Issue #24763: Fix resource warnings when asyncio.BaseSubprocessTransport
constructor fails, if subprocess.Popen raises an exception for example.
Patch written by Martin Richard, test written by me.
* Fix ResourceWarning warnings in test_streams
* Return True from StreamReader.eof_received() to fix
http://bugs.python.org/issue24539 (but still needs a unittest).
Add StreamReader.__repr__() for easy debugging.
* remove unused imports
* Issue #234: Drop JoinableQueue on Python 3.5+
Previous approach of installing coroutine wrapper in loop.set_debug() and
uninstalling it in loop.close() was very fragile. Most of asyncio tests
do not call loop.close() at all. Since coroutine wrapper is a global
setting, we have to make sure that it's only set when the loop is
running, and is automatically unset when it stops running.
Issue #24017.
again if the first call to connect() raises an InterruptedError.
When the C function connect() fails with EINTR, the connection runs in
background. We have to wait until the socket becomes writable to be notified
when the connection succeed or fails.
Merge JoinableQueue with Queue. To more closely match the standard Queue,
asyncio.Queue has "join" and "task_done". JoinableQueue is deleted.
Docstring for Queue.join shouldn't mention threads.
Restore JoinableQueue as a deprecated alias for Queue. To more closely match
the standard Queue, asyncio.Queue has "join" and "task_done". JoinableQueue
remains as a deprecated alias for Queue to avoid needlessly breaking too much
code that depended on it.
Patch written by A. Jesse Jiryu Davis <jesse@mongodb.com>.
* _check_resolved_address() is implemented with getaddrinfo() which is slow
* If available, use socket.inet_pton() instead of socket.getaddrinfo(), because
it is much faster
Microbenchmark (timeit) on Fedora 21 (Python 3.4, Linux 3.17, glibc 2.20) to
validate the IPV4 address "127.0.0.1" or the IPv6 address "::1":
* getaddrinfo() 10.4 usec per loop
* inet_pton(): 0.285 usec per loop
On glibc older than 2.14, getaddrinfo() always requests the list of all local
IP addresses to the kernel (using a NETLINK socket). getaddrinfo() has other
known issues, it's better to avoid it when it is possible.
transport was closed. The check broken a Tulip example and this limitation is
arbitrary. Check if _proc is None should be enough.
Enhance also close(): do nothing when called the second time.
Issue #23347: send_signal(), kill() and terminate() methods of
BaseSubprocessTransport now check if the transport was closed and if the
process exited.
Issue #23347: Refactor creation of subprocess transports. Changes on
BaseSubprocessTransport:
* Add a wait() method to wait until the child process exit
* The constructor now accepts an optional waiter parameter. The _post_init()
coroutine must not be called explicitly anymore. It makes subprocess
transports closer to other transports, and it gives more freedom if we want
later to change completly how subprocess transports are created.
* close() now kills the process instead of kindly terminate it: the child
process may ignore SIGTERM and continue to run. Call explicitly terminate()
and wait() if you want to kindly terminate the child process.
* close() now logs a warning in debug mode if the process is still running and
needs to be killed
* _make_subprocess_transport() is now fully asynchronous again: if the creation
of the transport failed, wait asynchronously for the process eixt. Before the
wait was synchronous. This change requires close() to *kill*, and not
terminate, the child process.
* Remove the _kill_wait() method, replaced with a more agressive close()
method. It fixes _make_subprocess_transport() on error.
BaseSubprocessTransport.close() calls the close() method of pipe transports,
whereas _kill_wait() closed directly pipes of the subprocess.Popen object
without unregistering file descriptors from the selector (which caused severe
bugs).
These changes simplifies the code of subprocess.py.
* Cleanup gather(): use cancelled() method instead of using private Future
attribute
* Fix _UnixReadPipeTransport and _UnixWritePipeTransport. Only start reading
when connection_made() has been called.
* Issue #23333: Fix BaseSelectorEventLoop._accept_connection(). Close the
transport on error. In debug mode, log errors using call_exception_handler()
* _SelectorTransport constructor: extra parameter is now optional
* Fix _SelectorDatagramTransport constructor. Only start reading after
connection_made() has been called.
