###############################################################################
#
# The MIT License (MIT)
#
# Copyright (c) Crossbar.io Technologies GmbH
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
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#
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
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###############################################################################
import itertools
import random
from functools import partial
import txaio
from autobahn.util import ObservableMixin
from autobahn.websocket.util import parse_url as parse_ws_url
from autobahn.rawsocket.util import parse_url as parse_rs_url
from autobahn.wamp.types import ComponentConfig, SubscribeOptions, RegisterOptions
from autobahn.wamp.exception import SessionNotReady, ApplicationError
from autobahn.wamp.auth import create_authenticator, IAuthenticator
from autobahn.wamp.serializer import SERID_TO_SER
__all__ = (
'Component'
)
def _validate_endpoint(endpoint, check_native_endpoint=None):
"""
Check a WAMP connecting endpoint configuration.
"""
if check_native_endpoint:
check_native_endpoint(endpoint)
elif not isinstance(endpoint, dict):
raise ValueError(
"'endpoint' must be a dict"
)
# note, we're falling through here -- check_native_endpoint can
# disallow or allow dict-based config as it likes, but if it
# *does* allow a dict through, we want to check "base options"
# here so that both Twisted and asyncio don't have to check these
# things as well.
if isinstance(endpoint, dict):
# XXX what about filling in anything missing from the URL? Or
# is that only for when *nothing* is provided for endpoint?
if 'type' not in endpoint:
# could maybe just make tcp the default?
raise ValueError("'type' required in endpoint configuration")
if endpoint['type'] not in ['tcp', 'unix']:
raise ValueError('invalid type "{}" in endpoint'.format(endpoint['type']))
for k in endpoint.keys():
if k not in ['type', 'host', 'port', 'path', 'tls', 'timeout', 'version']:
raise ValueError(
"Invalid key '{}' in endpoint configuration".format(k)
)
if endpoint['type'] == 'tcp':
for k in ['host', 'port']:
if k not in endpoint:
raise ValueError(
"'{}' required in 'tcp' endpoint config".format(k)
)
for k in ['path']:
if k in endpoint:
raise ValueError(
"'{}' not valid in 'tcp' endpoint config".format(k)
)
elif endpoint['type'] == 'unix':
for k in ['path']:
if k not in endpoint:
raise ValueError(
"'{}' required for 'unix' endpoint config".format(k)
)
for k in ['host', 'port', 'tls']:
if k in endpoint:
raise ValueError(
"'{}' not valid in 'unix' endpoint config".format(k)
)
else:
assert False, 'should not arrive here'
def _create_transport(index, transport, check_native_endpoint=None):
"""
Internal helper to insert defaults and create _Transport instances.
:param transport: a (possibly valid) transport configuration
:type transport: dict
:returns: a _Transport instance
:raises: ValueError on invalid configuration
"""
if type(transport) != dict:
raise ValueError('invalid type {} for transport configuration - must be a dict'.format(type(transport)))
valid_transport_keys = [
'type', 'url', 'endpoint', 'serializer', 'serializers', 'options',
'max_retries', 'max_retry_delay', 'initial_retry_delay',
'retry_delay_growth', 'retry_delay_jitter', 'proxy',
]
for k in transport.keys():
if k not in valid_transport_keys:
raise ValueError(
"'{}' is not a valid configuration item".format(k)
)
kind = 'websocket'
if 'type' in transport:
if transport['type'] not in ['websocket', 'rawsocket']:
raise ValueError('Invalid transport type {}'.format(transport['type']))
kind = transport['type']
else:
transport['type'] = 'websocket'
if 'proxy' in transport and kind != 'websocket':
raise ValueError(
"proxy= only supported for type=websocket transports"
)
proxy = transport.get("proxy", None)
if proxy is not None:
for k in proxy.keys():
if k not in ['host', 'port']:
raise ValueError(
"Unknown key '{}' in proxy config".format(k)
)
for k in ['host', 'port']:
if k not in proxy:
raise ValueError(
"Proxy config requires '{}'".formaT(k)
)
options = dict()
if 'options' in transport:
options = transport['options']
if not isinstance(options, dict):
raise ValueError(
'options must be a dict, not {}'.format(type(options))
)
if kind == 'websocket':
for key in ['url']:
if key not in transport:
raise ValueError("Transport requires '{}' key".format(key))
