fix: defer automatic uploads while device synchronization is pending

pigway_frame_flow/display/service.py

@@ -174,7 +174,7 @@ class DisplayService:
         if result:
             row = self.db.one("SELECT result FROM operations WHERE id=?", (id,))
             previous = json.loads(row["result"]) if row and row["result"] else {}
-            for key in ("photo_attempts", "upload_intent"):
+            for key in ("photo_attempts", "upload_intent", "sync_observations"):
                 if key in previous:
                     result = {**result, key: previous[key]}
         self.db.execute(
@@ -519,6 +519,23 @@ class DisplayService:
                     continue
                 payload = json.loads(op["payload"])
                 if op["action"] == "display":
+                    if op["client_id"] in (
+                        "scheduler",
+                        "scheduler-retry",
+                    ) and self.db.one(
+                        "SELECT id FROM operations WHERE device_id=? AND action='display' "
+                        "AND status='SYNCING' AND write_started=1 AND updated_at>? LIMIT 1",
+                        (
+                            op["device_id"],
+                            (
+                                datetime.now(UTC)
+                                - timedelta(seconds=self.settings.sync_timeout)
+                            ).isoformat(),
+                        ),
+                    ):
+                        # Upload activates a new image upstream. Give the prior
+                        # image its existing confirmation window before replacing it.
+                        continue
                     priority = payload["options"]["priority"]
                     top = self.top(op["device_id"])
                     if top and priority < top["priority"]:
@@ -823,6 +840,7 @@ class DisplayService:
             try:
                 driver = self.registry.get(op["device_id"])
                 device = driver.device(refresh=True)
+                self.recovery.observe_device(op, device=device)
                 if intent:
                     expected = self.upload_reconciliation.check(op, driver, device)
                     if (
@@ -850,7 +868,8 @@ class DisplayService:
                         if device.current_content.id == expected
                         else "target_mismatch",
                     )
-            except FlowError:
+            except FlowError as exc:
+                self.recovery.observe_device(op, error=exc)
                 self.recovery.observe(op, "read_unavailable")
             except Exception:
                 # Bad vendor metadata for one operation must not stop the worker.
@@ -858,6 +877,7 @@ class DisplayService:
         for op in self.db.all("SELECT * FROM operations WHERE status='SYNCING'"):
             try:
                 device = self.registry.get(op["device_id"]).device()
+                observation = self.recovery.observe_device(op, device=device)
                 target = json.loads(op["result"])["image_id"]
                 if (
                     device.current_content.id == target
@@ -878,11 +898,11 @@ class DisplayService:
                             "code": E.WRITE_RESULT_UNKNOWN,
                             "message": "Frame refresh was not confirmed",
                             "request_id": op["request_id"],
-                            "details": {},
+                            "details": {"last_device_observation": observation},
                         },
                     )
-            except FlowError:
-                pass
+            except FlowError as exc:
+                self.recovery.observe_device(op, error=exc)
 
         self.recovery.close_superseded_displays()