[Twisted-Python] question about subprocess

[Glyph]

On Sep 26, 2013, at 6:51 PM, Jonathan Vanasco <twisted-python at 2xlp.com> wrote:

> 
> Quick question about (sub)processes in twisted :
> 
> 	how bad is it to use the subprocess module  ? ( in general / in this application )

It's pretty bad ;-).

> I have the following setup :
> 
> 	- Twisted Daemon that does 5 things (very well!)
> 	- A new requirement -- to execute 2 scripts on the commandline , one after the other ( ie, blocking )  
> 
> the 2 commandline scripts are just tossing some PostgreSQL commands via `postgresql db < file.txt` 
> 
> i was looking at reactor.SpawnProcess -- which I know is more correct.  it just seems to be a bit annoying to use , and I know the subprocess module already.  

The subprocess module does not have any way to spawn a subprocess and get its output and exit status as events in the reactor; its methods all block.  You can sort of re-build spawnProcess yourself from scratch, but ... then you'd just have spawnProcess with a slightly more subprocess-y API, and you'd be better off writing a utility function that wraps spawnProcess for yourself.

Could you write up why you feel it's "annoying"?  Maybe we can improve spawnProcess so it works better for you in the future.

-glyph