295 lines
11 KiB
Python
295 lines
11 KiB
Python
"""Persistentní Modbus TCP klient na sdílené Waveshare / RS485 bráně (jedno spojení + lock)."""
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from __future__ import annotations
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import asyncio
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import hashlib
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import logging
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import os
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from collections.abc import AsyncIterator
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from contextlib import asynccontextmanager
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from pathlib import Path
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from pymodbus.client import AsyncModbusTcpClient
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try:
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import fcntl
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_FCNTL = True
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except ImportError:
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fcntl = None # type: ignore[assignment]
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_FCNTL = False
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logger = logging.getLogger(__name__)
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_flock_warned = False
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_BACKEND_ROOT = Path(__file__).resolve().parent.parent
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_DEFAULT_LOCK_DIR = _BACKEND_ROOT / ".ems-modbus-locks"
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def _gateway_lock_path(host: str, port: int) -> Path:
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# Výchozí = backend/.ems-modbus-locks (v Dockeru /app → mount ./backend), aby flock sdílel
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# hostitel + kontejner při dvou backend procesech na stejné bráně; přepiš EMS_MODBUS_LOCK_DIR.
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base = Path(os.getenv("EMS_MODBUS_LOCK_DIR", str(_DEFAULT_LOCK_DIR)))
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h = hashlib.sha256(f"{host.strip()}:{int(port)}".encode()).hexdigest()[:20]
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return base / f"{h}.lock"
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@asynccontextmanager
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async def _gateway_exclusive(host: str, port: int):
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"""
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Jedna RS485 linka přes levné TCP↔serial brány nesmí obsluhovat dva procesy najednou —
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odpovědi pak mají cizí transaction_id (např. 22 vs 54000). flock serializuje napříč PID.
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Vypnout: EMS_MODBUS_DISABLE_FLOCK=1 (nebo neexistující fcntl, např. Windows).
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"""
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global _flock_warned
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port_i = int(port)
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host_s = host.strip()
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if (
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not _FCNTL
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or os.getenv("EMS_MODBUS_DISABLE_FLOCK", "").lower() in ("1", "true", "yes")
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):
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if not _FCNTL and not _flock_warned:
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logger.warning(
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"Modbus: fcntl nedostupný — meziprocesová serializace na bránu %s:%s "
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"neaktivní (riziko kolizí při dvou masterech)",
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host_s,
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port_i,
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)
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_flock_warned = True
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yield
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return
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path = _gateway_lock_path(host_s, port_i)
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path.parent.mkdir(parents=True, exist_ok=True)
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f = open(path, "a+b") # noqa: SIM115
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try:
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await asyncio.to_thread(fcntl.flock, f.fileno(), fcntl.LOCK_EX)
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yield
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finally:
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try:
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await asyncio.to_thread(fcntl.flock, f.fileno(), fcntl.LOCK_UN)
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except OSError:
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pass
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f.close()
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class ModbusBatch:
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"""Více read/write pod jedním držením locku (žádný jiný task na stejném klientovi mezi nimi)."""
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def __init__(self, owner: PersistentModbusClient, device_id: int) -> None:
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self._o = owner
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self._device_id = device_id
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async def read_register(self, address: int) -> int:
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return await self._o._read_register_locked(address, self._device_id)
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async def read_register_signed(self, address: int) -> int:
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raw = await self.read_register(address)
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return raw - 65536 if raw > 32767 else raw
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async def read_holding_registers(self, address: int, count: int) -> list[int]:
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"""Jedna PDU (FC3) pro po sobě jdoucí registry — méně kolizí na RS485 bránách."""
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return await self._o._read_holding_registers_locked(
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address, count, self._device_id
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)
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async def write_register(self, address: int, value: int) -> bool:
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return await self._o._write_register_locked(address, value, self._device_id)
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async def write_registers(self, address: int, values: list[int]) -> bool:
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return await self._o._write_registers_locked(address, values, self._device_id)
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class PersistentModbusClient:
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"""
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Jedno persistentní TCP spojení na převodník (host:port).
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Unit ID se předává u každé operace — serial servery často nezvládají
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paralelní TCP sockety na stejnou bránu (pližící se transaction_id mismatch).
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Serializuje všechny požadavky přes asyncio.Lock().
