Inheritance diagram for tornado.ioloop.IOLoop:
Detailed Description
A level-triggered I/O loop.
We use ``epoll`` (Linux) or ``kqueue`` (BSD and Mac OS X) if they
are available, or else we fall back on select(). If you are
implementing a system that needs to handle thousands of
simultaneous connections, you should use a system that supports
either ``epoll`` or ``kqueue``.
Example usage for a simple TCP server::
import errno
import functools
import ioloop
import socket
def connection_ready(sock, fd, events):
while True:
try:
connection, address = sock.accept()
except socket.error, e:
if e.args[0] not in (errno.EWOULDBLOCK, errno.EAGAIN):
raise
return
connection.setblocking(0)
handle_connection(connection, address)
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0)
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sock.setblocking(0)
sock.bind(("", port))
sock.listen(128)
io_loop = ioloop.IOLoop.instance()
callback = functools.partial(connection_ready, sock)
io_loop.add_handler(sock.fileno(), callback, io_loop.READ)
io_loop.start()
Member Function Documentation
| def tornado.ioloop.IOLoop._run_callback | ( | self, | |
| callback | |||
| ) | [private] |
| def tornado.ioloop.IOLoop._setup_logging | ( | self | ) | [private] |
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. This method should be called from start() in subclasses.
| def tornado.ioloop.IOLoop.add_callback | ( | self, | |
| callback, | |||
| args, | |||
| kwargs | |||
| ) |
Calls the given callback on the next I/O loop iteration. It is safe to call this method from any thread at any time, except from a signal handler. Note that this is the **only** method in `IOLoop` that makes this thread-safety guarantee; all other interaction with the `IOLoop` must be done from that `IOLoop`'s thread. `add_callback()` may be used to transfer control from other threads to the `IOLoop`'s thread. To add a callback from a signal handler, see `add_callback_from_signal`.
Reimplemented in tornado.ioloop.PollIOLoop, tornado.platform.twisted.TwistedIOLoop, and tornado.platform.asyncio.BaseAsyncIOLoop.
| def tornado.ioloop.IOLoop.add_callback_from_signal | ( | self, | |
| callback, | |||
| args, | |||
| kwargs | |||
| ) |
Calls the given callback on the next I/O loop iteration. Safe for use from a Python signal handler; should not be used otherwise. Callbacks added with this method will be run without any `.stack_context`, to avoid picking up the context of the function that was interrupted by the signal.
Reimplemented in tornado.ioloop.PollIOLoop, and tornado.platform.twisted.TwistedIOLoop.
| def tornado.ioloop.IOLoop.add_future | ( | self, | |
| future, | |||
| callback | |||
| ) |
| def tornado.ioloop.IOLoop.add_handler | ( | self, | |
| fd, | |||
| handler, | |||
| events | |||
| ) |
Registers the given handler to receive the given events for ``fd``. The ``fd`` argument may either be an integer file descriptor or a file-like object with a ``fileno()`` method (and optionally a ``close()`` method, which may be called when the `IOLoop` is shut down). The ``events`` argument is a bitwise or of the constants ``IOLoop.READ``, ``IOLoop.WRITE``, and ``IOLoop.ERROR``. When an event occurs, ``handler(fd, events)`` will be run. .. versionchanged:: 4.0 Added the ability to pass file-like objects in addition to raw file descriptors.
Reimplemented in tornado.ioloop.PollIOLoop, tornado.platform.twisted.TwistedIOLoop, and tornado.platform.asyncio.BaseAsyncIOLoop.
| def tornado.ioloop.IOLoop.add_timeout | ( | self, | |
| deadline, | |||
| callback, | |||
| args, | |||
| kwargs | |||
| ) |
Runs the ``callback`` at the time ``deadline`` from the I/O loop. Returns an opaque handle that may be passed to `remove_timeout` to cancel. ``deadline`` may be a number denoting a time (on the same scale as `IOLoop.time`, normally `time.time`), or a `datetime.timedelta` object for a deadline relative to the current time. Since Tornado 4.0, `call_later` is a more convenient alternative for the relative case since it does not require a timedelta object. Note that it is not safe to call `add_timeout` from other threads. Instead, you must use `add_callback` to transfer control to the `IOLoop`'s thread, and then call `add_timeout` from there. Subclasses of IOLoop must implement either `add_timeout` or `call_at`; the default implementations of each will call the other. `call_at` is usually easier to implement, but subclasses that wish to maintain compatibility with Tornado versions prior to 4.0 must use `add_timeout` instead. .. versionchanged:: 4.0 Now passes through ``*args`` and ``**kwargs`` to the callback.
