Since Python 3.3, the C signal handler writes the signal number into the wakeup
file descriptor and then schedules the Python call using Py_AddPendingCall().
asyncio uses the wakeup file descriptor to wake up the event loop, and relies
on Py_AddPendingCall() to schedule the final callback with call_soon().
If the C signal handler is called in a thread different than the thread of the
event loop, the loop is awaken but Py_AddPendingCall() was not called yet. In
this case, the event loop has nothing to do and go to sleep again.
Py_AddPendingCall() is called while the event loop is sleeping again and so the
final callback is not scheduled immediatly.
This patch changes how asyncio handles signals. Instead of relying on
Py_AddPendingCall() and the wakeup file descriptor, asyncio now only relies on
the wakeup file descriptor. asyncio reads signal numbers from the wakeup file
descriptor to call its signal handler.
If you want to handle the BrokenPipeError, you can easily reimplement
communicate().
Add also a unit test to ensure that stdin.write() + stdin.drain() raises
BrokenPipeError.
* Tulip issue #184: Log subprocess events in debug mode
- Log stdin, stdout and stderr transports and protocols
- Log process identifier (pid)
- Log connection of pipes
- Log process exit
- Log Process.communicate() tasks: feed stdin, read stdout and stderr
- Add __repr__() method to many classes related to subprocesses
* Add BaseSubprocessTransport._pid attribute. Store the pid so it is still
accessible after the process exited. It's more convinient for debug.
* create_connection(): add the socket in the "connected to" debug log
* Clean up some docstrings and comments. Remove unused unimplemented
_read_from_self().
* Tulip issue #183: log socket events in debug mode
- Log most important socket events: socket connected, new client, connection
reset or closed by peer (EOF), etc.
- Log time elapsed in DNS resolution (getaddrinfo)
- Log pause/resume reading
- Log time of SSL handshake
- Log SSL handshake errors
- Add a __repr__() method to many classes
* Fix ProactorEventLoop() in debug mode. ProactorEventLoop._make_self_pipe()
doesn't call call_soon() directly because it checks for the current loop
which fails, because the method is called to build the event loop.
* Cleanup _ProactorReadPipeTransport constructor. Not need to set again
_read_fut attribute to None, it is already done in the base class.
- loop, waiters and active_count attributes are now private
- attach(), detach() and wakeup() methods are now private
The sockets attribute remains public.
* Tulip issue #182: Improve logs of BaseEventLoop._run_once()
- Don't log non-blocking poll
- Only log polling with a timeout if it gets events or if it timed out after
more than 1 second.
* Fix some pyflakes warnings: remove unused imports
- CoroWrapper.__del__() now reuses repr(CoroWrapper) to log the "... was never
yielded from" warning
- Improve CoroWrapper: copy also the qualified name on Python 3.4, not only on
Python 3.5+
- repr(Task) and repr(CoroWrapper) now also includes where these objects were
created. If the coroutine is not a generator (don't use "yield from"), use
the location of the function, not the location of the coro() wrapper.
- Fix create_task(): truncate the traceback to hide the call to create_task().
- Issues #21936, #21163: Fix sporadic failures of
test_future_exception_never_retrieved()
- Handle.cancel() now clears references to callback and args
- In debug mode, repr(Handle) now contains the location where the Handle was
created.
- Tulip issue 185: Add a create_task() method to event loops. The create_task()
method can be overriden in custom event loop to implement their own task
class. For example, greenio and Pulsar projects use their own task class. The
create_task() method is now preferred over creating directly task using the
Task class.
- tests: fix a warning
- fix typo in the name of a test function
- Update AbstractEventLoop: add new event loop methods; update also the unit test
- Tulip issue #181: Faster create_connection(). Call directly
waiter.set_result() in the constructor of _ProactorBasePipeTransport and
_SelectorSocketTransport, instead of using of delaying the call with
call_soon().
- Cleanup iscoroutine()
* _UnixSubprocessTransport: fix file mode of stdin. Open stdin in write mode,
not in read mode
* Examples: close the event loop at exit
* More reliable CoroWrapper.__del__. If the constructor is interrupted by
KeyboardInterrupt or the coroutine objet is destroyed lately, some the
_source_traceback attribute doesn't exist anymore.
* repr(Task): include also the future the task is waiting for
- Sort imports
- Simplify/optimize iscoroutine(). Inline inspect.isgenerator(obj): replace it
with isinstance(obj, types.GeneratorType)
- CoroWrapper: check at runtime if Python has the yield-from bug #21209. If
Python has the bug, check if CoroWrapper.send() was called by yield-from to
decide if parameters must be unpacked or not.
- Fix "Task was destroyed but it is pending!" warning in
test_task_source_traceback()
Handle objects are created. Pass the traceback to call_exception_handler() in
the 'source_traceback' key.
The traceback is truncated to hide internal calls in asyncio, show only the
traceback from user code.
Add tests for the new source_traceback, and a test for the 'Future/Task
exception was never retrieved' log.
done: use the first line number of the code object instead of the current line
number of the generator frame.
The name of the coroutine is not enough because many coroutines may have the
same name. It's a common case in asyncio tests for example.
exception if the current loop is not None.
Guido van Rossum wrote:
"The behavior that you can set the loop to None (and keep track of it
explicitly) is part of the spec, and this should still be supported even in
debug mode. The behavior that we raise an error if you are caught having
multiple active loops per thread is just a debugging heuristic, and it
shouldn't break code that follows the spec."
available bytes from the "self pipe", not only a single byte. This change
reduces the risk of having the pipe full and so getting the innocuous
"BlockingIOError: [Errno 11] Resource temporarily unavailable" message.
Python 3.5
- Drop __slots__ optimization of CoroWrapper to be able to set the __qualname__
attribute.
- Add tests on __name__, __qualname__ and __module__ of a coroutine function
and coroutine object.
- Fix test_tasks when run in debug mode (PYTHONASYNCIODEBUG env var set) on
Python 3.3 or 3.4
repr(Handle) is shorter for function: "foo" instead of "<function foo at
0x...>". It now also includes the source of the callback, filename and line
number where it was defined, if available.
repr(Task) now also includes the current position in the code, filename and
line number, if available. If the coroutine (generator) is done, the line
number is omitted and "done" is added.
Add BaseEventLoop._closed attribute and use it to check if the event loop was
closed or not, instead of checking different attributes in each subclass of
BaseEventLoop.
run_forever() and run_until_complete() methods now raise a RuntimeError('Event loop is
closed') exception if the event loop was closed.
BaseProactorEventLoop.close() now also cancels "accept futures".
Victor Stinner