I've been working on http://twistedmatrix.com/trac/ticket/4159 and there has been a bit of discussion on IRC regarding appropriate interfaces for various things. I think in the long run, the only python state that setupChild should be allowed to modify should be args, environment, and the win32 StartupInfo object. This leaves my own personal use case for it impossible, but I'm working out how to handle that - special childFDs objects. My proposal so far is that there be a ProcessFileDescriptor object that inherits from FileDescriptor. It would add a setup method, which Process would call in the parent, and separate finishChild and finishParent methods that would handle things like closing the other end of any pipe-like objects, and would return a file descriptor - the child would place this fd in childFDs, the parent would use it for communications with the child, in the case of objects that wrap pipes or PTYs. I would also extend the win32 implementation to include some limited support for childFDs - they could be used to allow the child to inherit specific file handles as its stdin, stdout, and stderr, instead of using these exclusively for communications with the parent, so that redirection to a pipe, to a file, and the building of pipelines could be accomplished on win32 (I have a project that uses twisted for this purpose, and I don't use windows, but I would like support to at least be possible).
I'm seeking comments on whether an extended childFDs interface is the best way to manipulate the inherited files of the child process, and whether, if so, fdmap ought to be visible in setupChild at all - in my opinion, setupChild should be strictly for things like setting the child PID in an environment variable or as a command line argument, manipulating scheduler and other parameters external to twisted itself, and other things of that nature, and the existing childFDs mechanism should handle any manipulation of file redirection or inheritance. If there are suggestions on what an extended childFD object ought to look like, these are welcome as well - I think the specified methods should handle trivial cases even on platforms without fork, and should handle nearly anything that really is a file descriptor on POSIX platforms, but maybe there is something I have missed. -- Andrew Mahone andrew DOT mahone AT gmail DOT com _______________________________________________ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
