`docker compose build` without NEXUS_TOKEN produced a Nexus 401 forty
seconds in, worded as a credentials problem when it was really an unset
variable. The mount's `required=true` asserts the secret was *declared*,
not that it holds anything, so an empty one sailed past it and npm sent
an empty `_authToken`.
The install moves to tools/docker-install-deps.sh, which checks the
secret before touching the network and fails in under a second with the
three ways to supply it. It is a file rather than inline shell because
BuildKit echoes an inline command twice on failure and buries the
message.
Also ignore .env. It carries NEXUS_TOKEN, compose reads it at build
time, and it was not gitignored — .env.example stays tracked. Nothing
had been committed: the only prior commit predates all of this.
Verified: empty token fails in 0.2s with the message; .env and the
environment variable both build; the image carries no trace of the
token and serves the full page.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
