Files
hyperframes/packages/engine/src/services/browserManager.ts
T
Miguel Ángel b57dc13cb6 fix(engine): stop SwiftShader ghosting in software screenshot captures (#3096)
Apply the --disable-gpu-compositing workaround to every software capture, not just BeginFrame ones. SwiftShader's compositor re-presents stale raster for a partially invalidated layer, so successive screenshot captures accumulate copies of earlier seeks; alpha renders are forced onto the screenshot path and were the only ones left unprotected.

Refreshes the byte-strict png-sequence alpha baseline for the resulting antialiasing delta (content unchanged, min PSNR 41.3 dB).

Fixes #3049.
2026-08-07 15:18:52 -07:00

1001 lines
37 KiB
TypeScript

/**
* Browser Manager
*
* Manages Puppeteer browser lifecycle: Chrome executable resolution,
* launch args, pooled browser acquisition/release.
*/
import type { Browser, PuppeteerNode } from "puppeteer-core";
import { execSync } from "child_process";
import { existsSync, readdirSync } from "fs";
import { join } from "path";
import { homedir } from "os";
import { DEFAULT_CONFIG, type EngineConfig } from "../config.js";
import { getSystemTotalMb, LOW_MEMORY_TOTAL_MB_THRESHOLD } from "./systemMemory.js";
import {
BrowserLeasePool,
type BrowserLaunchFingerprint,
type BrowserLease,
type CaptureMode,
} from "./browserLeasePool.js";
export { BrowserLeasePool } from "./browserLeasePool.js";
export type {
BrowserLaunchFingerprint,
BrowserLease,
BrowserPoolState,
CaptureMode,
} from "./browserLeasePool.js";
let _puppeteer: PuppeteerNode | undefined;
interface WebGlProbeInfo {
hasWebGL: boolean;
vendor: string;
renderer: string;
}
function isSoftwareWebGlRenderer(rendererInfo: string): boolean {
const renderer = rendererInfo.trim().toLowerCase();
return (
renderer.includes("swiftshader") ||
renderer.includes("llvmpipe") ||
renderer.includes("lavapipe") ||
renderer.includes("softpipe") ||
renderer.includes("mesa offscreen") ||
renderer.includes("microsoft basic render driver") ||
renderer.includes("software rasterizer")
);
}
async function getPuppeteer(): Promise<PuppeteerNode> {
if (_puppeteer) return _puppeteer;
try {
const mod = await import("puppeteer" as string);
_puppeteer = mod.default;
} catch {
const mod = await import("puppeteer-core");
_puppeteer = mod.default;
}
if (!_puppeteer) throw new Error("Neither puppeteer nor puppeteer-core found");
return _puppeteer;
}
async function probeHardwareWebGlInfo(
ppt: PuppeteerNode,
options: {
args: string[];
browserTimeout: number;
executablePath: string | undefined;
},
): Promise<WebGlProbeInfo> {
let probeBrowser: Browser | undefined;
try {
probeBrowser = await ppt.launch({
headless: true,
args: options.args,
defaultViewport: { width: 64, height: 64 },
executablePath: options.executablePath,
timeout: options.browserTimeout,
});
const page = await probeBrowser.newPage();
return await page.evaluate(() => {
const unavailable = { hasWebGL: false, vendor: "", renderer: "" };
const c = document.createElement("canvas");
let gl = c.getContext("webgl") as WebGLRenderingContext | null;
if (gl === null) {
gl = c.getContext("experimental-webgl") as WebGLRenderingContext | null;
}
if (gl === null) return unavailable;
const ext = gl.getExtension("WEBGL_debug_renderer_info") as {
UNMASKED_VENDOR_WEBGL: number;
UNMASKED_RENDERER_WEBGL: number;
} | null;
let vendorParam: number = gl.VENDOR;
let rendererParam: number = gl.RENDERER;
if (ext !== null) {
vendorParam = ext.UNMASKED_VENDOR_WEBGL;
rendererParam = ext.UNMASKED_RENDERER_WEBGL;
}
const vendor = gl.getParameter(vendorParam);
const renderer = gl.getParameter(rendererParam);
return {
hasWebGL: true,
vendor: vendor == null ? "" : String(vendor),
renderer: renderer == null ? "" : String(renderer),
};
});
} finally {
await probeBrowser?.close().catch(() => {});
}
}
export type AcquiredBrowser = BrowserLease;
function compareBrowserVersionsDescending(left: string, right: string): number {
const parse = (value: string): number[] => {
const version = value.slice(value.indexOf("-") + 1);
const segments: number[] = [];
for (const segment of version.split(".")) {
const parsed = Number.parseInt(segment, 10);
if (!Number.isFinite(parsed)) break;
segments.push(parsed);
}
return segments;
};
const leftSegments = parse(left);
const rightSegments = parse(right);
const length = Math.max(leftSegments.length, rightSegments.length);
for (let index = 0; index < length; index += 1) {
const difference = (rightSegments[index] ?? 0) - (leftSegments[index] ?? 0);
if (difference !== 0) return difference;
}
return 0;
}
const CACHED_HEADLESS_SHELL_EXECUTABLES: Readonly<
Record<string, readonly [directory: string, executable: string]>
> = {
"darwin/arm64": ["chrome-headless-shell-mac-arm64", "chrome-headless-shell"],
"darwin/x64": ["chrome-headless-shell-mac-x64", "chrome-headless-shell"],
"linux/x64": ["chrome-headless-shell-linux64", "chrome-headless-shell"],
"win32/ia32": ["chrome-headless-shell-win32", "chrome-headless-shell.exe"],
"win32/x64": ["chrome-headless-shell-win64", "chrome-headless-shell.exe"],
};
function cachedHeadlessShellExecutable(
hostPlatform = process.platform,
hostArch = process.arch,
): readonly [directory: string, executable: string] | undefined {
// Chrome for Testing cache entries are host-specific. Resolve exactly one
// platform/architecture directory so a foreign binary cannot win by probe order.
