fix: delete data connector when its slug is deleted (#865)

Closes #859.

Author: leafty

components/renku_data_services/migrations/versions/f4ad62b7b323_cleanup_data_connector_when_slug_is_.py

@@ -0,0 +1,50 @@
+"""Cleanup data connector when slug is removed
+
+Revision ID: f4ad62b7b323
+Revises: dcb9648c3c15
+Create Date: 2025-05-19 07:15:11.989650
+
+"""
+
+import sqlalchemy as sa
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision = "f4ad62b7b323"
+down_revision = "dcb9648c3c15"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    """Register a trigger and function to remove a data connector when its slug is removed.
+
+    This is necessary because we only have a foreign key on the slugs table pointing to Data Connectors, so
+    we remove slugs when a data connector is removed. But we also want to remove projects when a slug is removed
+    because this can occur when you delete a group and all data connectors within the group should also be deleted."""
+    op.execute(sa.text("LOCK TABLE common.entity_slugs IN EXCLUSIVE MODE"))
+    op.execute(sa.text("LOCK TABLE storage.data_connectors IN EXCLUSIVE MODE"))
+    # NOTE: OLD variable holds the name of the row that is being deleted (i.e. the trigger)
+    op.execute("""CREATE OR REPLACE FUNCTION delete_data_connector_after_slug_deletion()
+RETURNS TRIGGER AS
+$$
+BEGIN
+    DELETE FROM storage.data_connectors WHERE data_connectors.id = OLD.data_connector_id;
+    RETURN OLD;
+END;
+$$
+LANGUAGE plpgsql;""")
+    op.execute("""CREATE OR REPLACE TRIGGER delete_data_connector_after_slug_deletion
+AFTER DELETE ON common.entity_slugs
+FOR EACH ROW
+EXECUTE FUNCTION delete_data_connector_after_slug_deletion();""")
+    # NOTE: Here we cleanup the data connectors which have neither a namespaced slug nor a global slug.
+    op.execute("""DELETE FROM storage.data_connectors
+WHERE data_connectors.id NOT IN (
+    SELECT entity_slugs.data_connector_id FROM common.entity_slugs WHERE entity_slugs.data_connector_id IS NOT NULL
+) AND data_connectors.global_slug IS NULL""")
+
+
+def downgrade() -> None:
+    op.execute("DROP TRIGGER IF EXISTS delete_data_connector_after_slug_deletion ON storage.data_connectors CASCADE;")
+    op.execute("DROP FUNCTION IF EXISTS delete_data_connector_after_slug_deletion CASCADE;")