homarr/scripts/benchmarks/stress-restore.mts

/**
 * Dashboard stress benchmark.
 *
 * Measures container memory for a *populated* Homarr rather than an empty one:
 * boots a fresh container, restores a real backup through the onboarding
 * restore UI (the same flow a user takes, including the "I understand"
 * confirmation), signs in, opens the busiest board, then hammers navigation and
 * soaks idle while sampling cgroup memory.
 *
 * The backup is supplied by path and never copied into the repo — it contains
 * real integration secrets.
 *
 * Usage:
 *   STRESS_IMAGE=homarr-bench:baseline \
 *   STRESS_BACKUP_ZIP=~/Downloads/homarr-backup.zip \
 *   node --experimental-strip-types scripts/benchmarks/stress-restore.mts
 */
import { execFile } from "node:child_process";
import { mkdir, readFile, rm, writeFile } from "node:fs/promises";
import os from "node:os";
import path from "node:path";
import { promisify } from "node:util";
import { chromium } from "@playwright/test";
import type { Browser, Page } from "@playwright/test";

import { parseStressSnapshot, stressMemoryScript, summarizeStress, toMiB } from "./stress-restore-lib.mts";
import type { StressCheckpoint } from "./stress-restore-lib.mts";

const execFileAsync = promisify(execFile);

const requireEnv = (name: string) => {
  const value = process.env[name];
  if (!value) throw new Error(`${name} is required`);
  return value;
};

const image = requireEnv("STRESS_IMAGE");
const backupZip = path.resolve(requireEnv("STRESS_BACKUP_ZIP").replace(/^~/, os.homedir()));
const label = process.env.STRESS_LABEL ?? image.replace(/[^a-z0-9]+/gi, "-");
const memoryLimit = process.env.STRESS_MEMORY_LIMIT ?? "2g";
const heapMb = process.env.STRESS_HEAP_MB ?? "";
const nodeOptions = process.env.STRESS_NODE_OPTIONS ?? "";
const navIterations = Number(process.env.STRESS_NAV_ITERATIONS ?? 6);
const soakMs = Number(process.env.STRESS_SOAK_MS ?? 120_000);
const soakIntervalMs = Number(process.env.STRESS_SOAK_INTERVAL_MS ?? 20_000);
const keepContainer = process.env.STRESS_KEEP_CONTAINER === "true";
/** Dump a browser heap snapshot here (analyse with analyze-react-fibers.mjs). */
const clientSnapshotPath = process.env.STRESS_CLIENT_SNAPSHOT;
/** Dump a *server* heap snapshot taken at peak, with all tabs still open. */
const peakSnapshotPath = process.env.STRESS_PEAK_SNAPSHOT
  ? path.resolve(process.env.STRESS_PEAK_SNAPSHOT)
  : undefined;
/**
 * Extra `docker run` wiring, so a diagnostics-only preload can be injected into a
 * shipped image without rebuilding it. Used to mount scripts/benchmarks at /probe and
 * point NODE_OPTIONS at memory-probe.cjs, which is what makes per-V8-space and
 * per-module attribution possible at every capture stage.
 *   STRESS_MOUNT="hostPath:containerPath:ro"  (comma-separated for several)
 *   STRESS_ENV="KEY=value,KEY2=value2"
 */
const extraMounts = (process.env.STRESS_MOUNT ?? "")
  .split(",")
  .map((entry) => entry.trim())
  .filter(Boolean);
const extraEnv = (process.env.STRESS_ENV ?? "")
  .split(",")
  .map((entry) => entry.trim())
  .filter(Boolean);
const outputDirectory = path.resolve(process.env.STRESS_OUTPUT ?? `.bench/stress/${label}`);

