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import asyncio
import signal
import ssl
from functools import wraps
import txaio
from autobahn.asyncio.rawsocket import WampRawSocketClientFactory
from autobahn.asyncio.util import get_or_create_event_loop
from autobahn.asyncio.wamp import Session
from autobahn.asyncio.websocket import WampWebSocketClientFactory
from autobahn.wamp import component
from autobahn.wamp.exception import TransportLost
from autobahn.wamp.serializer import (
create_transport_serializer,
create_transport_serializers,
)
__all__ = ("Component", "run")
def _camel_case_from_snake_case(snake):
parts = snake.split("_")
return parts[0] + "".join(s.capitalize() for s in parts[1:])
def _create_transport_factory(loop, transport, session_factory):
"""
Create a WAMP-over-XXX transport factory.
"""
if transport.type == "websocket":
serializers = create_transport_serializers(transport)
factory = WampWebSocketClientFactory(
session_factory,
url=transport.url,
serializers=serializers,
proxy=transport.proxy, # either None or a dict with host, port
)
elif transport.type == "rawsocket":
serializer = create_transport_serializer(transport.serializers[0])
factory = WampRawSocketClientFactory(session_factory, serializer=serializer)
else:
assert False, "should not arrive here"
# set the options one at a time so we can give user better feedback
for k, v in transport.options.items():
try:
factory.setProtocolOptions(**{k: v})
except (TypeError, KeyError):
# this allows us to document options as snake_case
# until everything internally is upgraded from
# camelCase
try:
factory.setProtocolOptions(**{_camel_case_from_snake_case(k): v})
except (TypeError, KeyError):
raise ValueError(
f"Unknown {transport.type} transport option: {k}={v}"
)
return factory
[docs]
class Component(component.Component):
"""
A component establishes a transport and attached a session
to a realm using the transport for communication.
The transports a component tries to use can be configured,
as well as the auto-reconnect strategy.
"""
[docs]
log = txaio.make_logger()
[docs]
session_factory = Session
"""
The factory of the session we will instantiate.
"""
[docs]
def _is_ssl_error(self, e):
"""
Internal helper.
"""
return isinstance(e, ssl.SSLError)
[docs]
def _check_native_endpoint(self, endpoint):
if isinstance(endpoint, dict):
if "tls" in endpoint:
tls = endpoint["tls"]
if isinstance(tls, dict | bool):
pass
elif isinstance(tls, ssl.SSLContext):
pass
else:
raise ValueError(
"'tls' configuration must be a dict, bool or "
"SSLContext instance"
)
else:
raise ValueError(
"'endpoint' configuration must be a dict or IStreamClientEndpoint"
" provider"
)
# async function
[docs]
def _connect_transport(self, loop, transport, session_factory, done):
"""
Create and connect a WAMP-over-XXX transport.
"""
factory = _create_transport_factory(loop, transport, session_factory)
# XXX the rest of this should probably be factored into its
# own method (or three!)...
if transport.proxy:
timeout = transport.endpoint.get("timeout", 10) # in seconds
if type(timeout) != int:
raise ValueError(
f"invalid type {type(timeout)} for timeout in client endpoint configuration"
)
# do we support HTTPS proxies?
f = loop.create_connection(
protocol_factory=factory,
host=transport.proxy["host"],
port=transport.proxy["port"],
)
time_f = asyncio.ensure_future(asyncio.wait_for(f, timeout=timeout))
return self._wrap_connection_future(transport, done, time_f)
elif transport.endpoint["type"] == "tcp":
version = transport.endpoint.get("version", 4)
if version not in [4, 6]:
raise ValueError(
f"invalid IP version {version} in client endpoint configuration"
)
host = transport.endpoint["host"]
if type(host) != str:
raise ValueError(
f"invalid type {type(host)} for host in client endpoint configuration"
)
port = transport.endpoint["port"]
if type(port) != int:
raise ValueError(
f"invalid type {type(port)} for port in client endpoint configuration"
)
timeout = transport.endpoint.get("timeout", 10) # in seconds
if type(timeout) != int:
raise ValueError(
f"invalid type {type(timeout)} for timeout in client endpoint configuration"
)
tls = transport.endpoint.get("tls", None)
tls_hostname = None
# create a TLS enabled connecting TCP socket
if tls:
if isinstance(tls, dict):
for k in tls.keys():
if k not in ["hostname", "trust_root"]:
raise ValueError(
f"Invalid key '{k}' in 'tls' config"
)
hostname = tls.get("hostname", host)
if type(hostname) != str:
raise ValueError(
f"invalid type {hostname} for hostname in TLS client endpoint configuration"
)
cert_fname = tls.get("trust_root", None)
tls_hostname = hostname
tls = True
if cert_fname is not None:
tls = ssl.create_default_context(
purpose=ssl.Purpose.SERVER_AUTH,
cafile=cert_fname,
)
elif isinstance(tls, ssl.SSLContext):
# tls=<an SSLContext> is valid
tls_hostname = host
elif tls in [False, True]:
if tls:
tls_hostname = host
else:
raise RuntimeError(
f'unknown type {type(tls)} for "tls" configuration in transport'
)
f = loop.create_connection(
protocol_factory=factory,
host=host,
port=port,
ssl=tls,
server_hostname=tls_hostname,
)
time_f = asyncio.ensure_future(asyncio.wait_for(f, timeout=timeout))
return self._wrap_connection_future(transport, done, time_f)
elif transport.endpoint["type"] == "unix":
path = transport.endpoint["path"]
timeout = int(transport.endpoint.get("timeout", 10)) # in seconds
f = loop.create_unix_connection(
protocol_factory=factory,
path=path,
)
time_f = asyncio.ensure_future(asyncio.wait_for(f, timeout=timeout))
return self._wrap_connection_future(transport, done, time_f)
else:
assert False, "should not arrive here"
[docs]
def _wrap_connection_future(self, transport, done, conn_f):
def on_connect_success(result):
# async connect call returns a 2-tuple
transport, proto = result
# in the case where we .abort() the transport / connection
# during setup, we still get on_connect_success but our
# transport is already closed (this will happen if
# e.g. there's an "open handshake timeout") -- I don't
# know if there's a "better" way to detect this? #python
# doesn't know of one, anyway
if transport.is_closing():
if not txaio.is_called(done):
reason = getattr(
proto, "_onclose_reason", "Connection already closed"
)
txaio.reject(done, TransportLost(reason))