# endpoint not required; we will deduce from URL if it's not provided
# XXX not in the branch I rebased; can this go away? (is it redundant??)
if 'endpoint' not in transport:
is_secure, host, port, resource, path, params = parse_ws_url(transport['url'])
endpoint_config = {
'type': 'tcp',
'host': host,
'port': port,
'tls': is_secure,
}
else:
# note: we're avoiding mutating the incoming "configuration"
# dict, so this should avoid that too...
endpoint_config = transport['endpoint']
_validate_endpoint(endpoint_config, check_native_endpoint)
if 'serializer' in transport:
raise ValueError("'serializer' is only for rawsocket; use 'serializers'")
if 'serializers' in transport:
if not isinstance(transport['serializers'], (list, tuple)):
raise ValueError("'serializers' must be a list of strings")
if not all([
isinstance(s, (str, str))
for s in transport['serializers']]):
raise ValueError("'serializers' must be a list of strings")
valid_serializers = SERID_TO_SER.keys()
for serial in transport['serializers']:
if serial not in valid_serializers:
raise ValueError(
"Invalid serializer '{}' (expected one of: {})".format(
serial,
', '.join([repr(s) for s in valid_serializers]),
)
)
serializer_config = transport.get('serializers', ['cbor', 'json'])
elif kind == 'rawsocket':
if 'endpoint' not in transport:
if transport['url'].startswith('rs'):
# # try to parse RawSocket URL ..
isSecure, host, port = parse_rs_url(transport['url'])
elif transport['url'].startswith('ws'):
# try to parse WebSocket URL ..
isSecure, host, port, resource, path, params = parse_ws_url(transport['url'])
else:
raise RuntimeError()
if host == 'unix':
# here, "port" is actually holding the path on the host, eg "/tmp/file.sock"
endpoint_config = {
'type': 'unix',
'path': port,
}
else:
endpoint_config = {
'type': 'tcp',
'host': host,
'port': port,
}
else:
endpoint_config = transport['endpoint']
if 'serializers' in transport:
raise ValueError("'serializers' is only for websocket; use 'serializer'")
# always a list; len == 1 for rawsocket
if 'serializer' in transport:
if not isinstance(transport['serializer'], (str, str)):
raise ValueError("'serializer' must be a string")
serializer_config = [transport['serializer']]
else:
serializer_config = ['cbor']
else:
assert False, 'should not arrive here'
kw = {}
for key in ['max_retries', 'max_retry_delay', 'initial_retry_delay',
'retry_delay_growth', 'retry_delay_jitter']:
if key in transport:
kw[key] = transport[key]
return _Transport(
index,
kind=kind,
url=transport.get('url', None),
endpoint=endpoint_config,
serializers=serializer_config,
proxy=proxy,
options=options,
**kw
)
class _Transport(object):
"""
Thin-wrapper for WAMP transports used by a Connection.
