824 lines
31 KiB
Python
824 lines
31 KiB
Python
#!/usr/bin/env python
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#
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# Copyright 2009 Facebook
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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"""An I/O event loop for non-blocking sockets.
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Typical applications will use a single `IOLoop` object, in the
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`IOLoop.instance` singleton. The `IOLoop.start` method should usually
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be called at the end of the ``main()`` function. Atypical applications may
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use more than one `IOLoop`, such as one `IOLoop` per thread, or per `unittest`
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case.
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In addition to I/O events, the `IOLoop` can also schedule time-based events.
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`IOLoop.add_timeout` is a non-blocking alternative to `time.sleep`.
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"""
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from __future__ import absolute_import, division, print_function, with_statement
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import datetime
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import errno
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import functools
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import heapq
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import logging
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import numbers
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import os
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import select
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import sys
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import threading
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import time
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import traceback
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from tornado.concurrent import Future, TracebackFuture
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from tornado.log import app_log, gen_log
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from tornado import stack_context
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from tornado.util import Configurable
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try:
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import signal
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except ImportError:
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signal = None
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try:
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import thread # py2
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except ImportError:
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import _thread as thread # py3
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from tornado.platform.auto import set_close_exec, Waker
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class TimeoutError(Exception):
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pass
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class IOLoop(Configurable):
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"""A level-triggered I/O loop.
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We use ``epoll`` (Linux) or ``kqueue`` (BSD and Mac OS X) if they
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are available, or else we fall back on select(). If you are
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implementing a system that needs to handle thousands of
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simultaneous connections, you should use a system that supports
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either ``epoll`` or ``kqueue``.
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Example usage for a simple TCP server::
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import errno
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import functools
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import ioloop
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import socket
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def connection_ready(sock, fd, events):
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while True:
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try:
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connection, address = sock.accept()
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except socket.error, e:
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if e.args[0] not in (errno.EWOULDBLOCK, errno.EAGAIN):
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raise
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return
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connection.setblocking(0)
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handle_connection(connection, address)
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sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0)
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sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
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sock.setblocking(0)
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sock.bind(("", port))
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sock.listen(128)
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io_loop = ioloop.IOLoop.instance()
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callback = functools.partial(connection_ready, sock)
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io_loop.add_handler(sock.fileno(), callback, io_loop.READ)
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io_loop.start()
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"""
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# Constants from the epoll module
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_EPOLLIN = 0x001
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_EPOLLPRI = 0x002
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_EPOLLOUT = 0x004
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_EPOLLERR = 0x008
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_EPOLLHUP = 0x010
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_EPOLLRDHUP = 0x2000
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_EPOLLONESHOT = (1 << 30)
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_EPOLLET = (1 << 31)
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# Our events map exactly to the epoll events
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NONE = 0
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READ = _EPOLLIN
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WRITE = _EPOLLOUT
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ERROR = _EPOLLERR | _EPOLLHUP
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# Global lock for creating global IOLoop instance
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_instance_lock = threading.Lock()
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_current = threading.local()
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@staticmethod
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def instance():
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"""Returns a global `IOLoop` instance.
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Most applications have a single, global `IOLoop` running on the
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main thread. Use this method to get this instance from
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another thread. To get the current thread's `IOLoop`, use `current()`.
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"""
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if not hasattr(IOLoop, "_instance"):
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with IOLoop._instance_lock:
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if not hasattr(IOLoop, "_instance"):
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# New instance after double check
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IOLoop._instance = IOLoop()
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return IOLoop._instance
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@staticmethod
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def initialized():
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"""Returns true if the singleton instance has been created."""
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return hasattr(IOLoop, "_instance")
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def install(self):
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"""Installs this `IOLoop` object as the singleton instance.
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This is normally not necessary as `instance()` will create
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an `IOLoop` on demand, but you may want to call `install` to use
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a custom subclass of `IOLoop`.
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"""
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assert not IOLoop.initialized()
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IOLoop._instance = self
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@staticmethod
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def current():
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"""Returns the current thread's `IOLoop`.
