Unhinged

Absurd is Armin Ronacher's durable execution engine for Postgres. Unhinged is the same engine on SQLite. No server, no dependencies, one file on disk.

from unhinged import Unhinged

app = Unhinged("app.db", queue_name="orders")

@app.register_task("fulfil-order")
def fulfil_order(params, ctx):
    payment = ctx.step("charge", lambda: charge_card(params["card"], params["amount"]))
    ctx.sleep_for("cooldown", 60)
    shipment = ctx.await_event(f"shipped:{params['order_id']}", timeout=86400)
    return {"payment": payment, "tracking": shipment["tracking"]}

app.spawn("fulfil-order", {"order_id": 42, "card": "tok_1", "amount": 1999})
app.start_worker(concurrency=4)

Steps run once. If the worker crashes, sleeps, or waits for an event, the next run skips the steps that already finished.

How it works

Same tables as Absurd, same procedure names. The stored procedures are Python methods on Engine, each one a BEGIN IMMEDIATE transaction. Workers poll. Several worker processes can share one file; examples/chaos.py runs eight of them and kills one at random every hundred milliseconds, and the test suite checks that every task still completes, no run was ever executed by two processes, and a step only re-ran when its lease had been reclaimed.

Every commit is fsynced, which survives a crash. On macOS that is not the same as surviving a power cut; pass fullfsync=True for that, and expect it to be slow. docs/durability.md has the whole story, including what to do when the disk dies.

Run it

uv venv && uv pip install -e '.[dev]'
pytest
python examples/crash_demo.py
python examples/bench.py     # calibrates the disk first; see BENCHMARKS.md

examples/release/ is a release checklist that survives Ctrl-C and waits for approval. examples/pipeline/ is a resumable batch job. examples/agent/ is an agent loop where every model call is a step. python -m unhinged is the CLI.

What's not here

Partitioned queues, pg_cron, and the async SDK. Nothing deletes old tasks unless you call app.cleanup() or pass maintenance_interval to start_worker.

License

Apache-2.0, same as Absurd.