"""
def __init__(self, idx, kind, url, endpoint, serializers,
max_retries=-1,
max_retry_delay=300,
initial_retry_delay=1.5,
retry_delay_growth=1.5,
retry_delay_jitter=0.1,
proxy=None,
options=None):
"""
"""
if options is None:
options = dict()
self.idx = idx
self.type = kind
self.url = url
self.endpoint = endpoint
self.options = options
self.serializers = serializers
if self.type == 'rawsocket' and len(serializers) != 1:
raise ValueError(
"'rawsocket' transport requires exactly one serializer"
)
self.max_retries = max_retries
self.max_retry_delay = max_retry_delay
self.initial_retry_delay = initial_retry_delay
self.retry_delay_growth = retry_delay_growth
self.retry_delay_jitter = retry_delay_jitter
self.proxy = proxy # this is a dict of proxy config
# used via can_reconnect() and failed() to record this
# transport is never going to work
self._permanent_failure = False
self.reset()
def reset(self):
"""
set connection failure rates and retry-delay to initial values
"""
self.connect_attempts = 0
self.connect_sucesses = 0
self.connect_failures = 0
self.retry_delay = self.initial_retry_delay
def failed(self):
"""
Mark this transport as failed, meaning we won't try to connect to
it any longer (that is: can_reconnect() will always return
False afer calling this).
"""
self._permanent_failure = True
def can_reconnect(self):
if self._permanent_failure:
return False
if self.max_retries == -1:
return True
return self.connect_attempts < self.max_retries + 1
def next_delay(self):
if self.connect_attempts == 0:
# if we never tried before, try immediately
return 0
elif self.max_retries != -1 and self.connect_attempts >= self.max_retries + 1:
raise RuntimeError('max reconnects reached')
else:
self.retry_delay = self.retry_delay * self.retry_delay_growth
self.retry_delay = random.normalvariate(self.retry_delay, self.retry_delay * self.retry_delay_jitter)
if self.retry_delay > self.max_retry_delay:
self.retry_delay = self.max_retry_delay
return self.retry_delay
def describe_endpoint(self):
"""
returns a human-readable description of the endpoint
"""
if isinstance(self.endpoint, dict):
return self.endpoint['type']
return repr(self.endpoint)
# this could probably implement twisted.application.service.IService
# if we wanted; or via an adapter...which just adds a startService()
# and stopService() [latter can be async]
[docs]class Component(ObservableMixin):
"""
A WAMP application component. A component holds configuration for
(and knows how to create) transports and sessions.
"""
session_factory = None
"""
The factory of the session we will instantiate.
"""
[docs] def subscribe(self, topic, options=None, check_types=False):
"""
A decorator as a shortcut for subscribing during on-join
For example::
@component.subscribe(
"some.topic",
options=SubscribeOptions(match='prefix'),
)
def topic(*args, **kw):
print("some.topic({}, {}): event received".format(args, kw))
"""
assert options is None or isinstance(options, SubscribeOptions)
def decorator(fn):
def do_subscription(session, details):
return session.subscribe(fn, topic=topic, options=options, check_types=check_types)
self.on('join', do_subscription)
return fn
return decorator
[docs] def register(self, uri, options=None, check_types=False):
"""
A decorator as a shortcut for registering during on-join
For example::
@component.register(
"com.example.add",
options=RegisterOptions(invoke='roundrobin'),
)
def add(*args, **kw):
print("add({}, {}): event received".format(args, kw))
"""
assert options is None or isinstance(options, RegisterOptions)
def decorator(fn):
def do_registration(session, details):
return session.register(fn, procedure=uri, options=options, check_types=check_types)
self.on('join', do_registration)
return fn
return decorator
def __init__(self, main=None, transports=None, config=None, realm='realm1', extra=None,
authentication=None, session_factory=None, is_fatal=None):
"""
:param main: After a transport has been connected and a session
has been established and joined to a realm, this (async)
procedure will be run until it finishes -- which signals that
the component has run to completion. In this case, it usually
doesn't make sense to use the ``on_*`` kwargs. If you do not
pass a main() procedure, the session will not be closed
(unless you arrange for .leave() to be called).