// Chrome for Testing does not publish Linux ARM64 binaries. Windows ARM64 can
// emulate x64 only on supported Windows 11 builds, which this platform/arch-only
// resolver cannot prove, so both hosts deliberately fall through to system
// browser discovery instead of attempting a potentially foreign cached binary.
return CACHED_HEADLESS_SHELL_EXECUTABLES[`${hostPlatform}/${hostArch}`];
}
function findCachedHeadlessShell(baseDir: string): string | undefined {
if (!existsSync(baseDir)) return undefined;
const executable = cachedHeadlessShellExecutable();
if (!executable) return undefined;
try {
const versions = readdirSync(baseDir).sort(compareBrowserVersionsDescending);
for (const version of versions) {
const binary = join(baseDir, version, ...executable);
if (existsSync(binary)) return binary;
}
} catch {
// Ignore unreadable cache directories and continue browser discovery.
}
return undefined;
}
/**
* Resolve chrome-headless-shell binary for deterministic BeginFrame rendering.
* Checks config.chromePath, then PRODUCER_HEADLESS_SHELL_PATH env var,
* then the CLI browser override, HyperFrames' managed cache, and Puppeteer's cache.
*/
export function resolveHeadlessShellPath(
config?: Partial<Pick<EngineConfig, "chromePath">>,
): string | undefined {
if (config?.chromePath) {
return config.chromePath;
}
if (process.env.PRODUCER_HEADLESS_SHELL_PATH) {
const envPath = process.env.PRODUCER_HEADLESS_SHELL_PATH;
if (!existsSync(envPath)) {
throw new Error(
`[BrowserManager] Chrome binary not found at PRODUCER_HEADLESS_SHELL_PATH="${envPath}". ` +
"Run `hyperframes browser ensure` to re-download.",
);
}
return envPath;
}
if (process.env.HYPERFRAMES_BROWSER_PATH) {
const envPath = process.env.HYPERFRAMES_BROWSER_PATH;
if (!existsSync(envPath)) {
throw new Error(
`[BrowserManager] Chrome binary not found at HYPERFRAMES_BROWSER_PATH="${envPath}". ` +
"Run `hyperframes browser ensure` to re-download.",
);
}
return envPath;
}
const home = homedir();
return (
findCachedHeadlessShell(
join(home, ".cache", "hyperframes", "chrome", "chrome-headless-shell"),
) ?? findCachedHeadlessShell(join(home, ".cache", "puppeteer", "chrome-headless-shell"))
);
}
// Preserve the producer-era export so re-export shims keep the same public API.
export const ENABLE_BROWSER_POOL = DEFAULT_CONFIG.enableBrowserPool;
// Flags only meaningful when Chrome's compositor is driven by
// HeadlessExperimental.beginFrame. If we fall back to screenshot mode they
// must be stripped — `--enable-begin-frame-control` in particular makes the
// compositor wait for frames we'll never send, producing blank screenshots.
const BEGINFRAME_ONLY_FLAGS = new Set([
"--deterministic-mode",
"--enable-begin-frame-control",
"--disable-new-content-rendering-timeout",
"--run-all-compositor-stages-before-draw",
"--disable-threaded-animation",
"--disable-threaded-scrolling",
"--disable-checker-imaging",
"--disable-image-animation-resync",
"--enable-surface-synchronization",
]);
function stripBeginFrameFlags(args: string[]): string[] {
return args.filter((a) => !BEGINFRAME_ONLY_FLAGS.has(a));
}
/**
* Probe the complete HeadlessExperimental.beginFrame runtime contract.
*
* Domain registration alone is insufficient: BeginFrame control must be
* enabled at launch and a renderer-ready target must return a real PNG.
* Every operation shares one short deadline so a wedged CDP call cannot hold
* a serverless cold start until Puppeteer's much longer protocol timeout.
