sahou 0.0.2

Sahou runtime — schema-first typed messaging for creative installations (on Zenoh)

sahou (Python runtime)

Typed communication over real Zenoh, using just a contract (descriptor.json) plus a node name. The boundary semantics are delegated to the Rust core (sahou-core / sahou._core); this glue layer only handles the transport (zenoh-python) and threading.

Usage

import sahou
node = sahou.connect("descriptor.json", node="sensor")   # default = automatic discovery on the same LAN
# (the path is up to you. When using the output of `sahou gen --out-dir gen`, use "gen/descriptor.json")
node.publish("touch", {"x": 0.5, "phase": "move"})        # a NO is SahouRejected (nothing is put)

@node.subscribe("cue")
def on_cue(payload): ...                                   # a NO never reaches the handler (goes to on_reject)

res = node.query_confirmed("get_state", {"sel": "levels"})  # 200/400/500 equivalent + smart retry
node.answer("get_state", lambda req: {"level": 3})

Development

uv venv && uv pip install maturin pytest "eclipse-zenoh>=1.9,<2"
.venv/Scripts/maturin develop        # build the core with feature "python"
.venv/Scripts/python -m pytest tests/

• Contract version differences are decided by a handshake (contract queryable + verdict cache): additive = pass through / breaking = NO / unfetchable = conservative NO. There is no path that silently passes or drops.
• Not yet implemented (planned follow-ups): auto-launch of sahou link (for Node/browser, ②b) / tap, doctor, type stubs (②c).