0f5c1e3408
The compute proof of concept had never been run with the agent as umbra-poc. Running it that way found three defects, all the same shape: a check that passed because its mechanism did nothing. The demonstration never reached the agent at all. It held the pid it spawned, which under `sudo -n -u` is the sudo wrapper - sudo forks the agent before exec'ing. Signalling that killed the wrapper and left the worker running, renewing its lease and holding the job indefinitely, under a printed note saying "exactly like a power cut". An unprivileged process cannot signal another account's process at all, and kill(2) on a process group succeeds as soon as one member is signalled, so the wrapper's death read as the agent's. Every run leaked an agent. Lease recovery was a diagnosis rather than a mechanism. sweep_expired_leases documented itself as "called by the controller's own timer" and there was no timer; a killed node's job came back only when somebody noticed a stalled job and posted to an administrative route by hand. The proof of concept swept by hand and recorded the result as automatic. app.py now runs the loop for the life of the application, building the compute repository at startup so a restart mid-job still recovers it. The power cut is now the agent's own: os._exit(137) the instant it claims a job, before running it, because a process that does not own the agent cannot signal it. A clean stop goes through a stop_file the agent polls, for the same reason. Liveness is measured by finding the worker's own pid in /proc matched on its config path, sampled repeatedly and accumulated - the wrapper and the worker are not simultaneous, so a single sample finds only the wrapper. The node key travels by `sudo --preserve-env` rather than as VAR=value in argv, because argv is world-readable through /proc/<pid>/cmdline and the environment is not. The demonstration checks whether the key will survive before starting and falls back to a pipe, which node_agent.py --node-key-stdin accepts. Neither a file nor argv ever holds it. Eight tests, each verified to fail against a mutation of the code it covers: three for the sweeper (it must return an expired lease, must survive a failing round, must not invent a repository it has no database for) and five driving a real agent process against a stub controller (stops on the stop file, exits 137 holding an uncompleted job, takes the key from both routes and neither, reports an empty pipe as an empty pipe). 448 pass with a database, 421 without. The deployment database is untouched: users=2 orgs=3 projects=0 audit=43, no compute tables.
UmbraTrans local bootstrap workspace
This workspace contains the unprivileged agent-comm server requested by the Oldbox handoff. It does not contain the UmbraTrans application source: no application bundle was present locally. A staged archive, if present, is left untouched.
Layout
agent_comm/— Python 3.11+ standard-library, stdio-only MCP server.agent_comm/tests/— dependency-free unit tests.umbratrans_web/— phase-1 account/user-management backend slice (FastAPI, Argon2id, sessions, admin routes, in-memory and local JSON development repositories). It does not connect to PostgreSQL; seeumbratrans_web/README.md.umbratrans_web/migrations/— proposed, unapplied phase-1 identity SQL and its rollback.opencode.json— non-secret OpenCode registration for the confirmed NAS2 mailbox.agent-comm.local.example.json— non-secret local fallback registration..env.example— non-secret environment template.DATA-SEPARATION.md— development/production boundary.
Confirmed NAS2 mailbox
The oldbox desktop account mounted NAS2 netbackup through its user GVfs session and confirmed the UmbraTrans directory readable, searchable, and writable. The server requires the explicit NAS deployment mode, the enclosing GVfs mount, and an affirmative mount confirmation:
/run/user/1002/gvfs/smb-share:server=nas2.local,share=netbackup/UmbraTrans/agent-mailbox
Run read-only health checks:
cd /home/umbra/src/UmbraTrans
AGENT_COMM_MODE=nas \
AGENT_COMM_NAS_MOUNT=/run/user/1002/gvfs \
AGENT_COMM_NAS_CONFIRMED=1 \
AGENT_COMM_ROOT='/run/user/1002/gvfs/smb-share:server=nas2.local,share=netbackup/UmbraTrans/agent-mailbox' \
/home/umbra/.local/bin/uv run python -m agent_comm --check
If the user GVfs session is absent, do not guess another path or broaden share permissions. Use the private local fallback documented in agent-comm.local.example.json, or have a privileged operator restore the confirmed user mount.
The server speaks newline-delimited MCP JSON-RPC over stdin/stdout. It opens no network socket and never executes queued instructions.
OpenCode registration
opencode.json contains the exact NAS configuration and paths only. It must never contain passwords, tokens, private keys, or other secrets. A Mac-side reader still needs separate configuration and verification before an outbox message can be considered received.
Development workflow
The project uses uv and a workspace-local virtual environment:
cd /home/umbra/src/UmbraTrans
/home/umbra/.local/bin/uv sync --python /usr/bin/python3
/home/umbra/.local/bin/uv run python -m unittest discover -s agent_comm/tests -v
/home/umbra/.local/bin/uv run ruff check .
/home/umbra/.local/bin/uv run ruff format --check .
/home/umbra/.local/bin/uv run python -m compileall -q agent_comm
make check
The tests cover schema and size validation, atomic no-overwrite writes, restrictive modes, path traversal, symlink refusal, secret-pattern redaction, inbox processing, and read-only initialization.
The account-management slice has its own targets:
cd /home/umbra/src/UmbraTrans
/home/umbra/.local/bin/uv run pytest umbratrans_web/tests
make web-check
Its tests use the in-memory repository and generated per-run passwords; they never read a production configuration, never connect to a database, and contain no credential material.
Backups
scripts/umbratrans_backup.sh is installed root-owned as /usr/local/sbin/umbratrans-backup and scheduled by the enabled umbratrans-backup.timer. It writes only to the confirmed NAS2 netbackup/UmbraTrans/backups tree:
- PostgreSQL:
pg_dumpcustom-format logical dump, never a live data-directory copy. - Configuration: PostgreSQL configuration files only.
- Workspace: source/configuration archive excluding
.venv, Git internals, runtime data, local mailboxes, and secret-bearing files.
Each file is staged outside the share, published with an atomic rename as umbra, checksummed, and verified after publication. Retention is 30 days for PostgreSQL/configuration/manifests and 14 days for workspace archives; stale temporary files older than one hour are removed. The timer fails closed if the user GVfs mount is absent and does not mount or broaden the NAS share.
The current first-run backup set is present under:
/run/user/1002/gvfs/smb-share:server=nas2.local,share=netbackup/UmbraTrans/backups
Check timer status with systemctl status umbratrans-backup.timer and the last run with journalctl -u umbratrans-backup.service.