fix(system): keep worker telemetry polling live

apps/control-station/src/core/system/sequentialPolling.ts

@@ -0,0 +1,45 @@
+export interface SequentialPollingScheduler {
+  setTimeout(callback: () => void, delayMilliseconds: number): number;
+  clearTimeout(handle: number): void;
+}
+
+function createBrowserScheduler(): SequentialPollingScheduler {
+  return {
+    setTimeout: (callback, delayMilliseconds) =>
+      window.setTimeout(callback, delayMilliseconds),
+    clearTimeout: (handle) => window.clearTimeout(handle),
+  };
+}
+
+export function startSequentialPolling(
+  task: () => Promise<void>,
+  delayMilliseconds: number,
+  scheduler = createBrowserScheduler(),
+): () => void {
+  let stopped = false;
+  let timer: number | null = null;
+
+  const run = async () => {
+    if (stopped) return;
+    try {
+      await task();
+    } catch {
+      // The caller owns error reporting. A transient failure must not stop polling.
+    }
+    if (stopped) return;
+    timer = scheduler.setTimeout(() => {
+      timer = null;
+      void run();
+    }, delayMilliseconds);
+  };
+
+  void run();
+
+  return () => {
+    stopped = true;
+    if (timer !== null) {
+      scheduler.clearTimeout(timer);
+      timer = null;
+    }
+  };
+}

apps/control-station/src/core/system/useWorkerTelemetry.ts

@@ -4,6 +4,7 @@ import {
   fetchWorkerTelemetry,
   type WorkerTelemetry,
 } from "./workerTelemetry";
+import { startSequentialPolling } from "./sequentialPolling";
 import { normalizeWorkerTelemetryPollMilliseconds } from "./telemetryPollInterval";
 
 export const DEFAULT_WORKER_TELEMETRY_POLL_MILLISECONDS = 3_000;
@@ -38,28 +39,31 @@ export function useWorkerTelemetry(
       return;
     }
     const controller = new AbortController();
-    setLoading(true);
-    void fetchWorkerTelemetry(contourId, controller.signal)
-      .then((document) => {
+    const stopPolling = startSequentialPolling(async () => {
+      setLoading(true);
+      try {
+        const document = await fetchWorkerTelemetry(contourId, controller.signal);
         if (controller.signal.aborted) return;
         setTelemetry(document);
         setError(null);
-      })
-      .catch((reason: unknown) => {
+      } catch (reason: unknown) {
         if (controller.signal.aborted) return;
         setError(reason instanceof Error ? reason.message : "Worker 006 не ответил.");
-      })
-      .finally(() => {
+      } finally {
         if (!controller.signal.aborted) setLoading(false);
-      });
-    return () => controller.abort();
-  }, [contourId, enabled, externalRefreshGeneration, generation]);
-
-  useEffect(() => {
-    if (!enabled || loading) return;
-    const timer = window.setTimeout(refresh, normalizedPollMilliseconds);
-    return () => window.clearTimeout(timer);
-  }, [enabled, loading, normalizedPollMilliseconds, refresh]);
+      }
+    }, normalizedPollMilliseconds);
+    return () => {
+      stopPolling();
+      controller.abort();
+    };
+  }, [
+    contourId,
+    enabled,
+    externalRefreshGeneration,
+    generation,
+    normalizedPollMilliseconds,
+  ]);
 
   return { telemetry, loading, error, refresh };
 }

apps/control-station/test/systemTelemetry.test.mjs

@@ -24,6 +24,7 @@ test("Worker 006 telemetry remains a bounded system feature slice", async () =>
     contourSettings,
     contourContract,
     pollIntervalContract,
+    pollingScheduler,
     telemetryStyles,
     styles,
   ] = await Promise.all([
@@ -40,6 +41,7 @@ test("Worker 006 telemetry remains a bounded system feature slice", async () =>
     read("components/system/ComputeContourSettingsWindow.tsx"),
     read("core/system/computeContours.ts"),
     read("core/system/telemetryPollInterval.ts"),
+    read("core/system/sequentialPolling.ts"),
     read("styles/system-telemetry.css"),
     read("styles.css"),
   ]);
@@ -109,6 +111,9 @@ test("Worker 006 telemetry remains a bounded system feature slice", async () =>
   );
   assert.match(pollIntervalContract, /MIN_TELEMETRY_POLL_INTERVAL_SECONDS\s*=\s*1/);
   assert.match(telemetryPolling, /normalizeWorkerTelemetryPollMilliseconds/);
+  assert.match(telemetryPolling, /startSequentialPolling/);
+  assert.doesNotMatch(telemetryPolling, /if\s*\(\s*!enabled\s*\|\|\s*loading\s*\)/);
+  assert.match(pollingScheduler, /A transient failure must not stop polling/);
   assert.match(styles, /system-telemetry\.css/);
 });
 
@@ -145,3 +150,59 @@ test("MQTT polling interval keeps an unrestricted draft until explicit commit",
   assert.equal(contract.normalizeWorkerTelemetryPollMilliseconds(100), 1_000);
   assert.equal(contract.normalizeWorkerTelemetryPollMilliseconds(3_000), 3_000);
 });
+
+test("Worker telemetry polling repeats after fast responses and transient errors", async () => {
+  const source = await read("core/system/sequentialPolling.ts");
+  const javascript = ts.transpileModule(source, {
+    compilerOptions: {
+      module: ts.ModuleKind.ES2022,
+      target: ts.ScriptTarget.ES2022,
+    },
+  }).outputText;
+  const polling = await import(
+    `data:text/javascript;base64,${Buffer.from(javascript).toString("base64")}`
+  );
+
+  let nextHandle = 1;
+  const timers = new Map();
+  const cleared = [];
+  const scheduler = {
+    setTimeout(callback, delayMilliseconds) {
+      const handle = nextHandle++;
+      timers.set(handle, { callback, delayMilliseconds });
+      return handle;
+    },
+    clearTimeout(handle) {
+      cleared.push(handle);
+      timers.delete(handle);
+    },
+  };
+  let attempts = 0;
+  const stop = polling.startSequentialPolling(async () => {
+    attempts += 1;
+    if (attempts === 2) throw new Error("transient");
+  }, 3_000, scheduler);
+
+  await new Promise((resolve) => setImmediate(resolve));
+  assert.equal(attempts, 1);
+  assert.equal(timers.size, 1);
+  assert.equal([...timers.values()][0].delayMilliseconds, 3_000);
+
+  let [handle, scheduled] = [...timers.entries()][0];
+  timers.delete(handle);
+  scheduled.callback();
+  await new Promise((resolve) => setImmediate(resolve));
+  assert.equal(attempts, 2);
+  assert.equal(timers.size, 1, "a transient error must schedule the next poll");
+
+  [handle, scheduled] = [...timers.entries()][0];
+  timers.delete(handle);
+  scheduled.callback();
+  await new Promise((resolve) => setImmediate(resolve));
+  assert.equal(attempts, 3);
+  assert.equal(timers.size, 1);
+
+  stop();
+  assert.equal(timers.size, 0);
+  assert.deepEqual(cleared, [nextHandle - 1]);
+});