[Web-SIG] [Proposal] "website" and first-level conf (was: more comments on Paste Deploy)

Chad Whitacre chad at zetaweb.com
Sun Mar 4 05:27:29 CET 2007

> >> >    2. I'm not clear on how Paste Deploy's abstractions map to the
> >> >       filesystem. What does my website root look like?
> >>
> >> The way I have generally configured websites like this is like:
> >>
> >>    [composite:main]
> >>    use = egg:Paste#urlmap
> >>    / = config:root.ini
> >>    /blog = config:superblog.ini
> >
> > Right, that's the configuration, but where is "egg:Paste#urlmap" on
> > the filesystem? Are the three ini files alone in some directory? Where
> > is paste? Where is SuperBlog? Where is the rest of the site? I find it
> > easier to start with the filesystem and then move up into
> > object/config abstractions.
> You just have to understand what egg:Paste#urlmap is, probably from some
> documentation.  Admittedly that's boilerplate in the eyes of most people
> who use it.  It's there explicitly because Paste Deploy doesn't build
> *any* WSGI anything into it, it only composes pieces, one of the most
> common being urlmap.  You can see docs for it with "paster points
> paste.composite_factory urlmap", though I now notice I haven't written
> any docs for it (bad of me), and that is hardly a simple command line.
> I would certainly want to build a command-line help/browser (and
> probably web one too) as part of a rewrite of the system.
> The three ini files do go in the same directory, though of course you
> could do config:superblog/app.ini or something like that if you wanted
> to set it up differently.  It's a relative filename, relative to the
> file where it is given.
> The applications themselves are eggs.  You install them however you want
> to install them (of course I'd strongly recommend workingenv,
> virtual-python, or zc.buildout, but that's a separate concern).  Some
> people have mentioned some frustration about having to build full
> libraries with a namespace, setup.py, eggs, etc. just to use
> applications.  But I think even pretty modest shops writing very one-off
> apps gain a real benefit from these patterns, once you get over the
> initial hump (and we can build tools to make the initial hump not so
> bad, that's the point of paster create).  Anyway, here's one reply I
> made to that request:
> http://pythonpaste.org/archives/message/20070215.192041.1534ce27.en.html
> There's a lot of practices around library management that *has* to be
> done, because people use libraries.  Most of this applies pretty well to
> applications as well -- and since everyone *needs* to learn how to
> manage their libraries, using the same mechanisms for managing
> applications has some advantage.
> Incidentally, one change to the config format that would make it
> possible to remove the explicit idea of "composite" apps, is to make
> some key syntax that will instantiate the named object.  E.g.,:
>    app / = config:root.ini
> Then the keywords passed would just be {"/": <actual WSGI app>}, instead
> of the current {"/": "config:root.ini"} (where the "config:root.ini" is
> passed to the loader object that the composite factory gets).

Dude, my eyes are seriously glazing over. I want you to say something
simple, like:

  $ cd /usr/local/www
  $ workingenv.py example.com
  $ cd example.com
  $ source bin/activate
  (example.com)$ mkdir etc

  Then stick a config file in etc/ and run a simple command to start
your website.

That's the kind of thing I imagine you doing (eh?), and it's also the
thing that Aspen does. The difference is mostly in the config files.

Now, Jim: it looks like Zope still uses a Unix-y userland for
INSTANCE_HOME, yes? So that's Paste, Pylons(?), Aspen, Zope2 and Zope3
all using the same filesystem layout. IINM the filesystem structures
of Django and CP/TurboGears are module-level (Bob?), so they could
easily fit into lib/python.

If we could agree on a really simple first-line config file that
handles basic process configuration--address, user/group, threads,
etc.--and then points to the next layer config--be it zope.conf,
paste.ini, apps.conf, or settings.py--then we'd be pretty far towards
a common app server.

That is to say, I think we are really discussing three increasing
levels of cooperation:

  1) Server benchmarks and inter-op standards (Jim)
  2) Common process management library (Bob)
  3) Common web app server

Without discouraging the first two efforts, I'd like to champion the
third. Here would be my proposal:

First, we define a "website" on the filesystem as a Unix-y userland
with, at minimum, the following:


Second, we adopt a simple ini-style format for <foo>.conf, which
handles low-level process config. This file would then point to a
second, framework-specific configuration layer.

I suggest that this isn't too far from where we each are now, nor from
where our discussion has already led. It fits long-established
patterns (etc, ini), and doesn't preclude cooperation on benchmarks,
inter-op, or libraries. Furthermore, collaborating here would spread
around what amounts to grunt work, and give Python web deployment a
simple and compelling story, while in no way crippling more advanced
use cases.

Are you guys interested in this proposal? If so, I can write it up in
more detail.


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