def wrapper(*args, **kwargs):
# type: (*Any, **Any) -> Future[_T]
# This function is type-annotated with a comment to work around
# https://bitbucket.org/pypy/pypy/issues/2868/segfault-with-args-type-annotation-in
future = _create_future()
if contextvars is not None:
ctx_run = contextvars.copy_context().run # type: Callable
else:
ctx_run = _fake_ctx_run
try:
result = ctx_run(func, *args, **kwargs)
except (Return, StopIteration) as e:
result = _value_from_stopiteration(e)
except Exception:
future_set_exc_info(future, sys.exc_info())
try:
return future
finally:
# Avoid circular references
future = None # type: ignore
else:
if isinstance(result, Generator):
# Inline the first iteration of Runner.run. This lets us
# avoid the cost of creating a Runner when the coroutine
# never actually yields, which in turn allows us to
# use "optional" coroutines in critical path code without
# performance penalty for the synchronous case.
try:
yielded = ctx_run(next, result)
except (StopIteration, Return) as e:
future_set_result_unless_cancelled(
future, _value_from_stopiteration(e))
except Exception:
future_set_exc_info(future, sys.exc_info())
else:
# Provide strong references to Runner objects as long
# as their result future objects also have strong
# references (typically from the parent coroutine's
# Runner). This keeps the coroutine's Runner alive.
# We do this by exploiting the public API
# add_done_callback() instead of putting a private
# attribute on the Future.
# (GitHub issues #1769, #2229).
runner = Runner(ctx_run, result, future, yielded)
future.add_done_callback(lambda _: runner)
yielded = None
try:
return future
finally:
# Subtle memory optimization: if next() raised an exception,
# the future's exc_info contains a traceback which
# includes this stack frame. This creates a cycle,
# which will be collected at the next full GC but has
# been shown to greatly increase memory usage of
# benchmarks (relative to the refcount-based scheme
# used in the absence of cycles). We can avoid the
# cycle by clearing the local variable after we return it.
future = None # type: ignore
future_set_result_unless_cancelled(future, result)
return future
def callback(ret: int) -> None:
if ret != 0 and raise_error:
# Unfortunately we don't have the original args any more.
future_set_exception_unless_cancelled(
future, CalledProcessError(ret, "unknown"))
else:
future_set_result_unless_cancelled(future, ret)
def _finish_request(self, future: "Optional[Future[None]]") -> None:
self._clear_callbacks()
if not self.is_client and self._disconnect_on_finish:
self.close()
return
# Turn Nagle's algorithm back on, leaving the stream in its
# default state for the next request.
self.stream.set_nodelay(False)
if not self._finish_future.done():
future_set_result_unless_cancelled(self._finish_future, None)
def _on_connection_close(self) -> None:
# Note that this callback is only registered on the IOStream
# when we have finished reading the request and are waiting for
# the application to produce its response.
if self._close_callback is not None:
callback = self._close_callback
self._close_callback = None
callback()
if not self._finish_future.done():
future_set_result_unless_cancelled(self._finish_future, None)
self._clear_callbacks()
def notify(self, n: int = 1) -> None:
"""Wake ``n`` waiters."""
waiters = [] # Waiters we plan to run right now.
while n and self._waiters:
waiter = self._waiters.popleft()
if not waiter.done(): # Might have timed out.
n -= 1
waiters.append(waiter)
for waiter in waiters:
future_set_result_unless_cancelled(waiter, True)
def _on_write_complete(self, future: "Future[None]") -> None:
exc = future.exception()
if exc is not None and not isinstance(exc, iostream.StreamClosedError):
future.result()
if self._write_callback is not None:
callback = self._write_callback
self._write_callback = None
self.stream.io_loop.add_callback(callback)
if self._write_future is not None:
future = self._write_future
self._write_future = None
future_set_result_unless_cancelled(future, None)
def run(self) -> None:
"""Starts or resumes the generator, running until it reaches a
yield point that is not ready.
"""
if self.running or self.finished:
return
try:
self.running = True
while True:
future = self.future
if future is None:
raise Exception("No pending future")
if not future.done():
return
self.future = None
try:
exc_info = None
try:
value = future.result()
except Exception:
exc_info = sys.exc_info()
future = None
if exc_info is not None:
try:
yielded = self.gen.throw(*exc_info) # type: ignore
finally:
# Break up a reference to itself
# for faster GC on CPython.
exc_info = None
else:
yielded = self.gen.send(value)
except (StopIteration, Return) as e:
self.finished = True
self.future = _null_future
future_set_result_unless_cancelled(
self.result_future, _value_from_stopiteration(e)
)
self.result_future = None # type: ignore
return
except Exception:
self.finished = True
self.future = _null_future
future_set_exc_info(self.result_future, sys.exc_info())
self.result_future = None # type: ignore
return
if not self.handle_yield(yielded):
return
yielded = None
finally:
self.running = False
def detach(self) -> iostream.IOStream:
"""Take control of the underlying stream.
Returns the underlying `.IOStream` object and stops all further
HTTP processing. May only be called during
`.HTTPMessageDelegate.headers_received`. Intended for implementing
protocols like websockets that tunnel over an HTTP handshake.
"""
self._clear_callbacks()
stream = self.stream
self.stream = None # type: ignore
if not self._finish_future.done():
future_set_result_unless_cancelled(self._finish_future, None)
return stream
def put_nowait(self, item: _T) -> None:
"""Put an item into the queue without blocking.
If no free slot is immediately available, raise `QueueFull`.
"""
self._consume_expired()
if self._getters:
assert self.empty(), "queue non-empty, why are getters waiting?"
getter = self._getters.popleft()
self.__put_internal(item)
future_set_result_unless_cancelled(getter, self._get())
elif self.full():
raise QueueFull
else:
self.__put_internal(item)
def get_nowait(self) -> _T:
"""Remove and return an item from the queue without blocking.
Return an item if one is immediately available, else raise
`QueueEmpty`.
"""
self._consume_expired()
if self._putters:
assert self.full(), "queue not full, why are putters waiting?"
item, putter = self._putters.popleft()
self.__put_internal(item)
future_set_result_unless_cancelled(putter, None)
return self._get()
elif self.qsize():
return self._get()
else:
raise QueueEmpty
def callback(fut: Future) -> None:
unfinished_children.remove(fut)
if not unfinished_children:
result_list = []
for f in children_futs:
try:
result_list.append(f.result())
except Exception as e:
if future.done():
if not isinstance(e, quiet_exceptions):
app_log.error("Multiple exceptions in yield list",
exc_info=True)
else:
future_set_exc_info(future, sys.exc_info())
if not future.done():
if keys is not None:
future_set_result_unless_cancelled(
future, dict(zip(keys, result_list)))
else:
future_set_result_unless_cancelled(future, result_list)
def sleep(duration: float) -> "Future[None]":
"""Return a `.Future` that resolves after the given number of seconds.
When used with ``yield`` in a coroutine, this is a non-blocking
analogue to `time.sleep` (which should not be used in coroutines
because it is blocking)::
yield gen.sleep(0.5)
Note that calling this function on its own does nothing; you must
wait on the `.Future` it returns (usually by yielding it).
.. versionadded:: 4.1
"""
f = _create_future()
IOLoop.current().call_later(
duration, lambda: future_set_result_unless_cancelled(f, None))
return f
def close(self) -> None:
if self.stream is not None:
self.stream.close()
self._clear_callbacks()
if not self._finish_future.done():
future_set_result_unless_cancelled(self._finish_future, None)
def multi_future(
children: Union[List[_Yieldable], Dict[Any, _Yieldable]],
quiet_exceptions: "Union[Type[Exception], Tuple[Type[Exception], ...]]" = (),
) -> "Union[Future[List], Future[Dict]]":
"""Wait for multiple asynchronous futures in parallel.
Since Tornado 6.0, this function is exactly the same as `multi`.
.. versionadded:: 4.0
.. versionchanged:: 4.2
If multiple ``Futures`` fail, any exceptions after the first (which is
raised) will be logged. Added the ``quiet_exceptions``
argument to suppress this logging for selected exception types.
.. deprecated:: 4.3
Use `multi` instead.
"""
if isinstance(children, dict):
keys = list(children.keys()) # type: Optional[List]
children_seq = children.values() # type: Iterable
else:
keys = None
children_seq = children
children_futs = list(map(convert_yielded, children_seq))
assert all(is_future(i) or isinstance(i, _NullFuture) for i in children_futs)
unfinished_children = set(children_futs)
future = _create_future()
if not children_futs:
future_set_result_unless_cancelled(future, {} if keys is not None else [])
def callback(fut: Future) -> None:
unfinished_children.remove(fut)
if not unfinished_children:
result_list = []
for f in children_futs:
try:
result_list.append(f.result())
except Exception as e:
if future.done():
if not isinstance(e, quiet_exceptions):
app_log.error(
"Multiple exceptions in yield list", exc_info=True
)
else:
future_set_exc_info(future, sys.exc_info())
if not future.done():
if keys is not None:
future_set_result_unless_cancelled(
future, dict(zip(keys, result_list))
)
else:
future_set_result_unless_cancelled(future, result_list)
listening = set() # type: Set[Future]
for f in children_futs:
if f not in listening:
listening.add(f)
future_add_done_callback(f, callback)
return future
def on_timeout() -> None:
if not waiter.done():
future_set_result_unless_cancelled(waiter, False)
self._garbage_collect()
def handle_response(response: "HTTPResponse") -> None:
if response.error:
if raise_error or not response._error_is_response_code:
future_set_exception_unless_cancelled(future, response.error)
return
future_set_result_unless_cancelled(future, response)
