Fix audit findings in queue fairness and official account lifecycle

pigway_frame_flow/display/service.py

@@ -217,11 +217,23 @@ class DisplayService:
             (device_id, now_iso()),
         )
 
+    def queued_operations(self):
+        cursor_time, cursor_id = "", ""
+        while True:
+            rows = self.db.all(
+                "SELECT * FROM operations WHERE status='QUEUED' AND "
+                "(created_at>? OR (created_at=? AND id>?)) "
+                "ORDER BY created_at,id LIMIT 50",
+                (cursor_time, cursor_time, cursor_id),
+            )
+            if not rows:
+                return
+            yield from rows
+            cursor_time, cursor_id = rows[-1]["created_at"], rows[-1]["id"]
+
     def process_one(self):
         with self.lock:
-            for op in self.db.all(
-                "SELECT * FROM operations WHERE status='QUEUED' ORDER BY created_at LIMIT 50"
-            ):
+            for op in self.queued_operations():
                 if op["action"] not in ("render", "local-upload") and self.blocked(
                     op["device_id"]
                 ):