Reimplemented in tornado.platform.twisted.TwistedIOLoop.
| def tornado.ioloop.IOLoop.call_at | ( | self, | |
| when, | |||
| callback, | |||
| args, | |||
| kwargs | |||
| ) |
Runs the ``callback`` at the absolute time designated by ``when``. ``when`` must be a number using the same reference point as `IOLoop.time`. Returns an opaque handle that may be passed to `remove_timeout` to cancel. Note that unlike the `asyncio` method of the same name, the returned object does not have a ``cancel()`` method. See `add_timeout` for comments on thread-safety and subclassing. .. versionadded:: 4.0
Reimplemented in tornado.ioloop.PollIOLoop, and tornado.platform.asyncio.BaseAsyncIOLoop.
| def tornado.ioloop.IOLoop.call_later | ( | self, | |
| delay, | |||
| callback, | |||
| args, | |||
| kwargs | |||
| ) |
Runs the ``callback`` after ``delay`` seconds have passed. Returns an opaque handle that may be passed to `remove_timeout` to cancel. Note that unlike the `asyncio` method of the same name, the returned object does not have a ``cancel()`` method. See `add_timeout` for comments on thread-safety and subclassing. .. versionadded:: 4.0
| def tornado.ioloop.IOLoop.clear_current | ( | ) | [static] |
| def tornado.ioloop.IOLoop.clear_instance | ( | ) | [static] |
| def tornado.ioloop.IOLoop.close | ( | self, | |
all_fds = False |
|||
| ) |
Closes the `IOLoop`, freeing any resources used. If ``all_fds`` is true, all file descriptors registered on the IOLoop will be closed (not just the ones created by the `IOLoop` itself). Many applications will only use a single `IOLoop` that runs for the entire lifetime of the process. In that case closing the `IOLoop` is not necessary since everything will be cleaned up when the process exits. `IOLoop.close` is provided mainly for scenarios such as unit tests, which create and destroy a large number of ``IOLoops``. An `IOLoop` must be completely stopped before it can be closed. This means that `IOLoop.stop()` must be called *and* `IOLoop.start()` must be allowed to return before attempting to call `IOLoop.close()`. Therefore the call to `close` will usually appear just after the call to `start` rather than near the call to `stop`. .. versionchanged:: 3.1 If the `IOLoop` implementation supports non-integer objects for "file descriptors", those objects will have their ``close`` method when ``all_fds`` is true.
Reimplemented in tornado.ioloop.PollIOLoop, tornado.platform.twisted.TwistedIOLoop, and tornado.platform.asyncio.BaseAsyncIOLoop.
| def tornado.ioloop.IOLoop.close_fd | ( | self, | |
| fd | |||
| ) |
Utility method to close an ``fd``. If ``fd`` is a file-like object, we close it directly; otherwise we use `os.close`. This method is provided for use by `IOLoop` subclasses (in implementations of ``IOLoop.close(all_fds=True)`` and should not generally be used by application code. .. versionadded:: 4.0
| def tornado.ioloop.IOLoop.configurable_base | ( | cls | ) |
Returns the base class of a configurable hierarchy. This will normally return the class in which it is defined. (which is *not* necessarily the same as the cls classmethod parameter).
Reimplemented from tornado.util.Configurable.
| def tornado.ioloop.IOLoop.configurable_default | ( | cls | ) |
Returns the implementation class to be used if none is configured.
Reimplemented from tornado.util.Configurable.
| def tornado.ioloop.IOLoop.current | ( | ) | [static] |
Returns the current thread's `IOLoop`.
If an `IOLoop` is currently running or has been marked as current
by `make_current`, returns that instance. Otherwise returns
`IOLoop.instance()`, i.e. the main thread's `IOLoop`.