*/
interface BeginFrameProbeResult {
supported: boolean;
detail: string;
durationMs: number;
}
const BEGINFRAME_SCREENSHOT_PROBE_ATTEMPTS = 10;
const BEGINFRAME_PROBE_TIMEOUT_MS = 2000;
const BEGINFRAME_PROBE_CLEANUP_TIMEOUT_MS = 250;
async function awaitBeforeDeadline<T>(
operation: Promise<T>,
deadline: number,
label: string,
): Promise<T> {
const remainingMs = deadline - Date.now();
if (remainingMs <= 0) {
throw new Error(`beginFrame probe timeout before ${label}`);
}
let timeout: ReturnType<typeof setTimeout> | undefined;
try {
return await Promise.race([
operation,
new Promise<never>((_, reject) => {
timeout = setTimeout(
() => reject(new Error(`beginFrame probe timeout during ${label}`)),
remainingMs,
);
}),
]);
} finally {
if (timeout) clearTimeout(timeout);
}
}
async function settleWithin(operation: Promise<unknown>, timeoutMs: number): Promise<boolean> {
let timeout: ReturnType<typeof setTimeout> | undefined;
try {
return await Promise.race([
operation.then(
() => true,
() => false,
),
new Promise<false>((resolveTimeout) => {
timeout = setTimeout(() => resolveTimeout(false), timeoutMs);
}),
]);
} finally {
if (timeout) clearTimeout(timeout);
}
}
async function closeBrowserAfterFailedProbe(
browser: Browser,
timeoutMs = BEGINFRAME_PROBE_CLEANUP_TIMEOUT_MS,
): Promise<void> {
if (await settleWithin(browser.close(), timeoutMs)) return;
// A wedged CDP transport can make graceful close inherit Puppeteer's
// multi-minute protocol timeout. Kill the owned process and disconnect so
// screenshot fallback can launch promptly.
try {
browser.process()?.kill("SIGKILL");
} catch {
// Best effort; disconnect below still releases Puppeteer's transport.
}
await settleWithin(browser.disconnect(), timeoutMs);
}
// The probe keeps its renderer setup, bounded CDP sequence, PNG validation,
// diagnostics, and cleanup together so every failure uses one contract.
// fallow-ignore-next-line complexity
async function probeBeginFrameSupport(
browser: Browser,
timeoutMs = BEGINFRAME_PROBE_TIMEOUT_MS,
): Promise<BeginFrameProbeResult> {
const started = Date.now();
const deadline = started + timeoutMs;
let page;
let result: BeginFrameProbeResult;
try {
page = await awaitBeforeDeadline(browser.newPage(), deadline, "newPage");
// `browser.newPage()` resolves before a cold renderer has necessarily
// submitted its first surface. Cloud Run exposed this as a false
// "unsupported Chromium" result: probing the untouched about:blank
// target raced renderer initialization, while the same binary passed
// once a real document was ready. Navigate first so this tests protocol
// capability rather than target-startup timing.
await awaitBeforeDeadline(
page.goto(
"data:text/html,<style>html,body{margin:0;background:%23173}</style><div>hf-beginframe-probe</div>",
{ waitUntil: "domcontentloaded", timeout: timeoutMs },
),
deadline,
"navigation",
);
const client = await awaitBeforeDeadline(
page.createCDPSession(),
deadline,
"CDP session creation",
);
await awaitBeforeDeadline(
client.send("HeadlessExperimental.enable"),
deadline,
"HeadlessExperimental.enable",
);
await awaitBeforeDeadline(
client.send("HeadlessExperimental.beginFrame", {
frameTimeTicks: 0,
interval: 33,
noDisplayUpdates: true,
}),
deadline,
"warm-up beginFrame",
);
let bytes = Buffer.alloc(0);
let isPng = false;
let attempts = 0;
for (attempts = 1; attempts <= BEGINFRAME_SCREENSHOT_PROBE_ATTEMPTS; attempts += 1) {
const response = await awaitBeforeDeadline(
client.send("HeadlessExperimental.beginFrame", {
frameTimeTicks: 1000 + (attempts - 1) * 33,
interval: 33,
screenshot: { format: "png" },
}),
deadline,
`screenshot beginFrame attempt ${attempts}`,
);
const screenshot = response.screenshotData ?? "";
bytes = screenshot ? Buffer.from(screenshot, "base64") : Buffer.alloc(0);
isPng =
bytes.length >= 8 &&
bytes[0] === 0x89 &&
bytes[1] === 0x50 &&
bytes[2] === 0x4e &&
bytes[3] === 0x47;
if (isPng) break;
await awaitBeforeDeadline(
new Promise((resolveDelay) => setTimeout(resolveDelay, 10)),
deadline,
`screenshot retry delay ${attempts}`,
);
}
if (!isPng) {
throw new Error(
`beginFrame screenshot returned ${bytes.length} bytes after ` +
`${BEGINFRAME_SCREENSHOT_PROBE_ATTEMPTS} attempts with signature ` +
`${bytes.length >= 4 ? bytes.subarray(0, 4).toString("hex") : "<empty>"}`,
);
}
await awaitBeforeDeadline(client.detach(), deadline, "CDP detach").catch(() => {});
result = {
supported: true,
detail:
`enable + warm-up + ${bytes.length}-byte PNG beginFrame succeeded ` +
`after ${attempts} screenshot attempt(s)`,
durationMs: Date.now() - started,
};
} catch (error) {
result = {
supported: false,
detail: error instanceof Error ? error.message : String(error),
durationMs: Date.now() - started,
};
}
if (page && !(await settleWithin(page.close(), BEGINFRAME_PROBE_CLEANUP_TIMEOUT_MS))) {
return {
supported: false,
detail: `${result.detail}; probe page cleanup timed out`,
durationMs: Date.now() - started,
};
}
return result;
}
/** Test-only export for the renderer-readiness + PNG capability contract. */
export const _probeBeginFrameSupportForTests = probeBeginFrameSupport;
/** Test-only export for the forced browser-cleanup fallback. */
export const _closeBrowserAfterFailedProbeForTests = closeBrowserAfterFailedProbe;
/**
* Outcome of the one-shot WebGL probe.
