krustymonkey
I'm wondering if anyone can help with a workaround for a problem I
currently have. I'm trying to set up a prefork tcp server.
Specifically, I'm setting up a server that forks children and has them
listen on pipes created with os.pipe(). The parent process for the
group starts an inet:tcp server on a given port. In the parent, after
a "socket.accept( )", I'm trying to pickle the connection object to
send over an IPC pipe (as stated previously), but I get the following
error:
File "/usr/lib/python2.4/copy_reg.py", line 76, in _reduce_ex
raise TypeError("a class that defines __slots__ without "
TypeError: a class that defines __slots__ without defining
__getstate__ cannot be pickled
Does anyone know of a workaround for this? Maybe my approach to this
is wrong? Any help would be appreciated.
Jay
Jun 27 '08
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castironpi
On May 11, 6:21*pm, krustymon...@gm ail.com wrote:
On May 8, 7:29 pm, castiro...@gmai l.com wrote:On May 8, 4:35 pm, Hrvoje Niksic <hnik...@xemacs .orgwrote:Marc 'BlackJack' Rintsch <bj_...@gmx.net writes:On Thu, 08 May 2008 08:55:35 -0700, krustymonkey wrote:The thing is, I'm not using slots by choice. *I'm using the standard
lib "socket" class, which apparently uses slots.`socket` objects can't be pickled. *Not just because of the
`__slot__`\s but because a substantial part of their state lives in
the operating system's space.Of course, if it makes sense to pickle sockets in the application, one
is can do so by defining __getstate__ and __setstate__:class Connection(obje ct):
* * def __init__(self, host, port):
* * * * self.host = host
* * * * self.port = port
* * * * self.init_sock( )* * def init_sock(self) :
* * * * self.sock = socket.socket()
* * * * self.sock.conne ct((host, port))
* * * * ... init communication ...* * def __getstate__(se lf):
* * * * # pickle self as a (host, port) pair
* * * * return self.host, self.port* * def __setstate__(se lf, state):
* * * * # reinstate self by setting host and port and
* * * * # recreating the socket
* * * * self.host, self.port = state
* * * * self.init_sock( )I, local, am mystified that you'd want to pickle a socket. *It's a
live connection, which flies on a pocket dollar. *You don't want it on
disk, do you?If you're running a net buoy through a cluster somewhere, do you want
to drop a server and reconnect? *Is Amazon's EC2 up and running?Certainly no one was talking on the internet. *Were you?I don't think you hit anything but banks surfing the web, and the
American dollar is notoriously stuffy. *Pump a wi-fi to a diner,
though, and you're just talking more. *Where's Usenet?
The idea is a pre-fork socket server. *What I want to do is fork off
some child processes from the parent and use IPC to send the
connection object (via socket.accept() ) over a pipe to one of the
preexisting child processes and have said child handle the
transaction. *Think Apache, if you want an example of what I'm trying
to do here. *This alleviates the process startup cost that occurs when
you fork. *If the socket object can't be serialized, is there another
way to go about handling this in python?- Hide quoted text -- Show quoted text -
That's out of my expertise. You would have to either hack it on a
router you are running (masquerade), or choose a different family of
sockets. For HTTP, you could issue a 'reroute' return. Just multi-
thread your server process.
Jun 27 '08 #11
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