Python select.html() Examples

def __init__(self, _kqueueImpl=select):
        """
        Initialize kqueue object, file descriptor tracking dictionaries, and
        the base class.

        See:
            - http://docs.python.org/library/select.html
            - www.freebsd.org/cgi/man.cgi?query=kqueue
            - people.freebsd.org/~jlemon/papers/kqueue.pdf

        @param _kqueueImpl: The implementation of L{_IKQueue} to use. A
            hook for testing.
        """
        self._impl = _kqueueImpl
        self._kq = self._impl.kqueue()
        self._reads = set()
        self._writes = set()
        self._selectables = {}
        posixbase.PosixReactorBase.__init__(self) 

def __init__(self, _kqueueImpl=select):
        """
        Initialize kqueue object, file descriptor tracking dictionaries, and
        the base class.

        See:
            - http://docs.python.org/library/select.html
            - www.freebsd.org/cgi/man.cgi?query=kqueue
            - people.freebsd.org/~jlemon/papers/kqueue.pdf

        @param _kqueueImpl: The implementation of L{_IKQueue} to use. A
            hook for testing.
        """
        self._impl = _kqueueImpl
        self._kq = self._impl.kqueue()
        self._reads = set()
        self._writes = set()
        self._selectables = {}
        posixbase.PosixReactorBase.__init__(self) 

def __init__(self, watch_manager, default_proc_fun=None, read_freq=0,
                 threshold=0, timeout=None):
        """
        Initialization, initialize base classes. read_freq, threshold and
        timeout parameters are used when looping.

        @param watch_manager: Watch Manager.
        @type watch_manager: WatchManager instance
        @param default_proc_fun: Default processing method. See base class.
        @type default_proc_fun: instance of ProcessEvent
        @param read_freq: if read_freq == 0, events are read asap,
                          if read_freq is > 0, this thread sleeps
                          max(0, read_freq - (timeout / 1000)) seconds.
        @type read_freq: int
        @param threshold: File descriptor will be read only if the accumulated
                          size to read becomes >= threshold. If != 0, you likely
                          want to use it in combination with an appropriate
                          value set for read_freq because without that you would
                          keep looping without really reading anything and that
                          until the amount of events to read is >= threshold. At
                          least with read_freq you might sleep.
        @type threshold: int
        @param timeout: see read_freq above. If provided, it must be set in
                        milliseconds. See
                        https://docs.python.org/2/library/select.html#select.poll.poll
        @type timeout: int
        """
        # Init threading base class
        threading.Thread.__init__(self)
        # Stop condition
        self._stop_event = threading.Event()
        # Init Notifier base class
        Notifier.__init__(self, watch_manager, default_proc_fun, read_freq,
                          threshold, timeout)
        # Create a new pipe used for thread termination
        self._pipe = os.pipe()
        self._pollobj.register(self._pipe[0], select.POLLIN) 

def tail_file(file_path, from_head=False):
        """
        创建子进程tail file
        Args:
            file_path: 文件路径
            from_head: 是否重头开始读取文件

        Returns:

        """
        # 安全注释, 防止OP不小心kill子进程
        safe_comment = "'(Do not kill me, parent PID: %d)'" % os.getpid()
        if from_head is True:
            # 先输出现有文件全部内容, 然后tail文件
            # -F 当文件变化时能切换到新的文件
            cmd = "cat %s && tail -F %s %s" % (file_path, file_path, safe_comment)
        else:
            cmd = "tail -F %s %s" % (file_path, safe_comment)

        try:
            process = subprocess.Popen(cmd, stdout=subprocess.PIPE, shell=True, bufsize=-1)
        except OSError as e:
            return False, str(e)
        else:
            # https://docs.python.org/2/library/select.html
            poll = select.epoll()
            poll.register(process.stdout)

            return process, poll 

def __init__(self, watch_manager, default_proc_fun=None, read_freq=0,
                 threshold=0, timeout=None):
        """
        Initialization, initialize base classes. read_freq, threshold and
        timeout parameters are used when looping.

        @param watch_manager: Watch Manager.
        @type watch_manager: WatchManager instance
        @param default_proc_fun: Default processing method. See base class.
        @type default_proc_fun: instance of ProcessEvent
        @param read_freq: if read_freq == 0, events are read asap,
                          if read_freq is > 0, this thread sleeps
                          max(0, read_freq - (timeout / 1000)) seconds.
        @type read_freq: int
        @param threshold: File descriptor will be read only if the accumulated
                          size to read becomes >= threshold. If != 0, you likely
                          want to use it in combination with an appropriate
                          value set for read_freq because without that you would
                          keep looping without really reading anything and that
                          until the amount of events to read is >= threshold. At
                          least with read_freq you might sleep.
        @type threshold: int
        @param timeout: see read_freq above. If provided, it must be set in
                        milliseconds. See
                        https://docs.python.org/3/library/select.html#select.poll.poll
        @type timeout: int
        """
        # Init threading base class
        threading.Thread.__init__(self)
        # Stop condition
        self._stop_event = threading.Event()
        # Init Notifier base class
        Notifier.__init__(self, watch_manager, default_proc_fun, read_freq,
                          threshold, timeout)
        # Create a new pipe used for thread termination
        self._pipe = os.pipe()
        self._pollobj.register(self._pipe[0], select.POLLIN) 

def __init__(self, watch_manager, default_proc_fun=None, read_freq=0,
                 threshold=0, timeout=None):
        """
        Initialization. read_freq, threshold and timeout parameters are used
        when looping.