*
* `cause` distinguishes the two ways a probe lands on `"software"`, because
* they need OPPOSITE remediation:
* - `"no-gpu"` — the probe ran and Chrome reported a software renderer
* (SwiftShader / llvmpipe). Remediation: GPU passthrough.
* - `"probe-error"` — the probe itself failed (Chrome couldn't launch, bad
* executable path, sandbox denied). We have NO evidence
* about the GPU either way; telling the operator to fix GPU
* passthrough would send them chasing the wrong problem.
*/
interface GpuProbeOutcome {
mode: "software" | "hardware";
cause?: "no-gpu" | "probe-error";
}
/**
* Cached *in-flight or resolved* probe Promise, shared by BOTH the `"auto"`
* and explicit `"hardware"` entry points of `resolveBrowserGpuMode`.
*
* Caching the Promise (rather than the resolved value) deduplicates concurrent
* callers — the parallel coordinator runs N workers via `Promise.all`, so a
* `--workers 4` render against a no-GPU host would otherwise fire 4
* simultaneous probe Chromes. The first call assigns the Promise and every
* other concurrent caller awaits the same one, paying the ~240 ms probe cost
* exactly once per process lifetime.
*/
let _autoBrowserGpuModeCache: Promise<GpuProbeOutcome> | undefined;
/** Test-only: reset the cached probe result. */
export function _resetAutoBrowserGpuModeCacheForTests(): void {
_autoBrowserGpuModeCache = undefined;
_unverifiedHardwareGpuWarned = false;
}
async function getPuppeteerOrNull(): Promise<PuppeteerNode | null> {
try {
return await getPuppeteer();
} catch {
return null;
}
}
function getHardwareGpuProbeArgs(platform: NodeJS.Platform): string[] {
return [
"--no-sandbox",
"--disable-setuid-sandbox",
"--disable-dev-shm-usage",
"--enable-webgl",
"--ignore-gpu-blocklist",
...getBrowserGpuArgs("hardware", platform),
];
}
function resolveWebGlProbeMode(info: WebGlProbeInfo): "software" | "hardware" {
if (!info.hasWebGL) return "software";
if (!info.vendor.trim() && !info.renderer.trim()) return "software";
return isSoftwareWebGlRenderer(info.renderer) ? "software" : "hardware";
}
function describeWebGlProbe(info: WebGlProbeInfo): string {
if (!info.hasWebGL) return "WebGL unavailable";
return `WebGL renderer vendor=${JSON.stringify(info.vendor)} renderer=${JSON.stringify(info.renderer)}`;
}
function formatProbeFailure(err: unknown): string {
return `probe failed (${err instanceof Error ? err.message : String(err)})`;
}
async function probeAutoBrowserGpuMode(options: {
chromePath?: string;
browserTimeout?: number;
platform?: NodeJS.Platform;
}): Promise<GpuProbeOutcome> {
const platform = options.platform ?? process.platform;
const browserTimeout = options.browserTimeout ?? DEFAULT_CONFIG.browserTimeout;
const executablePath = options.chromePath ?? resolveHeadlessShellPath({});
const ppt = await getPuppeteerOrNull();
if (ppt === null) {
logResolvedBrowserGpuMode("software", "puppeteer unavailable");
return { mode: "software", cause: "probe-error" };
}
try {
const info = await probeHardwareWebGlInfo(ppt, {
args: getHardwareGpuProbeArgs(platform),
browserTimeout,
executablePath,
});
const resolved = resolveWebGlProbeMode(info);
logResolvedBrowserGpuMode(resolved, describeWebGlProbe(info));
return resolved === "hardware" ? { mode: "hardware" } : { mode: "software", cause: "no-gpu" };
} catch (err) {
logResolvedBrowserGpuMode("software", formatProbeFailure(err));
return { mode: "software", cause: "probe-error" };
}
}
/**
* Resolve `browserGpuMode` to a concrete `"software" | "hardware"` answer.
