infra/docs/architecture/chrome-service.md

chrome-service — In-cluster headed Chromium pool

Overview

chrome-service is a single-replica, persistent-profile, bearer-token-gated Playwright launch-server that exposes a headed Chromium browser over a WebSocket. Sibling services connect to it instead of running their own in-process Chromium when the upstream's anti-bot tooling (disable-devtool.js redirect-to-google trap, console-clear timing tricks, navigator.webdriver checks) defeats a headless browser.

Initial caller: f1-stream's playback_verifier. Future callers attach via the WS+token contract documented in stacks/chrome-service/README.md.

Why a separate stack

In-process Chromium inside f1-stream:

• Runs headless by default (no Xvfb/DISPLAY).
• Has the HeadlessChromium/... UA suffix and navigator.webdriver === true.
• Trips disable-devtool.js's Performance detector — Playwright's CDP adds latency to console.log(largeArray) vs console.table(largeArray), which the lib reads as "DevTools is open" and redirects to https://www.google.com/.

chrome-service solves this by:

1. Running headed under Xvfb :99 (via playwright launch-server with a JSON config that pins headless: false).
2. Living in a long-lived pod so JIT browser launch latency disappears.
3. Allowing a per-context init script (stacks/chrome-service/files/stealth.js ~ 40 lines, vendored from puppeteer-extra-plugin-stealth) to spoof webdriver, chrome.runtime, plugins, languages, Permissions.query, WebGL renderer strings, and to hide the disable-devtool-auto script-tag attribute so the lib's IIFE exits early.

Wire protocol

                  ws://chrome-service.chrome-service.svc.cluster.local:3000/<TOKEN>
                                            │
            ┌───────────────────────────────┼───────────────────────────────┐
            │ caller pod                    │                  chrome-service pod
            │  (e.g. f1-stream)             │                  (single replica)
            │                               │
            │  CHROME_WS_URL  ──────────────┘
            │  CHROME_WS_TOKEN ─── from `secret/chrome-service.api_bearer_token` (ESO)
            │
            │  await chromium.connect(f"{ws}/{token}")
            │  await ctx.add_init_script(STEALTH_JS)
            │  page.goto("https://upstream.com/embed/...")
            │
            └─── ←── pages render under Xvfb, headed Chromium ──── ─────────┘

Image pin

Both the server image (mcr.microsoft.com/playwright:v1.48.0-noble in stacks/chrome-service/main.tf) and the Python client (playwright==1.48.0 in callers' requirements.txt) must match minor-versions. Bump in lockstep — Playwright protocol changes between minors and the client cannot connect to a mismatched server.

The Microsoft image ships only the browser binaries, not the playwright npm SDK; the start command runs npx -y playwright@1.48.0 launch-server which downloads the SDK on first start (cached under $HOME/.npm via the PVC) and reuses it on subsequent restarts.

Storage

• chrome-service-profile-encrypted (PVC, 2Gi → 10Gi autoresize, proxmox-lvm-encrypted) — Chromium user-data dir + npm cache. Encrypted because cookies/localStorage may include third-party auth tokens for sites callers drive. HOME=/profile so npx caches there.
• chrome-service-backup-host (NFS, RWX) — destination for a 6-hourly CronJob that tar -czf /backup/<YYYY_MM_DD_HH>.tar.gz -C /profile ., retention 30 days.

Auth + secrets

• Vault KV secret/chrome-service.api_bearer_token — 32-byte URL-safe random, rotated by hand: vault kv put secret/chrome-service api_bearer_token=$(python3 -c 'import secrets; print(secrets.token_urlsafe(32))').
• ESO syncs into namespace-local Secret chrome-service-secrets (server pod) and chrome-service-client-secrets (each caller pod).
• Reloader (reloader.stakater.com/auto = "true") cascades token rotation to both server and any annotated caller — no manual rollout.

Network controls

• kubernetes_network_policy_v1.ws_ingress — only namespaces labelled chrome-service.viktorbarzin.me/client = "true" (plus an explicit fallback for f1-stream by kubernetes.io/metadata.name) can reach TCP/3000.
• WS port 3000 is internal-only (no ingress, no Cloudflare DNS).
• HTTP port 80 (sidecar nginxinc/nginx-unprivileged:alpine) serves a static health stub at chrome.viktorbarzin.me, Authentik-gated. Lets a human confirm pod liveness without spinning a browser.

Adding a new caller

See stacks/chrome-service/README.md for the four-step recipe:

1. Label the caller's namespace.
2. Add an ExternalSecret pulling secret/chrome-service.
3. Inject CHROME_WS_URL + CHROME_WS_TOKEN env vars.
4. Vendor stealth.js and apply via await context.add_init_script(...) after every new_context().

Limits + risks

• Anti-bot vs stealth arms race — when an upstream beats us (DRM license check, device-fingerprint mismatch, hotlink protection that whitelists specific parent domains), the verifier returns is_playable=False and the extractor moves on. No user-visible breakage, just empty stream lists for that source.
• JWPlayer DRM error 102630 — observed with several hmembeds embeds even from the headed chrome-service. The license check bails because the request origin isn't on the embed's allowlist; this is upstream policy, not an infra defect.
• Single replica + RWO PVC — the deployment uses Recreate strategy. Brief outage on rollout, ~30s for browser warmup.
• No /metrics endpoint — the cluster's generic KubePodCrashLooping rule covers basic alerting. A Prometheus scrape exporter is day-2 work.