_with_fk(self):
+        book = Book(isbn="1-84356-028-1")
+        book.save(using=self.db_name)
+        library = Library(book=book)
+        library.save(using=self.db_name)
+        # assert not created on default
+        self.assertRaises(ObjectDoesNotExist, library.history.get, book=book)
+        # assert created on dbtwo
+        try:
+            library.history.using(self.db_name).get(book=book)
+        except ObjectDoesNotExist:
+            self.fail("ObjectDoesNotExist unexpectedly raised.")
+
+    def test_multidb_with_using_keyword_in_save_and_update(self):
+        book = Book.objects.using(self.db_name).create(isbn="1-84356-028-1")
+        book.save(using=self.db_name)
+        self.assertEqual(
+            ["+", "~"],
+            [
+                obj.history_type
+                for obj in book.history.using(self.db_name)
+                .all()
+                .order_by("history_date")
+            ],
+        )
+
+    def test_multidb_with_using_keyword_in_save_and_delete(self):
+        HistoricalBook = get_history_model_for_model(Book)
+        book = Book.objects.using(self.db_name).create(isbn="1-84356-028-1")
+        book.save(using=self.db_name)
+        book.delete(using=self.db_name)
+        self.assertEqual(
+            ["+", "~", "-"],
+            [
+                obj.history_type
+                for obj in HistoricalBook.objects.using(self.db_name)
+                .all()
+                .order_by("history_date")
+            ],
+        )