*
* For `"software"` this is a pure pass-through. For `"auto"` it launches a
* tiny Chrome with the platform's hardware GPU args, runs a one-shot WebGL
* availability probe, and falls back to `"software"` if hardware-mode WebGL
* is unavailable. The Promise is cached for the process lifetime, so
* concurrent callers (parallel workers) share the same probe.
*
* `"hardware"` (an explicit `--browser-gpu` / `PRODUCER_BROWSER_GPU_MODE=
* hardware`) is honoured verbatim — the operator asked for it — but runs the
* SAME probe to VERIFY it, because Chrome's hardware GL args are advisory:
* with no usable GPU in the sandbox (no `/dev/dri`, no NVIDIA container
* runtime, missing EGL/driver libraries) Chrome silently falls back to
* software WebGL and the render just runs at CPU speed. Without this check
* the only trace is a buried `Automatic fallback to software WebGL` browser
* warning — heygen-com/hyperframes#2967 rendered 19186 frames on CPU while
* `--browser-gpu` was set and nothing said so. The probe result never
* changes the returned mode; it only makes the fallback loud.
*
* Any probe failure (Chrome launch error, navigation timeout, missing canvas
* API, etc.) is treated as a `"software"` result. The render path with
* SwiftShader always works, so a misclassification toward software is the
* safe failure mode; misclassifying toward hardware would error on the real
* render.
*/
export function resolveBrowserGpuMode(
mode: EngineConfig["browserGpuMode"],
options: {
chromePath?: string;
browserTimeout?: number;
platform?: NodeJS.Platform;
} = {},
): Promise<"software" | "hardware"> {
if (mode === "software") return Promise.resolve(mode);
_autoBrowserGpuModeCache ??= probeAutoBrowserGpuMode(options);
if (mode === "auto") return _autoBrowserGpuModeCache.then((probed) => probed.mode);
return _autoBrowserGpuModeCache.then((probed) => {
// Warn once per cache lifetime, not once per caller: `createCaptureSession`
// resolves the mode for the probe browser AND every parallel worker, so
// an un-deduplicated warning prints N+1 times and buries itself.
if (probed.mode === "software" && !_unverifiedHardwareGpuWarned) {
_unverifiedHardwareGpuWarned = true;
console.warn(
buildUnverifiedHardwareGpuWarning(options.platform ?? process.platform, probed.cause),
);
}
return "hardware";
});
}
/**
* Latch for the explicit-hardware-probed-to-software warning: fires once per
* cache lifetime (re-armed by `_resetAutoBrowserGpuModeCacheForTests`).
*/
let _unverifiedHardwareGpuWarned = false;
/**
* Warning text for "you asked for hardware GPU and we could not confirm it".
*
* Splits on `cause` because the two failure shapes need opposite remediation.
* A probe that RAN and saw SwiftShader is a GPU-passthrough problem. A probe
* that could not run tells us nothing about the GPU — pointing that operator
* at `--gpus all` would send them chasing a phantom while their Chrome
* install is the actual fault.
*/
function buildUnverifiedHardwareGpuWarning(
platform: NodeJS.Platform | string,
cause: GpuProbeOutcome["cause"],
): string {
if (cause === "probe-error") {
return (
"[hyperframes] browserGpuMode=hardware was requested, but the GPU probe could not run, " +
"so hardware acceleration is UNVERIFIED — if Chrome falls back to software WebGL the " +
"capture will run at CPU speed. Honouring the explicit request anyway.\n" +
" This is a probe failure, not evidence of a missing GPU: see the " +
"`browserGpuMode probe → software (probe failed ...)` line above for the underlying " +
"error, which usually means Chrome could not launch (bad HYPERFRAMES_BROWSER_PATH, " +
"missing shared libraries, or a denied sandbox) rather than a GPU problem.\n" +
" Run `hyperframes doctor` to check the Chrome install."
);
}
const remediation =
platform === "linux"
? "Inside Docker, the container needs GPU passthrough: `--gpus all` with the NVIDIA " +
"Container Toolkit installed, or `--device /dev/dri` for Mesa/AMD/Intel. The image " +
"also needs the matching userspace driver + libEGL. Verify with " +
"`hyperframes render --browser-gpu` and watch for this warning disappearing."
