evennia/contrib/procpools/ampoule/rpool.py

65 lines
2.7 KiB
Python

"""
This module implements a remote pool to use with AMP.
"""
from twisted.protocols import amp
class AMPProxy(amp.AMP):
"""
A Proxy AMP protocol that forwards calls to a wrapped
callRemote-like callable.
"""
def __init__(self, wrapped, child):
"""
@param wrapped: A callRemote-like callable that takes an
L{amp.Command} as first argument and other
optional keyword arguments afterwards.
@type wrapped: L{callable}.
@param child: The protocol class of the process pool children.
Used to forward only the methods that are actually
understood correctly by them.
@type child: L{amp.AMP}
"""
amp.AMP.__init__(self)
self.wrapped = wrapped
self.child = child
localCd = set(self._commandDispatch.keys())
childCd = set(self.child._commandDispatch.keys())
assert localCd.intersection(childCd) == set(["StartTLS"]), \
"Illegal method overriding in Proxy"
def locateResponder(self, name):
"""
This is a custom locator to forward calls to the children
processes while keeping the ProcessPool a transparent MITM.
This way of working has a few limitations, the first of which
is the fact that children won't be able to take advantage of
any dynamic locator except for the default L{CommandLocator}
that is based on the _commandDispatch attribute added by the
metaclass. This limitation might be lifted in the future.
"""
if name == "StartTLS":
# This is a special case where the proxy takes precedence
return amp.AMP.locateResponder(self, "StartTLS")
# Get the dict of commands from the child AMP implementation.
cd = self.child._commandDispatch
if name in cd:
# If the command is there, then we forward stuff to it.
commandClass, _responderFunc = cd[name]
# We need to wrap the doWork function because the wrapping
# call doesn't pass the command as first argument since it
# thinks that we are the actual receivers and callable is
# already the responder while it isn't.
doWork = lambda **kw: self.wrapped(commandClass, **kw)
# Now let's call the right function and wrap the result
# dictionary.
return self._wrapWithSerialization(doWork, commandClass)
# of course if the name of the command is not in the child it
# means that it might be in this class, so fallback to the
# default behavior of this module.
return amp.AMP.locateResponder(self, name)