def chain_future(a, b):
"""Chain two futures together so that when one completes, so does the other.
The result (success or failure) of ``a`` will be copied to ``b``, unless
``b`` has already been completed or cancelled by the time ``a`` finishes.
.. versionchanged:: 5.0
Now accepts both Tornado/asyncio `Future` objects and
`concurrent.futures.Future`.
"""
def copy(future):
assert future is a
if b.done():
return
if (hasattr(a, 'exc_info') and
a.exc_info() is not None):
future_set_exc_info(b, a.exc_info())
elif a.exception() is not None:
b.set_exception(a.exception())
else:
b.set_result(a.result())
if isinstance(a, Future):
future_add_done_callback(a, copy)
else:
# concurrent.futures.Future
from tornado_py2.ioloop import IOLoop
IOLoop.current().add_future(a, copy)
def wrapper(self, *args, **kwargs):
callback = kwargs.pop("callback", None)
async_future = Future()
conc_future = getattr(self, executor).submit(fn, self, *args, **kwargs)
chain_future(conc_future, async_future)
if callback:
warnings.warn("callback arguments are deprecated, use the returned Future instead",
DeprecationWarning)
from tornado_py2.ioloop import IOLoop
IOLoop.current().add_future(
async_future, lambda future: callback(future.result()))
return async_future
def add_done_callback(self, fn):
"""Attaches the given callback to the `Future`.
It will be invoked with the `Future` as its argument when the Future
has finished running and its result is available. In Tornado
consider using `.IOLoop.add_future` instead of calling
`add_done_callback` directly.
"""
if self._done:
from tornado_py2.ioloop import IOLoop
IOLoop.current().add_callback(fn, self)
else:
self._callbacks.append(fn)
def add_accept_handler(sock, callback):
"""Adds an `.IOLoop` event handler to accept new connections on ``sock``.
When a connection is accepted, ``callback(connection, address)`` will
be run (``connection`` is a socket object, and ``address`` is the
address of the other end of the connection). Note that this signature
is different from the ``callback(fd, events)`` signature used for
`.IOLoop` handlers.
A callable is returned which, when called, will remove the `.IOLoop`
event handler and stop processing further incoming connections.
.. versionchanged:: 5.0
The ``io_loop`` argument (deprecated since version 4.1) has been removed.
.. versionchanged:: 5.0
A callable is returned (``None`` was returned before).
"""
io_loop = IOLoop.current()
removed = [False]
def accept_handler(fd, events):
# More connections may come in while we're handling callbacks;
# to prevent starvation of other tasks we must limit the number
# of connections we accept at a time. Ideally we would accept
# up to the number of connections that were waiting when we
# entered this method, but this information is not available
# (and rearranging this method to call accept() as many times
# as possible before running any callbacks would have adverse
# effects on load balancing in multiprocess configurations).
# Instead, we use the (default) listen backlog as a rough
# heuristic for the number of connections we can reasonably
# accept at once.
for i in xrange(_DEFAULT_BACKLOG):
if removed[0]:
# The socket was probably closed
return
try:
connection, address = sock.accept()
except socket.error as e:
# _ERRNO_WOULDBLOCK indicate we have accepted every
# connection that is available.
if errno_from_exception(e) in _ERRNO_WOULDBLOCK:
return
# ECONNABORTED indicates that there was a connection
# but it was closed while still in the accept queue.
# (observed on FreeBSD).
if errno_from_exception(e) == errno.ECONNABORTED:
continue
raise
set_close_exec(connection.fileno())
callback(connection, address)
def remove_handler():
io_loop.remove_handler(sock)
removed[0] = True
io_loop.add_handler(sock, accept_handler, IOLoop.READ)
return remove_handler
def _set_done(self):
self._done = True
if self._callbacks:
from tornado_py2.ioloop import IOLoop
loop = IOLoop.current()
for cb in self._callbacks:
loop.add_callback(cb, self)
self._callbacks = None
def initialize(self, executor=None, close_executor=True):
self.io_loop = IOLoop.current()
if executor is not None:
self.executor = executor
self.close_executor = close_executor
else:
self.executor = dummy_executor
self.close_executor = False
def _handle_connection(self, connection, address):
if self.ssl_options is not None:
assert ssl, "Python 2.6+ and OpenSSL required for SSL"
try:
connection = ssl_wrap_socket(connection,
self.ssl_options,
server_side=True,
do_handshake_on_connect=False)
except ssl.SSLError as err:
if err.args[0] == ssl.SSL_ERROR_EOF:
return connection.close()
else:
raise
except socket.error as err:
# If the connection is closed immediately after it is created
# (as in a port scan), we can get one of several errors.
# wrap_socket makes an internal call to getpeername,
# which may return either EINVAL (Mac OS X) or ENOTCONN
# (Linux). If it returns ENOTCONN, this error is
# silently swallowed by the ssl module, so we need to
# catch another error later on (AttributeError in
# SSLIOStream._do_ssl_handshake).
# To test this behavior, try nmap with the -sT flag.
# https://github.com/tornadoweb/tornado/pull/750
if errno_from_exception(err) in (errno.ECONNABORTED,
errno.EINVAL):
return connection.close()
else:
raise
try:
if self.ssl_options is not None:
stream = SSLIOStream(connection,
max_buffer_size=self.max_buffer_size,
read_chunk_size=self.read_chunk_size)
else:
stream = IOStream(connection,
max_buffer_size=self.max_buffer_size,
read_chunk_size=self.read_chunk_size)
future = self.handle_stream(stream, address)
if future is not None:
IOLoop.current().add_future(gen.convert_yielded(future),
lambda f: f.result())
except Exception:
app_log.error("Error in connection callback", exc_info=True)
def sleep(duration):
"""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 start(self):
old_current = IOLoop.current(instance=False)
try:
self._setup_logging()
self.make_current()
self.reactor.run()
finally:
if old_current is None:
IOLoop.clear_current()
else:
old_current.make_current()
def __init__(self, addrinfo, connect):
self.io_loop = IOLoop.current()
self.connect = connect
self.future = Future()
self.timeout = None
self.connect_timeout = None
self.last_error = None
self.remaining = len(addrinfo)
self.primary_addrs, self.secondary_addrs = self.split(addrinfo)
self.streams = set()
def __init__(self, client, request, release_callback, final_callback,
max_buffer_size, tcp_client, max_header_size, max_body_size):
self.io_loop = IOLoop.current()
self.start_time = self.io_loop.time()
self.start_wall_time = time.time()
self.client = client
self.request = request
self.release_callback = release_callback
self.final_callback = final_callback
self.max_buffer_size = max_buffer_size
self.tcp_client = tcp_client
self.max_header_size = max_header_size
self.max_body_size = max_body_size
self.code = None
self.headers = None
self.chunks = []
self._decompressor = None
# Timeout handle returned by IOLoop.add_timeout
self._timeout = None
self._sockaddr = None
IOLoop.current().add_callback(self.run)
def __init__(self, future):
"""Adapts a `.Future` to the `YieldPoint` interface.
.. versionchanged:: 5.0
The ``io_loop`` argument (deprecated since version 4.1) has been removed.
.. deprecated:: 5.1
This class will be removed in 6.0.
"""
warnings.warn("YieldFuture is deprecated, use Futures instead",
DeprecationWarning)
self.future = future
self.io_loop = IOLoop.current()
def __new__(cls, force_instance=False, **kwargs):
io_loop = IOLoop.current()
if force_instance:
instance_cache = None
else:
instance_cache = cls._async_clients()
if instance_cache is not None and io_loop in instance_cache:
return instance_cache[io_loop]
instance = super(AsyncHTTPClient, cls).__new__(cls, **kwargs)
# Make sure the instance knows which cache to remove itself from.
# It can't simply call _async_clients() because we may be in
# __new__(AsyncHTTPClient) but instance.__class__ may be
# SimpleAsyncHTTPClient.
instance._instance_cache = instance_cache
if instance_cache is not None:
instance_cache[instance.io_loop] = instance
return instance
def __init__(self, gen, result_future, first_yielded):
self.gen = gen
self.result_future = result_future
self.future = _null_future
self.yield_point = None
self.pending_callbacks = None
self.results = None
self.running = False
self.finished = False
self.had_exception = False
self.io_loop = IOLoop.current()
# For efficiency, we do not create a stack context until we
# reach a YieldPoint (stack contexts are required for the historical
# semantics of YieldPoints, but not for Futures). When we have
# done so, this field will be set and must be called at the end
# of the coroutine.
self.stack_context_deactivate = None
if self.handle_yield(first_yielded):
gen = result_future = first_yielded = None
self.run()
def connect(self,
host,
port,
af=socket.AF_UNSPEC,
ssl_options=None,
max_buffer_size=None,
source_ip=None,
source_port=None,
timeout=None):
"""Connect to the given host and port.
Asynchronously returns an `.IOStream` (or `.SSLIOStream` if
``ssl_options`` is not None).
Using the ``source_ip`` kwarg, one can specify the source
IP address to use when establishing the connection.
In case the user needs to resolve and
use a specific interface, it has to be handled outside
of Tornado as this depends very much on the platform.
Raises `TimeoutError` if the input future does not complete before
``timeout``, which may be specified in any form allowed by
`.IOLoop.add_timeout` (i.e. a `datetime.timedelta` or an absolute time
relative to `.IOLoop.time`)
Similarly, when the user requires a certain source port, it can
be specified using the ``source_port`` arg.
.. versionchanged:: 4.5
Added the ``source_ip`` and ``source_port`` arguments.
.. versionchanged:: 5.0
Added the ``timeout`` argument.