: "Check that the host exposes a GPU to this process and that the graphics drivers are " +
"installed.";
return (
"[hyperframes] browserGpuMode=hardware was requested, but the WebGL probe found no " +
"hardware GPU — Chrome will silently fall back to software WebGL and the capture will " +
"run at CPU speed. Honouring the explicit request anyway.\n" +
` ${remediation}\n` +
" Pass --no-browser-gpu to select deterministic SwiftShader instead of waiting on a " +
"hardware path that is not there."
);
}
/**
* Single observability surface for the GPU probe outcome. Logged exactly
* once per process (the probe runs once); without this line, a regression
* to "always software even with a GPU present" would be invisible in
* production. Goes to stderr to stay out of stdout pipelines. Says "probe"
* rather than "auto" because explicit `browserGpuMode=hardware` runs the
* same probe to verify itself.
*/
function logResolvedBrowserGpuMode(resolved: "hardware" | "software", reason: string): void {
console.error(`[hyperframes] browserGpuMode probe → ${resolved} (${reason})`);
}
function createBrowserLaunchFingerprint(
chromeArgs: string[],
config?: Partial<
Pick<EngineConfig, "browserTimeout" | "protocolTimeout" | "chromePath" | "forceScreenshot">
>,
): BrowserLaunchFingerprint {
const launchConfig = {
browserTimeout: DEFAULT_CONFIG.browserTimeout,
protocolTimeout: DEFAULT_CONFIG.protocolTimeout,
forceScreenshot: DEFAULT_CONFIG.forceScreenshot,
...config,
};
const headlessShell = resolveHeadlessShellPath(launchConfig);
// The launch arguments are the authoritative capture-mode contract.
// A caller can pass `forceScreenshot:false` while a later safety clamp
// deliberately omits BeginFrame control flags. Inferring solely from the
// raw config in that case makes BrowserManager probe a capability it never
// enabled, then mislabel the result as an unsupported Chromium build.
const beginFrameControlEnabled = chromeArgs.includes("--enable-begin-frame-control");
const requestedCaptureMode: CaptureMode =
headlessShell &&
process.platform === "linux" &&
!launchConfig.forceScreenshot &&
beginFrameControlEnabled
? "beginframe"
: "screenshot";
return {
args: chromeArgs,
executablePath: headlessShell,
browserTimeoutMs: launchConfig.browserTimeout,
protocolTimeoutMs: launchConfig.protocolTimeout,
requestedCaptureMode,
};
}
/** Test-only export for launch-argument/capture-mode agreement. */
export const _createBrowserLaunchFingerprintForTests = createBrowserLaunchFingerprint;
export async function acquireBrowser(
chromeArgs: string[],
config?: Partial<
Pick<
EngineConfig,
"browserTimeout" | "protocolTimeout" | "enableBrowserPool" | "chromePath" | "forceScreenshot"
>
>,
): Promise<AcquiredBrowser> {
const enablePool = config?.enableBrowserPool ?? DEFAULT_CONFIG.enableBrowserPool;
return browserLeasePool.acquire(createBrowserLaunchFingerprint(chromeArgs, config), enablePool);
}
// fallow-ignore-next-line complexity
async function launchBrowser(
fingerprint: Readonly<BrowserLaunchFingerprint>,
): Promise<{ browser: Browser; captureMode: CaptureMode }> {
const ppt = await getPuppeteer();
let captureMode = fingerprint.requestedCaptureMode;
let browser: Browser | undefined;
try {
browser = await ppt.launch({
headless: true,
args: [...fingerprint.args],
defaultViewport: null,
executablePath: fingerprint.executablePath,
timeout: fingerprint.browserTimeoutMs,
protocolTimeout: fingerprint.protocolTimeoutMs,
});
const browserVersion = await browser.version().catch(() => "unknown");
const gpuFlags = fingerprint.args.filter(
(a) => a.startsWith("--use-gl=") || a.startsWith("--use-angle="),
);
console.log(
`[BrowserManager] Browser launched (${browserVersion}, ${captureMode}, gl=${gpuFlags.join(" ") || "default"}, headlessShell=${!!fingerprint.executablePath}, platform=${process.platform})`,
);
if (captureMode === "beginframe") {
const probe = await probeBeginFrameSupport(browser).catch((error) => ({
supported: true,
detail: `probe harness error ignored: ${error instanceof Error ? error.message : String(error)}`,
durationMs: 0,
}));
if (!probe.supported) {
await closeBrowserAfterFailedProbe(browser);
browser = undefined;
console.warn(
`[BrowserManager] HeadlessExperimental.beginFrame probe failed after ${probe.durationMs}ms: ` +
`${probe.detail}; falling back to screenshot mode.`,
);
captureMode = "screenshot";
browser = await ppt.launch({
headless: true,
args: stripBeginFrameFlags([...fingerprint.args]),
defaultViewport: null,
executablePath: fingerprint.executablePath,
timeout: fingerprint.browserTimeoutMs,
protocolTimeout: fingerprint.protocolTimeoutMs,
});
}
}
return { browser, captureMode };
} catch (error) {
await browser?.close().catch(() => {});
throw error;
}
}
function forceCloseBrowserProcess(browser: Browser): void {
const proc = (
browser as unknown as {
process?: () => { kill: (signal?: NodeJS.Signals) => boolean; killed?: boolean } | null;
}
).process?.();
if (proc && !proc.killed) {
try {
proc.kill("SIGKILL");
} catch {
// Best-effort cleanup.