:type main: callable taking two args ``reactor`` and ``ISession``
:param transports: Transport configurations for creating
transports. Each transport can be a WAMP URL, or a dict
containing the following configuration keys:
- ``type`` (optional): ``websocket`` (default) or ``rawsocket``
- ``url``: the router URL
- ``endpoint`` (optional, derived from URL if not provided):
- ``type``: "tcp" or "unix"
- ``host``, ``port``: only for TCP
- ``path``: only for unix
- ``timeout``: in seconds
- ``tls``: ``True`` or (under Twisted) an
``twisted.internet.ssl.IOpenSSLClientComponentCreator``
instance (such as returned from
``twisted.internet.ssl.optionsForClientTLS``) or
``CertificateOptions`` instance.
- ``max_retries``: Maximum number of reconnection attempts. Unlimited if set to -1.
- ``initial_retry_delay``: Initial delay for reconnection attempt in seconds (Default: 1.0s).
- ``max_retry_delay``: Maximum delay for reconnection attempts in seconds (Default: 60s).
- ``retry_delay_growth``: The growth factor applied to the retry delay between reconnection attempts (Default 1.5).
- ``retry_delay_jitter``: A 0-argument callable that introduces nose into the delay. (Default random.random)
- ``serializer`` (only for raw socket): Specify an accepted serializer (e.g. 'json', 'msgpack', 'cbor', 'ubjson', 'flatbuffers')
- ``serializers``: Specify list of accepted serializers
- ``options``: tbd
- ``proxy``: tbd
:type transports: None or str or list
:param realm: the realm to join
:type realm: str
:param authentication: configuration of authenticators
:type authentication: dict
:param session_factory: if None, ``ApplicationSession`` is
used, otherwise a callable taking a single ``config`` argument
that is used to create a new `ApplicationSession` instance.
:param is_fatal: a callable taking a single argument, an
``Exception`` instance. The callable should return ``True`` if
this error is "fatal", meaning we should not try connecting to
the current transport again. The default behavior (on None) is
to always return ``False``
"""
self.set_valid_events(
[
'start', # fired by base class
'connect', # fired by ApplicationSession
'join', # fired by ApplicationSession
'ready', # fired by ApplicationSession
'leave', # fired by ApplicationSession
'disconnect', # fired by ApplicationSession
'connectfailure', # fired by base class
]
)
if is_fatal is not None and not callable(is_fatal):
raise ValueError('"is_fatal" must be a callable or None')
self._is_fatal = is_fatal
if main is not None and not callable(main):
raise ValueError('"main" must be a callable if given')
self._entry = main
# use WAMP-over-WebSocket to localhost when no transport is specified at all
if transports is None:
transports = 'ws://127.0.0.1:8080/ws'
# allows to provide a URL instead of a list of transports
if isinstance(transports, (str, str)):
url = transports
# 'endpoint' will get filled in by parsing the 'url'
transport = {
'type': 'websocket',
'url': url,
}
transports = [transport]
# allows single transport instead of a list (convenience)
elif isinstance(transports, dict):
transports = [transports]
# XXX do we want to be able to provide an infinite iterable of
# transports here? e.g. a generator that makes new transport
# to try?
# now check and save list of transports
self._transports = []
for idx, transport in enumerate(transports):
# allows to provide a URL instead of transport dict
if type(transport) == str:
_transport = {
'type': 'websocket',
'url': transport,
}
else:
_transport = transport
self._transports.append(
_create_transport(idx, _transport, self._check_native_endpoint)
)
# XXX should have some checkconfig support
self._authentication = authentication or {}
if session_factory:
self.session_factory = session_factory
self._realm = realm
self._extra = extra
self._delay_f = None
self._done_f = None
self._session = None
self._stopping = False
def _can_reconnect(self):
# check if any of our transport has any reconnect attempt left
for transport in self._transports:
if transport.can_reconnect():
return True
return False
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/Deferred which will resolve (to ``None``) when we are
"done" or with an error if something went wrong.
