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serve the web console from the node and drop the websocket bridge
The browser reached this node through `dora-websocket-transceiver`: a second
node, a second port, and a round trip through the dataflow for every button
press, to carry a UI only this node can interpret. The node now serves the
page and holds the browsers' sockets itself on one port, so the console is
one URL and a consumer wires nothing for it.

`dora_teleop/server.py` runs aiohttp on a thread of its own and meets the
control loop at two non-blocking points: a bounded queue the tick drains, and
a snapshot handed back. Both queues are bounded deliberately — a flood is
dropped rather than grown, and a slow browser loses stale snapshots rather
than the newest — because nothing a browser does may stall the thread that
stops the arm. A port already in use stops the node rather than leaving it
announcing a console nobody can open.

The web deadman moved but did not change: it was a `clients` message from the
bridge and is now the open-socket count read each tick. One hop fewer, same
meaning.

Contract, so 0.2.0 -> 0.3.0: `ui_command` and `clients` are gone. `ui_state`
stays published for `dora topic echo` and the bench, with no browser reading
it. New WEB_HOST and WEB_PORT (7000; 0 opens no port).

The console itself is laid out like the arm's own pendant — two rings
quartered into arc sectors you hold, each with its out-of-plane axis as pills
above. Directions and signs match xArm Studio on the controller, `Y+` on the
left included: two consoles driving one arm that disagree about which way is
+Y is a trap, not a preference.

Also sends a velocity only when it changes, repeating an unchanged one on
JOG_KEEPALIVE_S (0.2 s) purely to beat the consumer's own expiry. Repeating
every tick made `dora-ulite6` re-plan the same motion twenty times a second.
That turned out not to be the whole cause of the stepping an operator felt —
the rest was fixed in dora-ulite6 v0.3.1, pinned here — but sending 18
messages where 83 went before is worth keeping on its own.

`dora-joy` moves to v0.1.1: v0.1 is an annotated tag, and dora 1.0.1 records
the tag object's id as the commit hash and then rejects its own checkout for
sitting on the peeled commit. Neither dataflow could be built before this.
2026-09-16 14:50:21 -03:00

108 lines
4.0 KiB
Python

"""A bench stand-in for the arm and the browser, so teleop can run with neither.
Run by `dataflow.yml`. It answers every service, publishes plausible telemetry,
and prints the velocities it is sent — which is enough to drive the node from a
real gamepad and watch what a real arm would have been told to do.
**It is not a simulator.** It does not integrate the velocity, move a pose, or
model the arm in any way; a jog is printed and forgotten. Its job is to close
the loop so the node's own behaviour can be watched, not to stand in for
`dora-ulite6`. Anything that needs the arm to actually respond needs the arm.
"""
import json
import pyarrow as pa
from dora import Node
REQUEST_ID = "request_id"
# Somewhere in front of the robot, tool pointing down. Fixed, because a moving
# pose here would look like the arm was responding, which it is not.
POSE = [250.0, 0.0, 200.0, 180.0, 0.0, 0.0]
JOINTS = [0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
def main() -> None:
"""Answer whatever teleop asks and report what it would have moved."""
node = Node("bench")
announced = False
tool_engaged = False
freedrive = False
jogs = 0
shown = None
for event in node:
if event["type"] != "INPUT":
continue
if event["id"] == "tick":
if not announced:
announced = True
node.send_output("robot_state", pa.array(["ready"]))
node.send_output("tcp_pose", pa.array(POSE, type=pa.float32()), {"units_position": "mm"})
node.send_output("joint_pose", pa.array(JOINTS, type=pa.float32()), {"units": "deg"})
elif event["id"] == "jog":
velocity = event["value"][0].as_py()["velocity"]
jogs += 1
moving = any(velocity)
shown = ", ".join(f"{v:+7.2f}" for v in velocity)
print(f"jog {jogs:5d} [{shown}] {'' if moving else '<- stop'}", flush=True)
elif event["id"] == "request":
row = event["value"][0].as_py()
service = row.get("service", "")
request_id = event["metadata"].get(REQUEST_ID, "")
if service == "grasp":
tool_engaged = True
elif service == "release":
tool_engaged = False
elif service == "freedrive":
freedrive = bool(row.get("enabled", True))
if service != "get_state":
print(f"service {service} ({request_id})", flush=True)
node.send_output(
"response",
pa.array([_answer(service, tool_engaged, freedrive)]),
{REQUEST_ID: request_id},
)
elif event["id"] == "ui_state":
# No browser is attached, so this is where the console's picture of
# the arm would go. Printing it on change rather than on every tick
# makes the things worth watching — the lease moving, the arm
# starting and stopping — visible without 20 lines a second.
snapshot = json.loads(event["value"][0].as_py())
if snapshot.get("type") != "telemetry":
continue
current = (snapshot["arm_state"], snapshot["owner"], snapshot["estop"])
if current != shown:
shown = current
state, owner, estop = current
print(
f"console would show: {state}, owner {owner}" + (", E-STOPPED" if estop else ""),
flush=True,
)
def _answer(service: str, tool_engaged: bool, freedrive: bool) -> dict:
"""Build the response row the arm node would have sent."""
if service == "get_state":
return {
"ok": True,
"service": service,
"message": "ready",
"connected": True,
"ready": True,
"tool_engaged": tool_engaged,
"freedrive": freedrive,
"pose": POSE,
"joints": JOINTS,
}
return {"ok": True, "service": service, "message": f"{service} accepted by the bench"}
if __name__ == "__main__":
main()