camas 0.1.3

Generic parallel/sequential task runner

Camas

Generic parallel/sequential task runner with a live tree-style TUI.

Install

uv add camas

or

pip install camas

Quick start

Camas takes a typed Python expression describing a tree of Task, Sequential, and Parallel nodes and runs it, streaming progress into a live tree in your terminal.

Run two checks in parallel:

python -m camas 'Parallel(tasks=(Task("ruff check ."), Task("mypy .")))'

A typical CI pipeline — format-check, then checks in parallel, then tests:

python -m camas 'Sequential(tasks=(
    Task("ruff format . --check"),
    Parallel(tasks=(Task("mypy ."), Task("pyright ."))),
    Task("pytest"),
))'

Run one task across a matrix of Python versions in parallel:

python -m camas 'Parallel(
    tasks=(Task("pytest --python {PY}"),),
    matrix={"PY": ("3.12", "3.13", "3.14")},
)'

Use --dry-run to print the task tree without executing it.

Library

The same building blocks are available as a library:

import asyncio
from camas import Parallel, Sequential, Task, run
from camas.effect.termtree import Termtree, TermtreeOptions

task = Sequential(tasks=(
    Task("ruff format . --check"),
    Parallel(tasks=(Task("mypy ."), Task("pyright ."))),
    Task("pytest"),
))

result = asyncio.run(run(task, effects=(Termtree(TermtreeOptions()),)))
raise SystemExit(result.returncode)

Task, Sequential, and Parallel are immutable NamedTuple values. A Sequential short-circuits on the first non-zero exit; a Parallel runs its children concurrently. Both accept an optional matrix mapping for variable expansion in task commands, names, and environments.

License

MIT