}
}
try {
browser.disconnect();
} catch {
// Best-effort cleanup.
}
}
const browserLeasePool = new BrowserLeasePool({
launch: launchBrowser,
close: async (browser) => browser.close(),
forceClose: forceCloseBrowserProcess,
});
export async function releaseBrowser(
browser: Browser,
_config?: Partial<Pick<EngineConfig, "enableBrowserPool">>,
): Promise<void> {
await browserLeasePool.releaseByBrowser(browser);
}
export function forceReleaseBrowser(browser: Browser): void {
browserLeasePool.forceReleaseByBrowser(browser);
}
/**
* Forcefully close the pooled browser if one exists, regardless of refCount.
* Used for explicit cleanup at process exit or between independent render jobs
* that should not share browser state.
*/
export async function drainBrowserPool(): Promise<void> {
await browserLeasePool.drain();
}
/** Test-only: reset all pool state. */
export function _resetBrowserPoolForTests(): void {
browserLeasePool.reset();
}
/** Test-only: inject a mock PuppeteerNode so tests bypass the dynamic import. */
export function _setPuppeteerForTests(mock: PuppeteerNode | undefined): void {
_puppeteer = mock;
}
let _cachedVramMb: number | null = null;
function probeNvidiaVramMb(): number | null {
if (_cachedVramMb !== null) return _cachedVramMb;
try {
// Synchronous, runs once per process (cached). ~50ms on typical systems.
const out = execSync("nvidia-smi --query-gpu=memory.total --format=csv,noheader,nounits", {
timeout: 3000,
encoding: "utf-8",
stdio: ["pipe", "pipe", "pipe"],
}).trim();
const mb = parseInt(out.split("\n")[0] ?? "", 10);
if (Number.isFinite(mb) && mb > 0) {
_cachedVramMb = mb;
return mb;
}
} catch {
// nvidia-smi not available or no NVIDIA GPU
}
return null;
}
function getGpuMemBudgetMb(): number {
const vram = probeNvidiaVramMb();
if (vram) return Math.min(vram, 16384);
const total = getSystemTotalMb();
if (total < 4096) return 512;
if (total <= LOW_MEMORY_TOTAL_MB_THRESHOLD) return 1024;
return Math.min(Math.floor(total / 2), 16384);
}
function getLowMemoryFlags(): string[] {
const total = getSystemTotalMb();
if (total > LOW_MEMORY_TOTAL_MB_THRESHOLD) return [];
const heapMb = total < 4096 ? 256 : 512;
return [`--js-flags=--max-old-space-size=${heapMb}`];
}
export interface BuildChromeArgsOptions {
width: number;
height: number;
captureMode?: CaptureMode;
platform?: NodeJS.Platform;
}
const CANVAS_DRAW_ELEMENT_FEATURE_FLAG = "--enable-features=CanvasDrawElement";
const WEBGPU_FLAG = "--enable-unsafe-webgpu";
export function buildChromeArgs(
options: BuildChromeArgsOptions,
config?: Partial<Pick<EngineConfig, "browserGpuMode" | "disableGpu" | "chromePath">>,
): string[] {
const platform = options.platform ?? process.platform;
const gpuDisabled = config?.disableGpu ?? DEFAULT_CONFIG.disableGpu;
const browserGpuMode = gpuDisabled
? "software"
: (config?.browserGpuMode ?? DEFAULT_CONFIG.browserGpuMode);
// Chrome flags tuned for headless rendering performance. The set below is a
// fairly standard "headless-for-capture" configuration — similar profiles
// appear in Puppeteer's defaults, Playwright, Remotion, and Chrome's own
// headless-shell guidance.
const chromeArgs = [
"--no-sandbox",
"--disable-setuid-sandbox",
"--disable-dev-shm-usage",
CANVAS_DRAW_ELEMENT_FEATURE_FLAG,
"--enable-webgl",
"--ignore-gpu-blocklist",
...getBrowserGpuArgs(browserGpuMode, platform),
"--font-render-hinting=none",
"--force-color-profile=srgb",
`--window-size=${options.width},${options.height}`,
// Prevent Chrome from throttling background tabs/timers — critical when the
// page is offscreen during headless capture
"--disable-background-timer-throttling",
"--disable-backgrounding-occluded-windows",
"--disable-renderer-backgrounding",
"--disable-background-media-suspend",
// Reduce overhead from unused Chrome features
"--disable-breakpad",
"--disable-component-extensions-with-background-pages",
"--disable-default-apps",
"--disable-extensions",
"--disable-hang-monitor",
"--disable-ipc-flooding-protection",
"--disable-popup-blocking",
"--disable-sync",
"--disable-component-update",
"--disable-domain-reliability",
"--disable-print-preview",
"--no-pings",
"--no-zygote",
// Memory — scale GPU budget to available system RAM
`--force-gpu-mem-available-mb=${getGpuMemBudgetMb()}`,
"--disk-cache-size=268435456",
...getLowMemoryFlags(),
// Disable features that add overhead
"--disable-features=AudioServiceOutOfProcess,IsolateOrigins,site-per-process,Translate,BackForwardCache,IntensiveWakeUpThrottling",
// Allow AudioContext to start without a user gesture in headless Chrome.