A common pattern for classes that depend on ``IOLoops`` is to use
a default argument to enable programs with multiple ``IOLoops``
but not require the argument for simpler applications::
class MyClass(object):
def __init__(self, io_loop=None):
self.io_loop = io_loop or IOLoop.current()
In general you should use `IOLoop.current` as the default when
constructing an asynchronous object, and use `IOLoop.instance`
when you mean to communicate to the main thread from a different
one.
| def tornado.ioloop.IOLoop.handle_callback_exception | ( | self, | |
| callback | |||
| ) |
This method is called whenever a callback run by the `IOLoop` throws an exception. By default simply logs the exception as an error. Subclasses may override this method to customize reporting of exceptions. The exception itself is not passed explicitly, but is available in `sys.exc_info`.
| def tornado.ioloop.IOLoop.initialize | ( | self | ) |
Initialize a `Configurable` subclass instance. Configurable classes should use `initialize` instead of ``__init__``.
Reimplemented from tornado.util.Configurable.
Reimplemented in tornado.platform.asyncio.AsyncIOLoop, and tornado.platform.asyncio.AsyncIOMainLoop.
| def tornado.ioloop.IOLoop.initialized | ( | ) | [static] |
| def tornado.ioloop.IOLoop.install | ( | self | ) |
| def tornado.ioloop.IOLoop.instance | ( | ) | [static] |
| def tornado.ioloop.IOLoop.log_stack | ( | self, | |
| signal, | |||
| frame | |||
| ) |
| def tornado.ioloop.IOLoop.make_current | ( | self | ) |
Makes this the `IOLoop` for the current thread. An `IOLoop` automatically becomes current for its thread when it is started, but it is sometimes useful to call `make_current` explictly before starting the `IOLoop`, so that code run at startup time can find the right instance.
| def tornado.ioloop.IOLoop.remove_handler | ( | self, | |
| fd | |||
| ) |
Stop listening for events on ``fd``. .. versionchanged:: 4.0 Added the ability to pass file-like objects in addition to raw file descriptors.
Reimplemented in tornado.ioloop.PollIOLoop, tornado.platform.twisted.TwistedIOLoop, and tornado.platform.asyncio.BaseAsyncIOLoop.
| def tornado.ioloop.IOLoop.remove_timeout | ( | self, | |
| timeout | |||
| ) |
Cancels a pending timeout. The argument is a handle as returned by `add_timeout`. It is safe to call `remove_timeout` even if the callback has already been run.
Reimplemented in tornado.ioloop.PollIOLoop, tornado.platform.twisted.TwistedIOLoop, and tornado.platform.asyncio.BaseAsyncIOLoop.
| def tornado.ioloop.IOLoop.run_sync | ( | self, | |
| func, | |||
timeout = None |
|||
| ) |
Starts the `IOLoop`, runs the given function, and stops the loop.
If the function returns a `.Future`, the `IOLoop` will run
until the future is resolved. If it raises an exception, the
`IOLoop` will stop and the exception will be re-raised to the
caller.
The keyword-only argument ``timeout`` may be used to set
a maximum duration for the function. If the timeout expires,
a `TimeoutError` is raised.
This method is useful in conjunction with `tornado.gen.coroutine`
to allow asynchronous calls in a ``main()`` function::
@gen.coroutine
def main():
# do stuff...
if __name__ == '__main__':
IOLoop.instance().run_sync(main)
| def tornado.ioloop.IOLoop.set_blocking_log_threshold | ( | self, | |
| seconds | |||
| ) |
| def tornado.ioloop.IOLoop.set_blocking_signal_threshold | ( | self, | |
| seconds, | |||
| action | |||
| ) |
Sends a signal if the `IOLoop` is blocked for more than ``s`` seconds. Pass ``seconds=None`` to disable. Requires Python 2.6 on a unixy platform. The action parameter is a Python signal handler. Read the documentation for the `signal` module for more information. If ``action`` is None, the process will be killed if it is blocked for too long.
