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Base implementation of event loop. The event loop can be broken up into a multiplexer (the part responsible for notifying us of I/O events) and the event loop proper, which wraps a multiplexer with functionality for scheduling callbacks, immediately or at a given time in the future. Whenever a public API takes a callback, subsequent positional arguments will be passed to the callback if/when it is called. This avoids the proliferation of trivial lambdas implementing closures. Keyword arguments for the callback are not supported; this is a conscious design decision, leaving the door open for keyword arguments to modify the meaning of the API call itself.
add_reader(self, fd, callback, *args)
add_signal_handler(self, sig, callback, *args)
add_writer(self, fd, callback, *args)
call_at(self, when, callback, *args, context=None)
Like call_later(), but uses an absolute time.
Absolute time corresponds to the event loop's time() method.
call_exception_handler(self, context)
Call the current event loop's exception handler.
The context argument is a dict containing the following keys:
- 'message': Error message;
- 'exception' (optional): Exception object;
- 'future' (optional): Future instance;
- 'task' (optional): Task instance;
- 'handle' (optional): Handle instance;
- 'protocol' (optional): Protocol instance;
- 'transport' (optional): Transport instance;
- 'socket' (optional): Socket instance;
- 'asyncgen' (optional): Asynchronous generator that caused
the exception.
New keys maybe introduced in the future.
Note: do not overload this method in an event loop subclass.
For custom exception handling, use the
`set_exception_handler()` method.
call_later(self, delay, callback, *args, context=None)
Arrange for a callback to be called at a given time.
Return a Handle: an opaque object with a cancel() method that
can be used to cancel the call.
The delay can be an int or float, expressed in seconds. It is
always relative to the current time.
Each callback will be called exactly once. If two callbacks
are scheduled for exactly the same time, it undefined which
will be called first.
Any positional arguments after the callback will be passed to
the callback when it is called.
call_soon(self, callback, *args, context=None)
Arrange for a callback to be called as soon as possible.
This operates as a FIFO queue: callbacks are called in the
order in which they are registered. Each callback will be
called exactly once.
Any positional arguments after the callback will be passed to
the callback when it is called.
call_soon_threadsafe(self, callback, *args, context=None) Like call_soon(), but thread-safe.
close(self)
Close the event loop.
This clears the queues and shuts down the executor,
but does not wait for the executor to finish.
The event loop must not be running.
connect_accepted_socket(self, protocol_factory, sock, *, ssl=None, ssl_handshake_timeout=None)
Handle an accepted connection.
This is used by servers that accept connections outside of
asyncio but that use asyncio to handle connections.
This method is a coroutine. When completed, the coroutine
returns a (transport, protocol) pair.
connect_read_pipe(self, protocol_factory, pipe)
connect_write_pipe(self, protocol_factory, pipe)
create_connection(self, protocol_factory, host=None, port=None, *, ssl=None, family=0, proto=0, flags=0, sock=None, local_addr=None, server_hostname=None, ssl_handshake_timeout=None, happy_eyeballs_delay=None, interleave=None)
Connect to a TCP server.
Create a streaming transport connection to a given Internet host and
port: socket family AF_INET or socket.AF_INET6 depending on host (or
family if specified), socket type SOCK_STREAM. protocol_factory must be
a callable returning a protocol instance.
This method is a coroutine which will try to establish the connection
in the background. When successful, the coroutine returns a
(transport, protocol) pair.
create_datagram_endpoint(self, protocol_factory, local_addr=None, remote_addr=None, *, family=0, proto=0, flags=0, reuse_address=<object object at 0x7f92bfcfeb40>, reuse_port=None, allow_broadcast=None, sock=None) Create datagram connection.
create_future(self) Create a Future object attached to the loop.
create_server(self, protocol_factory, host=None, port=None, *, family=<AddressFamily.AF_UNSPEC: 0>, flags=<AddressInfo.AI_PASSIVE: 1>, sock=None, backlog=100, ssl=None, reuse_address=None, reuse_port=None, ssl_handshake_timeout=None, start_serving=True)
Create a TCP server.
The host parameter can be a string, in that case the TCP server is
bound to host and port.
The host parameter can also be a sequence of strings and in that case
the TCP server is bound to all hosts of the sequence. If a host
appears multiple times (possibly indirectly e.g. when hostnames
resolve to the same IP address), the server is only bound once to that
host.
Return a Server object which can be used to stop the service.
This method is a coroutine.
create_task(self, coro, *, name=None)
Schedule a coroutine object.
Return a task object.
create_unix_connection(self, protocol_factory, path=None, *, ssl=None, sock=None, server_hostname=None, ssl_handshake_timeout=None)
create_unix_server(self, protocol_factory, path=None, *, sock=None, backlog=100, ssl=None, ssl_handshake_timeout=None, start_serving=True)
A coroutine which creates a UNIX Domain Socket server.
