secs-gem/clients/python/secsgem_client/_client.py

"""The Equipment client: a complete GEM tool integration in plain Python.

The secs_gemd daemon owns everything SEMI — the HSMS link to the host, the
GEM state machines, message formats, timers, spooling. This client only ever
does two things: tell the equipment about itself (variables, events, alarms)
and react to what the host asks (commands). Names are the ones from your
equipment.yaml; values are plain Python.

    from secsgem_client import Equipment

    eq = Equipment("localhost:50051")
    eq.set(ChamberPressure=2.5)
    eq.fire("ProcessStarted")

    @eq.on("START")
    def start(cmd):
        run_recipe(cmd.params.get("PPID"))

    eq.listen()   # blocks, dispatching host commands to your handlers
"""

from __future__ import annotations

import threading
from dataclasses import dataclass
from typing import Callable, Dict, Iterator, Optional

import grpc

from ._proto import equipment_pb2 as pb
from ._proto import equipment_pb2_grpc as rpc
from ._values import from_value, to_value


class SecsGemError(RuntimeError):
    """The daemon declined a request (unknown name, bad value, wrong state)."""

    def __init__(self, code: int, message: str):
        super().__init__(message or pb.Ack.Code.Name(code))
        self.code = code


def _check(ack: pb.Ack) -> None:
    if ack.code != pb.Ack.ACCEPT:
        raise SecsGemError(ack.code, ack.message)


@dataclass
class Command:
    """A remote command from the host (e.g. START). The host has already been
    told "accepted, will finish later" — report the real outcome by firing an
    event (success) or raising an alarm (failure) from your handler."""

    id: str
    name: str
    params: Dict[str, object]
    _eq: "Equipment"

    def done(self, ok: bool = True) -> None:
        """Mark the command complete (for the daemon's audit trail). Called
        automatically after your handler returns; call early if you want."""
        self._eq._complete(self.id, ok)
        self._done = True


@dataclass
class Health:
    link: str           # "DISCONNECTED" | "CONNECTED" | "SELECTED"
    control_state: str  # "HOST_OFFLINE" | "ONLINE_REMOTE" | ...
    spool_depth: int


class Equipment:
    """A connection to the secs_gemd daemon — your equipment, by name."""

    def __init__(self, address: str = "localhost:50051",
                 connect_timeout: float = 10.0):
        self._channel = grpc.insecure_channel(address)
        grpc.channel_ready_future(self._channel).result(timeout=connect_timeout)
        self._stub = rpc.EquipmentStub(self._channel)
        self._handlers: Dict[str, Callable[[Command], object]] = {}
        self._listen_thread: Optional[threading.Thread] = None
        self._stop = threading.Event()

    # ---- report state to the host -------------------------------------------

    def set(self, values: Optional[Dict[str, object]] = None, **kwargs) -> None:
        """Update status/data variables by name: eq.set(ChamberPressure=2.5).
        The host sees the new values immediately when it polls."""
        merged = dict(values or {})
        merged.update(kwargs)
        req = pb.VariableUpdate()
        for name, v in merged.items():
            req.values[name].CopyFrom(to_value(v))
        _check(self._stub.SetVariables(req))

    def get(self, *names: str) -> Dict[str, object]:
        """Read variables back from the equipment. No names = all of them."""
        try:
            snap = self._stub.GetVariables(pb.VariableQuery(names=list(names)))
        except grpc.RpcError as e:
            raise SecsGemError(pb.Ack.PARAMETER_INVALID, e.details()) from None
        return {k: from_value(v) for k, v in snap.values.items()}

    def __setitem__(self, name: str, value) -> None:
        self.set({name: value})

    def __getitem__(self, name: str):
        return self.get(name)[name]

    def fire(self, event: str, **data) -> None:
        """Fire a collection event by name; the daemon assembles the configured
        report and sends it to the host. kwargs set variable values for this
        event first: eq.fire("WaferComplete", Thickness=1.2)."""
        req = pb.Event(name=event)
        for name, v in data.items():
            req.data[name].CopyFrom(to_value(v))
        _check(self._stub.FireEvent(req))

    def alarm(self, name: str) -> None:
        """Raise an alarm by its config name (or stringified ALID)."""
        _check(self._stub.SetAlarm(pb.Alarm(name=name)))

    def clear(self, name: str) -> None:
        """Clear a previously raised alarm."""
        _check(self._stub.ClearAlarm(pb.Alarm(name=name)))

    # ---- control state & health ---------------------------------------------

    @property
    def control_state(self) -> str:
        """The GEM control state, e.g. "ONLINE_REMOTE"."""
        cs = self._stub.GetControlState(pb.Empty())
        return pb.ControlState.State.Name(cs.state)

    def request_control_state(self, desired: str) -> None:
        """Operator-panel transition, e.g. eq.request_control_state("HOST_OFFLINE")
        before maintenance. Raises if the E30 table says no from here."""
        req = pb.ControlStateRequest(
            desired=pb.ControlState.State.Value(desired))
        _check(self._stub.RequestControlState(req))

    def health(self) -> Health:
        """One health snapshot (link / control state / spool depth)."""
        for h in self._stub.WatchHealth(pb.Empty()):
            return Health(pb.Health.LinkState.Name(h.link),
                          pb.ControlState.State.Name(h.control_state),
                          h.spool_depth)
        raise SecsGemError(pb.Ack.CANNOT_DO_NOW, "health stream ended")

    def watch_health(self) -> Iterator[Health]:
        """Yields a Health snapshot on every link/state change."""
        for h in self._stub.WatchHealth(pb.Empty()):
            yield Health(pb.Health.LinkState.Name(h.link),
                         pb.ControlState.State.Name(h.control_state),
                         h.spool_depth)

    # ---- react to the host ----------------------------------------------------

    def on(self, command: str):
        """Decorator: run this function when the host sends `command`.
        Use "*" to catch commands with no specific handler."""

        def register(fn: Callable[[Command], object]):
            self._handlers[command] = fn
            return fn

        return register

    def listen(self, background: bool = False) -> None:
        """Consume host requests and dispatch them to @eq.on handlers.
        Blocks; pass background=True to run on a daemon thread instead."""
        if background:
            self._listen_thread = threading.Thread(target=self._listen_loop,
                                                   daemon=True)
            self._listen_thread.start()
            return
        self._listen_loop()

    def close(self) -> None:
        self._stop.set()
        self._channel.close()

    # ---- internals -------------------------------------------------------------

    def _listen_loop(self) -> None:
        try:
            for hr in self._stub.Subscribe(pb.SubscribeRequest(client="secsgem_client")):
                if self._stop.is_set():
                    return
                if not hr.HasField("command"):
                    continue  # future HostRequest variants (jobs, carriers, ...)
                cmd = hr.command
                handler = self._handlers.get(cmd.name) or self._handlers.get("*")
                command = Command(cmd.id, cmd.name,
                                  {k: from_value(v) for k, v in cmd.params.items()},
                                  self)
                ok = True
                try:
                    if handler is not None:
                        handler(command)
                except Exception:
                    ok = False
                    raise
                finally:
                    if not getattr(command, "_done", False):
                        self._complete(cmd.id, ok)
        except grpc.RpcError:
            if not self._stop.is_set():
                raise

    def _complete(self, command_id: str, ok: bool) -> None:
        ack = pb.Ack(code=pb.Ack.ACCEPT if ok else pb.Ack.REJECTED)
        self._stub.CompleteCommand(pb.CommandResult(id=command_id, ack=ack))