const password = process.env.STRESS_PASSWORD ?? "demodemo";
const username = process.env.STRESS_USERNAME ?? "demo";
/** Board to stress. The backup's busiest board (28 items / 16 widget kinds). */
const boardName = process.env.STRESS_BOARD ?? "default";
/**
 * Real usage is several tabs on several boards, not one tab on one board, and the
 * browser heap turned out to matter more than the container's. Comma-separated.
 */
const boardNames = (process.env.STRESS_BOARDS ?? boardName)
  .split(",")
  .map((name) => name.trim())
  .filter(Boolean);
const tabsPerBoard = Number(process.env.STRESS_TABS_PER_BOARD ?? 1);

const containerName = `homarr-stress-${Date.now()}`;
const checkpoints: StressCheckpoint[] = [];
let startedAt = Date.now();

const log = (message: string) => console.log(`[stress:${label}] ${message}`);

/** Port the injected memory probe serves JSON on, if one was wired up via STRESS_ENV. */
const probePort = /HOMARR_PROBE_PORT=(\d+)/.exec(extraEnv.join(","))?.[1];

/**
 * Pulls the probe's V8-space and loaded-module attribution alongside the coarse memory
 * numbers. Saved per stage so the *delta* between stages is attributable — "the 90 MiB
 * that appeared at sign-in was old-space objects, not code" is a different problem from
 * "the code got bigger", and only per-stage capture can tell them apart.
 */
const fetchProbeAsync = async (probePath: string) => {
  const script = `fetch("http://127.0.0.1:${probePort}${probePath}").then((r) => r.text()).then((t) => console.log(t)).catch((e) => console.log(JSON.stringify({ error: String(e && e.message) })));`;
  // NODE_OPTIONS is cleared so this helper does not also run the server's --require preload.
  const { stdout } = await execFileAsync("docker", ["exec", "-e", "NODE_OPTIONS=", containerName, "node", "-e", script], {
    maxBuffer: 32 * 1024 * 1024,
  }).catch((error: Error) => ({ stdout: JSON.stringify({ error: error.message }) }));
  return stdout;
};

const captureProbeAsync = async (name: string) => {
  if (!probePort) return;
  await writeFile(path.join(outputDirectory, `${name}.probe.json`), await fetchProbeAsync("/"));
  // Buffer allocation sites, when tracking is enabled. Cumulative, so the useful reading is
  // the difference between two stages: that isolates what one workload allocated.
  const buffers = await fetchProbeAsync("/buffers");
  if (!buffers.includes('"disabled"')) {
    await writeFile(path.join(outputDirectory, `${name}.buffers.json`), buffers);
  }
  const fetches = await fetchProbeAsync("/fetches");
  if (!fetches.includes('"disabled"')) {
    await writeFile(path.join(outputDirectory, `${name}.fetches.json`), fetches);
  }
  // Allocation totals are cumulative since boot, so a single capture cannot separate "the
  // app loaded its code" from "four tabs churned through memory". Capturing at every stage
  // makes those subtractable.
  const allocations = await fetchProbeAsync("/allocations");
  if (!allocations.includes('"disabled"')) {
    await writeFile(path.join(outputDirectory, `${name}.allocations.json`), allocations);
  }
  // The address-space map is the only place JS heap, JIT code, native malloc and file-backed
  // pages are distinguishable, and `rss - heapTotal - external` grew by ~85 MiB between boot
  // and peak with no JS-side explanation. Captured every stage because which stage is the
  // true high-water mark is not known in advance — it is not always the multi-tab one.
  const maps = await fetchProbeAsync("/maps");
  if (!maps.includes('"error"')) {
    await writeFile(path.join(outputDirectory, `${name}.smaps.json`), maps);
  }
};

