HJ-319 Updated updated_at field of DBCache even when value doesn't change

CHANGELOG.md

@@ -29,6 +29,7 @@ Changes can also be flagged with a GitHub label for tracking purposes. The URL o
 - Updated brand link url [#5656](https://github.com/ethyca/fides/pull/5656)
 - Changed "Reclassify" D&D button to show in an overflow menu when row actions are overcrowded [#5655](https://github.com/ethyca/fides/pull/5655)
 - Removed primary key requirements for BigQuery and Postgres erasures [#5591](https://github.com/ethyca/fides/pull/5591)
+- Updated `DBCache` model so setting cache value always updates the updated_at field [#5669](https://github.com/ethyca/fides/pull/5669)
 
 ### Fixed
 - Fixed issue where the custom report "reset" button was not working as expected [#5649](https://github.com/ethyca/fides/pull/5649)

src/fides/api/models/db_cache.py

@@ -4,6 +4,7 @@
 from sqlalchemy import Column, Index, String
 from sqlalchemy.dialects.postgresql import BYTEA
 from sqlalchemy.orm import Session
+from sqlalchemy.orm.attributes import flag_modified
 
 from fides.api.db.base_class import Base
 
@@ -78,6 +79,9 @@ def set_cache_value(
         db_cache_entry = cls.get_cache_entry(db, namespace, cache_key)
         if db_cache_entry:
             db_cache_entry.cache_value = cache_value
+            # We manually flag it as modified so that the update runs even if the cache_value hasn't changed
+            # so the updated_at field of the cache entry gets updated.
+            flag_modified(db_cache_entry, "cache_value")
         else:
             db_cache_entry = cls(
                 namespace=namespace.value, cache_key=cache_key, cache_value=cache_value

tests/ops/models/test_dbcache.py

@@ -47,19 +47,32 @@ def test_update_cache_value(self, db):
             ).decode()
             == "value 1"
         )
+        assert cache_value.updated_at is not None
+
+        original_timestamp = cache_value.updated_at
 
         # Update the cache value
         cache_value = DBCache.set_cache_value(
             db, DBCacheNamespace.LIST_PRIVACY_EXPERIENCE, "some-key", "value 2".encode()
         )
         assert cache_value.cache_value.decode() == "value 2"
+        assert cache_value.updated_at > original_timestamp
 
         # Check the value was actually updated
         updated_value = DBCache.get_cache_value(
             db, DBCacheNamespace.LIST_PRIVACY_EXPERIENCE, "some-key"
         )
         assert updated_value.decode() == "value 2"
 
+        previous_timestamp = cache_value.updated_at
+
+        # Updating the value with the same value should still update the timestamp
+        cache_value = DBCache.set_cache_value(
+            db, DBCacheNamespace.LIST_PRIVACY_EXPERIENCE, "some-key", "value 2".encode()
+        )
+        assert cache_value.cache_value.decode() == "value 2"
+        assert cache_value.updated_at > previous_timestamp
+
     def test_delete_cache_entry(self, db):
         # Add two entries
         DBCache.set_cache_value(