[Python-ideas] Tulip / PEP 3156 - subprocess events

[Andrew Bennetts]

Guido van Rossum wrote:
[…]
> I have a more-or-less working but probably incomplete version checked
> into the tulip repo:
> http://code.google.com/p/tulip/source/browse/tulip/subprocess_transport.py
> 
> Note that this completely ignores stderr -- this makes the code
> simpler while still useful (there's plenty of useful stuff you can do
> without reading stderr), and avoids the questions Greg Ewing brought
> up about needing two transports (one for stdout, another for stderr).

Although 3 pipes to a subprocess (stdin, stdout, stderr) is the usual
convention, it's not the only possibility, so that configuration
shouldn't be hard-coded.  On POSIX some programs can and do make use of
the ability to have more pipes to a subprocess; e.g. the various *fd
options of gnupg (--status-fd, --logger-fd, --command-fd, and so on).
And some programs give the child process file descriptors that aren't
pipes, like sockets (e.g. an inetd-like server that accepts a socket
then spawns a subprocess to serve it).

So I hope tulip will support these possibilities (although obviously the
stdin/out/err style should be the convenient default).  You will be
unsurprised to hear that Twisted does :)

(Please forgive me if this was already pointed out.  It's hard keeping
up with python-ideas.)

-Andrew.