carterkit 0.4.0

Build and drive CAR-TER layouts from Python — the control docs are the library.

carterkit

Build and drive CAR-TER layouts from Python.

The control docs are the library. Every control's schema, fields, and examples are parsed at runtime from the ControlDocs markdown bundled inside the package — the exact same docs the CAR-TER app renders — so the catalog never drifts from the definitions.

pip install carterkit

Explore the controls (zero config)

import carterkit

carterkit.controls()            # {type: schema} for every placeable control
carterkit.doc("gauge")          # full parsed doc: fields, themeFields, examples
print(carterkit.doc_markdown("gauge"))   # the rendered documentation prose
carterkit.examples("button")    # documented example snippets

Build a layout

Controls are methods on the layout, ids are positional, tabs and groups are context managers, and bindings fold into kwargs. Each control method returns a handle you can use as a binding target or patch later. Unknown control types and bad enum values raise instead of silently shipping a broken layout:

from carterkit import Layout

with Layout("Dashboard", cols=4, rows=4) as ui:
    ui.connect("ws://192.168.1.50:8765", channel="home")
    with ui.tab("Main", icon="gauge"):
        cpu = ui.gauge("cpu", label="CPU", min=0, max=100, span=(2, 2),
                       listen="cpu", when={"msg_type": "metrics"})
        ui.status_light("warn", visible=cpu > 90)      # handle → visibility condition
        ui.button("refresh", label="Refresh", send="refresh", request=True)

print(ui.findings())        # schema + grid + binding lint against the bundled catalog
ui.save("dashboard.json")   # the composed layout, ready to push/load

Binding sugar: listen=/when=/event= build a sync, and send=/request=/payload= build an action; pass sync=[...]/action={...} (via carterkit.bind) for anything fancier. A handle comparison (cpu > 90) becomes a real visibility condition; ==/!= stay normal Python, so use .eq()/.neq(). help(carterkit.build.gauge) prints any control's documentation, straight from the bundled docs.

Prefer a declarative style? A class veneer compiles to the same layout — ids come from attribute names, tabs/groups are nested classes (great for fixed dashboards; the flat builder reads better for generated ones):

from carterkit.declare import Screen, Tab, Connect, Gauge, Button, StatusLight

class Dashboard(Screen, cols=4, rows=4):
    relay = Connect("ws://192.168.1.50:8765", channel="home")
    class Main(Tab, icon="gauge"):
        cpu  = Gauge(label="CPU", min=0, max=100, span=(2, 2), listen="cpu")
        warn = StatusLight(visible=cpu > 90)
        refresh = Button(label="Refresh", send="refresh", request=True)

Dashboard.save("dashboard.json")

Dynamic groups

Generate controls in for/if loops (auto-placed in the group's own grid), or mark a group dynamic="event" and replace its children live at runtime. Build that replacement payload with Fragment, then lint it against the broadcasts your server actually emits — catching events that never arrive, missing children arrays, and off-grid/invalid injected controls before they ship:

import carterkit
from carterkit import Fragment

ui.group("Now Playing", span=(3, 4), cols=4, rows=3, dynamic="player_state")

frag = Fragment(cols=4, rows=3)
frag.label("title", text="Song", span=(1, 4))
frag.button("play", label="Play", send="play")
# your server broadcasts frag.payload("player_state") == {"msg_type": ..., "children": [...]}

print(carterkit.format_findings(
    carterkit.lint_dynamic_traffic(ui.layout, [frag.payload("player_state")])))

Prefer surgical edits? LayoutBuffer gives add_control / update_control / move_control over a held draft; lay.buffer exposes it.

infer.build_layout(payload) generates a wired layout from a sample telemetry dict; codegen.generate_service_stub(layout) emits a runnable MeshSocket server skeleton; theming.theme_for(...) and tune.tune_gauge(...) round out the authoring tools.

CLI

carterkit catalog                 # list every control type
carterkit doc gauge               # print a control's documentation
carterkit examples button         # list a control's examples (--name to print one)
carterkit validate layout.json    # lint a layout (exit 1 on errors)
carterkit gen layout.json         # generate a MeshSocket service stub
carterkit relay --port 8765       # run the bundled MeshSocket relay

Drive a device

import asyncio
from carterkit import CarterClient

async def main():
    async with CarterClient(gateway_url="ws://localhost:18080", token="<mesh token>",
                            channel="home", role="device", name="my-hub") as c:
        c.on("toggle", lambda d: {"ok": True, **d})
        await c.broadcast("reading", {"temp_c": 21.4})
        await asyncio.sleep(60)
    # leaving the `async with` disconnects automatically

asyncio.run(main())

End-to-end encryption (ChaCha20-Poly1305 + per-session salt) is transparent when you pass an e2ee_key. Send a push to every device on a Connect+ account with CarterClient.notify(...) or the stdlib-only carterkit.notify_http(...).

Built on

meshsocket — the WebSocket mesh transport.

The ControlDocs are vendored from the CAR-TER app repo; refresh them with scripts/sync-controldocs.sh.