Hi,
At 09:48 AM 4/7/2002 -0400, Richard Dice wrote:
>Hi everyone...
>
>I notice that Doug MacEachern has just posted a mod_perl 2.0 pre-release
>announcement on [EMAIL PROTECTED], and in it he says that it requires
>Perl 5.6.0. I know that the p5ee effort decided that Perl 5.5.3 is all
>that should be required for p5ee. I guess I should ask, to what degree
>is (will) mod_perl (be) integrated with the p5ee effort? I'm not
>asking if Doug will sign the copyright over to p5ee or anything like that.
>:-) Just, how much will p5ee tie into and depend on mod_perl, anyhow?
>And might this influence the version of Perl that p5ee requires?
>From what I understand, this is really two questions:
1. What is the relation between P5EE and mod_perl?
2. What does it mean for P5EE to support Perl 5.5.3 if some
of its components require a higher version of Perl?
1. Relation Between P5EE and mod_perl
The people who have been developing and working on mod_perl have done
an incredible service to Enterprise Perl in general, and therefore
the P5EE in particular. Other efforts that dramatically enhance
Enterprise Perl are SOAP projects, XML projects, DBD/DBI::*,
Templating projects, etc. These are all making dramatic contributions,
and they need not change anything they are doing in order to continue
to do so.
On the contrary, the responsibility is on the designers of the P5EE
to accommodate and incorporate these many enterprise-class technologies
into an integrates whole. Browse the classes envisioned for P5EE
by P5EEx::Blue to see one way that these might fit together. Take
special note of the "Classes (Planned)" at the bottom of the
"All Classes" frame.
http://www.officevision.com/pub/p5ee/software/htdocs/api/
As for mod_perl, it would seem to be the container of choice for
web applications and SOAP services.
http://www.officevision.com/pub/p5ee/software/htdocs/P5EEx/Blue/Context.html
There is no need for the mod_perl project to explicitly
integrate with P5EE. However, in the spirit of community,
as the P5EE grows in its capabilities, I would imagine a
natural cross-fertilization of ideas would occur so that if P5EE needed
any specific feature in mod_perl it would be implemented without
too much trouble.
However, P5EE reaches further than just running in a mod_perl Context.
P5EE is equipped with (when they are written, of course) a variety of
Context classes which allow P5EE software to run in many other Contexts
besides mod_perl.
2. P5EE Support for Perl 5.5.3
The P5EE (as envisioned in P5EEx::Blue) is like a software backplane
for many services required by an enterprise application. Into that
backplane plug the P5EE Services. There may be many implementations
of each of the P5EE Services, making for an almost limitless array
of possible combinations. (Hopefully, favorites will emerge.)
The Context is a Core Service, like Session and Config.
(A Core Service is one that is not derived from P5EEx::Blue::Service
but maintains the concept of "a pluggable implementation of an
abstract service".) An examination of the P5EEx::Blue::Context
documentation will show that there are many Contexts from which
the implementer may choose to deploy the software, and the software
could reasonably run on all of them. The fact that (the envisioned)
P5EEx::Blue::Context::Modperl2 depends on 5.6.0 does not invalidate
the fact that the P5EE depends only on 5.5.3. Implementers who
choose to deploy with Services that have higher Perl version
dependencies must of course satisfy those dependencies.
The important thing to realize is that there is some combination of
implementations of Services which will run on 5.5.3. Thus, the
implementer who is stuck with 5.5.3 on a platform does indeed have a
set of possible combinations of Services which will work.
The dependency on Perl version is not the only issue like this.
Some modules are dependent upon certain operating systems.
It is acceptable for a Service implementation to use these OS-specific
functions as long as there is some other Service implementation
(perhaps lower performing) which meets the cross-platform requirement.
i.e. P5EEx::Blue::Context::Modperl2 may require 5.6.0, but
P5EEx::Blue::Context::Modperl and P5EEx::Blue::Context::CGI will
both run on 5.5.3.
Sometimes when we think about Enterprise Systems, we think about
big budget projects with the latest new hardware. My experience
with customers who are large enterprises is that they have an
incredible mish-mash of systems and legacy environments. I envision
that P5EE software could be installed on every platform they own
(isn't Perl almost the most-ported language on the planet?).
That is why I believe that P5EE must support 5.5.3 (or perhaps
earlier, but I won't go there yet until I see a real need to
and understand exactly what I would be giving up).
Stephen