        @param watch_manager: Watch Manager.
        @type watch_manager: WatchManager instance
        @param default_proc_fun: Default processing method. If None, a new
                                 instance of PrintAllEvents will be assigned.
        @type default_proc_fun: instance of ProcessEvent
        @param read_freq: if read_freq == 0, events are read asap,
                          if read_freq is > 0, this thread sleeps
                          max(0, read_freq - (timeout / 1000)) seconds. But
                          if timeout is None it may be different because
                          poll is blocking waiting for something to read.
        @type read_freq: int
        @param threshold: File descriptor will be read only if the accumulated
                          size to read becomes >= threshold. If != 0, you likely
                          want to use it in combination with an appropriate
                          value for read_freq because without that you would
                          keep looping without really reading anything and that
                          until the amount of events to read is >= threshold.
                          At least with read_freq set you might sleep.
        @type threshold: int
        @param timeout: see read_freq above. If provided, it must be set in
                        milliseconds. See
                        https://docs.python.org/2/library/select.html#polling-objects
        @type timeout: int
        """
        # Watch Manager instance
        self._watch_manager = watch_manager
        # File descriptor
        self._fd = self._watch_manager.get_fd()
        # Poll object and registration
        self._pollobj = select.poll()
        self._pollobj.register(self._fd, select.POLLIN)
        # This pipe is correctely initialized and used by ThreadedNotifier
        self._pipe = (-1, -1)
        # Event queue
        self._eventq = deque()
        # System processing functor, common to all events
        self._sys_proc_fun = _SysProcessEvent(self._watch_manager, self)
        # Default processing method
        self._default_proc_fun = default_proc_fun
        if default_proc_fun is None:
            self._default_proc_fun = PrintAllEvents()
        # Loop parameters
        self._read_freq = read_freq
        self._threshold = threshold
        self._timeout = timeout
        # Coalesce events option
        self._coalesce = False
        # set of str(raw_event), only used when coalesce option is True
        self._eventset = set() 

def __init__(self, watch_manager, default_proc_fun=None, read_freq=0,
                 threshold=0, timeout=None):
        """
        Initialization. read_freq, threshold and timeout parameters are used
        when looping.

        @param watch_manager: Watch Manager.
        @type watch_manager: WatchManager instance
        @param default_proc_fun: Default processing method. If None, a new
                                 instance of PrintAllEvents will be assigned.
        @type default_proc_fun: instance of ProcessEvent
        @param read_freq: if read_freq == 0, events are read asap,
                          if read_freq is > 0, this thread sleeps
                          max(0, read_freq - (timeout / 1000)) seconds. But if
                          timeout is None it may be different because
                          poll is blocking waiting for something to read.
        @type read_freq: int
        @param threshold: File descriptor will be read only if the accumulated
                          size to read becomes >= threshold. If != 0, you likely
                          want to use it in combination with an appropriate
                          value for read_freq because without that you would
                          keep looping without really reading anything and that
                          until the amount of events to read is >= threshold.
                          At least with read_freq set you might sleep.
        @type threshold: int
        @param timeout: see read_freq above. If provided, it must be set in
                        milliseconds. See
                        https://docs.python.org/3/library/select.html#select.poll.poll
        @type timeout: int
        """
        # Watch Manager instance
        self._watch_manager = watch_manager
        # File descriptor
        self._fd = self._watch_manager.get_fd()
        # Poll object and registration
        self._pollobj = select.poll()
        self._pollobj.register(self._fd, select.POLLIN)
        # This pipe is correctely initialized and used by ThreadedNotifier
        self._pipe = (-1, -1)
        # Event queue
        self._eventq = deque()
        # System processing functor, common to all events
        self._sys_proc_fun = _SysProcessEvent(self._watch_manager, self)
        # Default processing method
        self._default_proc_fun = default_proc_fun
        if default_proc_fun is None:
            self._default_proc_fun = PrintAllEvents()
        # Loop parameters
        self._read_freq = read_freq
        self._threshold = threshold
        self._timeout = timeout
        # Coalesce events option
        self._coalesce = False
        # set of str(raw_event), only used when coalesce option is True
        self._eventset = set()