Replace getProcess* helpers with a single, better, API.

	spiv reported
Trac ID	trac#3997
Type	enhancement
Created	2009-09-03 04:11:54Z

I think the subprocess module has the right idea: give you a single good way to start a function, and declare whether you want to capture/discard/ignore the various stdio streams etc, and then return an object with useful attributes.

So I propose that instead of getProcessValue, getProcessOutput, getProcessOutputAndValue (did I miss any?) we have a single method, that takes args like:

  foo(stdout=fileLikeObject, ...)

and returns a Deferred that yields an object with a .exitValue attribute, and perhaps others (for finding out if a signal terminated it, maybe?). Returning an object certainly seems like a much better API than e.g. the tuples from getProcessOutputAndValue. Obviously this new function would need a better name than foo.

Probably any new API here should try to address the problems with the existing APIs described by exarkun in a comment at http://twistedmatrix.com/trac/ticket/280.

Quite possibly the proposal in this vague sketch could be improved even further. Please feel free to criticise, suggest improvements, suggest more precise details for the signature, etc. I figured it was better to capture a rough idea than forget it entirely.

trac-id__3997 3997
type__enhancement enhancement
reporter__spiv spiv
priority__normal normal
milestone__ 
branch__ 
branch_author__ 
status__new new
resolution__None None
component__core core
keywords__ 
time__1251951114000000 1251951114000000
changetime__1359614387000000 1359614387000000
version__None None
owner__ 
cc__khorn cc__tom.prince

Start by reading the subprocess module and the existing getProcessValue, getProcessOutput, and getProcessOutputAndValue helpers. Review the problems described in ticket 280, then work out a precise unified API for stdio handling and process results. Done means the proposal is specified well enough to implement and replace the existing helper use cases.