/**
 * Grabs the two artefacts that only make sense at the high-water mark, with load still on:
 * a heap snapshot (what peak memory *retains*) and the cumulative allocation profile (what
 * peak memory *churned through*, which no snapshot can show because V8 GCs before it
 * serialises one). Set STRESS_PEAK_SNAPSHOT to a host path to keep the snapshot.
 */
const capturePeakAsync = async () => {
  if (!probePort) return;
  // Mappings first, and before any snapshot: this is the only reading that separates JS heap
  // from native, JIT and file-backed pages, and it must reflect the loaded process rather
  // than the process plus whatever the act of snapshotting allocated.
  const maps = await fetchProbeAsync("/maps");
  if (!maps.includes('"error"')) {
    await writeFile(path.join(outputDirectory, "peak.smaps.json"), maps);
    log("peak: address-space map captured");
  }
  const allocations = await fetchProbeAsync("/allocations");
  if (!allocations.includes('"disabled"')) {
    await writeFile(path.join(outputDirectory, "peak.allocations.json"), allocations);
    log("peak: allocation profile captured");
  }
  if (!peakSnapshotPath) return;
  const inContainer = "/tmp/peak.heapsnapshot";
  const result = await fetchProbeAsync(`/snapshot?path=${encodeURIComponent(inContainer)}`);
  if (result.includes('"error"')) {
    log(`peak: snapshot failed — ${result.slice(0, 160)}`);
    return;
  }
  await execFileAsync("docker", ["cp", `${containerName}:${inContainer}`, peakSnapshotPath]);
  await execFileAsync("docker", ["exec", containerName, "rm", "-f", inContainer]).catch(() => undefined);
  log(`peak: heap snapshot saved to ${peakSnapshotPath}`);
};

const captureAsync = async (name: string) => {
  const { stdout } = await execFileAsync("docker", ["exec", containerName, "sh", "-c", stressMemoryScript], {
    maxBuffer: 8 * 1024 * 1024,
  });
  await writeFile(path.join(outputDirectory, `${name}.txt`), stdout);
  await captureProbeAsync(name);
  const checkpoint = parseStressSnapshot(name, Date.now() - startedAt, stdout);
  checkpoints.push(checkpoint);
  log(`${name}: container=${toMiB(checkpoint.container.currentBytes)} MiB`);
  return checkpoint;
};

const waitForReadyAsync = async (baseUrl: string, timeoutMs = 180_000) => {
  const deadline = Date.now() + timeoutMs;
  while (Date.now() < deadline) {
    try {
      const response = await fetch(`${baseUrl}/api/health/ready`);
      if (response.ok) return;
    } catch {
      // Socket not listening yet.
    }
    await new Promise((resolve) => setTimeout(resolve, 1_000));
  }
  throw new Error(`Container never became ready at ${baseUrl}`);
};

/**
 * Ensures the benchmark user can open the target board, and reports what it had
 * to change. A backup where that user is already an admin with the board as
 * their home board reports "none" — which keeps the run honest about how much
 * the harness touched the restored state.
 */
const applyAccessFixtureAsync = async () => {
  const script = `
const Database = require("/app/node_modules/better-sqlite3");
const db = new Database("/appdata/db/db.sqlite");
const user = db.prepare("SELECT id, home_board_id FROM user WHERE name = ?").get(process.argv[1]);
if (!user) throw new Error("user not found: " + process.argv[1]);
const board = db.prepare("SELECT id FROM board WHERE name = ?").get(process.argv[2]);
if (!board) throw new Error("board not found: " + process.argv[2]);
const adminGroup = db.prepare("SELECT group_id AS id FROM groupPermission WHERE permission = 'admin' LIMIT 1").get();
const changes = [];
if (adminGroup) {
  const already = db
    .prepare("SELECT 1 AS ok FROM groupMember WHERE group_id = ? AND user_id = ?")
    .get(adminGroup.id, user.id);
  if (!already) {
    db.prepare("INSERT INTO groupMember (group_id, user_id) VALUES (?, ?)").run(adminGroup.id, user.id);
    changes.push("granted-admin");
  }
}
if (user.home_board_id !== board.id) {
  db.prepare("UPDATE user SET home_board_id = ?, mobile_home_board_id = ? WHERE id = ?").run(board.id, board.id, user.id);
  changes.push("set-home-board");
}
db.close();
console.log("FIXTURE:" + (changes.length ? changes.join(",") : "none"));
`;
  const { stdout } = await execFileAsync("docker", ["exec", containerName, "node", "-e", script, username, boardName]);
  const applied = /FIXTURE:(.*)/.exec(stdout)?.[1]?.trim();
  if (!applied) throw new Error(`Access fixture failed: ${stdout}`);
  log(`access fixture changes: ${applied}`);
  return applied;
};

