[sos-devel] [RFC] wrap commands in /usr/bin/timeout when available

[Jesse Jaggars]

On Tue, Mar 20, 2012 at 06:32:25PM +0000, Bryn M. Reeves wrote:
> On 03/20/2012 06:21 PM, Jesse Jaggars wrote:
> > Using `timeout` is great for our situation since it allows us to offer a
> > shell to plugins (for easy pipelines). Also, there isn't much extra overhead
> > since we are forking from python anyways.
> 
> That's true actually - I'd not thought of that extra side effect but
> it's neat.
> 
> > The only major downside is that we will rely on the binary to implement
> > the timeout mechanism for us. This means that we either have to
> > implement alternative timeout methods for platforms that lack `timeout`
> > or fail to supply a timeout on those platforms. This is no worse than we
> > do today, so it's not much of a downside I don't suppose.
> 
> Also true.. I think the fallback approach sounds like a good idea. This
> would also let us work on distributions that ship pre-7.x coreutils.
> Although I'd like to get timeout backported into the older Red Hat stuff
> we can still run into machines with outdated packages.
> 
> > Given that we will likely want to try to provide an alternative timeout
> > method we should probably plan to plug in different implementations
> > somehow. Currently the method to fork a subprocess and do some work is
> > just a thin wrapper around subprocess.Popen. It would make sense to
> > allow a Policy object to override this implementation, though that might
> > be overkill for now since we can see if `timeout` exists and use it or
> > just do what we do now and hope for the best.
> 
> If we're going to allow falling back on Linux hosts too I reckon this
> might be the way to go - policies can then look for a usable binary and
> decide which way to go. Or maybe it's better in the general plugin
> support code.. dunno - I think I'd need to see how it looked.
> 
> Cheers,
> Bryn.
> 

I think, in the simplest form, this commit shows how we can do this:

https://github.com/jhjaggars/sosreport/commit/2300c2e0d61ad6a241e82ffbcfcb72822f1f70ee

This patch offers no policy-level customization, but that might not
matter right away.

Jesse
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