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If an `IOLoop` is currently running or has been marked as current
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by `make_current`, returns that instance. Otherwise returns
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`IOLoop.instance()`, i.e. the main thread's `IOLoop`.
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A common pattern for classes that depend on ``IOLoops`` is to use
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a default argument to enable programs with multiple ``IOLoops``
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but not require the argument for simpler applications::
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class MyClass(object):
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def __init__(self, io_loop=None):
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self.io_loop = io_loop or IOLoop.current()
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In general you should use `IOLoop.current` as the default when
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constructing an asynchronous object, and use `IOLoop.instance`
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when you mean to communicate to the main thread from a different
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one.
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"""
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current = getattr(IOLoop._current, "instance", None)
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if current is None:
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return IOLoop.instance()
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return current
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def make_current(self):
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"""Makes this the `IOLoop` for the current thread.
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An `IOLoop` automatically becomes current for its thread
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when it is started, but it is sometimes useful to call
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`make_current` explictly before starting the `IOLoop`,
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so that code run at startup time can find the right
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instance.
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"""
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IOLoop._current.instance = self
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@staticmethod
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def clear_current():
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IOLoop._current.instance = None
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@classmethod
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def configurable_base(cls):
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return IOLoop
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@classmethod
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def configurable_default(cls):
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if hasattr(select, "epoll"):
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from tornado.platform.epoll import EPollIOLoop
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return EPollIOLoop
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if hasattr(select, "kqueue"):
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# Python 2.6+ on BSD or Mac
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from tornado.platform.kqueue import KQueueIOLoop
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return KQueueIOLoop
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from tornado.platform.select import SelectIOLoop
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return SelectIOLoop
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def initialize(self):
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pass
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def close(self, all_fds=False):
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"""Closes the `IOLoop`, freeing any resources used.
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If ``all_fds`` is true, all file descriptors registered on the
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IOLoop will be closed (not just the ones created by the
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`IOLoop` itself).
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Many applications will only use a single `IOLoop` that runs for the
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entire lifetime of the process. In that case closing the `IOLoop`
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is not necessary since everything will be cleaned up when the
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process exits. `IOLoop.close` is provided mainly for scenarios
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such as unit tests, which create and destroy a large number of
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``IOLoops``.
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An `IOLoop` must be completely stopped before it can be closed. This
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means that `IOLoop.stop()` must be called *and* `IOLoop.start()` must
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be allowed to return before attempting to call `IOLoop.close()`.
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Therefore the call to `close` will usually appear just after
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the call to `start` rather than near the call to `stop`.
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.. versionchanged:: 3.1
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If the `IOLoop` implementation supports non-integer objects
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for "file descriptors", those objects will have their
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``close`` method when ``all_fds`` is true.
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"""
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raise NotImplementedError()
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def add_handler(self, fd, handler, events):
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"""Registers the given handler to receive the given events for fd.
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The ``events`` argument is a bitwise or of the constants
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``IOLoop.READ``, ``IOLoop.WRITE``, and ``IOLoop.ERROR``.
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When an event occurs, ``handler(fd, events)`` will be run.
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"""
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raise NotImplementedError()
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def update_handler(self, fd, events):
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"""Changes the events we listen for fd."""
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raise NotImplementedError()
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def remove_handler(self, fd):
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"""Stop listening for events on fd."""
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raise NotImplementedError()
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def set_blocking_signal_threshold(self, seconds, action):
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"""Sends a signal if the `IOLoop` is blocked for more than
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``s`` seconds.
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Pass ``seconds=None`` to disable. Requires Python 2.6 on a unixy
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platform.
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The action parameter is a Python signal handler. Read the
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documentation for the `signal` module for more information.
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If ``action`` is None, the process will be killed if it is
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blocked for too long.
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"""
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raise NotImplementedError()
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def set_blocking_log_threshold(self, seconds):
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"""Logs a stack trace if the `IOLoop` is blocked for more than
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``s`` seconds.
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Equivalent to ``set_blocking_signal_threshold(seconds,
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self.log_stack)``
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"""
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self.set_blocking_signal_threshold(seconds, self.log_stack)
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def log_stack(self, signal, frame):
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"""Signal handler to log the stack trace of the current thread.
