def async_call(self, *args, **kwargs):
"""Call the actual HTTP method asynchronously."""
content = self._check_authentication()
if content is not None:
self.finish(content)
return
# Authentication check passed, run the method in a thread
if PY2:
# On Python 2, the original exception stack trace is not passed from the executor.
# This is a workaround based on https://stackoverflow.com/a/27413025/7597273
tornado_future = TornadoFuture()
def wrapper():
try:
result = method(*args, **kwargs)
except: # noqa: E722 [do not use bare 'except']
tornado_future.set_exc_info(sys.exc_info())
else:
tornado_future.set_result(result)
# `executor.submit()` returns a `concurrent.futures.Future`; wait for it to finish, but ignore the result
yield executor.submit(wrapper)
# When this future is yielded, any stored exceptions are raised (with the correct stack trace).
content = yield tornado_future
else:
# On Python 3+, exceptions contain their original stack trace.
prepared = partial(method, *args, **kwargs)
content = yield IOLoop.current().run_in_executor(
executor, prepared)
self.finish(content)
def get_read_version(self, tr):
tornado_future = TornadoFuture()
callback = lambda fdb_future: self._handle_fdb_result(
fdb_future, tornado_future)
get_future = tr.get_read_version()
get_future.on_ready(callback)
return tornado_future
def get_range(self,
tr,
key_slice,
limit=0,
streaming_mode=fdb.StreamingMode.iterator,
iteration=1,
reverse=False,
snapshot=False):
tx_reader = tr
if snapshot:
tx_reader = tr.snapshot
begin = key_slice.start
if not isinstance(begin, fdb.KeySelector):
begin = fdb.KeySelector.first_greater_or_equal(begin)
end = key_slice.stop
if not isinstance(end, fdb.KeySelector):
end = fdb.KeySelector.first_greater_or_equal(end)
tornado_future = TornadoFuture()
callback = lambda fdb_future: self._handle_fdb_result(
fdb_future, tornado_future)
get_future = tx_reader._get_range(begin, end, limit, streaming_mode,
iteration, reverse)
get_future.on_ready(callback)
return tornado_future
def get(self, tr, key, snapshot=False):
tx_reader = tr
if snapshot:
tx_reader = tr.snapshot
tornado_future = TornadoFuture()
callback = lambda fdb_future: self._handle_fdb_result(
fdb_future, tornado_future)
get_future = tx_reader.get(key)
get_future.on_ready(callback)
return tornado_future
def commit(self, tr, convert_exceptions=True):
tornado_future = TornadoFuture()
callback = lambda fdb_future: self._handle_fdb_result(
fdb_future, tornado_future)
commit_future = tr.commit()
commit_future.on_ready(callback)
try:
yield tornado_future
except fdb.FDBError as fdb_error:
if convert_exceptions:
raise InternalError(fdb_error.description)
else:
raise
def test_await_future(self):
f = Future()
tf = TornadoFuture()
def finish_later():
time.sleep(0.1)
f.set_result('future')
tf.set_result('tornado')
Thread(target=finish_later).start()
assert self.client.wait([f, tf])
assert f.done()
assert tf.done()
assert f.result() == 'future'
assert tf.result() == 'tornado'
def maybe_future(obj):
"""Like tornado's gen.maybe_future
but more compatible with asyncio for recent versions
of tornado
"""
if isinstance(obj, TornadoFuture):
return obj
elif isawaitable(obj):
return asyncio.ensure_future(obj)
elif isinstance(obj, ConcurrentFuture):
return asyncio.wrap_future(obj)
else:
# not awaitable, wrap scalar in future
f = TornadoFuture()
f.set_result(obj)
return f
def execute(self, query, parameters=None, *args, **kwargs):
""" Runs a Cassandra query asynchronously.
Returns:
A Tornado future.
"""
tornado_future = TornadoFuture()
io_loop = IOLoop.current()
cassandra_future = self._session.execute_async(query, parameters,
*args, **kwargs)
cassandra_future.add_callbacks(self._handle_page,
self._handle_failure,
callback_args=(io_loop, tornado_future,
cassandra_future),
errback_args=(io_loop, tornado_future,
query))
return tornado_future
def execute(self, query, parameters=None, *args, **kwargs):
""" Runs a Cassandra query asynchronously.
Returns:
A Tornado future.
"""
tornado_future = TornadoFuture()
io_loop = IOLoop.current()
cassandra_future = self._session.execute_async(query, parameters,
*args, **kwargs)
# This list is passed around in order to collect each page of results.
results = []
cassandra_future.add_callbacks(
self._handle_page,
self._handle_failure,
callback_args=(io_loop, tornado_future, cassandra_future, results),
errback_args=(io_loop, tornado_future, query))
return tornado_future