def convert_yielded(yielded):
"""Convert a yielded object into a `.Future`.
The default implementation accepts lists, dictionaries, and Futures.
If the `~functools.singledispatch` library is available, this function
may be extended to support additional types. For example::
@convert_yielded.register(asyncio.Future)
def _(asyncio_future):
return tornado.platform.asyncio.to_tornado_future(asyncio_future)
.. versionadded:: 4.1
"""
# Lists and dicts containing YieldPoints were handled earlier.
if yielded is None:
return moment
elif isinstance(yielded, (list, dict)):
return multi(yielded)
elif is_future(yielded):
return yielded
elif isawaitable(yielded):
return _wrap_awaitable(yielded)
else:
raise BadYieldError("yielded unknown object %r" % (yielded,))
def multi_future(children, quiet_exceptions=()):
"""Wait for multiple asynchronous futures in parallel.
This function is similar to `multi`, but does not support
`YieldPoints <YieldPoint>`.
.. 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())
children = children.values()
else:
keys = None
children = list(map(convert_yielded, children))
assert all(is_future(i) for i in children)
unfinished_children = set(children)
future = Future()
if not children:
future.set_result({} if keys is not None else [])
def callback(f):
unfinished_children.remove(f)
if not unfinished_children:
result_list = []
for f in children:
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(sys.exc_info())
if not future.done():
if keys is not None:
future.set_result(dict(zip(keys, result_list)))
else:
future.set_result(result_list)
listening = set()
for f in children:
if f not in listening:
listening.add(f)
f.add_done_callback(callback)
return future
def add_future(self, future, callback):
"""Schedules a callback on the ``IOLoop`` when the given
`.Future` is finished.
The callback is invoked with one argument, the
`.Future`.
"""
assert is_future(future)
callback = stack_context.wrap(callback)
future.add_done_callback(
lambda future: self.add_callback(callback, future))
def __init__(self, children, quiet_exceptions=()):
self.keys = None
if isinstance(children, dict):
self.keys = list(children.keys())
children = children.values()
self.children = []
for i in children:
if not isinstance(i, YieldPoint):
i = convert_yielded(i)
if is_future(i):
i = YieldFuture(i)
self.children.append(i)
assert all(isinstance(i, YieldPoint) for i in self.children)
self.unfinished_children = set(self.children)
self.quiet_exceptions = quiet_exceptions
def run():
try:
result = func()
if result is not None:
from salt.ext.tornado.gen import convert_yielded
result = convert_yielded(result)
except Exception:
future_cell[0] = TracebackFuture()
future_cell[0].set_exc_info(sys.exc_info())
else:
if is_future(result):
future_cell[0] = result
else:
future_cell[0] = TracebackFuture()
future_cell[0].set_result(result)
self.add_future(future_cell[0], lambda future: self.stop())
def maybe_future(x):
"""Converts ``x`` into a `.Future`.
If ``x`` is already a `.Future`, it is simply returned; otherwise
it is wrapped in a new `.Future`. This is suitable for use as
``result = yield gen.maybe_future(f())`` when you don't know whether
``f()`` returns a `.Future` or not.
.. deprecated:: 4.3
This function only handles ``Futures``, not other yieldable objects.
Instead of `maybe_future`, check for the non-future result types
you expect (often just ``None``), and ``yield`` anything unknown.
"""
if is_future(x):
return x
else:
fut = Future()
fut.set_result(x)
return fut