Socket snapshot carries the nodes waiting for a machine, so a reconnecting browser restores their queued dots

backend/fluksio/api/routes/flows.py

@@ -907,6 +907,8 @@ def snapshot_payload(
     two have to agree, so they build the message here rather than each their
     own. ``emits`` is what the bus counted while nobody was listening — a
     client that reconnects between two pages would otherwise start from zero.
+    ``queued`` is the nodes waiting for a machine, for the same reason: the bus
+    announces a wait once, and a client that missed it would draw the node idle.
 
     ``only`` bounds it to a set of message names, which is what a wall panel
     gets: the values its own dashboards draw, and none of the rest — no node
@@ -925,6 +927,7 @@ def snapshot_payload(
             "paused": [],
             "logs": [],
             "emits": {},
+            "queued": [],
         }
     return {
         "type": "snapshot",
@@ -934,6 +937,7 @@ def snapshot_payload(
         "paused": controller.paused_flows(),
         "logs": list(event_bus.recent_logs),
         "emits": dict(event_bus.emits),
+        "queued": controller.placer.snapshot()["waiting"] if controller.placer else [],
     }
 
 

backend/tests/flow/test_placement.py

@@ -193,6 +193,26 @@ def test_a_node_waits_for_a_busy_machine_and_says_so(loop):
     assert placer.snapshot()["waiting"] == []
 
 
+def test_a_reconnecting_client_is_told_what_is_waiting(tmp_path):
+    """The wait is announced once, so the socket's snapshot carries it again.
+
+    A panel is sent none of it, the same as node status.
+    """
+    from fluksio.api.routes.flows import snapshot_payload
+    from fluksio.flow.controller import FlowController
+    from fluksio.flow.store import FlowStore
+
+    placer = Placer(local=ResourceAccountant(cpus=2))
+    placer._announce("study.b", "r1", time.monotonic(), "waiting for 2 cpu(s)")
+    controller = FlowController(FlowStore(tmp_path / "flows"), placer=placer)
+
+    queued = snapshot_payload(controller)["queued"]
+    assert [(e["node"], e["reason"]) for e in queued] == [
+        ("study.b", "waiting for 2 cpu(s)")
+    ]
+    assert snapshot_payload(controller, set())["queued"] == []
+
+
 def test_a_worker_attaching_wakes_what_was_waiting_for_one(loop):
     """A node waiting inside one machine's books could not hear this."""
     hub = RemoteWorkerHub()