`nginx:alpine` ships a config that serves the directory and does nothing else: no compression, and no
cache headers at all. Every asset on the live site carried a TTL of zero, so a returning visitor
re-downloaded all of it — 1.1 MB by Lighthouse's count.
Written out on every start rather than kept as a file somebody edits, so what nginx does is decided in
this file and cannot drift from it.
Three lifetimes, because there are three kinds of file. `derived/` renditions are rebuilt IN PLACE —
av-club replaces the contents of `1280.webp` rather than writing a new name — so they cannot be
`immutable` however much they look like they could be, or a re-crop stays invisible for a year to
everyone who saw the old one. Bundled assets change only when a build runs, and a build changes the
HTML that names them: a week. HTML revalidates every time, because anything longer makes a publish
invisible to whoever already visited, which is the one failure that makes the whole panel look broken.
`^~` on the prefix locations. A regex location beats a prefix location in nginx, so the extension rule
would otherwise capture /derived/…/1280.webp and give it the wrong lifetime.
Validated with `nginx -t` in the real image rather than by reading it.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
pastilhasandClaude Opus 5
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