data-collector-debugtool/app/services/bacnet_service.py

from __future__ import annotations

import asyncio
import os
import socket
import threading
import warnings
from contextlib import closing
from typing import Any

BAC0_REGISTERED_WARNING = r"object type .* for vendor identifier 842 already registered.*"

warnings.filterwarnings("ignore", message=BAC0_REGISTERED_WARNING)

import BAC0

from app.response import response_payload
from app.schemas.bacnet import (
    BacnetPointReadRequest,
    BacnetPointSearchRequest,
    BacnetPointSpec,
    bac0_object_type,
    normalize_object_type,
)


POINT_OBJECT_TYPES = {
    "AnalogInput",
    "AnalogOutput",
    "AnalogValue",
    "BinaryInput",
    "BinaryOutput",
    "BinaryValue",
    "MultiStateInput",
    "MultiStateOutput",
    "MultiStateValue",
}

_BACNET_LOCK = threading.Lock()


try:
    BAC0.log_level("silence")
except Exception:
    pass


class BacnetCommunicationError(RuntimeError):
    def __init__(self, message: str) -> None:
        super().__init__(message)


def device_payload(request: BacnetPointReadRequest | BacnetPointSearchRequest) -> dict[str, Any]:
    return {
        "device_type": "BACnet/IP",
        "ip": request.ip,
        "port": request.port,
        "bacnet_device_id": request.bacnet_device_id,
    }


def bacnet_address(ip: str, port: int) -> str:
    return f"{ip}:{port}"


def property_read_args(address: str, object_type: str, object_id: int, property_name: str) -> str:
    return f"{address} {bac0_object_type(object_type)} {object_id} {property_name}"


def get_local_ip(remote_ip: str, remote_port: int) -> str:
    configured_ip = os.getenv("BACNET_LOCAL_IP")
    if configured_ip:
        return configured_ip
    with closing(socket.socket(socket.AF_INET, socket.SOCK_DGRAM)) as sock:
        sock.connect((remote_ip, remote_port))
        return str(sock.getsockname()[0])


def get_free_udp_port() -> int:
    configured_port = os.getenv("BACNET_LOCAL_PORT")
    if configured_port:
        return int(configured_port)
    with closing(socket.socket(socket.AF_INET, socket.SOCK_DGRAM)) as sock:
        sock.bind(("", 0))
        return int(sock.getsockname()[1])


def local_bacnet_ip(remote_ip: str, remote_port: int) -> str:
    local_ip = get_local_ip(remote_ip, remote_port)
    local_mask = int(os.getenv("BACNET_LOCAL_MASK", "24"))
    return f"{local_ip}/{local_mask}"


def json_value(value: Any) -> Any:
    if value is None or isinstance(value, bool | int | float | str):
        return value
    if isinstance(value, list | tuple):
        return [json_value(item) for item in value]
    if isinstance(value, dict):
        return {str(key): json_value(item) for key, item in value.items()}
    if hasattr(value, "value") and isinstance(value.value, bool | int | float | str):
        return value.value
    return str(value)


async def read_property_or_none(bacnet: Any, address: str, object_type: str, object_id: int, property_name: str) -> Any:
    try:
        value = await bacnet.read(property_read_args(address, object_type, object_id, property_name))
    except Exception:
        return None
    return json_value(value)


async def read_present_value(bacnet: Any, address: str, point: BacnetPointSpec) -> Any:
    try:
        value = await bacnet.read(property_read_args(address, point.object_type, point.object_id, "presentValue"))
    except Exception as exc:
        raise BacnetCommunicationError(
            f"no response from BACnet device {address} while reading "
            f"{point.object_type} {point.object_id} presentValue"
        ) from exc
    return json_value(value)


def ignore_cancelled_bacnet_broadcast_endpoint(loop: asyncio.AbstractEventLoop, context: dict[str, Any]) -> None:
    message = str(context.get("message", ""))
    exception = context.get("exception")
    if isinstance(exception, asyncio.CancelledError) and "set_broadcast_transport_protocol" in message:
        return
    loop.default_exception_handler(context)