* Fix _SelectorSslTransport.close(). Don't call protocol.connection_lost() if
protocol.connection_made() was not called yet: if the SSL handshake failed or
is still in progress. The close() method can be called if the creation of the
connection is cancelled, by a timeout for example.
* Rephrase also the comment explaining why the waiter is not awaken immediatly.
* SSLProtocol.eof_received() doesn't instanciate ConnectionResetError exception
directly, it will be done by Future.set_exception(). The exception is not
used if the waiter was cancelled or if there is no waiter.
* Remove unused SSLProtocol._closing attribute
* test_sslproto: skip test if ssl module is missing
* Python issue #23208: Don't use the traceback of the current handle if we
already know the traceback of the source. The handle may be more revelant,
but having 3 tracebacks (handle, source, exception) becomes more difficult to
read. The handle may be preferred later but it requires more work to make
this choice.
If ReadFile() fails with ERROR_BROKEN_PIPE, the operation is not pending: don't
register the overlapped.
I don't know if WSARecv() can fail with ERROR_BROKEN_PIPE. Since
Overlapped.WSARecv() already handled ERROR_BROKEN_PIPE, let me guess that it
has the same behaviour than ReadFile().
If UnregisterWaitEx() fais with ERROR_IO_PENDING, it doesn't mean that the wait
is unregistered yet. We still have to wait until the wait is cancelled.
Use a coroutine with asyncio.sleep() instead of call_later() to ensure that the
schedule call is cancelled.
Add also a unit test cancelling connect_pipe().
In debug mode, BaseEventLoop._run_once() now sets the
BaseEventLoop._current_handle attribute to the handle currently executed.
In release mode or when no handle is executed, the attribute is None.
BaseEventLoop.default_exception_handler() displays the traceback of the current
handle if available.
Overlapped.ConnectNamedPipe() now returns a boolean: True if the pipe is
connected (if ConnectNamedPipe() failed with ERROR_PIPE_CONNECTED), False if
the connection is in progress.
This change removes multiple hacks in IocpProactor.
Add _overlapped.ConnectPipe() which tries to connect to the pipe for
asynchronous I/O (overlapped): call CreateFile() in a loop until it doesn't
fail with ERROR_PIPE_BUSY. Use an increasing delay between 1 ms and 100 ms.
Remove Overlapped.WaitNamedPipeAndConnect() which is no more used.
This change fixes a race conditon related to _WaitHandleFuture.cancel() leading
to Python crash or "GetQueuedCompletionStatus() returned an unexpected event"
logs. Before, the overlapped object was destroyed too early, it was possible
that the wait completed whereas the overlapped object was already destroyed.
Sometimes, a different overlapped was allocated at the same address, leading to
unexpected completition.
_WaitHandleFuture.cancel() now waits until the wait is cancelled to clear its
reference to the overlapped object. To wait until the cancellation is done,
UnregisterWaitEx() is used with an event instead of UnregisterWait().
To wait for this event, a new _WaitCancelFuture class was added. It's a
simplified version of _WaitCancelFuture. For example, its cancel() method calls
UnregisterWait(), not UnregisterWaitEx(). _WaitCancelFuture should not be
cancelled.
The overlapped object is kept alive in _WaitHandleFuture until the wait is
unregistered.
Other changes:
* Add _overlapped.UnregisterWaitEx()
* Remove fast-path in IocpProactor.wait_for_handle() to immediatly set the
result if the wait already completed. I'm not sure that it's safe to
call immediatly UnregisterWaitEx() before the completion was signaled.
* Add IocpProactor._unregistered() to forget an overlapped which may never be
signaled, but may be signaled for the next loop iteration. It avoids to
block forever IocpProactor.close() if a wait was cancelled, and it may also
avoid some "... unexpected event ..." warnings.
* Handle correctly CancelledError: just exit
* On error, log the exception and exit
Don't try to close the event loop, it is probably running and so it cannot be
closed.
StreamWriter: close() now clears the reference to the transport
StreamWriter now raises an exception if it is closed: write(), writelines(),
write_eof(), can_write_eof(), get_extra_info(), drain().
