fix(display): retry a display that could not start, and re-resolve a running one periodically

A kiosk that booted before its server, as after a power cut, stopped on 'This display could not be reached' until someone pressed Retry: with the network up, no online event ever came. It now retries on its own, from two seconds doubling to a minute. A running display also re-resolves its descriptor every five minutes in the background, so a module upgraded on the server is picked up without a reload, and the same answer disturbs nothing. Co-Authored-By: Claude Opus 5.5 <[email protected]>
2026-10-12 21:45:37 -05:00
parent 8f90871be0
commit 9331a8f7df
2 changed files with 110 additions and 1 deletions
@@ -1161,4 +1161,69 @@ describe("display host — continuity across reconnects and revocation", () => {
    });
    expect(query("display-offline")?.textContent).toBe("Offline — reconnecting");
  });
+
+  it("starts on its own when the server comes up after the screen did", async () => {
+    // A kiosk that boots before its server: the network is up, so no `online` event will ever come.
+    let up = false;
+    const fetch = vi.fn(async (input: RequestInfo | URL) => {
+      const url = String(input);
+      if (url.endsWith("/api/v1/module-displays/announcements")) {
+        return up ? json(descriptorPayload()) : json({ code: "UNAVAILABLE" }, 503);
+      }
+      return json({ code: "NOT_FOUND" }, 404);
+    }) as unknown as typeof globalThis.fetch;
+    const display = countingArtifact();
+    await act(async () => {
+      root.render(
+        <DisplayApp
+          config={{ apiBaseUrl, fetch }}
+          importModule={display.importModule}
+          moduleId="announcements"
+          offlineIndicatorDelayMs={0}
+          retryBaseMs={20}
+        />,
+      );
+    });
+    await flush();
+    expect(query("display-host-error")).not.toBeNull();
+
+    up = true;
+    await act(async () => {
+      await new Promise((resolve) => setTimeout(resolve, 200));
+    });
+    await flush();
+    expect(display.counts.mounts).toBe(1);
+    expect(query("display-host-error")).toBeNull();
+  });
+
+  it("re-resolves a running display periodically, remounting only for a new version", async () => {
+    const server = changingServer();
+    const display = countingArtifact();
+    await act(async () => {
+      root.render(
+        <DisplayApp
+          config={{ apiBaseUrl, fetch: server.fetch }}
+          importModule={display.importModule}
+          moduleId="announcements"
+          offlineIndicatorDelayMs={0}
+          periodicRevalidationMs={40}
+        />,
+      );
+    });
+    await flush();
+    const before = server.descriptorCalls();
+    await act(async () => {
+      await new Promise((resolve) => setTimeout(resolve, 150));
+    });
+    await flush();
+    expect(server.descriptorCalls()).toBeGreaterThan(before);
+    expect(display.counts).toEqual({ mounts: 1, unmounts: 0 });
+
+    server.set(200, descriptorPayload("announcements", "2.0.0"));
+    await act(async () => {
+      await new Promise((resolve) => setTimeout(resolve, 150));
+    });
+    await flush();
+    expect(display.counts.mounts).toBe(2);
+  });
 });