"""
# we can only be "start()ed" once before we stop .. but that
# doesn't have to be an error we can give back another future
# that fires when our "real" _done_f is completed.
if self._done_f is not None:
d = txaio.create_future()
def _cb(arg):
txaio.resolve(d, arg)
txaio.add_callbacks(self._done_f, _cb, _cb)
return d
# this future will be returned, and thus has the semantics
# specified in the docstring.
self._done_f = txaio.create_future()
def _reset(arg):
"""
if the _done_f future is resolved (good or bad), we want to set it
to None in our class
"""
self._done_f = None
return arg
txaio.add_callbacks(self._done_f, _reset, _reset)
# Create a generator of transports that .can_reconnect()
transport_gen = itertools.cycle(self._transports)
# this is a 1-element list so we can set it from closures in
# this function
transport_candidate = [0]
def error(fail):
self._delay_f = None
if self._stopping:
# might be better to add framework-specific checks in
# subclasses to see if this is CancelledError (for
# Twisted) and whatever asyncio does .. but tracking
# if we're in the shutdown path is fine too
txaio.resolve(self._done_f, None)
else:
self.log.info("Internal error {msg}", msg=txaio.failure_message(fail))
self.log.debug("{tb}", tb=txaio.failure_format_traceback(fail))
txaio.reject(self._done_f, fail)
def attempt_connect(_):
self._delay_f = None
def handle_connect_error(fail):
# FIXME - make txaio friendly
# Can connect_f ever be in a cancelled state?
# if txaio.using_asyncio and isinstance(fail.value, asyncio.CancelledError):
# unrecoverable_error = True
self.log.debug('component failed: {error}', error=txaio.failure_message(fail))
self.log.debug('{tb}', tb=txaio.failure_format_traceback(fail))
# If this is a "fatal error" that will never work,
# we bail out now
if isinstance(fail.value, ApplicationError):
self.log.error("{msg}", msg=fail.value.error_message())
elif isinstance(fail.value, OSError):
# failed to connect entirely, like nobody
# listening etc.
self.log.info("Connection failed with OS error: {msg}", msg=txaio.failure_message(fail))
elif self._is_ssl_error(fail.value):
# Quoting pyOpenSSL docs: "Whenever
# [SSL.Error] is raised directly, it has a
# list of error messages from the OpenSSL
# error queue, where each item is a tuple
# (lib, function, reason). Here lib, function
# and reason are all strings, describing where
# and what the problem is. See err(3) for more
# information."
# (and 'args' is a 1-tuple containing the above
# 3-tuple...)
ssl_lib, ssl_func, ssl_reason = fail.value.args[0][0]
self.log.error("TLS failure: {reason}", reason=ssl_reason)
else:
self.log.error(
'Connection failed: {error}',
error=txaio.failure_message(fail),
)
if self._is_fatal is None:
is_fatal = False
else:
is_fatal = self._is_fatal(fail.value)
if is_fatal:
self.log.info("Error was fatal; failing transport")
transport_candidate[0].failed()
txaio.call_later(0, transport_check, None)
return
def notify_connect_error(fail):
chain_f = txaio.create_future()
