I'm not very experienced in Python, but while tracking down an issue 
with a "too many open files" error I think I found a missing resource 
release in asyncore's file_wrapper. Since Rev. 64062 added the os.dup() 
in __init__ this class reads as follows:

if os.name == 'posix':
    import fcntl

    class file_wrapper:
        # Here we override just enough to make a file
        # look like a socket for the purposes of asyncore.
        # The passed fd is automatically os.dup()'d

        def __init__(self, fd):
            self.fd = os.dup(fd)

        def recv(self, *args):
            return os.read(self.fd, *args)

        def send(self, *args):
            return os.write(self.fd, *args)

        read = recv
        write = send

        def close(self):
            os.close(self.fd)

        def fileno(self):
            return self.fd


I think that a "def __del__(self): self.close()" or a variant thereof 
would solve the problem I was seeing since it would release the file 
descriptor acquired in __init__ by os.dup(). But since I don't know why 
the os.dup() was added in the first place I'm not sure if there aren't 
any arguments against this release. Any comment appreciated!

I'm not sure how to reproduce this issue but I doubt calling close() from __del__ would solve the problem, neither would be a good idea as close() might end up being called more than once, which is not desirable.

Try to paste the code you're using: the problem might be that your application is not calling close() for some reason.

Closing out because no response has been provided by the OP.