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For use with `set_blocking_signal_threshold`.
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"""
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gen_log.warning('IOLoop blocked for %f seconds in\n%s',
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self._blocking_signal_threshold,
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''.join(traceback.format_stack(frame)))
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def start(self):
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"""Starts the I/O loop.
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The loop will run until one of the callbacks calls `stop()`, which
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will make the loop stop after the current event iteration completes.
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"""
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raise NotImplementedError()
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def stop(self):
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"""Stop the I/O loop.
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If the event loop is not currently running, the next call to `start()`
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will return immediately.
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To use asynchronous methods from otherwise-synchronous code (such as
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unit tests), you can start and stop the event loop like this::
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ioloop = IOLoop()
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async_method(ioloop=ioloop, callback=ioloop.stop)
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ioloop.start()
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``ioloop.start()`` will return after ``async_method`` has run
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its callback, whether that callback was invoked before or
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after ``ioloop.start``.
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Note that even after `stop` has been called, the `IOLoop` is not
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completely stopped until `IOLoop.start` has also returned.
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Some work that was scheduled before the call to `stop` may still
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be run before the `IOLoop` shuts down.
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"""
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raise NotImplementedError()
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def run_sync(self, func, timeout=None):
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"""Starts the `IOLoop`, runs the given function, and stops the loop.
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If the function returns a `.Future`, the `IOLoop` will run
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until the future is resolved. If it raises an exception, the
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`IOLoop` will stop and the exception will be re-raised to the
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caller.
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The keyword-only argument ``timeout`` may be used to set
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a maximum duration for the function. If the timeout expires,
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a `TimeoutError` is raised.
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This method is useful in conjunction with `tornado.gen.coroutine`
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to allow asynchronous calls in a ``main()`` function::
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@gen.coroutine
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def main():
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# do stuff...
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if __name__ == '__main__':
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IOLoop.instance().run_sync(main)
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"""
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future_cell = [None]
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def run():
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try:
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result = func()
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except Exception:
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future_cell[0] = TracebackFuture()
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future_cell[0].set_exc_info(sys.exc_info())
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else:
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if isinstance(result, Future):
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future_cell[0] = result
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else:
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future_cell[0] = Future()
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future_cell[0].set_result(result)
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self.add_future(future_cell[0], lambda future: self.stop())
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self.add_callback(run)
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if timeout is not None:
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timeout_handle = self.add_timeout(self.time() + timeout, self.stop)
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self.start()
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if timeout is not None:
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self.remove_timeout(timeout_handle)
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if not future_cell[0].done():
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raise TimeoutError('Operation timed out after %s seconds' % timeout)
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return future_cell[0].result()
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def time(self):
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"""Returns the current time according to the `IOLoop`'s clock.
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The return value is a floating-point number relative to an
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unspecified time in the past.
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By default, the `IOLoop`'s time function is `time.time`. However,
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it may be configured to use e.g. `time.monotonic` instead.
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Calls to `add_timeout` that pass a number instead of a
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`datetime.timedelta` should use this function to compute the
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appropriate time, so they can work no matter what time function
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is chosen.
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"""
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return time.time()
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def add_timeout(self, deadline, callback):
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"""Runs the ``callback`` at the time ``deadline`` from the I/O loop.
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Returns an opaque handle that may be passed to
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`remove_timeout` to cancel.
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``deadline`` may be a number denoting a time (on the same
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scale as `IOLoop.time`, normally `time.time`), or a
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`datetime.timedelta` object for a deadline relative to the
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current time.
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Note that it is not safe to call `add_timeout` from other threads.
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Instead, you must use `add_callback` to transfer control to the
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`IOLoop`'s thread, and then call `add_timeout` from there.
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"""
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raise NotImplementedError()
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def remove_timeout(self, timeout):
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"""Cancels a pending timeout.
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The argument is a handle as returned by `add_timeout`. It is
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safe to call `remove_timeout` even if the callback has already
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been run.
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"""
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raise NotImplementedError()
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def add_callback(self, callback, *args, **kwargs):
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"""Calls the given callback on the next I/O loop iteration.