The return value is a Server object, which can be used to stop
the service.
path is a str, representing a file system path to bind the
server socket to.
sock can optionally be specified in order to use a preexisting
socket object.
backlog is the maximum number of queued connections passed to
listen() (defaults to 100).
ssl can be set to an SSLContext to enable SSL over the
accepted connections.
ssl_handshake_timeout is the time in seconds that an SSL server
will wait for the SSL handshake to complete (defaults to 60s).
start_serving set to True (default) causes the created server
to start accepting connections immediately. When set to False,
the user should await Server.start_serving() or Server.serve_forever()
to make the server to start accepting connections.
default_exception_handler(self, context)
Default exception handler.
This is called when an exception occurs and no exception
handler is set, and can be called by a custom exception
handler that wants to defer to the default behavior.
This default handler logs the error message and other
context-dependent information. In debug mode, a truncated
stack trace is also appended showing where the given object
(e.g. a handle or future or task) was created, if any.
The context parameter has the same meaning as in
`call_exception_handler()`.
get_debug(self)
get_exception_handler(self)
Return an exception handler, or None if the default one is in use.
get_task_factory(self) Return a task factory, or None if the default one is in use.
getaddrinfo(self, host, port, *, family=0, type=0, proto=0, flags=0)
getnameinfo(self, sockaddr, flags=0)
is_closed(self) Returns True if the event loop was closed.
is_running(self) Returns True if the event loop is running.
remove_reader(self, fd)
remove_signal_handler(self, sig)
remove_writer(self, fd)
run_forever(self) Run until stop() is called.
run_in_executor(self, executor, func, *args)
run_until_complete(self, future)
Run until the Future is done.
If the argument is a coroutine, it is wrapped in a Task.
WARNING: It would be disastrous to call run_until_complete()
with the same coroutine twice -- it would wrap it in two
different Tasks and that can't be good.
Return the Future's result, or raise its exception.
sendfile(self, transport, file, offset=0, count=None, *, fallback=True)
Send a file to transport.
Return the total number of bytes which were sent.
The method uses high-performance os.sendfile if available.
file must be a regular file object opened in binary mode.
offset tells from where to start reading the file. If specified,
count is the total number of bytes to transmit as opposed to
sending the file until EOF is reached. File position is updated on
return or also in case of error in which case file.tell()
can be used to figure out the number of bytes
which were sent.
fallback set to True makes asyncio to manually read and send
the file when the platform does not support the sendfile syscall
(e.g. Windows or SSL socket on Unix).
Raise SendfileNotAvailableError if the system does not support
sendfile syscall and fallback is False.
set_debug(self, enabled)
set_default_executor(self, executor)
set_exception_handler(self, handler)
Set handler as the new event loop exception handler.
If handler is None, the default exception handler will
be set.
If handler is a callable object, it should have a
signature matching '(loop, context)', where 'loop'
will be a reference to the active event loop, 'context'
will be a dict object (see `call_exception_handler()`
documentation for details about context).
set_task_factory(self, factory)
Set a task factory that will be used by loop.create_task().
If factory is None the default task factory will be set.
If factory is a callable, it should have a signature matching
'(loop, coro)', where 'loop' will be a reference to the active
event loop, 'coro' will be a coroutine object. The callable
must return a Future.
shutdown_asyncgens(self) Shutdown all active asynchronous generators.
shutdown_default_executor(self) Schedule the shutdown of the default executor.
sock_accept(self, sock)
sock_connect(self, sock, address)
sock_recv(self, sock, nbytes)
sock_recv_into(self, sock, buf)
sock_sendall(self, sock, data)
sock_sendfile(self, sock, file, offset=0, count=None, *, fallback=True)
start_tls(self, transport, protocol, sslcontext, *, server_side=False, server_hostname=None, ssl_handshake_timeout=None)
Upgrade transport to TLS.
Return a new transport that *protocol* should start using
immediately.
stop(self)
Stop running the event loop.
Every callback already scheduled will still run. This simply informs
run_forever to stop looping after a complete iteration.
subprocess_exec(self, protocol_factory, program, *args, stdin=-1, stdout=-1, stderr=-1, universal_newlines=False, shell=False, bufsize=0, encoding=None, errors=None, text=None, **kwargs)
subprocess_shell(self, protocol_factory, cmd, *, stdin=-1, stdout=-1, stderr=-1, universal_newlines=False, shell=True, bufsize=0, encoding=None, errors=None, text=None, **kwargs)
time(self)
Return the time according to the event loop's clock.
This is a float expressed in seconds since an epoch, but the
epoch, precision, accuracy and drift are unspecified and may
differ per event loop.
close(self)
get_loop(self)
is_serving(self)
serve_forever(self)
start_serving(self)
wait_closed(self)
sockets = <property object at 0x7f92bf3a1cc0>
MAXIMUM_SELECT_TIMEOUT = 86400
logger = <Logger asyncio (INFO)>