# hmm, if connectfailure took a _Transport instead of
# (or in addition to?) self it could .failed() the
# transport and we could do away with the is_fatal
# listener?
handler_f = self.fire('connectfailure', self, fail.value)
txaio.add_callbacks(
handler_f,
lambda _: txaio.reject(chain_f, fail),
lambda _: txaio.reject(chain_f, fail)
)
return chain_f
def connect_error(fail):
notify_f = notify_connect_error(fail)
txaio.add_callbacks(notify_f, None, handle_connect_error)
def session_done(x):
txaio.resolve(self._done_f, None)
connect_f = txaio.as_future(
self._connect_once,
loop, transport_candidate[0],
)
txaio.add_callbacks(connect_f, session_done, connect_error)
def transport_check(_):
self.log.debug('Entering re-connect loop')
if not self._can_reconnect():
err_msg = "Component failed: Exhausted all transport connect attempts"
self.log.info(err_msg)
try:
raise RuntimeError(err_msg)
except RuntimeError as e:
txaio.reject(self._done_f, e)
return
while True:
transport = next(transport_gen)
if transport.can_reconnect():
transport_candidate[0] = transport
break
delay = transport.next_delay()
self.log.warn(
'trying transport {transport_idx} ("{transport_url}") using connect delay {transport_delay}',
transport_idx=transport.idx,
transport_url=transport.url,
transport_delay=delay,
)
self._delay_f = txaio.sleep(delay)
txaio.add_callbacks(self._delay_f, attempt_connect, error)
# issue our first event, then start reconnect loop
start_f = self.fire('start', loop, self)
txaio.add_callbacks(start_f, transport_check, error)
return self._done_f
def stop(self):
self._stopping = True
if self._session and self._session.is_attached():
return self._session.leave()
elif self._delay_f:
# This cancel request will actually call the "error" callback of
# the _delay_f future. Nothing to worry about.
return txaio.as_future(txaio.cancel, self._delay_f)
# if (for some reason -- should we log warning here to figure
# out if this can evern happen?) we've not fired _done_f, we
# do that now (causing our "main" to exit, and thus react() to
# quit)
if not txaio.is_called(self._done_f):
txaio.resolve(self._done_f, None)
return txaio.create_future_success(None)
def _connect_once(self, reactor, transport):
self.log.info(
'connecting once using transport type "{transport_type}" '
'over endpoint "{endpoint_desc}"',
transport_type=transport.type,
endpoint_desc=transport.describe_endpoint(),
)
done = txaio.create_future()
# factory for ISession objects
def create_session():
cfg = ComponentConfig(self._realm, self._extra)
try:
self._session = session = self.session_factory(cfg)
for auth_name, auth_config in self._authentication.items():
if isinstance(auth_config, IAuthenticator):
session.add_authenticator(auth_config)
else:
authenticator = create_authenticator(auth_name, **auth_config)
session.add_authenticator(authenticator)
except Exception as e:
# couldn't instantiate session calls, which is fatal.
# let the reconnection logic deal with that
f = txaio.create_failure(e)
txaio.reject(done, f)
raise
else:
# hook up the listener to the parent so we can bubble
# up events happning on the session onto the
# connection. This lets you do component.on('join',
# cb) which will work just as if you called
# session.on('join', cb) for every session created.
session._parent = self
# listen on leave events; if we get errors
# (e.g. no_such_realm), an on_leave can happen without
# an on_join before
def on_leave(session, details):
self.log.info(
"session leaving '{details.reason}'",
details=details,
)
if not txaio.is_called(done):
if details.reason in ["wamp.close.normal", "wamp.close.goodbye_and_out"]:
txaio.resolve(done, None)
else:
f = txaio.create_failure(
ApplicationError(details.reason, details.message)
)
txaio.reject(done, f)
session.on('leave', on_leave)
# if we were given a "main" procedure, we run through
# it completely (i.e. until its Deferred fires) and
# then disconnect this session
def on_join(session, details):
transport.reset()
transport.connect_sucesses += 1
self.log.debug("session on_join: {details}", details=details)
d = txaio.as_future(self._entry, reactor, session)
def main_success(_):
self.log.debug("main_success")
def leave():
try:
session.leave()
except SessionNotReady:
# someone may have already called
# leave()
pass
txaio.call_later(0, leave)
def main_error(err):
self.log.debug("main_error: {err}", err=err)
txaio.reject(done, err)
session.disconnect()
txaio.add_callbacks(d, main_success, main_error)
if self._entry is not None:
session.on('join', on_join)
# listen on disconnect events. Note that in case we
# had a "main" procedure, we could have already
# resolve()'d our "done" future
def on_disconnect(session, was_clean):
self.log.debug(
"session on_disconnect: was_clean={was_clean}",
was_clean=was_clean,
)
if not txaio.is_called(done):
if not was_clean:
self.log.warn(
"Session disconnected uncleanly"
)
else:
# eg the session has left the realm, and the transport was properly
# shut down. successfully finish the connection
txaio.resolve(done, None)
session.on('disconnect', on_disconnect)
# return the fresh session object
return session
transport.connect_attempts += 1
d = txaio.as_future(
self._connect_transport,
reactor, transport, create_session, done,
)
def on_error(err):
"""
this may seem redundant after looking at _connect_transport, but
it will handle a case where something goes wrong in
_connect_transport itself -- as the only connect our
caller has is the 'done' future
"""
transport.connect_failures += 1
# something bad has happened, and maybe didn't get caught
# upstream yet
if not txaio.is_called(done):
txaio.reject(done, err)
txaio.add_callbacks(d, None, on_error)
return done
[docs] def on_join(self, fn):
"""
A decorator as a shortcut for listening for 'join' events.