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"""
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def __init__(self, host: str, port: int) -> None:
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self.host = host.strip()
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self.port = int(port)
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self._client: AsyncModbusTcpClient | None = None
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self._lock = asyncio.Lock()
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async def _ensure_connected(self) -> None:
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if self._client is not None and self._client.connected:
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return
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if self._client is not None:
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self._client.close()
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self._client = None
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logger.info("Modbus connecting %s:%s", self.host, self.port)
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self._client = AsyncModbusTcpClient(
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self.host,
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port=self.port,
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timeout=8,
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retries=3,
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)
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await self._client.connect()
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if not self._client.connected:
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self._client.close()
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self._client = None
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raise ConnectionError(f"Cannot connect Modbus {self.host}:{self.port}")
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logger.info("Modbus connected %s:%s", self.host, self.port)
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async def _read_register_locked(self, address: int, device_id: int) -> int:
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if self._client is None or not self._client.connected:
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await self._ensure_connected()
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assert self._client is not None
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try:
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r = await self._client.read_holding_registers(
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address, count=1, device_id=int(device_id)
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)
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if r.isError() or not getattr(r, "registers", None):
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raise OSError(f"Read error 0x{address:04X}: {r!r}")
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return int(r.registers[0])
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except Exception as e:
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logger.warning("Modbus read 0x%04X failed: %s", address, e)
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self._client.close()
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self._client = None
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raise
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async def _read_holding_registers_locked(
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self, address: int, count: int, device_id: int
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) -> list[int]:
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if count < 1 or count > 125:
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raise ValueError(f"invalid holding register count: {count}")
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if self._client is None or not self._client.connected:
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await self._ensure_connected()
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assert self._client is not None
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try:
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r = await self._client.read_holding_registers(
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address, count=count, device_id=int(device_id)
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)
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if r.isError() or not getattr(r, "registers", None):
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raise OSError(f"Read error 0x{address:04X} x{count}: {r!r}")
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if len(r.registers) != count:
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raise OSError(
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f"Read 0x{address:04X}: expected {count} regs, got {len(r.registers)}"
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)
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return [int(x) for x in r.registers]
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except Exception as e:
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logger.warning(
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"Modbus read 0x%04X count=%s failed: %s", address, count, e
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)
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self._client.close()
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self._client = None
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raise
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async def _write_registers_locked(
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self, address: int, values: list[int], device_id: int
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) -> bool:
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if self._client is None or not self._client.connected:
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await self._ensure_connected()
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assert self._client is not None
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try:
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clamped = [max(0, min(65535, int(v))) for v in values]
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r = await self._client.write_registers(
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address, clamped, device_id=int(device_id)
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)
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if r.isError():
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raise OSError(f"Write error 0x{address:04X}={clamped}: {r!r}")
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return True
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except Exception as e:
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logger.warning(
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"Modbus write_registers 0x%04X failed: %s", address, e
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)
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self._client.close()
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self._client = None
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raise
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async def _write_register_locked(
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self, address: int, value: int, device_id: int
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) -> bool:
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if self._client is None or not self._client.connected:
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await self._ensure_connected()
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assert self._client is not None
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try:
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v = max(0, min(65535, int(value)))
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r = await self._client.write_register(
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address, v, device_id=int(device_id)
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)
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if r.isError():
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raise OSError(f"Write error 0x{address:04X}={v}: {r!r}")
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return True
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except Exception as e:
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logger.warning("Modbus write 0x%04X=%s failed: %s", address, value, e)
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self._client.close()
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self._client = None
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raise
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async def read_register(self, address: int, device_id: int = 1) -> int:
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async with _gateway_exclusive(self.host, self.port):
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async with self._lock:
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await self._ensure_connected()
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return await self._read_register_locked(address, device_id)
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async def read_register_signed(self, address: int, device_id: int = 1) -> int:
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raw = await self.read_register(address, device_id)
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return raw - 65536 if raw > 32767 else raw
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async def read_holding_registers(
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self, address: int, count: int, device_id: int = 1
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) -> list[int]:
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"""FC 0x03 – souvislé holding registry (ověřování po blocích)."""
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async with _gateway_exclusive(self.host, self.port):
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async with self._lock:
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await self._ensure_connected()
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return await self._read_holding_registers_locked(
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address, count, device_id
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)
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async def write_register(self, address: int, value: int, device_id: int = 1) -> bool:
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async with _gateway_exclusive(self.host, self.port):
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async with self._lock:
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await self._ensure_connected()
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return await self._write_register_locked(address, value, device_id)
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async def write_registers(
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self, address: int, values: list[int], device_id: int = 1
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) -> bool:
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"""FC 0x10 – povinné pro Deye registry 60–499 (jeden i více registrů)."""
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async with _gateway_exclusive(self.host, self.port):
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async with self._lock:
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await self._ensure_connected()
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return await self._write_registers_locked(address, values, device_id)
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async def force_disconnect(self) -> None:
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"""Uzavře socket pod lockem (např. před retry po chybě)."""
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async with _gateway_exclusive(self.host, self.port):
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async with self._lock:
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if self._client is not None:
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self._client.close()
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self._client = None
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@asynccontextmanager
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async def batch(self, device_id: int = 1) -> AsyncIterator[ModbusBatch]:
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"""Drží lock pro více po sobě jdoucích operací (telemetrie vs. control na stejné bráně)."""
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async with _gateway_exclusive(self.host, self.port):
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async with self._lock:
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await self._ensure_connected()
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yield ModbusBatch(self, int(device_id))
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def close(self) -> None:
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if self._client is not None:
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self._client.close()
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self._client = None
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_clients: dict[str, PersistentModbusClient] = {}
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_registry_lock = asyncio.Lock()
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async def get_modbus_client(host: str, port: int) -> PersistentModbusClient:
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"""Jedno TCP spojení na převodník podle host:port (unit ID u jednotlivých volání)."""
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key = f"{host.strip()}:{int(port)}"
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async with _registry_lock:
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if key not in _clients:
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_clients[key] = PersistentModbusClient(host.strip(), port)
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return _clients[key]
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