Don't call immediatly self._process_write_backlog() but schedule the call using
call_soon(). _on_handshake_complete() can be called indirectly from
_process_write_backlog(), and _process_write_backlog() is not reentrant.
* PipeHandle now uses None instead of -1 for a closed handle
* Sort imports in windows_utils.
* Fix test_events on Python older than 3.5. Skip SSL tests on the
ProactorEventLoop if ssl.MemoryIO is missing
* Fix BaseEventLoop._create_connection_transport(). Close the transport if the
creation of the transport (if the waiter) gets an exception.
* _ProactorBasePipeTransport now sets _sock to None when the transport is
closed.
* Fix BaseSubprocessTransport.close(). Ignore pipes for which the protocol is
not set yet (still equal to None).
* TestLoop.close() now calls the close() method of the parent class
(BaseEventLoop).
* Cleanup BaseSelectorEventLoop: create the protocol on a separated line for
readability and ease debugging.
* Fix BaseSubprocessTransport._kill_wait(). Set the _returncode attribute, so
close() doesn't try to terminate the process.
* Tests: explicitly close event loops and transports
* UNIX pipe transports: add closed/closing in repr(). Add "closed" or "closing"
state in the __repr__() method of _UnixReadPipeTransport and
_UnixWritePipeTransport classes.
* If an exception is raised during the creation of a subprocess, kill the
subprocess (close pipes, kill and read the return status). Log an error in
such case.
* Fix SubprocessStreamProtocol.connection_made() to handle cancelled waiter.
Add unit test cancelling subprocess methods.
- Add a new _wakeup_waiter() method
- Replace _create_waiter() method with a _wait_for_data() coroutine function
- Use the value None instead of True or False to wake up the waiter
The new SSL implementation is based on the new ssl.MemoryBIO which is only
available on Python 3.5. On Python 3.4 and older, the legacy SSL implementation
(using SSL_write, SSL_read, etc.) is used. The proactor event loop only
supports the new implementation.
The new asyncio.sslproto module adds _SSLPipe, SSLProtocol and
_SSLProtocolTransport classes. _SSLPipe allows to "wrap" or "unwrap" a socket
(switch between cleartext and SSL/TLS).
Patch written by Antoine Pitrou. sslproto.py is based on gruvi/ssl.py of the
gruvi project written by Geert Jansen.
This change adds SSL support to ProactorEventLoop on Python 3.5 and newer!
It becomes also possible to implement STARTTTLS: switch a cleartext socket to
SSL.
Close the IocpProactor before closing the event loop. IocpProactor.close() can
call loop.call_soon(), which is forbidden when the event loop is closed.
* Tulip issue 184: FlowControlMixin constructor now get the event loop if the
loop parameter is not set. Add unit tests to ensure that constructor of
StreamReader and StreamReaderProtocol classes get the event loop.
* Remove outdated TODO/XXX
* Document why set_result() calls are safe
* Cleanup gather(). Use public methods instead of hacks to consume the
exception of a future.
* sock_connect(): pass directly the fd to _sock_connect_done instead of the
socket.
asyncio.BaseEventLoop now use the identifier of the current thread to ensure
that they are called from the thread running the event loop.
Before, the get_event_loop() method was used to check the thread, and no
exception was raised when the thread had no event loop. Now the methods always
raise an exception in debug mode when called from the wrong thread. It should
help to notice misusage of the API.
* Fix a race condition in BaseSubprocessTransport._try_finish().
If the process exited before the _post_init() method was called, scheduling
the call to _call_connection_lost() with call_soon() is wrong:
connection_made() must be called before connection_lost().
Reuse the BaseSubprocessTransport._call() method to schedule the call to
_call_connection_lost() to ensure that connection_made() and
connection_lost() are called in the correct order.
* Add repr(PipeHandle)
* Fix typo
written by Torsten Landschoff.
create_task(), call_at(), call_soon(), call_soon_threadsafe() and
run_in_executor() now raise an error if the event loop is closed.
functions:
* add_signal_handler()
* call_at()
* call_later()
* call_soon()
* call_soon_threadsafe()
* run_in_executor()
Fix also the error message of add_signal_handler() (fix the name of the
function).