Reimplemented in tornado.ioloop.PollIOLoop.
| def tornado.ioloop.IOLoop.spawn_callback | ( | self, | |
| callback, | |||
| args, | |||
| kwargs | |||
| ) |
Calls the given callback on the next IOLoop iteration. Unlike all other callback-related methods on IOLoop, ``spawn_callback`` does not associate the callback with its caller's ``stack_context``, so it is suitable for fire-and-forget callbacks that should not interfere with the caller. .. versionadded:: 4.0
| def tornado.ioloop.IOLoop.split_fd | ( | self, | |
| fd | |||
| ) |
Returns an (fd, obj) pair from an ``fd`` parameter. We accept both raw file descriptors and file-like objects as input to `add_handler` and related methods. When a file-like object is passed, we must retain the object itself so we can close it correctly when the `IOLoop` shuts down, but the poller interfaces favor file descriptors (they will accept file-like objects and call ``fileno()`` for you, but they always return the descriptor itself). This method is provided for use by `IOLoop` subclasses and should not generally be used by application code. .. versionadded:: 4.0
| def tornado.ioloop.IOLoop.start | ( | self | ) |
Starts the I/O loop. The loop will run until one of the callbacks calls `stop()`, which will make the loop stop after the current event iteration completes.
Reimplemented in tornado.ioloop.PollIOLoop, tornado.platform.twisted.TwistedIOLoop, and tornado.platform.asyncio.BaseAsyncIOLoop.
| def tornado.ioloop.IOLoop.stop | ( | self | ) |
Stop the I/O loop. If the event loop is not currently running, the next call to `start()` will return immediately. To use asynchronous methods from otherwise-synchronous code (such as unit tests), you can start and stop the event loop like this:: ioloop = IOLoop() async_method(ioloop=ioloop, callback=ioloop.stop) ioloop.start() ``ioloop.start()`` will return after ``async_method`` has run its callback, whether that callback was invoked before or after ``ioloop.start``. Note that even after `stop` has been called, the `IOLoop` is not completely stopped until `IOLoop.start` has also returned. Some work that was scheduled before the call to `stop` may still be run before the `IOLoop` shuts down.
Reimplemented in tornado.ioloop.PollIOLoop, tornado.platform.twisted.TwistedIOLoop, and tornado.platform.asyncio.BaseAsyncIOLoop.
| def tornado.ioloop.IOLoop.time | ( | self | ) |
Returns the current time according to the `IOLoop`'s clock. The return value is a floating-point number relative to an unspecified time in the past. By default, the `IOLoop`'s time function is `time.time`. However, it may be configured to use e.g. `time.monotonic` instead. Calls to `add_timeout` that pass a number instead of a `datetime.timedelta` should use this function to compute the appropriate time, so they can work no matter what time function is chosen.
Reimplemented in tornado.ioloop.PollIOLoop.
| def tornado.ioloop.IOLoop.update_handler | ( | self, | |
| fd, | |||
| events | |||
| ) |
Changes the events we listen for ``fd``. .. versionchanged:: 4.0 Added the ability to pass file-like objects in addition to raw file descriptors.
Reimplemented in tornado.ioloop.PollIOLoop, tornado.platform.twisted.TwistedIOLoop, and tornado.platform.asyncio.BaseAsyncIOLoop.
Member Data Documentation
tuple tornado::ioloop.IOLoop::_current = threading.local() [static, private] |
int tornado::ioloop.IOLoop::_EPOLLERR = 0x008 [static, private] |
tuple tornado::ioloop.IOLoop::_EPOLLET = (1 << 31) [static, private] |
int tornado::ioloop.IOLoop::_EPOLLHUP = 0x010 [static, private] |
int tornado::ioloop.IOLoop::_EPOLLIN = 0x001 [static, private] |
tuple tornado::ioloop.IOLoop::_EPOLLONESHOT = (1 << 30) [static, private] |
int tornado::ioloop.IOLoop::_EPOLLOUT = 0x004 [static, private] |
int tornado::ioloop.IOLoop::_EPOLLPRI = 0x002 [static, private] |
int tornado::ioloop.IOLoop::_EPOLLRDHUP = 0x2000 [static, private] |
tuple tornado::ioloop.IOLoop::_instance_lock = threading.Lock() [static, private] |
tornado::ioloop.IOLoop::ERROR = _EPOLLERR|_EPOLLHUP [static] |
int tornado::ioloop.IOLoop::NONE = 0 [static] |
tornado::ioloop.IOLoop::READ = _EPOLLIN [static] |
tornado::ioloop.IOLoop::WRITE = _EPOLLOUT [static] |
The documentation for this class was generated from the following file: