def _handle_timeout(self):
"""Called by IOLoop when the requested timeout has passed."""
with stack_context.NullContext():
self._timeout = None
while True:
try:
ret, num_handles = self._multi.socket_action(
pycurl.SOCKET_TIMEOUT, 0)
except pycurl.error as e:
ret = e.args[0]
if ret != pycurl.E_CALL_MULTI_PERFORM:
break
self._finish_pending_requests()
# In theory, we shouldn't have to do this because curl will
# call _set_timeout whenever the timeout changes. However,
# sometimes after _handle_timeout we will need to reschedule
# immediately even though nothing has changed from curl's
# perspective. This is because when socket_action is
# called with SOCKET_TIMEOUT, libcurl decides internally which
# timeouts need to be processed by using a monotonic clock
# (where available) while tornado uses python's time.time()
# to decide when timeouts have occurred. When those clocks
# disagree on elapsed time (as they will whenever there is an
# NTP adjustment), tornado might call _handle_timeout before
# libcurl is ready. After each timeout, resync the scheduled
# timeout with libcurl's current state.
new_timeout = self._multi.timeout()
if new_timeout >= 0:
self._set_timeout(new_timeout)
def _process_queue(self):
with stack_context.NullContext():
while self.queue and len(self.active) < self.max_clients:
key, request, callback = self.queue.popleft()
if key not in self.waiting:
continue
self._remove_timeout(key)
self.active[key] = (request, callback)
release_callback = functools.partial(self._release_fetch, key)
self._handle_request(request, release_callback, callback)
def 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
"""
with stack_context.NullContext():
self.add_callback(callback, *args, **kwargs)
def _handle_force_timeout(self):
"""Called by IOLoop periodically to ask libcurl to process any
events it may have forgotten about.
"""
with stack_context.NullContext():
while True:
try:
ret, num_handles = self._multi.socket_all()
except pycurl.error as e:
ret = e.args[0]
if ret != pycurl.E_CALL_MULTI_PERFORM:
break
self._finish_pending_requests()
def _process_queue(self):
with stack_context.NullContext():
while True:
started = 0
while self._free_list and self._requests:
started += 1
curl = self._free_list.pop()
(request, callback,
queue_start_time) = self._requests.popleft()
curl.info = {
"headers": httputil.HTTPHeaders(),
"buffer": BytesIO(),
"request": request,
"callback": callback,
"queue_start_time": queue_start_time,
"curl_start_time": time.time(),
"curl_start_ioloop_time":
self.io_loop.current().time(),
}
try:
self._curl_setup_request(curl, request,
curl.info["buffer"],
curl.info["headers"])
except Exception as e:
# If there was an error in setup, pass it on
# to the callback. Note that allowing the
# error to escape here will appear to work
# most of the time since we are still in the
# caller's original stack frame, but when
# _process_queue() is called from
# _finish_pending_requests the exceptions have
# nowhere to go.
self._free_list.append(curl)
callback(
HTTPResponse(request=request, code=599, error=e))
else:
self._multi.add_handle(curl)
if not started:
break
def add_callback_from_signal(self, callback, *args, **kwargs):
with stack_context.NullContext():
self.add_callback(callback, *args, **kwargs)