openwebrx/owrx/aprs/direwolf.py

from pycsdr.types import Format
from pycsdr.modules import Writer, TcpSource, ExecModule, CallbackWriter
from owrx.config.core import CoreConfig
from owrx.config import Config
from abc import ABC, abstractmethod
import time
import os
import random
import socket

import logging

logger = logging.getLogger(__name__)

FEET_PER_METER = 3.28084


class DirewolfConfigSubscriber(ABC):
    @abstractmethod
    def onConfigChanged(self):
        pass


class DirewolfConfig:
    config_keys = [
        "aprs_callsign",
        "aprs_igate_enabled",
        "aprs_igate_server",
        "aprs_igate_password",
        "receiver_gps",
        "aprs_igate_symbol",
        "aprs_igate_beacon",
        "aprs_igate_gain",
        "aprs_igate_dir",
        "aprs_igate_comment",
        "aprs_igate_height",
    ]

    def __init__(self):
        self.subscribers = []
        self.configSub = None
        self.port = None

    def wire(self, subscriber: DirewolfConfigSubscriber):
        self.subscribers.append(subscriber)
        if self.configSub is None:
            pm = Config.get()
            self.configSub = pm.filter(*DirewolfConfig.config_keys).wire(self._fireChanged)

    def unwire(self, subscriber: DirewolfConfigSubscriber):
        self.subscribers.remove(subscriber)
        if not self.subscribers and self.configSub is not None:
            self.configSub.cancel()

    def _fireChanged(self, changes):
        for sub in self.subscribers:
            try:
                sub.onConfigChanged()
            except Exception:
                logger.exception("Error while notifying Direwolf subscribers")

    def getPort(self):
        # direwolf has some strange hardcoded port ranges
        while self.port is None:
            try:
                port = random.randrange(1024, 49151)
                # test if port is available for use
                s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
                s.bind(("localhost", port))
                s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
                s.close()
                self.port = port
            except OSError:
                pass
        return self.port

    def getConfig(self, is_service):
        pm = Config.get()

        config = """
ACHANNELS 1
ADEVICE stdin null

CHANNEL 0
MYCALL {callsign}
MODEM 1200

KISSPORT {port}
AGWPORT off
        """.format(
            port=self.getPort(), callsign=pm["aprs_callsign"]
        )

        if is_service and pm["aprs_igate_enabled"]:
            pbeacon = ""

            if pm["aprs_igate_beacon"]:
                # Format beacon lat/lon
                lat = pm["receiver_gps"]["lat"]
                lon = pm["receiver_gps"]["lon"]
                direction_ns = "N" if lat > 0 else "S"
                direction_we = "E" if lon > 0 else "W"
                lat = abs(lat)
                lon = abs(lon)
                lat = "{0:02d}^{1:05.2f}{2}".format(int(lat), (lat - int(lat)) * 60, direction_ns)
                lon = "{0:03d}^{1:05.2f}{2}".format(int(lon), (lon - int(lon)) * 60, direction_we)

                # Convert height from meters to feet if specified
                height = ""
                if "aprs_igate_height" in pm:
                    try:
                        height_m = float(pm["aprs_igate_height"])
                        height_ft = round(height_m * FEET_PER_METER)
                        height = "HEIGHT=" + str(height_ft)
                    except:
                        logger.error(
                            "Cannot parse 'aprs_igate_height', expected float: " + str(pm["aprs_igate_height"])
                        )

                pbeacon = 'PBEACON sendto=IG delay=0:30 every=60:00 symbol={symbol} lat={lat} long={lon} {height} {gain} {adir} comment="{comment}"'.format(
                    symbol=pm["aprs_igate_symbol"],
                    lat=lat,
                    lon=lon,
                    height=height,
                    gain="GAIN=" + str(pm["aprs_igate_gain"]) if "aprs_igate_gain" in pm else "",
                    adir="DIR=" + str(pm["aprs_igate_dir"]) if "aprs_igate_dir" in pm else "",
                    comment=pm["aprs_igate_comment"],
                )

                logger.info("APRS PBEACON String: " + pbeacon)

            config += """
IGSERVER {server}
IGLOGIN {callsign} {password}
{pbeacon}
            """.format(
                server=pm["aprs_igate_server"],
                callsign=pm["aprs_callsign"],
                password=pm["aprs_igate_password"],
                pbeacon=pbeacon,
            )

        return config


class LogWriter(CallbackWriter):
    def __init__(self):
        self.retained = bytes()
        super().__init__(Format.CHAR)

    def write(self, data: bytes) -> None:
        self.retained += data
        lines = self.retained.split(b"\n")

        # keep the last line
        # this should either be empty if the last char was \n
        # or an incomplete line if the read returned early
        self.retained = lines[-1]

        # log all completed lines
        for line in lines[0:-1]:
            logger.info("{}: {}".format("STDOUT", line.strip(b'\n').decode()))


class DirewolfModule(ExecModule, DirewolfConfigSubscriber):
    def __init__(self, service: bool = False):
        self.tcpSource = None
        self.writer = None
        self.service = service
        self.direwolfConfigPath = "{tmp_dir}/openwebrx_direwolf_{myid}.conf".format(
            tmp_dir=CoreConfig().get_temporary_directory(), myid=id(self)
        )

        self.direwolfConfig = DirewolfConfig()
        self.direwolfConfig.wire(self)
        self.__writeConfig()

        super().__init__(Format.SHORT, Format.CHAR, ["direwolf", "-c", self.direwolfConfigPath, "-r", "48000", "-t", "0", "-q", "d", "-q", "h"])
        # direwolf supplies the data via a socket which we tap into in start()
        # the output on its STDOUT is informative, but we still want to log it
        super().setWriter(LogWriter())
        self.start()

    def __writeConfig(self):
        file = open(self.direwolfConfigPath, "w")
        file.write(self.direwolfConfig.getConfig(self.service))
        file.close()

    def setWriter(self, writer: Writer) -> None:
        self.writer = writer
        if self.tcpSource is not None:
            self.tcpSource.setWriter(writer)

    def start(self):
        delay = 0.5
        retries = 0
        while True:
            try:
                self.tcpSource = TcpSource(self.direwolfConfig.getPort(), Format.CHAR)
                if self.writer:
                    self.tcpSource.setWriter(self.writer)
                break
            except ConnectionError:
                if retries > 20:
                    logger.error("maximum number of connection attempts reached. did direwolf start up correctly?")
                    raise
                retries += 1
            time.sleep(delay)

    def restart(self):
        self.__writeConfig()
        super().restart()
        self.start()

    def onConfigChanged(self):
        self.restart()

    def stop(self) -> None:
        super().stop()
        os.unlink(self.direwolfConfigPath)
        self.direwolfConfig.unwire(self)
        self.direwolfConfig = None