_run_once awaited _subscribe_all_users() inline, before starting the header/scripthash consumer tasks, and that method subscribed one user at a time. At thousands of users that's thousands of sequential round-trips during which nothing else ran: tip_height was frozen and an in-flight draw's _wait_for_next_block made zero progress for the entire resubscribe - a reconnect (which the listener already treats as routine, not exceptional) could stall the lottery for minutes. _subscribe_all_users now fans out with bounded concurrency (asyncio.Semaphore, 20 at a time) instead of a serial loop, and one user's failure no longer stops the rest. _run_once now starts it as its own background task, created after the consumer tasks rather than awaited before them, so tip updates and already-subscribed users' notifications keep flowing throughout - its own completion is deliberately not raced against the session-ending tasks (unlike them, it's expected to finish normally), and its failure is logged the same way address_for_new_user's background task is (B-30). Left out: decoupling the listunspent refresh from the subscribe call itself (the third part of the proposed fix) - the periodic DepositReconciler (B-30) already provides a backstop for a slow or delayed initial refresh, so the added complexity wasn't worth it here. Suite grows from 182 to 185 tests, including an end-to-end test against _run_once proving a new tip is processed while a slow resubscribe is still in flight. BUGS.md moves B-31 to Previously fixed.
PLM Lottery
A periodic-round lottery system built on PLM, a Bitcoin-like coin (mainnet). Each user gets a dedicated server-derived P2WPKH address; they deposit PLM to that address, place a fixed-cost bet to enter the current round, and when the round closes a winner is drawn who receives 70% of the prize pool (the remaining 30% goes to fees).
This is a custodial system: private keys are generated and held server-side, encrypted at rest. See CLAUDE.md for the full architecture, domain decisions, and known gaps before treating this as production-ready.
Quick start
cp .env.example .env # then fill in the generated secrets, see docs/setup.md
python3 -m venv .venv && source .venv/bin/activate
pip install -e ".[dev]"
PYTHONPATH=. python scripts/generate_master_key.py
alembic upgrade head
uvicorn app.main:app --reload --port 8123
Open http://127.0.0.1:8123/ for the test UI, http://127.0.0.1:8123/admin
for the admin dashboard, http://127.0.0.1:8123/docs for the interactive API
docs.
Or run the whole stack (app + Caddy reverse proxy with automatic TLS) via Docker:
mkdir -p data/db data/keys data/logs
docker compose run --rm app python scripts/generate_master_key.py
docker compose up -d --build
See docs/setup.md and docs/running-the-server.md for the full walkthrough (both workflows, dev vs. production TLS).
Documentation
- CLAUDE.md — architecture, commands, domain decisions, known gaps (for anyone/anything working on the code)
- flowchart.mmd — the source-of-truth flow diagram the implementation follows node-by-node
- docs/setup.md — one-time setup (secrets, master key, migrations)
- docs/running-the-server.md — how to launch it (local venv vs. Docker+Caddy, dev vs. production TLS)
- docs/guida-utente.md — end-user guide to the test UI (Italian)
- docs/guida-admin.md — admin dashboard guide (Italian)
Tech stack
Python (FastAPI, SQLAlchemy async + Alembic, Argon2 + JWT auth), Electrum protocol for PLM network access (no full node), Docker + Caddy for deployment. See CLAUDE.md for the complete list and the reasoning behind each choice.
Testing
python -m pytest # all tests
python -m pytest tests/unit/test_hd.py # one file
76 unit tests cover HD derivation, PSBT building, the Electrum client, bets, deposits, withdrawals, the round/draw engine, RBF fee-bumping, admin config, the pending-inclusive balance calculation, and the SSE push channel. No automated integration tests against a live Electrum connection — mainnet verification so far has been manual (see CLAUDE.md's "Project status").