Move the _loop attribute from the constructor of _SelectorTransport,
_ProactorBasePipeTransport and _UnixWritePipeTransport classes to the
constructor of the _FlowControlMixin class.
Add also an assertion to explicit that the parent class must ensure that the
loop is defined (not None)
available
Since Python 3.5, socket.socketpair() is now also available on Windows.
Make csock blocking before calling the accept() method, and fix also a typo in
an error message.
There is a race condition in create_connection() used with wait_for() to have a
timeout. sock_connect() registers the file descriptor of the socket to be
notified of write event (if connect() raises BlockingIOError). When
create_connection() is cancelled with a TimeoutError, sock_connect() coroutine
gets the exception, but it doesn't unregister the file descriptor for write
event. create_connection() gets the TimeoutError and closes the socket.
If you call again create_connection(), the new socket will likely gets the same
file descriptor, which is still registered in the selector. When sock_connect()
calls add_writer(), it tries to modify the entry instead of creating a new one.
This issue was originally reported in the Trollius project, but the bug comes
from Tulip in fact (Trollius is based on Tulip):
https://bitbucket.org/enovance/trollius/issue/15/after-timeouterror-on-wait_for
This change fixes the race condition. It also makes sock_connect() more
reliable (and portable) is sock.connect() raises an InterruptedError.
Don't raise a TimeoutError if we reached the timeout and the future completed
in the same iteration of the event loop. A side effect of the bug is that
Queue.get() looses items.
* PipeServer.close() now cancels the "accept pipe" future which cancels the
overlapped operation.
* Fix _SelectorTransport.__repr__() if the transport was closed
* Fix debug log in BaseEventLoop.create_connection(): get the socket object
from the transport because SSL transport closes the old socket and creates a
new SSL socket object. Remove also the _SelectorSslTransport._rawsock
attribute: it contained the closed socket (not very useful) and it was not
used.
* Issue #22063: socket operations (sock_recv, sock_sendall, sock_connect,
sock_accept) of the proactor event loop don't raise an exception in debug
mode if the socket are in blocking mode. Overlapped operations also work on
blocking sockets.
* Fix unit tests in debug mode: mock a non-blocking socket for socket
operations which now raise an exception if the socket is blocking.
* _fatal_error() method of _UnixReadPipeTransport and _UnixWritePipeTransport
now log all exceptions in debug mode
* Don't log expected errors in unit tests
* Tulip issue 200: _WaitHandleFuture._unregister_wait() now catchs and logs
exceptions.
* Tulip issue 200: Log errors in debug mode instead of simply ignoring them.
* _WaitHandleFuture.cancel() now notify IocpProactor through the overlapped
object that the wait was cancelled.
* Optimize IocpProactor.wait_for_handle() gets the result if the wait is
signaled immediatly.
* Enhance representation of Future and Future subclasses
- Add "created at filename:lineno" in the representation
- Add Future._repr_info() method which can be more easily overriden than
Future.__repr__(). It should now be more easy to enhance Future
representation without having to modify each subclass. For example,
_OverlappedFuture and _WaitHandleFuture get the new "created at" information.
- Use reprlib to format Future result, and function arguments when formatting a
callback, to limit the length of the representation.
* Fix repr(_WaitHandleFuture)
* _WaitHandleFuture and _OverlappedFuture: hide frames of internal calls in the
source traceback.
* Cleanup ProactorIocp._poll(): set the timeout to 0 after the first call to
GetQueuedCompletionStatus()
* test_locks: close the temporary event loop and check the condition lock
* Remove workaround in test_futures, no more needed
in the _cache dictionary, even if we already got the result. We need to keep a
reference to the overlapped object, otherwise the memory may be reused and
GetQueuedCompletionStatus() may use random bytes and behaves badly.
There is still a hack for ConnectNamedPipe(): the overlapped object is not
register into _cache if the overlapped object completed directly.
Log also an error in debug mode in ProactorIocp._loop() if we get an unexpected
event.