// Without this flag, any code path that constructs an AudioContext
// (including GSAP tweening an <audio> element's volume) triggers the
// autoplay policy and causes the AudioContext to stay suspended. The
// frame-capture loop then blocks waiting for it, deadlocking the render.
"--autoplay-policy=no-user-gesture-required",
];
if (browserGpuMode !== "software") {
chromeArgs.push(WEBGPU_FLAG);
}
// SwiftShader's GPU compositor can retain a transformed layer for several
// sequential frames after a GSAP yoyo/reversal, and it re-presents stale
// raster for a partially invalidated layer: content already drawn in an
// earlier seek is never cleared, so successive captures accumulate copies of
// it (HF#3049 — a moving SVG group smears wider on every frame, and static
// siblings appear duplicated one band lower). The DOM and timeline are
// already at the requested time; the defect is in the compositor surface both
// BeginFrame and Page.captureScreenshot read, so it is not specific to a
// capture mode — it is specific to compositing on SwiftShader.
//
// Routing compositing through Chrome's software path is the only mitigation
// that holds: capture-side changes (fromSurface, captureBeyondViewport, a
// second capture, extra rAF ticks, a 250ms settle) and every raster/tiling
// flag (--disable-partial-raster, --disable-checker-imaging, --disable-zero-copy,
// forced tile sizes) leave the accumulation untouched. The cost is that
// SwiftShader rasterizes thin strokes and glyph edges slightly differently
// (antialiased edges only — measured on HF#3049's frame 0: 96 opaque pixels
// differ, by 1/255). Duplicated content in 68% of frames is the worse defect.
//
// Remove this workaround once the pinned chrome-headless-shell includes
// https://issues.chromium.org/issues/535256667.
if (browserGpuMode === "software") {
chromeArgs.push("--disable-gpu-compositing");
}
// BeginFrame flags — only when using chrome-headless-shell on Linux
if (options.captureMode !== "screenshot") {
chromeArgs.push(
"--deterministic-mode",
"--enable-begin-frame-control",
"--disable-new-content-rendering-timeout",
"--run-all-compositor-stages-before-draw",
"--disable-threaded-animation",
"--disable-threaded-scrolling",
"--disable-checker-imaging",
"--disable-image-animation-resync",
"--enable-surface-synchronization",
);
}
if (gpuDisabled) {
chromeArgs.push("--disable-gpu");
}
return chromeArgs;
}
function getBrowserGpuArgs(
mode: EngineConfig["browserGpuMode"],
platform: NodeJS.Platform,
): string[] {
if (mode === "software") {
// Chrome 120+ deprecated implicit SwiftShader fallback; the explicit
// path (--use-angle=swiftshader) keeps working but Chrome emits a
// deprecation warning unless --enable-unsafe-swiftshader is also set.
// Despite the name, this is exactly the behaviour Chrome had before;
// the flag exists to make CPU rasterisation an explicit opt-in rather
// than an implicit fallback for end users on the open web.
return ["--use-gl=angle", "--use-angle=swiftshader", "--enable-unsafe-swiftshader"];
}
if (mode === "auto") {
// Should not reach here — `resolveBrowserGpuMode` collapses "auto" to
// "software" or "hardware" before args are built. Be defensive: software
// is the always-safe fallback.
return ["--use-gl=angle", "--use-angle=swiftshader", "--enable-unsafe-swiftshader"];
}
switch (platform) {
case "darwin":
return ["--use-gl=angle", "--use-angle=metal", "--enable-gpu-rasterization"];
case "win32":
return ["--use-gl=angle", "--use-angle=d3d11", "--enable-gpu-rasterization"];
case "linux":
// Chrome 131+ headless shell only accepts (gl=angle, angle=gl-egl);
// the old --use-gl=egl causes the GPU process to exit silently.
// --ignore-gpu-blocklist: the operator explicitly opted into
// browserGpuMode="hardware", so trust their driver/GPU choice.
return [
"--use-gl=angle",
"--use-angle=gl-egl",
"--enable-gpu-rasterization",
"--ignore-gpu-blocklist",
"--disable-software-rasterizer",
];
default:
return ["--enable-gpu-rasterization"];
}
}