For example::
@component.on_join
def joined(session, details):
print("Session {} joined: {}".format(session, details))
"""
self.on('join', fn)
[docs] def on_leave(self, fn):
"""
A decorator as a shortcut for listening for 'leave' events.
"""
self.on('leave', fn)
[docs] def on_connect(self, fn):
"""
A decorator as a shortcut for listening for 'connect' events.
"""
self.on('connect', fn)
[docs] def on_disconnect(self, fn):
"""
A decorator as a shortcut for listening for 'disconnect' events.
"""
self.on('disconnect', fn)
[docs] def on_ready(self, fn):
"""
A decorator as a shortcut for listening for 'ready' events.
"""
self.on('ready', fn)
[docs] def on_connectfailure(self, fn):
"""
A decorator as a shortcut for listening for 'connectfailure' events.
"""
self.on('connectfailure', fn)
def _run(reactor, components, done_callback=None):
"""
Internal helper. Use "run" method from autobahn.twisted.wamp or
autobahn.asyncio.wamp
This is the generic parts of the run() method so that there's very
little code in the twisted/asyncio specific run() methods.
This is called by react() (or run_until_complete() so any errors
coming out of this should be handled properly. Logging will
already be started.
"""
# let user pass a single component to run, too
# XXX probably want IComponent? only demand it, here and below?
if isinstance(components, Component):
components = [components]
if type(components) != list:
raise ValueError(
'"components" must be a list of Component objects - encountered'
' {0}'.format(type(components))
)
for c in components:
if not isinstance(c, Component):
raise ValueError(
'"components" must be a list of Component objects - encountered'
'item of type {0}'.format(type(c))
)
# validation complete; proceed with startup
log = txaio.make_logger()
def component_success(comp, arg):
log.debug("Component '{c}' successfully completed: {arg}", c=comp, arg=arg)
return arg
def component_failure(comp, f):
log.error("Component '{c}' error: {msg}", c=comp, msg=txaio.failure_message(f))
log.debug("Component error: {tb}", tb=txaio.failure_format_traceback(f))
# double-check: is a component-failure still fatal to the
# startup process (because we passed consume_exception=False
# to gather() below?)
return None
def component_start(comp):
# the future from start() errbacks if we fail, or callbacks
# when the component is considered "done" (so maybe never)
d = txaio.as_future(comp.start, reactor)
txaio.add_callbacks(
d,
partial(component_success, comp),
partial(component_failure, comp),
)
return d
# note that these are started in parallel -- maybe we want to add
# a "connected" signal to components so we could start them in the
# order they're given to run() as "a" solution to dependencies.
dl = []
for comp in components:
d = component_start(comp)
dl.append(d)
done_d = txaio.gather(dl, consume_exceptions=False)
if done_callback:
def all_done(arg):
log.debug("All components ended; stopping reactor")
done_callback(reactor, arg)
txaio.add_callbacks(done_d, all_done, all_done)
return done_d