st-ten-1/src/components/component.py

import logging

from lib.helpers import timing
from PyQt5.QtCore import QObject, QSemaphore, Qt, QTimer, pyqtSignal


class Component(QObject):
    """emitted with data from the _get method"""
    out = pyqtSignal(list)
    _pause = pyqtSignal()
    _resume = pyqtSignal()
    _set_sources = pyqtSignal(dict)
    _set_period = pyqtSignal(dict)

    def __init__(
        self,
        config=None,
        name=None,
        period=None,
        lazy=True,
        paused=False,
        threaded=True,
    ):
        """
        parameters:
            config: value for self.config, should be instance of lib.helpers.config_reader.ConfigReader
            name: value for self.name, should be used to retrive component configuration section (self.config[self.name])
            period: period in seconds for periodic calls to _get, set to None to disable
            lazy: whether or not skip periodic _get calls if falling behind
            paused: whether or not periodic calls to_get are paused
            threaded: set this to tell the component if it should be thread synchronized or not(shoul be true if calls to methods are done from threads different from the component's one)
        """
        super().__init__()
        self.config = config
        self.name = name if name is not None else str(id(self))
        self._threaded = threaded
        self._period = period
        self._single_shot = lazy
        self._paused = paused
        self._started = False
        self._running = False
        self.sources = {}
        if self._threaded:
            self._lock = QSemaphore(1)
            self._lock.acquire(max(self._lock.available(), 1))
        self._timer = None
        self.log = logging.getLogger(f"{self.__class__.__name__} ({self.name})")
        if not self._threaded:
            self.start()

    def _config_changed(self):
        self.log.info("reconfigure")
        self.config_changed()
        self.log.debug(f"config: {self.config}")

    def config_changed(self):
        """
        this method should be overridden when inheriting from the Component class
        and should contain all the initialization code that needs to access self.config
        so that the component will reinitialize if configuration changes
        this method will be called on start and when self.config (ConfigReader) emits the updated signal
        """
        pass

    def start(self):
        """
        this method is automatically called if threaded is set to False at object creation
        otherwise if the component is in a thread this method should be used like this:
        component = ComponentSubclass(threaded=True)
        thread = QThread()
        thread.setTerminationEnabled(True)
        component.moveToThread(thread)
        thread.started.connect(component.start)
        thread.start()
        component.wait_ready()  # this is optional and will wait untill the component has finished started
        """
        self._pause.connect(self._do_pause)
        self._resume.connect(self._do_resume)
        self._set_sources.connect(self._do_set_sources)
        self._set_period.connect(self._do_set_period)
        self.config.updated.connect(self._config_changed)
        self._config_changed()
        self._init_periodic()
        self._started = True
        if not self._paused:
            self._do_resume()
        elif self._threaded:
            self._lock.release()
        self.log.info("started")

    @property
    def started(self):
        """returns True if the component has been started"""
        if self._threaded:
            self._lock.acquire(max(self._lock.available(), 1))
        started = self._started
        if self._threaded:
            self._lock.release()
        return started

    @property
    def running(self):
        """returns True if the periodic calls to _get are not paused"""
        if self._threaded:
            self._lock.acquire(max(self._lock.available(), 1))
        running = self._running
        if self._threaded:
            self._lock.release()
        return running

    def wait_ready(self, timeout=5):
        """
        waits untill the requested action has been completed by the component
        this will return immediately if threaded=False was passed at component initialization
        """
        if self._threaded:
            timeout = round(timeout * 1000)
            if self._lock.tryAcquire(max(self._lock.available(), 1), timeout):
                self._lock.release()
            else:
                self._lock.release()
                raise RuntimeError(f"{self.name} was not ready before timeout of {timeout}ms")

    def pause(self):
        """will pause periodic calls to _get and sources trigghers"""
        if self._threaded:
            self._lock.acquire(max(self._lock.available(), 1))
        if self._running is False:
            if self._threaded:
                self._lock.release()
            return
        if self._threaded:
            self._pause.emit()
            self.wait_ready()
        else:
            self._do_pause()

