/usr/lib/python2.7/dist-packages/foolscap/connection.py is in python-foolscap 0.10.1-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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from twisted.internet import protocol, reactor, error
from foolscap.tokens import (NoLocationHintsError, NegotiationError,
RemoteNegotiationError)
from foolscap.logging import log
from foolscap.logging.log import CURIOUS, UNUSUAL, OPERATIONAL
from foolscap.util import isSubstring
from foolscap.ipb import InvalidHintError
from foolscap.connection_plugins import convert_legacy_hint
class TubConnectorFactory(protocol.Factory, object):
# this is for internal use only. Application code should use
# Tub.getReference(url)
noisy = False
def __init__(self, tc, host, logparent):
self.tc = tc # the TubConnector
self.host = host
self._logparent = logparent
def __repr__(self):
# make it clear which remote Tub we're trying to connect to
base = object.__repr__(self)
at = base.find(" at ")
if at == -1:
# our annotation isn't really important, so don't fail just
# because we guessed the default __repr__ incorrectly
return base
assert self.tc.tub.tubID
origin = self.tc.tub.tubID[:8]
assert self.tc.target.getTubID()
target = self.tc.target.getTubID()[:8]
return base[:at] + " [from %s]" % origin + " [to %s]" % target + base[at:]
def buildProtocol(self, addr):
nc = self.tc.tub.negotiationClass # this is usually Negotiation
proto = nc(self._logparent)
proto.initClient(self.tc, self.host)
proto.factory = self
return proto
def get_endpoint(location, connectionPlugins):
hint = convert_legacy_hint(location)
if ":" not in hint:
raise InvalidHintError("no colon in hint")
hint_type = hint.split(":", 1)[0]
plugin = connectionPlugins.get(hint_type)
if not plugin:
raise InvalidHintError("no handler registered for hint")
ep, host = plugin.hint_to_endpoint(hint, reactor)
return ep, host
class TubConnector(object):
"""I am used to make an outbound connection. I am given a target TubID
and a list of locationHints, and I try all of them until I establish a
Broker connected to the target. I will consider redirections returned
along the way. The first hint that yields a connected Broker will stop
the search.
This is a single-use object. The connection attempt begins as soon as my
connect() method is called.
I live until all but one of the TCP connections I initiated have finished
closing down. This means that connection establishment attempts in
progress are cancelled, and established connections (the ones which did
*not* complete negotiation before the winning connection) have called
their connectionLost() methods.
"""
failureReason = None
CONNECTION_TIMEOUT = 60
timer = None
def __init__(self, parent, tubref, connectionPlugins):
self._logparent = log.msg(format="TubConnector created from "
"%(fromtubid)s to %(totubid)s",
fromtubid=parent.tubID,
totubid=tubref.getTubID(),
level=OPERATIONAL,
facility="foolscap.connection",
umid="pH4QDA")
self.tub = parent
self.target = tubref
self.connectionPlugins = connectionPlugins
self.remainingLocations = list(self.target.getLocations())
# attemptedLocations keeps track of where we've already tried to
# connect, so we don't try them twice, even if they appear in the
# hints multiple times. this isn't too clever: slight variations of
# the same hint will fool it, but it should be enough to avoid
# infinite redirection loops.
self.attemptedLocations = []
# pendingConnections contains a Deferred for each endpoint.connect()
# that has started (but not yet established) a connection. We keep
# track of these so we can shut them down (using d.cancel()) when we
# stop connecting (either because one of the other connections
# succeeded, or because someone told us to give up).
self.pendingConnections = set()
# self.pendingNegotiations maps Negotiation instances (connected but
# not finished negotiation) to the hint that got us the connection.
# We track these so we can abandon the negotiation.
self.pendingNegotiations = {}
def __repr__(self):
s = object.__repr__(self)
s = s[:-1]
s += " from %s to %s>" % (self.tub.tubID, self.target.getTubID())
return s
def log(self, *args, **kwargs):
kwargs['parent'] = kwargs.get('parent') or self._logparent
kwargs['facility'] = kwargs.get('facility') or "foolscap.connection"
return log.msg(*args, **kwargs)
def connect(self):
"""Begin the connection process. This should only be called once.
This will either result in the successful Negotiation object invoking
the parent Tub's brokerAttached() method, or us calling the Tub's
connectionFailed() method."""
