Optional browser rendering

Install the optional renderer with pip install 'newsworker[browser]' followed by playwright install chromium. Explicit --render always renders; automatic fallback requires render_fallback: true and runs once only when normal extraction returns zero items and the document has client-rendering signals.

Secure defaults are one concurrent render, a 15-second navigation deadline, a 10 MiB rendered-document cap, the shared five-hop redirect limit, and blocked media/font or network-policy-violating subresources. Browser contexts and processes close after every success, timeout, or crash. Run untrusted JavaScript only inside an OS/container sandbox with an outbound firewall; portable in-process memory enforcement is not a substitute for a container memory limit.

Reproduce the local no-network baseline with:

python benchmarks/browser_benchmark.py

The benchmark renders a deterministic loopback page five times and reports median/p95 latency plus parent and browser-child peak RSS. Measurements depend strongly on browser, OS, and cold/warm cache state, so compare regressions on the same runner.

The 2026-08-04 baseline on Python 3.13.7, Playwright 1.62/Chromium 151, and Apple Silicon measured 1,902.5 ms median render latency, a 3,540.7 ms five-sample maximum, 45.7 MiB parent peak RSS, and 139.8 MiB browser-child peak RSS. These results support the conservative default concurrency of one; deployments should enforce a container memory limit sized for their own pages and measured browser version.

See benchmarks and security.