    def resume(self):
        """will resume periodic calls to _get and sources trigghers"""
        if self._threaded:
            self._lock.acquire(max(self._lock.available(), 1))
        if self._running is True:
            if self._threaded:
                self._lock.release()
            return
        if self._threaded:
            self._resume.emit()
            self.wait_ready()
        else:
            self._do_resume()

    def set_sources(self, sources=None):  # sources should be {"source_name": signal_to_connect}
        """
        connect the given sources to trigger a call to _get
        the sources parameter should be:
            a dict of signals might containing one optional argument that will be passed as data to _get
            or None to disconnect all sources
        """
        if self._threaded:
            self._lock.acquire(max(self._lock.available(), 1))
            self._set_sources.emit(sources)
            self.wait_ready()
        else:
            self._do_set_sources(sources)

    def _init_periodic(self):
        if self._period is not None:
            if self._timer is None:
                self._timer = QTimer()
                self._timer.setTimerType(Qt.PreciseTimer)
            self._timer.setSingleShot(self._single_shot)
            self._timer.setInterval(round(self._period * 1000))
            self.log.debug(f"init periodic: period: {self._period}, single shot: {self._single_shot}")
        else:
            self.log.debug("no init periodic")

    def set_period(self, period=None, lazy=True):
        """will set the period for periodic calls to _get and whether or not those are lazy (see init parameters)"""
        if self._threaded:
            self._lock.acquire(max(self._lock.available(), 1))
            self._set_sources.emit({"period": period, "lazy": lazy})
            self.wait_ready()
        else:
            self._do_set_period({"period": period, "lazy": lazy})

    def _start_periodic(self):
        if self._timer is not None:
            self._timer.timeout.connect(self._get)
            self._timer.start()
            self.log.debug(f"started periodic: {list(self.sources)}")
        else:
            self.log.debug("no started periodic")

    def _stop_periodic(self):
        if self._timer is not None:
            self._timer.stop()
            try:
                self._timer.timeout.disconnect()
            except TypeError:
                pass
            self.log.debug(f"stopped periodic: {list(self.sources)}")
        else:
            self.log.debug("no stopped periodic")

    def _connect_sources(self):
        if self.sources is not None:
            for source in self.sources.values():
                source.connect(self._get)
            self.log.debug(f"connected sources: {list(self.sources)}")
        else:
            self.log.debug("no connected sources")

    def _disconnect_sources(self):
        if self.sources is not None:
            for source in self.sources.values():
                try:
                    source.disconnect()
                except TypeError:
                    pass
            self.log.debug(f"disconnected sources: {list(self.sources)}")
        else:
            self.log.debug("no disconnected sources")

    def _do_resume(self):
        self._start_periodic()
        self._connect_sources()
        self._running = True
        self.log.info("resumed")
        if self._threaded:
            self._lock.release()

    def _do_pause(self):
        self._stop_periodic()
        self._disconnect_sources()
        self._running = False
        self.log.info("paused")
        if self._threaded:
            self._lock.release()

    def _do_set_sources(self, sources):
        if self._running:
            self._disconnect_sources()
        self.sources = sources
        if self._running:
            self._connect_sources()
        self.log.info("set sources")
        if self._threaded:
            self._lock.release()

    def _do_set_period(self, spec):
        self._period = spec.get("period", None)
        self._single_shot = spec.get("lazy", True)
        self._init_periodic()
        self.log.info("set period")
        if self._threaded:
            self._lock.release()

    def _get(self, data=None):
        """
        this method should be overridden when inheriting from the Component class
        the overriding method should retrive all the data and then call super()._get(data)
        this will emit the data in the proper format
        """
        if data is None:
            data = [None]
        t = timing()
        got = [{"time": t, self.name: d} for d in data]
        self.out.emit(got)
        self.log.debug(f"_get: {got}")
        if self._timer is not None and self._single_shot:
            self._timer.start()

    def set(self, val):
        """
        this method should be overridden when inheriting from the Component class
        the overriding method should set the requested val and then call super()._set(set_value)
        this will log the value that has been set
        """
        self.log.debug(f"set: {val}")