|logo| tractor: distributed structured concurrency
tractor is a structured concurrency_ (SC), multi-processing_ runtime built on trio_.
Fundamentally, tractor provides parallelism via
trio-“actors”: independent Python processes (i.e.
non-shared-memory threads) which can schedule trio tasks whilst
maintaining end-to-end SC inside a distributed supervision tree.
Cross-process (and thus cross-host) SC is accomplished through the
combined use of our,
- “actor nurseries_” which provide for spawning multiple, and
possibly nested, Python processes each running a
trio scheduled
runtime - a call to trio.run(),
- an “SC-transitive supervision protocol” enforced as an
IPC-message-spec encapsulating all RPC-dialogs.
We believe the system adheres to the 3 axioms_ of an “actor model_”
but likely does not look like what you probably think an “actor
model” looks like, and that’s intentional.
Where do i start!?
New to trio and structured concurrency? Our docs collect the
best starting points and then walk you straight into a hands-on
quickstart:
https://goodboy.github.io/tractor/start/quickstart.html
Features
-
It’s just a trio API!
-
Infinitely nesteable process trees running embedded trio tasks.
-
Swappable, OS-specific, process spawning via multiple backends.
-
Modular IPC stack, allowing for custom interchange formats (eg.
as offered from msgspec_), varied transport protocols (TCP, RUDP,
QUIC, wireguard), and OS-env specific higher-perf primitives (UDS,
shm-ring-buffers).
-
Optionally distributed_: all IPC and RPC APIs work over multi-host
transports the same as local.
-
Builtin high-level streaming API that enables your app to easily
leverage the benefits of a "cheap or nasty" (un)protocol.
-
A “native UX” around a multi-process safe debugger REPL using
pdbp_ (a fork & fix of pdb++_)
-
“Infected asyncio” mode: support for starting an actor’s
runtime as a guest_ on the asyncio loop allowing us to
provide stringent SC-style trio.Task-supervision around any
asyncio.Task spawned via our tractor.to_asyncio APIs.
-
A very naive and still very much work-in-progress inter-actor
discovery_ sys with plans to support multiple modern protocol_
approaches.
-
Various trio extension APIs via tractor.trionics such as,
- task fan-out
broadcasting_,
- multi-task-single-resource-caching and fan-out-to-multi
__aenter__() APIs for @acm functions,
- (WIP) a
TaskMngr: one-cancels-one style nursery supervisor.
Status of main / infra
Install
tractor is still in a alpha-near-beta-stage for many
of its subsystems, however we are very close to having a stable
lowlevel runtime and API.
As such, it’s currently recommended that you clone and install the
repo from source::
pip install git+git://github.com/goodboy/tractor.git
We use the very hip uv_ for project mgmt::
git clone https://github.com/goodboy/tractor.git
cd tractor
uv sync --dev
uv run python examples/rpc_bidir_streaming.py
Consider activating a virtual/project-env before starting to hack on
the code base::
# you could use plain ol' venvs
# https://docs.astral.sh/uv/pip/environments/
uv venv tractor_py313 --python 3.13
# but @goodboy prefers the more explicit (and shell agnostic)
# https://docs.astral.sh/uv/configuration/environment/#uv_project_environment
UV_PROJECT_ENVIRONMENT="tractor_py313"
# hint hint, enter @goodboy's fave shell B)
uv run --dev xonsh
Alongside all this we ofc offer “releases” on PyPi::
pip install tractor
Just note that YMMV since the main git branch is often much further
ahead then any latest release.
Hacking on the docs themselves? The build + live-preview one-liners
(incl. nix-shell specifics) are collected in notes_to_self/howtodocs.md <https://github.com/goodboy/tractor/blob/main/notes_to_self/howtodocs.md>_,
and rendered as the “Building these docs” section of our dev-tips guide.
Example codez
We prefer to point you at the runnable scripts under examples/
- each is CI-run and
literalinclude-d straight into the docs, so
what you read there is what actually runs - rather than inline a
pile of them here. The one-minute pitch: spawn a subactor per core,
open a Context into each, then crash the root on purpose and
watch the runtime reap the whole tree - zero zombies, guaranteed (if
you can make a zombie child without a system signal, it is a
bug).
