LeaseLedger v0.1.0 — durable fenced job processing

What is included

A tested single-host, multi-process durable queue using Python and SQLite WAL:

• Atomic leases with fencing tokens that reject stale acknowledgements
• Idempotent submissions, delayed/prioritized scheduling, worker heartbeat
• Bounded exponential retries, persistent dead-letter jobs and an event journal
• CLI and trusted local Python handler interface
• 22 automated tests, including four separate OS processes claiming 48 jobs
• CI on Python 3.11, 3.12 and 3.13, Ruff lint/format and a measured benchmark smoke job

Reproducible setup

See README for install/CLI demo and docs/notes/why-fencing-tokens.md for the transaction and recovery reasoning.

Guarantees and limits

At-least-once, not exactly-once external effects. SQLite is a local single-host database, not a distributed consensus backend. The handlers run trusted local Python and are not sandboxed. Benchmarks report actual local measurements, not a production performance claim. This is an original engineering portfolio project rather than an existing deployed SaaS.