def run_bacnet(coro: Any) -> Any:
    loop = asyncio.new_event_loop()
    loop.set_exception_handler(ignore_cancelled_bacnet_broadcast_endpoint)
    try:
        asyncio.set_event_loop(loop)
        return loop.run_until_complete(coro)
    finally:
        pending = asyncio.all_tasks(loop)
        for task in pending:
            task.cancel()
        if pending:
            loop.run_until_complete(asyncio.gather(*pending, return_exceptions=True))
        loop.close()
        asyncio.set_event_loop(None)


def split_object_identifier(value: Any) -> tuple[str, int] | None:
    if isinstance(value, list | tuple) and len(value) == 2:
        raw_type, raw_id = value
        try:
            return normalize_object_type(str(raw_type).replace("ObjectType.", "")), int(raw_id)
        except (TypeError, ValueError):
            return None

    text = str(value).strip().strip("()")
    if "," in text:
        raw_type, raw_id = text.split(",", 1)
    elif ":" in text:
        raw_type, raw_id = text.split(":", 1)
    else:
        return None

    raw_type = raw_type.strip().strip("'\"").replace("ObjectType.", "")
    raw_id = raw_id.strip().strip("'\"")
    try:
        return normalize_object_type(raw_type), int(raw_id)
    except (TypeError, ValueError):
        return None


async def read_points_async(request: BacnetPointReadRequest) -> list[dict[str, Any]]:
    address = bacnet_address(request.ip, request.port)
    local_ip = local_bacnet_ip(request.ip, request.port)
    local_port = get_free_udp_port()
    points: list[dict[str, Any]] = []

    with warnings.catch_warnings():
        warnings.filterwarnings("ignore", message=BAC0_REGISTERED_WARNING)
        async with BAC0.start(ip=local_ip, port=local_port, ping=False) as bacnet:
            for point in request.points:
                points.append(
                    {
                        "object_type": point.object_type,
                        "object_id": point.object_id,
                        "present_value": await read_present_value(bacnet, address, point),
                    }
                )
    return points


async def search_points_async(request: BacnetPointSearchRequest) -> list[dict[str, Any]]:
    address = bacnet_address(request.ip, request.port)
    local_ip = local_bacnet_ip(request.ip, request.port)
    local_port = get_free_udp_port()
    points: list[dict[str, Any]] = []

    with warnings.catch_warnings():
        warnings.filterwarnings("ignore", message=BAC0_REGISTERED_WARNING)
        async with BAC0.start(ip=local_ip, port=local_port, ping=False) as bacnet:
            try:
                object_list = await bacnet.read(
                    property_read_args(address, "Device", request.bacnet_device_id, "objectList")
                )
            except Exception as exc:
                raise BacnetCommunicationError(
                    f"no response from BACnet device {address} while reading "
                    f"Device {request.bacnet_device_id} objectList"
                ) from exc
            for item in object_list or []:
                parsed = split_object_identifier(item)
                if parsed is None:
                    continue
                object_type, object_id = parsed
                if object_type not in POINT_OBJECT_TYPES:
                    continue
                points.append(
                    {
                        "name": await read_property_or_none(bacnet, address, object_type, object_id, "objectName"),
                        "description": await read_property_or_none(bacnet, address, object_type, object_id, "description"),
                        "object_type": object_type,
                        "object_id": object_id,
                        "present_value": await read_property_or_none(bacnet, address, object_type, object_id, "presentValue"),
                    }
                )
    return points


def read_points(request: BacnetPointReadRequest) -> dict[str, Any]:
    try:
        with _BACNET_LOCK:
            points = run_bacnet(read_points_async(request))
    except BacnetCommunicationError as exc:
        return response_payload(1, str(exc), {"device": device_payload(request), "points": []})
    except Exception as exc:
        return response_payload(1, str(exc), {"device": device_payload(request), "points": []})
    return response_payload(0, "success", {"device": device_payload(request), "points": points})


def search_points(request: BacnetPointSearchRequest) -> dict[str, Any]:
    try:
        with _BACNET_LOCK:
            points = run_bacnet(search_points_async(request))
    except BacnetCommunicationError as exc:
        return response_payload(1, str(exc), {"device": device_payload(request), "points": []})
    except Exception as exc:
        return response_payload(1, str(exc), {"device": device_payload(request), "points": []})
    return response_payload(0, "success", {"device": device_payload(request), "points": points})