See it run - plus the full tour (the flagship multi-process
debugger, bidirectional streaming over a Context, cancellation,
discovery, “infected asyncio”, typed messaging and worker-pool /
cluster patterns) - in the docs:
Under the hood
tractor is an attempt to pair trionic_ structured concurrency_ with distributed Python - think of it as trio
-across-processes, or as an opinionated replacement for the
stdlib’s multiprocessing built on async primitives from the
ground up. But really it is just trio: nurseries that
spawn processes and cancel-able streaming IPC between them. If
you can drive trio, you can drive tractor.
“But wait - don’t ‘actors’ have mailboxes and messages and
stuff?!” Well, we’ve got (well referenced) opinions on what an “actor
model” actually is (tl;dr: the 3 axioms_, not the cultural
baggage) - that whole riff lives in our docs:
https://goodboy.github.io/tractor/explain/sc-distributed.html#hold-up-is-this-an-actor-model
What’s on the TODO
The roadmap lives with our docs - see what the future holds <https://goodboy.github.io/tractor/project/index.html#what-the-future-holds>_
for where tractor is headed.
Feel like saying hi?
This project is very much coupled to the ongoing development of
trio (i.e. tractor gets most of its ideas from that brilliant
community). If you want to help, have suggestions or just want to
say hi, please feel free to reach us in our matrix channel. If
matrix seems too hip, we’re also mostly all in the the trio gitter channel!
… _distributed: https://en.wikipedia.org/wiki/Distributed_computing
… _multi-processing: https://en.wikipedia.org/wiki/Multiprocessing
… _trio: https://github.com/python-trio/trio
… _nurseries: https://vorpus.org/blog/notes-on-structured-concurrency-or-go-statement-considered-harmful/#nurseries-a-structured-replacement-for-go-statements
… _actor model: https://en.wikipedia.org/wiki/Actor_model
… _trionic: https://trio.readthedocs.io/en/latest/design.html#high-level-design-principles
… _3 axioms: https://www.youtube.com/watch?v=7erJ1DV_Tlo&t=162s
… … _3 axioms: https://en.wikipedia.org/wiki/Actor_model#Fundamental_concepts
… _trio gitter channel: https://gitter.im/python-trio/general
… _matrix channel: https://matrix.to/#/!tractor:matrix.org
… _broadcasting: https://github.com/goodboy/tractor/pull/229
… _pdbp: https://github.com/mdmintz/pdbp
… _pdb++: https://github.com/pdbpp/pdbpp
… _cheap or nasty: https://zguide.zeromq.org/docs/chapter7/#The-Cheap-or-Nasty-Pattern
… _(un)protocol: https://zguide.zeromq.org/docs/chapter7/#Unprotocols
… _discovery: https://zguide.zeromq.org/docs/chapter8/#Discovery
… _modern protocol: https://en.wikipedia.org/wiki/Rendezvous_protocol
… _structured concurrency: https://en.wikipedia.org/wiki/Structured_concurrency
… _uv: https://docs.astral.sh/uv/
… _msgspec: https://jcristharif.com/msgspec/
… _guest: https://trio.readthedocs.io/en/stable/reference-lowlevel.html?highlight=guest mode#using-guest-mode-to-run-trio-on-top-of-other-event-loops
…
NOTE, on generating badge links from the UI
https://docs.github.com/en/actions/how-tos/monitoring-and-troubleshooting-workflows/monitoring-workflows/adding-a-workflow-status-badge?ref=gitguardian-blog-automated-secrets-detection#using-the-ui
… |gh_actions| image:: https://github.com/goodboy/tractor/actions/workflows/ci.yml/badge.svg?branch=main
:target: https://github.com/goodboy/tractor/actions/workflows/ci.yml
… |docs| image:: https://github.com/goodboy/tractor/actions/workflows/docs.yml/badge.svg?branch=main
:target: https://goodboy.github.io/tractor/
:alt: Documentation
… |logo| image:: _static/tractor_logo_wire.svg
:width: 250
:align: middle
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