self.tub.connectorStarted(self)
timeout = self.tub._test_options.get('connect_timeout',
self.CONNECTION_TIMEOUT)
self.timer = reactor.callLater(timeout, self.connectionTimedOut)
self.active = True
self.connectToAll()
def stopConnectionTimer(self):
if self.timer:
self.timer.cancel()
del self.timer
def shutdown(self):
self.active = False
self.remainingLocations = []
self.stopConnectionTimer()
self.cancelRemainingConnections()
def cancelRemainingConnections(self):
for d in list(self.pendingConnections):
d.cancel()
# this will trigger self._connectionFailed(), via the errback,
# with a ConnectingCancelledError
for n in self.pendingNegotiations.keys():
n.transport.loseConnection()
# triggers n.connectionLost(), then self.negotiationFailed()
def connectToAll(self):
triedAnything = False
while self.remainingLocations:
location = self.remainingLocations.pop()
if location in self.attemptedLocations:
continue
self.attemptedLocations.append(location)
try:
ep, host = get_endpoint(location, self.connectionPlugins)
except InvalidHintError as e:
self.log(e, format="unable to use hint: '%(hint)s'",
hint=location, level=UNUSUAL, umid="z62ctA")
continue
triedAnything = True
lp = self.log("connectTCP to %s" % (location,))
f = TubConnectorFactory(self, host, lp)
d = ep.connect(f)
self.pendingConnections.add(d)
def _remove(res, d=d):
self.pendingConnections.remove(d)
return res
d.addBoth(_remove)
d.addCallback(self._connectionSuccess, location, lp)
d.addErrback(self._connectionFailed, location, lp)
if self.tub._test_options.get("debug_stall_second_connection"):
# for unit tests, hold off on making the second connection
# for a moment. This allows the first connection to get to a
# known state.
reactor.callLater(0.1, self.connectToAll)
return
if not triedAnything:
self.failureReason = Failure(NoLocationHintsError())
self.checkForFailure()
def connectionTimedOut(self):
# this timer is for the overall connection attempt, not each
# individual endpoint/TCP connector
self.timer = None
why = "no connection established within client timeout"
self.failureReason = Failure(NegotiationError(why))
self.shutdown()
self.failed()
def _connectionFailed(self, reason, hint, lp):
# this is called if some individual TCP connection cannot be
# established
if reason.check(error.ConnectionRefusedError):
self.log("connection refused for %s" % hint, level=OPERATIONAL,
parent=lp, umid="rSrUxQ")
elif reason.check(error.ConnectingCancelledError):
self.log("abandoned attempt to %s" % hint, level=OPERATIONAL,
parent=lp, umid="CC8vwg")
else:
log.err(reason, "failed to connect to %s" % hint, level=CURIOUS,
parent=lp, facility="foolscap.connection",
umid="2PEowg")
if not self.failureReason:
self.failureReason = reason
self.checkForFailure()
self.checkForIdle()
def _connectionSuccess(self, p, hint, lp):
# fires with the Negotiation protocol instance, after
# p.makeConnection(transport) returns, which is after
# p.connectionMade() returns
self.log("connected to %s, beginning negotiation" % hint,
level=OPERATIONAL, parent=lp, umid="VN0XGQ")
self.pendingNegotiations[p] = hint
def redirectReceived(self, newLocation):
# the redirected connection will disconnect soon, which will trigger
# negotiationFailed(), so we don't have to do a
self.remainingLocations.append(newLocation)
self.connectToAll()
def negotiationFailed(self, n, reason):
assert isinstance(n, self.tub.negotiationClass)
# this is called if protocol negotiation cannot be established, or if
# the connection is closed for any reason prior to switching to the
# Banana protocol
self.pendingNegotiations.pop(n)
assert isinstance(reason, Failure), \
"Hey, %s isn't a Failure" % (reason,)
if (not self.failureReason or
isinstance(reason, NegotiationError)):
# don't let mundane things like ConnectionFailed override the
# actually significant ones like NegotiationError
self.failureReason = reason
self.checkForFailure()
self.checkForIdle()
def negotiationComplete(self, n):
assert isinstance(n, self.tub.negotiationClass)
# 'factory' has just completed negotiation, so abandon all the other
# connection attempts
self.log("negotiationComplete, %s won" % n)
self.pendingNegotiations.pop(n) # this one succeeded
self.active = False
if self.timer:
self.timer.cancel()
self.timer = None
self.cancelRemainingConnections() # abandon the others
self.checkForIdle()
def checkForFailure(self):
if not self.active:
return
if (self.remainingLocations or
self.pendingConnections or self.pendingNegotiations):
return
# we have no more options, so the connection attempt will fail. The
# getBrokerForTubRef may have succeeded, however, if the other side
# tried to connect to us at exactly the same time, they were the
# master, they established their connection first (but the final
# decision is still in flight), and they hung up on our connection
# because they felt it was a duplicate. So, if self.failureReason
# indicates a duplicate connection, do not signal a failure here. We
# leave the connection timer in place in case they lied about having
# a duplicate connection ready to go.
if (self.failureReason.check(RemoteNegotiationError) and
isSubstring(self.failureReason.value.args[0],
"Duplicate connection")):
self.log("TubConnector.checkForFailure: connection attempt "
"failed because the other end decided ours was a "
"duplicate connection, so we won't signal the "
"failure here")
return
self.failed()
def failed(self):
self.stopConnectionTimer()
self.active = False
self.tub.connectionFailed(self.target, self.failureReason)
self.tub.connectorFinished(self)
def checkForIdle(self):
# When one connection finishes negotiation, the others are cancelled
# to hurry them along their way towards disconnection. The last one
# to resolve finally causes us to notify our parent Tub.
if (self.remainingLocations or
self.pendingConnections or self.pendingNegotiations):
return
# we have no more outstanding connections (either in progress or in
# negotiation), so this connector is finished.
self.log("connectorFinished (%s)" % self)
self.tub.connectorFinished(self)
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