[Python-Dev] Proposal for Python 3.3: dependence injection

[Antoine Pitrou]

On Fri, 25 Mar 2011 21:10:08 +1000
Nick Coghlan <ncoghlan at gmail.com> wrote:
> On Fri, Mar 25, 2011 at 12:22 PM, Glenn Linderman <v+python at g.nevcal.com> wrote:
> > On 3/24/2011 4:25 PM, Nick Coghlan wrote:
> >
> > As an example of the last point, perhaps rather than modifying all the
> > *clients* of the socket module, it may make more sense to have tools
> > in the socket module itself to temporarily customise the socket
> > creation process in the current thread. The advantage of such an
> > approach is that it would then work for 3rd party libraries that
> > create sockets, without requiring any further modification.
> >
> > Would be easier to implement that way, not requiring changes to every client
> > of the socket library, but in some circles that would be called "action at a
> > distance", and harder to understand.
> 
> Oh, it is definitely action at a distance, and quite deliberately so.
> 
> My model for the suggestion is the context objects in the decimal
> module. They offer a constrained way to affect the way the entire
> decimal module goes about its business, and through judicious use of
> thread local storage and context managers, allow this to be done
> without distorting the public API of the decimal objects themselves.

Making an API TLS-based means your code breaks mysteriously if you
start offloading tasks to separate threads (which is quite common with
network-related tasks).

Regards

Antoine.