return
# if e.g. an SSL handshake fails, we will have
# successfully connected (i.e. get here) but need to
# 'listen' for the "connection_lost" from the underlying
# protocol in case of handshake failure .. so we wrap
# it. Also, we don't increment transport.success_count
# here on purpose (because we might not succeed).
# XXX double-check that asyncio behavior on TLS handshake
# failures is in fact as described above
orig = proto.connection_lost
@wraps(orig)
def lost(fail):
rtn = orig(fail)
if not txaio.is_called(done):
# asyncio will call connection_lost(None) in case of
# a transport failure, in which case we create an
# appropriate exception
if fail is None:
fail = TransportLost("failed to complete connection")
txaio.reject(done, fail)
return rtn
proto.connection_lost = lost
def on_connect_failure(err):
transport.connect_failures += 1
# failed to establish a connection in the first place
txaio.reject(done, err)
txaio.add_callbacks(conn_f, on_connect_success, None)
# the errback is added as a second step so it gets called if
# there as an error in on_connect_success itself.
txaio.add_callbacks(conn_f, None, on_connect_failure)
return conn_f
# async function
[docs]
def start(self, loop=None):
"""
This starts the Component, which means it will start connecting
(and re-connecting) to its configured transports. A Component
runs until it is "done", which means one of:
- There was a "main" function defined, and it completed successfully;
- Something called ``.leave()`` on our session, and we left successfully;
- ``.stop()`` was called, and completed successfully;
- none of our transports were able to connect successfully (failure);
:returns: a Future which will resolve (to ``None``) when we are
"done" or with an error if something went wrong.
"""
if loop is None:
self.log.warn("Using default loop")
loop = get_or_create_event_loop()
return self._start(loop=loop)
[docs]
def run(components, start_loop=True, log_level="info"):
"""
High-level API to run a series of components.
This will only return once all the components have stopped
(including, possibly, after all re-connections have failed if you
have re-connections enabled). Under the hood, this calls
XXX fixme for asyncio
-- if you wish to manage the loop yourself, use the
:meth:`autobahn.asyncio.component.Component.start` method to start
each component yourself.
:param components: the Component(s) you wish to run
:type components: instance or list of :class:`autobahn.asyncio.component.Component`
:param start_loop: When ``True`` (the default) this method
start a new asyncio loop.
:type start_loop: bool
:param log_level: a valid log-level (or None to avoid calling start_logging)
:type log_level: string
"""
# actually, should we even let people "not start" the logging? I'm
# not sure that's wise... (double-check: if they already called
# txaio.start_logging() what happens if we call it again?)
if log_level is not None:
txaio.start_logging(level=log_level)
# No event loop may exist yet: CPython 3.14 no longer creates one implicitly (#1952,
# first fixed here inline by #1953; the same handling everywhere since #1965).
loop = get_or_create_event_loop()
txaio.config.loop = loop
log = txaio.make_logger()
# see https://github.com/python/asyncio/issues/341 asyncio has
# "odd" handling of KeyboardInterrupt when using Tasks (as
# run_until_complete does). Another option is to just resture
# default SIGINT handling, which is to exit:
# import signal
# signal.signal(signal.SIGINT, signal.SIG_DFL)
async def nicely_exit(signal):
log.info("Shutting down due to {signal}", signal=signal)
try:
tasks = asyncio.Task.all_tasks()
except AttributeError:
# this changed with python >= 3.7
tasks = asyncio.all_tasks()
for task in tasks:
# Do not cancel the current task.
try:
current_task = asyncio.Task.current_task()
except AttributeError:
current_task = asyncio.current_task()
if task is not current_task:
task.cancel()
def cancel_all_callback(fut):
try:
fut.result()
except asyncio.CancelledError:
log.debug("All task cancelled")
except Exception as e:
log.error("Error while shutting down: {exception}", exception=e)
finally:
loop.stop()
fut = asyncio.gather(*tasks)
fut.add_done_callback(cancel_all_callback)
try:
loop.add_signal_handler(
signal.SIGINT, lambda: asyncio.ensure_future(nicely_exit("SIGINT"))
)
loop.add_signal_handler(
signal.SIGTERM, lambda: asyncio.ensure_future(nicely_exit("SIGTERM"))
)
except NotImplementedError:
# signals are not available on Windows
pass
def done_callback(loop, arg):
loop.stop()
# returns a future; could run_until_complete() but see below
component._run(loop, components, done_callback)
if start_loop:
try:
loop.run_forever()
# this is probably more-correct, but then you always get
# "Event loop stopped before Future completed":
# loop.run_until_complete(f)
except asyncio.CancelledError:
pass
# finally:
# signal.signal(signal.SIGINT, signal.SIG_DFL)
# signal.signal(signal.SIGTERM, signal.SIG_DFL)
# Close the event loop at the end, otherwise an exception is
# thrown. https://bugs.python.org/issue23548
loop.close()