config.rs loads all runtime settings from an external sidecar.toml (path via
$UOLINK_CONFIG), with env-var overrides (UOLINK_WEB_TOKEN, UOLINK_WEB_BIND,
UOLINK_SHARD_BIND, UOLINK_DB_PATH). Nothing is compiled into the binary. On first
run the file is generated with a random 24-byte auth token, so the sidecar is
secured out of the box and the operator just copies the token to the website.
An axum middleware rejects any request to a non-/health route that does not
present the token, as Authorization: Bearer, X-Api-Key, or ?token= (the last so
browser WebSocket clients, which cannot set handshake headers, can authenticate).
The comparison is constant-time. An empty token disables auth and is only
tolerated on a loopback bind; binding to 0.0.0.0 with no token logs a warning.
Verified: /health open (200); /history 401 without a token, 401 with a wrong one,
200 with the right one via either Bearer or X-Api-Key; an authed shard query
falls through to 503 when no shard is connected; WS rejected (401) with a bad
?token= and upgraded (101) with the right one.
sidecar.toml is gitignored (holds the secret); sidecar.toml.example is committed
as the reference.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
