Reset MARC files on settings update (PP-4637)

src/palace/manager/api/admin/controller/catalog_services.py

@@ -8,7 +8,9 @@
 )
 from palace.manager.api.admin.form_data import ProcessFormData
 from palace.manager.api.admin.problem_details import MULTIPLE_SERVICES_FOR_LIBRARY
+from palace.manager.celery.tasks.marc import marc_export_reset
 from palace.manager.integration.catalog.marc.exporter import MarcExporter
+from palace.manager.integration.catalog.marc.settings import MarcExporterLibrarySettings
 from palace.manager.integration.goals import Goals
 from palace.manager.integration.settings import BaseSettings
 from palace.manager.sqlalchemy.listeners import site_configuration_has_changed
@@ -87,19 +89,50 @@ def process_post(self) -> Response | ProblemDetail:
             validated_settings = ProcessFormData.get_settings(settings_class, form_data)
             catalog_service.settings_dict = validated_settings.model_dump()
 
+            # Capture current library settings so we can detect changes after the
+            # update.
+            old_library_settings: dict[int, MarcExporterLibrarySettings] = {
+                lc.library_id: impl_cls.library_settings_load(lc)
+                for lc in catalog_service.library_configurations
+                if lc.library_id is not None
+            }
+
             # Update library settings
             if libraries_data:
                 self.process_libraries(
                     catalog_service, libraries_data, impl_cls.library_settings_class()
                 )
 
+            # Find libraries whose settings actually changed. A MARC export reset
+            # is queued for each so that the next run produces a fresh full
+            # export along with a full-content delta.
+            reset_library_ids = [
+                lc.library_id
+                for lc in catalog_service.library_configurations
+                if lc.library_id is not None
+                and lc.library_id in old_library_settings
+                and impl_cls.library_settings_load(lc)
+                != old_library_settings[lc.library_id]
+            ]
+
             # Trigger a site configuration change
             site_configuration_has_changed(self._db)
 
         except ProblemDetailException as e:
             self._db.rollback()
             return e.problem_detail
 
+        # Dispatch the resets before committing: a failed enqueue then rolls the
+        # settings change back, and a retried save re-queues the reset. The
+        # reverse order could commit the settings and then lose a reset, leaving
+        # delta-only consumers with stale records indefinitely. If the commit
+        # fails after dispatch, the cost is only a spurious reset: the files are
+        # regenerated from unchanged settings by the next scheduled export run.
+        if reset_library_ids:
+            for library_id in reset_library_ids:
+                marc_export_reset.delay(library_id)
+            self._db.commit()
+
         return Response(str(catalog_service.id), response_code)
 
     def process_delete(self, service_id: int) -> Response:

src/palace/manager/api/controller/marc.py

@@ -9,7 +9,7 @@
 from sqlalchemy.orm import Session
 
 from palace.manager.api.util.flask import get_request_library
-from palace.manager.integration.catalog.marc.exporter import MarcExporter
+from palace.manager.integration.catalog.marc.exporter import MARC_EPOCH, MarcExporter
 from palace.manager.service.integration_registry.catalog_services import (
     CatalogServicesRegistry,
 )
@@ -171,7 +171,12 @@ def download_page_body(self, session: Session, library: Library) -> str:
                     body += "<ul>"
                     for update in files.deltas:
                         update_url = self.storage_service.generate_url(update.key)
-                        update_label = f"Updates from {update.since.strftime(time_format)} to {update.created.strftime(time_format)}"
+                        # Avoid misleading label for full-content delta.
+                        update_label = (
+                            f"Full content as of {update.created.strftime(time_format)}"
+                            if update.since == MARC_EPOCH
+                            else f"Updates from {update.since.strftime(time_format)} to {update.created.strftime(time_format)}"
+                        )
                         body += f'<li><a href="{update_url}">{update_label}</a></li>'
                     body += "</ul>"