"""
if timeout is not None:
if isinstance(timeout, numbers.Real):
timeout = IOLoop.current().time() + timeout
elif isinstance(timeout, datetime.timedelta):
timeout = IOLoop.current().time() + timedelta_to_seconds(
timeout)
else:
raise TypeError("Unsupported timeout %r" % timeout)
if timeout is not None:
addrinfo = yield gen.with_timeout(
timeout, self.resolver.resolve(host, port, af))
else:
addrinfo = yield self.resolver.resolve(host, port, af)
connector = _Connector(
addrinfo,
functools.partial(self._create_stream,
max_buffer_size,
source_ip=source_ip,
source_port=source_port))
af, addr, stream = yield connector.start(connect_timeout=timeout)
# TODO: For better performance we could cache the (af, addr)
# information here and re-use it on subsequent connections to
# the same host. (http://tools.ietf.org/html/rfc6555#section-4.2)
if ssl_options is not None:
if timeout is not None:
stream = yield gen.with_timeout(
timeout,
stream.start_tls(False,
ssl_options=ssl_options,
server_hostname=host))
else:
stream = yield stream.start_tls(False,
ssl_options=ssl_options,
server_hostname=host)
raise gen.Return(stream)
def initialize(self):
self.io_loop = IOLoop.current()
self.channel = pycares.Channel(sock_state_cb=self._sock_state_cb)
self.fds = {}
def resolve(self, host, port, family=socket.AF_UNSPEC):
result = yield IOLoop.current().run_in_executor(
None, _resolve_addr, host, port, family)
raise gen.Return(result)
def wrapper(*args, **kwargs):
future = _create_future()
if replace_callback and 'callback' in kwargs:
warnings.warn(
"callback arguments are deprecated, use the returned Future instead",
DeprecationWarning,
stacklevel=2)
callback = kwargs.pop('callback')
IOLoop.current().add_future(
future, lambda future: callback(future.result()))
try:
result = 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
else:
if isinstance(result, GeneratorType):
# 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:
orig_stack_contexts = stack_context._state.contexts
yielded = next(result)
if stack_context._state.contexts is not orig_stack_contexts:
yielded = _create_future()
yielded.set_exception(
stack_context.StackContextInconsistentError(
'stack_context inconsistency (probably caused '
'by yield within a "with StackContext" block)')
)
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(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
future_set_result_unless_cancelled(future, result)
return future
def with_timeout(timeout, future, quiet_exceptions=()):
"""Wraps a `.Future` (or other yieldable object) in a timeout.
Raises `tornado.util.TimeoutError` if the input future does not
complete before ``timeout``, which may be specified in any form
allowed by `.IOLoop.add_timeout` (i.e. a `datetime.timedelta` or
an absolute time relative to `.IOLoop.time`)
If the wrapped `.Future` fails after it has timed out, the exception
will be logged unless it is of a type contained in ``quiet_exceptions``
(which may be an exception type or a sequence of types).
Does not support `YieldPoint` subclasses.
The wrapped `.Future` is not canceled when the timeout expires,
permitting it to be reused. `asyncio.wait_for` is similar to this
function but it does cancel the wrapped `.Future` on timeout.
.. versionadded:: 4.0
.. versionchanged:: 4.1
Added the ``quiet_exceptions`` argument and the logging of unhandled
exceptions.
.. versionchanged:: 4.4
Added support for yieldable objects other than `.Future`.
"""
# TODO: allow YieldPoints in addition to other yieldables?
# Tricky to do with stack_context semantics.
#
# It's tempting to optimize this by cancelling the input future on timeout
# instead of creating a new one, but A) we can't know if we are the only
# one waiting on the input future, so cancelling it might disrupt other
# callers and B) concurrent futures can only be cancelled while they are
# in the queue, so cancellation cannot reliably bound our waiting time.
future = convert_yielded(future)
result = _create_future()
chain_future(future, result)
io_loop = IOLoop.current()
def error_callback(future):
try:
future.result()
except Exception as e:
if not isinstance(e, quiet_exceptions):
app_log.error("Exception in Future %r after timeout",
future,
exc_info=True)
def timeout_callback():
if not result.done():
result.set_exception(TimeoutError("Timeout"))
# In case the wrapped future goes on to fail, log it.
future_add_done_callback(future, error_callback)
timeout_handle = io_loop.add_timeout(timeout, timeout_callback)
if isinstance(future, Future):
# We know this future will resolve on the IOLoop, so we don't
# need the extra thread-safety of IOLoop.add_future (and we also
# don't care about StackContext here.
future_add_done_callback(
future, lambda future: io_loop.remove_timeout(timeout_handle))
else:
# concurrent.futures.Futures may resolve on any thread, so we
# need to route them back to the IOLoop.
io_loop.add_future(
future, lambda future: io_loop.remove_timeout(timeout_handle))
return result
def initialize(self, defaults=None):
self.io_loop = IOLoop.current()
self.defaults = dict(HTTPRequest._DEFAULTS)
if defaults is not None:
self.defaults.update(defaults)
self._closed = False