const restoreBackupAsync = async (page: Page, baseUrl: string) => {
  // networkidle (not domcontentloaded): the toggle below is a client component, and
  // clicking it before hydration silently does nothing.
  await page.goto(`${baseUrl}/init`, { waitUntil: "networkidle" });

  // The onboarding start step hides the restore dropzone behind a toggle. Retry the
  // click until the dropzone's file input exists, so a slow hydration cannot make the
  // whole run fail.
  const expandRestore = page.getByRole("button", { name: /restore.*sqlite|sqlite.*restore|restore.*backup/i });
  const fileInput = page.locator('input[type="file"]');
  for (let attempt = 1; attempt <= 3; attempt++) {
    if ((await fileInput.count()) > 0) break;
    await expandRestore.first().click({ timeout: 30_000 });
    await fileInput
      .first()
      .waitFor({ state: "attached", timeout: 10_000 })
      .catch(() => log(`restore toggle click ${attempt} did not reveal the dropzone, retrying`));
  }
  await fileInput.first().waitFor({ state: "attached", timeout: 30_000 });

  await fileInput.first().setInputFiles(backupZip);
  log("backup uploaded, waiting for analysis");

  const continueButton = page.getByRole("button", { name: /continue to restore|continue/i });
  await continueButton.first().waitFor({ state: "visible", timeout: 180_000 });
  await continueButton.first().click();

  const confirmInput = page.locator('input[placeholder="I understand"]');
  await confirmInput.waitFor({ state: "visible", timeout: 30_000 });
  await confirmInput.fill("I understand");
  log('typed "I understand"');

  const submit = page.getByRole("button", { name: /restore|confirm/i }).last();
  await submit.click();
  log("restore submitted; server will exit and be restarted by run.sh");
};

/**
 * Control: the restored boards are private, so an anonymous visitor must not see
 * one. Without this, "28 widgets rendered" could mean the board was public and
 * the sign-in step never actually authenticated anything.
 */
const verifyAnonymousAccessDeniedAsync = async (browser: Browser, baseUrl: string) => {
  const context = await browser.newContext();
  try {
    const page = await context.newPage();
    await page.goto(`${baseUrl}/boards/${boardName}`, { waitUntil: "domcontentloaded" });
    const boardVisible = await page
      .locator("[data-homarr-dev-benchmark-board]")
      .waitFor({ state: "visible", timeout: 10_000 })
      .then(() => true)
      .catch(() => false);
    if (boardVisible) {
      throw new Error(
        `Anonymous request to /boards/${boardName} rendered the board — it is public, so the ` +
          `authenticated measurement would prove nothing about sign-in.`,
      );
    }
    log(`control: anonymous access to /boards/${boardName} denied (landed on ${new URL(page.url()).pathname})`);
    return new URL(page.url()).pathname;
  } finally {
    await context.close();
  }
};

const loginAsync = async (page: Page, baseUrl: string) => {
  // networkidle: submitting before the form hydrates is a no-op click, which then
  // looks exactly like an authentication failure.
  await page.goto(`${baseUrl}/auth/login`, { waitUntil: "networkidle" });

  for (let attempt = 1; attempt <= 3; attempt++) {
    // Selectors mirror e2e/lazy-widgets.spec.ts: getByLabel(/password/i) is ambiguous
    // because Mantine's PasswordInput also renders a visibility-toggle button.
    await page.getByLabel("Username").fill(username);
    await page.locator("#password").fill(password);
    await page.locator("css=button[type='submit']").first().click();
    try {
      // Poll location rather than page.waitForURL: sign-in redirects client-side, so
      // waitForURL's implicit "load" state is never reached for that navigation.
      await page.waitForFunction(() => !window.location.pathname.includes("/auth/login"), undefined, {
        timeout: 20_000,
      });
      // Leaving /auth/login is necessary but not sufficient — require the session
      // cookie Auth.js sets, so a redirect for any other reason cannot pass as auth.
      const sessionCookie = (await page.context().cookies()).find((cookie) => cookie.name.endsWith("session-token"));
      if (!sessionCookie) {
        throw new Error(`Navigated away from /auth/login but no session-token cookie was set for ${username}`);
      }
      log(`signed in as ${username} (session cookie "${sessionCookie.name}" present)`);
      return sessionCookie.name;
    } catch {
      if (attempt === 3) {
        const error = await page
          .locator('[role="alert"], .mantine-Alert-message')
          .first()
          .innerText()
          .catch(() => "(no alert on page)");
        throw new Error(`Login did not navigate away from /auth/login after 3 attempts. Page alert: ${error}`);
      }
      log(`login attempt ${attempt} did not navigate (likely a pre-hydration click), retrying`);
    }
  }
};

/**
 * Browser-side heap, via CDP. The container figure says nothing about this, and on a
 * real session the tab heap turned out to be the larger number of the two.
 */
const sampleClientHeapAsync = async (page: Page) => {
  const cdp = await page.context().newCDPSession(page);
  try {
    await cdp.send("HeapProfiler.enable");
    // Force a GC so the reading is retained memory rather than uncollected garbage.
    await cdp.send("HeapProfiler.collectGarbage");
    // Performance.getMetrics returns an empty list unless the domain is enabled
    // first — it does not throw, so this has to be unconditional.
    await cdp.send("Performance.enable");
    const { metrics } = await cdp.send("Performance.getMetrics");
    const byName = new Map(metrics.map((metric) => [metric.name, metric.value]));
    const counted = (name: string) => byName.get(name) ?? 0;
    return {
      jsHeapUsedBytes: counted("JSHeapUsedSize"),
      jsHeapTotalBytes: counted("JSHeapTotalSize"),
      documents: counted("Documents"),
      nodes: counted("Nodes"),
      jsEventListeners: counted("JSEventListeners"),
    };
  } finally {
    await cdp.detach().catch(() => undefined);
  }
};

/**
 * Clicks into widgets the way a person does — opening whatever detail/live views the
 * board exposes. Purely reading a board never exercised these paths.
 */
const interactWithWidgetsAsync = async (page: Page, maxClicks = 6) => {
  const clickable = page.locator(
    '[data-homarr-dev-benchmark-board] [data-type="item"] button:visible, ' +
      '[data-homarr-dev-benchmark-board] [data-type="item"] [role="tab"]:visible',
  );
  const available = await clickable.count().catch(() => 0);
  let clicked = 0;
  // Walk spread-out indices: adjacent controls usually belong to the same widget,
  // so stepping through hits more distinct widgets for the same number of clicks.
  const step = Math.max(1, Math.floor(available / maxClicks));
  for (let attempt = 0; attempt < maxClicks; attempt++) {
    const index = attempt * step;
    if (index >= available) break;
    try {
      // force: widgets overlay hover controls that Playwright considers obscured;
      // the click still exercises the handler, which is what costs memory.
      await clickable.nth(index).click({ timeout: 2_000, noWaitAfter: true, force: true });
      clicked++;
      await page.waitForTimeout(350);
      // Only dismiss if something modal actually opened, so we do not close the
      // live view we just paid to render.
      if (await page.locator('[role="dialog"]:visible').count()) {
        await page.keyboard.press("Escape").catch(() => undefined);
      }
    } catch {
      // Widget-specific controls come and go; a miss is not a failure.
    }
  }
  return { available, clicked };
};

/** Streams a browser heap snapshot to disk over CDP, for offline fiber analysis. */
const captureClientSnapshotAsync = async (page: Page, destination: string) => {
  const cdp = await page.context().newCDPSession(page);
  const chunks: string[] = [];
  cdp.on("HeapProfiler.addHeapSnapshotChunk", ({ chunk }) => chunks.push(chunk));
  try {
    await cdp.send("HeapProfiler.enable");
    await cdp.send("HeapProfiler.collectGarbage");
    await cdp.send("HeapProfiler.takeHeapSnapshot", { reportProgress: false });
    await writeFile(destination, chunks.join(""));
    log(`client heap snapshot -> ${destination}`);
  } finally {
    await cdp.detach().catch(() => undefined);
  }
};

const waitForBoardAsync = async (page: Page) => {
  const boardSelector = "[data-homarr-dev-benchmark-board]";
  await page.locator(boardSelector).waitFor({ state: "visible", timeout: 120_000 });
  // Every grid item must have mounted its content (ready or explicitly errored),
  // otherwise memory is sampled mid-render and understates the real cost.
  await page
    .waitForFunction(
      (selector) => {
        const board = document.querySelector(selector);
        const items = [...(board?.querySelectorAll('[data-type="item"]') ?? [])];
        return (
          items.length > 0 &&
          items.every(
            (item) =>
              item.querySelector("[data-homarr-widget-ready]") !== null ||
              item.querySelector("[data-homarr-widget-error]") !== null,
          )
        );
      },
      boardSelector,
      { timeout: 120_000 },
    )
    .catch(() => log("warning: not all widgets reported ready/error before timeout"));
  const outcome = await page.evaluate((selector) => {
    const board = document.querySelector(selector);
    const items = [...(board?.querySelectorAll('[data-type="item"]') ?? [])];
    return {
      items: items.length,
      ready: items.filter((item) => item.querySelector("[data-homarr-widget-ready]") !== null).length,
      errored: items.filter((item) => item.querySelector("[data-homarr-widget-error]") !== null).length,
    };
  }, boardSelector);
  log(`board rendered: ${outcome.items} items (${outcome.ready} ready, ${outcome.errored} errored)`);
  return outcome;
};

const main = async () => {
  await rm(outputDirectory, { recursive: true, force: true });
  await mkdir(outputDirectory, { recursive: true });
  await readFile(backupZip); // Fail fast if the backup path is wrong.

  log(`image=${image} memoryLimit=${memoryLimit} heapMb=${heapMb || "(image default)"}`);

  const runArgs = [
    "run",
    "-d",
    "--name",
    containerName,
    "--cpus",
    process.env.STRESS_CPUS ?? "4",
    "--memory",
    memoryLimit,
    "--memory-swap",
    memoryLimit,
    "-p",
    "0:7575",
    // Restore re-encrypts the backup's secrets to this key, so any 64-hex value works.
    "-e",
    `SECRET_ENCRYPTION_KEY=${"0".repeat(64)}`,
    // Silences Homarr's own outbound work (update check, icon repos, analytics) so
    // the measurement is not perturbed by internet reachability. Integration widget
    // requests are NOT gated by this flag, so integration clients still load.
    "-e",
    "NO_EXTERNAL_CONNECTION=true",
    "-e",
    "LOG_LEVEL=warn",
  ];
  if (heapMb) runArgs.push("-e", `HOMARR_MAX_OLD_SPACE_SIZE=${heapMb}`);
  // Escape hatch for A/B-ing V8 flags against an image whose run.sh does not read
  // HOMARR_MAX_OLD_SPACE_SIZE (e.g. measuring the heap cap against an older image).
  if (nodeOptions) runArgs.push("-e", `NODE_OPTIONS=${nodeOptions}`);
  for (const mount of extraMounts) runArgs.push("-v", mount);
  for (const entry of extraEnv) runArgs.push("-e", entry);
  runArgs.push(image);

  await execFileAsync("docker", runArgs);
  startedAt = Date.now();

  const browser = await chromium.launch();
  try {
    const { stdout: portOut } = await execFileAsync("docker", ["port", containerName, "7575"]);
    const mappedPort = portOut.trim().split("\n")[0]?.split(":").pop();
    if (!mappedPort) throw new Error(`Could not resolve mapped port from: ${portOut}`);
    const baseUrl = `http://127.0.0.1:${mappedPort}`;
    log(`container up at ${baseUrl}`);

    await waitForReadyAsync(baseUrl);
    // Let boot-time work (cron registration, first GC) settle before the idle baseline.
    await new Promise((resolve) => setTimeout(resolve, 15_000));
    await captureAsync("01-boot-idle");

    const context = await browser.newContext({ viewport: { width: 1920, height: 1080 } });
    const page = await context.newPage();

    await restoreBackupAsync(page, baseUrl);
    // The import route exits the process; run.sh restarts it.
    await new Promise((resolve) => setTimeout(resolve, 5_000));
    await waitForReadyAsync(baseUrl);
    await captureAsync("02-post-restore");

    const fixtureChanges = await applyAccessFixtureAsync();

    await context.close();
    const anonymousLanding = await verifyAnonymousAccessDeniedAsync(browser, baseUrl);

    const freshContext = await browser.newContext({ viewport: { width: 1920, height: 1080 } });
    const freshPage = await freshContext.newPage();

    const sessionCookieName = await loginAsync(freshPage, baseUrl);
    await captureAsync("03-post-login");

    await freshPage.goto(`${baseUrl}/boards/${boardName}`, { waitUntil: "domcontentloaded" });
    const boardOutcome = await waitForBoardAsync(freshPage);
    await captureAsync("04-board-loaded");

    log(`stress: ${navIterations} reload iterations`);
    const boardLoadMs: number[] = [];
    for (let iteration = 0; iteration < navIterations; iteration++) {
      const startedNav = Date.now();
      await freshPage.goto(`${baseUrl}/boards/${boardName}`, { waitUntil: "domcontentloaded" });
      await waitForBoardAsync(freshPage);
      // Wall time from navigation start to every widget having mounted — the
      // latency side of any memory/CPU trade-off.
      boardLoadMs.push(Date.now() - startedNav);
      await captureAsync(`nav-${String(iteration + 1).padStart(2, "0")}`);
    }
    // Multi-tab phase: hold several boards open at once, like a real session, and
    // measure the browser heap as well as the container.
    const openTabs: Page[] = [];
    const tabPlan = boardNames.flatMap((name) => Array.from({ length: tabsPerBoard }, () => name));
    let widgetInteractions = { available: 0, clicked: 0 };
    if (tabPlan.length > 1 || tabsPerBoard > 1) {
      log(`multi-tab: opening ${tabPlan.length} tabs across boards [${boardNames.join(", ")}]`);
      for (const [index, name] of tabPlan.entries()) {
        const tab = index === 0 ? freshPage : await freshContext.newPage();
        if (index > 0) openTabs.push(tab);
        await tab.goto(`${baseUrl}/boards/${name}`, { waitUntil: "domcontentloaded" });
        const outcome = await waitForBoardAsync(tab);
        log(`  tab ${index + 1} (${name}): ${outcome.items} items, ${outcome.ready} ready`);
        const interacted = await interactWithWidgetsAsync(tab);
        widgetInteractions = {
          available: widgetInteractions.available + interacted.available,
          clicked: widgetInteractions.clicked + interacted.clicked,
        };
      }
      log(`multi-tab: clicked ${widgetInteractions.clicked}/${widgetInteractions.available} widget controls`);
      await captureAsync("07-multi-tab");
      // Taken here, with every tab still open, because this is the high-water mark. Every
      // earlier snapshot was of a drained process and could not show what peak memory holds.
      await capturePeakAsync();
    }

    if (clientSnapshotPath) await captureClientSnapshotAsync(freshPage, clientSnapshotPath);

