Dev environment notes

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How the maintainer's machine is set up, and the throwaway services the Docker-backed tests expect. Nothing here is required to use Docker Commander — it is here so a development session doesn't start by rediscovering it.

For how the test suite is organised, see Testing. For behaviours of the app itself that are easy to get wrong, see Gotchas.

This machine

• Go lives at ~/.local/go and is not on the default PATH: export PATH="$HOME/.local/go/bin:$PATH" (with GOTOOLCHAIN=local).
• Don't use pkill in this sandbox — it exits 144 and aborts the rest of the command. Stop background servers explicitly: lsof -ti tcp:PORT | xargs kill.
• Build: make build (UI, then binary). The committed web/dist is what lets go build ./... work without Node installed.
• Frontend: make ui for every rebuild, Dependabot npm PRs included. It runs npm ci, so it installs exactly the locked tree and leaves package-lock.json alone. (It used to run npm install, which quietly rewrote the lockfile: an npm older than the one that wrote it drops fields it does not recognise — libc platform hints, most recently. Anything else running npm install over this repo, an IDE's npm integration included, still does that; if the lockfile turns up modified on its own, that is why.)
• CI checks the committed web/dist against web/src. If you change anything under web/src, rebuild and commit the bundle or the build fails. It matters because go install embeds the committed copy — tagged binaries rebuild it.
• Headless UI verification: puppeteer-core driving the system google-chrome, with a Node TOTP helper to get past mandatory 2FA. Two quirks worth knowing: controlled inputs need the native value-setter plus an input event, and checkboxes nested in a <label> double-fire on click — use focus and Space instead.

Throwaway services the tests use

Each is optional: the matching tests skip cleanly when the service isn't there.

Service	Command	Wire-up
Redis	docker run -d --rm -p 6399:6379 redis:7-alpine	DC_REDIS_ADDR=127.0.0.1:6399
SMTP sink	docker run -d -p 1025:1025 -p 8025:8025 axllent/mailpit	HTTP API on :8025 to read the mail back
LDAP	osixia/openldap:1.5.0	LDAP_DOMAIN=example.org, admin cn=admin,dc=example,dc=org; ldapadd a user
Auth registry	registry:2 with an htpasswd file	no htpasswd binary here — generate the bcrypt line with Go's x/crypto/bcrypt. localhost is insecure-by-default for the daemon
sshd	alpine + apk add openssh	the host key is exchanged before auth; DC_SSH_INTEGRATION runs TestSSHHostKeyEndToEnd
Second daemon	scripts/remote-test-daemon.sh up 2	prints the exact DC_REMOTE_DOCKER invocation; serves both TCP and SSH
Pinned Engine	docker run -d --privileged -e DOCKER_TLS_CERTDIR="" -p 127.0.0.1:12375:2375 docker:NN-dind --host=tcp://0.0.0.0:2375 --tls=false	DC_COMPAT_DOCKER and DOCKER_HOST must both point at it

Always pass -count=1 for anything driven by a DC_* environment variable. Go caches test results and an env-var change does not invalidate that cache, so a re-provisioned daemon otherwise replays the previous run's verdict.