# Entry-Point Runtime — Nginx

## Signals to gather
- `argv0` equals `nginx`.
- Config files: `/etc/nginx/nginx.conf`, `conf.d/*.conf`, `/usr/share/nginx/html`.
- Environment (`NGINX_ENTRYPOINT_QUIET_LOGS`, `NGINX_PORT`, `NGINX_ENVSUBST_TEMPLATE`).
- Listening sockets on 80/443 (dynamic mode) or `EXPOSE 80` (static).
- Modules or scripts shipped with the official Docker entrypoint (`docker-entrypoint.sh` collapsing to `nginx -g "daemon off;"`).

## Implementation notes
- Parse `nginx.conf` (basic directive traversal) to extract worker processes, include chains, upstream definitions.
- Handle official entrypoint idioms (`envsubst` templating) via ShellFlow.
- Distinguish pure reverse proxies from PHP-FPM combos; when both `nginx` and `php-fpm` run, classify container as `Supervisor`.
- Record static web content presence (`/usr/share/nginx/html/index.html`).

## Evidence & scoring
- Boost for confirmed config and workers.
- Add evidence for templating features, env substitution, or modules.
- Penalise if binary exists without config (likely not the entry point).

## Edge cases
- Alpine images may place configs under `/etc/nginx/conf.d`; include both.
- Custom builds might rename binary (`openresty`, `tengine`); consider aliases if common.
- Windows Nginx not supported; fall back to `Other`.