    const clientHeap = await sampleClientHeapAsync(freshPage);
    log(
      `client heap: used=${toMiB(clientHeap.jsHeapUsedBytes)} MiB total=${toMiB(clientHeap.jsHeapTotalBytes)} MiB ` +
        `nodes=${clientHeap.nodes} listeners=${clientHeap.jsEventListeners} docs=${clientHeap.documents}`,
    );

    const sortedLoads = [...boardLoadMs].sort((left, right) => left - right);
    const lowerMedian = sortedLoads[Math.floor((sortedLoads.length - 1) / 2)];
    const upperMedian = sortedLoads[Math.ceil((sortedLoads.length - 1) / 2)];
    const medianBoardLoadMs =
      lowerMedian === undefined || upperMedian === undefined ? null : (lowerMedian + upperMedian) / 2;
    log(`board load ms: [${boardLoadMs.join(", ")}] median=${medianBoardLoadMs}`);
    await captureAsync("05-after-stress");

    log(`soak: ${soakMs}ms idle with board open`);
    const soakDeadline = Date.now() + soakMs;
    let soakIndex = 0;
    while (Date.now() < soakDeadline) {
      await new Promise((resolve) => setTimeout(resolve, soakIntervalMs));
      await captureAsync(`soak-${String(++soakIndex).padStart(2, "0")}`);
    }
    await captureAsync("06-final");

    const summary = {
      label,
      image,
      imageRevision: (
        await execFileAsync("docker", [
          "image",
          "inspect",
          image,
          "--format",
          '{{index .Config.Labels "org.opencontainers.image.revision"}}',
        ])
      ).stdout.trim(),
      imageSizeBytes: Number(
        (await execFileAsync("docker", ["image", "inspect", image, "--format", "{{.Size}}"])).stdout.trim(),
      ),
      config: {
        memoryLimit,
        heapMb: heapMb || null,
        nodeOptions: nodeOptions || null,
        navIterations,
        soakMs,
        soakIntervalMs,
        boardName,
      },
      // Recorded so an A/B pair can be rejected if the two runs rendered
      // different amounts of the board (e.g. more widgets errored on one side).
      board: boardOutcome,
      latency: { boardLoadMs, medianBoardLoadMs },
      // The browser side. Container memory alone hid this entirely.
      client: {
        jsHeapUsedMiB: toMiB(clientHeap.jsHeapUsedBytes),
        jsHeapTotalMiB: toMiB(clientHeap.jsHeapTotalBytes),
        domNodes: clientHeap.nodes,
        jsEventListeners: clientHeap.jsEventListeners,
        documents: clientHeap.documents,
        tabsOpen: tabPlan.length,
        boards: boardNames,
        widgetInteractions,
      },
      // Evidence that the board was measured behind a real session rather than
      // because it happened to be publicly readable.
      auth: {
        username,
        sessionCookieName,
        anonymousBoardAccess: `denied (redirected to ${anonymousLanding})`,
        fixtureChanges,
      },
      ...summarizeStress(checkpoints),
    };
    await writeFile(path.join(outputDirectory, "summary.json"), `${JSON.stringify(summary, null, 2)}\n`);
    await writeFile(path.join(outputDirectory, "checkpoints.json"), `${JSON.stringify(checkpoints, null, 2)}\n`);
    console.log(JSON.stringify(summary, null, 2));

    await freshContext.close();
  } finally {
    await browser.close().catch(() => undefined);
    await execFileAsync("docker", ["logs", containerName])
      .then(({ stdout, stderr }) => writeFile(path.join(outputDirectory, "container.log"), `${stdout}\n${stderr}`))
      .catch(() => undefined);
    if (keepContainer) {
      log(`keeping container ${containerName}`);
    } else {
      // -v also drops the anonymous /appdata volume so repeated runs start clean.
      await execFileAsync("docker", ["rm", "-fv", containerName]).catch(() => undefined);
    }
  }
};

await main();