Add a protection in ProactorIocp.close() to avoid blocking, even if it should
not happen. I still don't understand exactly why some the completion of some
overlapped objects are not notified.
* Tulip issue #196: IocpProactor._poll() clears the reference to the
overlapped operation when the operation is done. It would be better to clear
the reference in a new _OverlappedFuture.set_result() method, but it cannot
be done yet because of a weird bug.
* BaseSelectorEventLoop._write_to_self() now logs errors in debug mode.
* Fix _WaitHandleFuture.cancel(): return the result of the parent cancel()
method.
* _OverlappedFuture.cancel() now clears its reference to the overlapped object.
Make also the _OverlappedFuture.ov attribute private.
* Check if _WaitHandleFuture completed before unregistering it in the callback.
Add also _WaitHandleFuture._poll() and repr(_WaitHandleFuture).
* _WaitHandleFuture now unregisters its wait handler if WaitForSingleObject()
raises an exception.
* _OverlappedFuture.set_exception() now cancels the overlapped operation.
Improve stability of the proactor event loop, especially operations on
overlapped objects:
* Tulip issue 195: Don't call UnregisterWait() twice if a _WaitHandleFuture is
cancelled twice to fix a crash.
* IocpProactor.close(): cancel futures to cancel overlapped operations, instead
of cancelling directly overlapped operations. Future objects may not call
ov.cancel() if the future was cancelled or if the overlapped was already
cancelled. The cancel() method of the future may also catch exceptions. Log
also errors on cancellation.
* tests: rename "f" to "fut"
* Add a __repr__() method to IocpProactor
* Add a destructor to IocpProactor which closes it
* _OverlappedFuture.cancel() doesn't cancel the overlapped anymore if it is
done: if it is already cancelled or completed. Log also an error if the
cancellation failed.
* Add the address of the overlapped object in repr(_OverlappedFuture)
* _OverlappedFuture truncates the source traceback to hide the call to the
parent constructor (useless in debug).
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".
Fix ResourceWarning: create_connection(), create_datagram_endpoint() and
create_unix_server() methods of event loop now close the newly created socket
on error.
loop in debug mode. Raise a RuntimeError if the event loop of the current
thread is different. The check should help to debug thread-safetly issue.
Patch written by David Foster.
* Issue #159: Fix windows_utils.socketpair()
- Use "127.0.0.1" (IPv4) or "::1" (IPv6) host instead of "localhost", because
"localhost" may be a different IP address
- Reject also invalid arguments: only AF_INET/AF_INET6 with SOCK_STREAM (and
proto=0) are supported
* Reject add/remove reader/writer when event loop is closed.
* Fix ResourceWarning warnings
Add also a PYTHONASYNCIODEBUG environment variable to debug coroutines since
Python startup, to be able to debug coroutines defined directly in the asyncio
module.
* Add a new asyncio.subprocess module
* Add new create_subprocess_exec() and create_subprocess_shell() functions
* The new asyncio.subprocess.SubprocessStreamProtocol creates stream readers
for stdout and stderr and a stream writer for stdin.
* The new asyncio.subprocess.Process class offers an API close to the
subprocess.Popen class:
- pid, returncode, stdin, stdout and stderr attributes
- communicate(), wait(), send_signal(), terminate() and kill() methods
* Remove STDIN (0), STDOUT (1) and STDERR (2) constants from base_subprocess
and unix_events, to not be confused with the symbols with the same name of
subprocess and asyncio.subprocess modules
* _ProactorBasePipeTransport.get_write_buffer_size() now counts also the size
of the pending write
* _ProactorBaseWritePipeTransport._loop_writing() may now pause the protocol if
the write buffer size is greater than the high water mark (64 KB by default)
Windows) instead of using the "duplex" pipe transport. The new class uses a
simpler overlapped read to be notified when the pipe is closed. So the protocol
doesn't need to implement eof_received(): connection_lost() is called instead.
_UnixWritePipeTransport has the same approach.
Yury Selivanov
Victor Stinner
Guido van Rossum
Serhiy Storchaka
Benjamin Peterson
Antoine Pitrou
R David Murray
Andrew Svetlov