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It is safe to call this method from any thread at any time,
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except from a signal handler. Note that this is the **only**
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method in `IOLoop` that makes this thread-safety guarantee; all
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other interaction with the `IOLoop` must be done from that
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`IOLoop`'s thread. `add_callback()` may be used to transfer
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control from other threads to the `IOLoop`'s thread.
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To add a callback from a signal handler, see
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`add_callback_from_signal`.
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"""
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raise NotImplementedError()
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def add_callback_from_signal(self, callback, *args, **kwargs):
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"""Calls the given callback on the next I/O loop iteration.
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Safe for use from a Python signal handler; should not be used
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otherwise.
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Callbacks added with this method will be run without any
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`.stack_context`, to avoid picking up the context of the function
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that was interrupted by the signal.
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"""
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raise NotImplementedError()
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def add_future(self, future, callback):
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"""Schedules a callback on the ``IOLoop`` when the given
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`.Future` is finished.
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The callback is invoked with one argument, the
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`.Future`.
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"""
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assert isinstance(future, Future)
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callback = stack_context.wrap(callback)
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future.add_done_callback(
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lambda future: self.add_callback(callback, future))
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def _run_callback(self, callback):
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"""Runs a callback with error handling.
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For use in subclasses.
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"""
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try:
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callback()
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except Exception:
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self.handle_callback_exception(callback)
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def handle_callback_exception(self, callback):
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"""This method is called whenever a callback run by the `IOLoop`
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throws an exception.
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By default simply logs the exception as an error. Subclasses
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may override this method to customize reporting of exceptions.
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The exception itself is not passed explicitly, but is available
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in `sys.exc_info`.
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"""
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app_log.error("Exception in callback %r", callback, exc_info=True)
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class PollIOLoop(IOLoop):
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"""Base class for IOLoops built around a select-like function.
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For concrete implementations, see `tornado.platform.epoll.EPollIOLoop`
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(Linux), `tornado.platform.kqueue.KQueueIOLoop` (BSD and Mac), or
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`tornado.platform.select.SelectIOLoop` (all platforms).
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"""
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def initialize(self, impl, time_func=None):
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super(PollIOLoop, self).initialize()
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self._impl = impl
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if hasattr(self._impl, 'fileno'):
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set_close_exec(self._impl.fileno())
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self.time_func = time_func or time.time
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self._handlers = {}
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self._events = {}
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self._callbacks = []
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self._callback_lock = threading.Lock()
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self._timeouts = []
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self._cancellations = 0
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self._running = False
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self._stopped = False
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self._closing = False
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self._thread_ident = None
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self._blocking_signal_threshold = None
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# Create a pipe that we send bogus data to when we want to wake
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# the I/O loop when it is idle
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self._waker = Waker()
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self.add_handler(self._waker.fileno(),
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lambda fd, events: self._waker.consume(),
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self.READ)
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def close(self, all_fds=False):
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with self._callback_lock:
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self._closing = True
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self.remove_handler(self._waker.fileno())
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if all_fds:
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for fd in self._handlers.keys():
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try:
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close_method = getattr(fd, 'close', None)
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if close_method is not None:
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close_method()
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else:
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os.close(fd)
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except Exception:
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gen_log.debug("error closing fd %s", fd, exc_info=True)
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self._waker.close()
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self._impl.close()
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def add_handler(self, fd, handler, events):
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self._handlers[fd] = stack_context.wrap(handler)
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self._impl.register(fd, events | self.ERROR)
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def update_handler(self, fd, events):
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self._impl.modify(fd, events | self.ERROR)
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|
def remove_handler(self, fd):
|
|
self._handlers.pop(fd, None)
|
|
self._events.pop(fd, None)
|
|
try:
|
|
self._impl.unregister(fd)
|
|
except Exception:
|
|
gen_log.debug("Error deleting fd from IOLoop", exc_info=True)
|
|
|
|
def set_blocking_signal_threshold(self, seconds, action):
|
|
if not hasattr(signal, "setitimer"):
|
|
gen_log.error("set_blocking_signal_threshold requires a signal module "
|
|
"with the setitimer method")
|
|
return
|
|
self._blocking_signal_threshold = seconds
|
|
if seconds is not None:
|
|
signal.signal(signal.SIGALRM,
|
|
action if action is not None else signal.SIG_DFL)
|
|
|
|
def start(self):
|
|
if not logging.getLogger().handlers:
|
|
# The IOLoop catches and logs exceptions, so it's
|
|
# important that log output be visible. However, python's
|
|
# default behavior for non-root loggers (prior to python
|
|
# 3.2) is to print an unhelpful "no handlers could be
|
|
# found" message rather than the actual log entry, so we
|
|
# must explicitly configure logging if we've made it this
|
|
# far without anything.
|
|
logging.basicConfig()
|
|
if self._stopped:
|
|
self._stopped = False
|
|
return
|
|
old_current = getattr(IOLoop._current, "instance", None)
|
|
IOLoop._current.instance = self
|
|
self._thread_ident = thread.get_ident()
|
|
self._running = True
|
|
|
|
# signal.set_wakeup_fd closes a race condition in event loops:
|
|
# a signal may arrive at the beginning of select/poll/etc
|
|
# before it goes into its interruptible sleep, so the signal
|
|
# will be consumed without waking the select. The solution is
|
|
# for the (C, synchronous) signal handler to write to a pipe,
|
|
# which will then be seen by select.
|
|
#
|
|
# In python's signal handling semantics, this only matters on the
|
|
# main thread (fortunately, set_wakeup_fd only works on the main
|
|
# thread and will raise a ValueError otherwise).
|
|
#
|
|
# If someone has already set a wakeup fd, we don't want to
|
|
# disturb it. This is an issue for twisted, which does its
|
|
# SIGCHILD processing in response to its own wakeup fd being
|
|
# written to. As long as the wakeup fd is registered on the IOLoop,
|
|
# the loop will still wake up and everything should work.
|
|
old_wakeup_fd = None
|
|
if hasattr(signal, 'set_wakeup_fd') and os.name == 'posix':
|
|
# requires python 2.6+, unix. set_wakeup_fd exists but crashes
|
|
# the python process on windows.
|
|
try:
|
|
old_wakeup_fd = signal.set_wakeup_fd(self._waker.write_fileno())
|
|
if old_wakeup_fd != -1:
|
|
# Already set, restore previous value. This is a little racy,
|
|
# but there's no clean get_wakeup_fd and in real use the
|
|
# IOLoop is just started once at the beginning.
|
|
signal.set_wakeup_fd(old_wakeup_fd)
|
|
old_wakeup_fd = None
|
|
except ValueError: # non-main thread
|
|
pass
|
|
|
|
while True:
|
|
poll_timeout = 3600.0
|
|
|
|
# Prevent IO event starvation by delaying new callbacks
|
|
# to the next iteration of the event loop.
|
|
with self._callback_lock:
|
|
callbacks = self._callbacks
|
|
self._callbacks = []
|
|
for callback in callbacks:
|
|
self._run_callback(callback)
|
|
|
|
if self._timeouts:
|
|
now = self.time()
|
|
while self._timeouts:
|
|
if self._timeouts[0].callback is None:
|
|
# the timeout was cancelled
|
|
heapq.heappop(self._timeouts)
|
|
self._cancellations -= 1
|
|
elif self._timeouts[0].deadline <= now:
|
|
timeout = heapq.heappop(self._timeouts)
|
|
self._run_callback(timeout.callback)
|
|
else:
|
|
seconds = self._timeouts[0].deadline - now
|
|
poll_timeout = min(seconds, poll_timeout)
|
|
break
|
|
if (self._cancellations > 512
|
|
and self._cancellations > (len(self._timeouts) >> 1)):
|
|
# Clean up the timeout queue when it gets large and it's
|
|
# more than half cancellations.
|
|
self._cancellations = 0
|
|
self._timeouts = [x for x in self._timeouts
|
|
if x.callback is not None]
|
|
heapq.heapify(self._timeouts)
|
|
|
|
if self._callbacks:
|
|
# If any callbacks or timeouts called add_callback,
|
|
# we don't want to wait in poll() before we run them.
|
|
poll_timeout = 0.0
|
|
|
|
if not self._running:
|
|
break
|
|
|
|
if self._blocking_signal_threshold is not None:
|
|
# clear alarm so it doesn't fire while poll is waiting for
|
|
# events.
|
|
signal.setitimer(signal.ITIMER_REAL, 0, 0)
|
|
|
|
try:
|
|
event_pairs = self._impl.poll(poll_timeout)
|
|
except Exception as e:
|
|
# Depending on python version and IOLoop implementation,
|
|
# different exception types may be thrown and there are
|
|
# two ways EINTR might be signaled:
|
|
# * e.errno == errno.EINTR
|
|
# * e.args is like (errno.EINTR, 'Interrupted system call')
|
|
if (getattr(e, 'errno', None) == errno.EINTR or
|
|
(isinstance(getattr(e, 'args', None), tuple) and
|
|
len(e.args) == 2 and e.args[0] == errno.EINTR)):
|
|
continue
|
|
else:
|
|
raise
|
|
|
|
if self._blocking_signal_threshold is not None:
|
|
signal.setitimer(signal.ITIMER_REAL,
|
|
self._blocking_signal_threshold, 0)
|
|
|
|
# Pop one fd at a time from the set of pending fds and run
|
|
# its handler. Since that handler may perform actions on
|
|
# other file descriptors, there may be reentrant calls to
|
|
# this IOLoop that update self._events
|
|
self._events.update(event_pairs)
|
|
while self._events:
|
|
fd, events = self._events.popitem()
|
|
try:
|
|
self._handlers[fd](fd, events)
|
|
except (OSError, IOError) as e:
|
|
if e.args[0] == errno.EPIPE:
|
|
# Happens when the client closes the connection
|
|
pass
|
|
else:
|
|
app_log.error("Exception in I/O handler for fd %s",
|
|
fd, exc_info=True)
|
|
except Exception:
|
|
app_log.error("Exception in I/O handler for fd %s",
|
|
fd, exc_info=True)
|
|
# reset the stopped flag so another start/stop pair can be issued
|
|
self._stopped = False
|
|
if self._blocking_signal_threshold is not None:
|
|
signal.setitimer(signal.ITIMER_REAL, 0, 0)
|
|
IOLoop._current.instance = old_current
|
|
if old_wakeup_fd is not None:
|
|
signal.set_wakeup_fd(old_wakeup_fd)
|
|
|
|
def stop(self):
|
|
self._running = False
|
|
self._stopped = True
|
|
self._waker.wake()
|
|
|
|
def time(self):
|
|
return self.time_func()
|
|
|
|
def add_timeout(self, deadline, callback):
|
|
timeout = _Timeout(deadline, stack_context.wrap(callback), self)
|
|
heapq.heappush(self._timeouts, timeout)
|
|
return timeout
|
|
|
|
def remove_timeout(self, timeout):
|
|
# Removing from a heap is complicated, so just leave the defunct
|
|
# timeout object in the queue (see discussion in
|
|
# http://docs.python.org/library/heapq.html).
|
|
# If this turns out to be a problem, we could add a garbage
|
|
# collection pass whenever there are too many dead timeouts.
|
|
timeout.callback = None
|
|
self._cancellations += 1
|
|
|
|
def add_callback(self, callback, *args, **kwargs):
|
|
with self._callback_lock:
|
|
if self._closing:
|
|
raise RuntimeError("IOLoop is closing")
|
|
list_empty = not self._callbacks
|
|
self._callbacks.append(functools.partial(
|
|
stack_context.wrap(callback), *args, **kwargs))
|
|
if list_empty and thread.get_ident() != self._thread_ident:
|
|
# If we're in the IOLoop's thread, we know it's not currently
|
|
# polling. If we're not, and we added the first callback to an
|
|
# empty list, we may need to wake it up (it may wake up on its
|
|
# own, but an occasional extra wake is harmless). Waking
|
|
# up a polling IOLoop is relatively expensive, so we try to
|
|
# avoid it when we can.
|
|
self._waker.wake()
|
|
|
|
def add_callback_from_signal(self, callback, *args, **kwargs):
|
|
with stack_context.NullContext():
|
|
if thread.get_ident() != self._thread_ident:
|
|
# if the signal is handled on another thread, we can add
|
|
# it normally (modulo the NullContext)
|
|
self.add_callback(callback, *args, **kwargs)
|
|
else:
|
|
# If we're on the IOLoop's thread, we cannot use
|
|
# the regular add_callback because it may deadlock on
|
|
# _callback_lock. Blindly insert into self._callbacks.
|
|
# This is safe because the GIL makes list.append atomic.
|
|
# One subtlety is that if the signal interrupted the
|
|
# _callback_lock block in IOLoop.start, we may modify
|
|
# either the old or new version of self._callbacks,
|
|
# but either way will work.
|
|
self._callbacks.append(functools.partial(
|
|
stack_context.wrap(callback), *args, **kwargs))
|
|
|
|
|
|
class _Timeout(object):
|
|
"""An IOLoop timeout, a UNIX timestamp and a callback"""
|
|
|
|
# Reduce memory overhead when there are lots of pending callbacks
|
|
__slots__ = ['deadline', 'callback']
|
|
|
|
def __init__(self, deadline, callback, io_loop):
|
|
if isinstance(deadline, numbers.Real):
|
|
self.deadline = deadline
|
|
elif isinstance(deadline, datetime.timedelta):
|
|
self.deadline = io_loop.time() + _Timeout.timedelta_to_seconds(deadline)
|
|
else:
|
|
raise TypeError("Unsupported deadline %r" % deadline)
|
|
self.callback = callback
|
|
|
|
@staticmethod
|
|
def timedelta_to_seconds(td):
|
|
"""Equivalent to td.total_seconds() (introduced in python 2.7)."""
|
|
return (td.microseconds + (td.seconds + td.days * 24 * 3600) * 10 ** 6) / float(10 ** 6)
|
|
|
|
# Comparison methods to sort by deadline, with object id as a tiebreaker
|
|
# to guarantee a consistent ordering. The heapq module uses __le__
|
|
# in python2.5, and __lt__ in 2.6+ (sort() and most other comparisons
|
|
# use __lt__).
|
|
def __lt__(self, other):
|
|
return ((self.deadline, id(self)) <
|
|
(other.deadline, id(other)))
|
|
|
|
def __le__(self, other):
|
|
return ((self.deadline, id(self)) <=
|
|
(other.deadline, id(other)))
|
|
|
|
|
|
class PeriodicCallback(object):
|
|
"""Schedules the given callback to be called periodically.
|
|
|
|
The callback is called every ``callback_time`` milliseconds.
|
|
|
|
`start` must be called after the `PeriodicCallback` is created.
|
|
"""
|
|
def __init__(self, callback, callback_time, io_loop=None):
|
|
self.callback = callback
|
|
if callback_time <= 0:
|
|
raise ValueError("Periodic callback must have a positive callback_time")
|
|
self.callback_time = callback_time
|
|
self.io_loop = io_loop or IOLoop.current()
|
|
self._running = False
|
|
self._timeout = None
|
|
|
|
def start(self):
|
|
"""Starts the timer."""
|
|
self._running = True
|
|
self._next_timeout = self.io_loop.time()
|
|
self._schedule_next()
|
|
|
|
def stop(self):
|
|
"""Stops the timer."""
|
|
self._running = False
|
|
if self._timeout is not None:
|
|
self.io_loop.remove_timeout(self._timeout)
|
|
self._timeout = None
|
|
|
|
def _run(self):
|
|
if not self._running:
|
|
return
|
|
try:
|
|
self.callback()
|
|
except Exception:
|
|
app_log.error("Error in periodic callback", exc_info=True)
|
|
self._schedule_next()
|
|
|
|
def _schedule_next(self):
|
|
if self._running:
|
|
current_time = self.io_loop.time()
|
|
while self._next_timeout <= current_time:
|
|
self._next_timeout += self.callback_time / 1000.0
|
|
self._timeout = self.io_loop.add_timeout(self._next_timeout, self._run)
|