While
I do agree that the translation (or interface normalization), caching and
aggregation are type of blueprints or patterns to follow.
I
don't necessarily think that a ESB is the right solution in all cases to
accomplish those concepts.
An ESB
is merely a way to realize the "interface normalization" for a particular
business domain within your implementation.
The
federated or virtualization concept around infrastructure should be something to
consider in the blueprints.
The
ESB in my opinion is still not fully defined and this is only one example of
usage.
Maybe
a federated portal bus with an ESB backing that is what you need...
:)
-
Dan
-----Original Message-----
From: Friedman, Eric D.
Sent: Monday, December 05, 2005 5:10 PM
To:
;
Subject: RE: [soa-blueprints]
The Myth of ESB... is it a blueprint or a pattern...
We’re 2+ years into a
production ESB implementation in my line of business, so I think I can speak
with some authority on this one.
Writing services has
become easier, but it’s still not easy. Having an ESB and an associated
team lets us approach services from a ‘center of excellence’ standpoint.
No vendor has come up
with good solutions to the challenge of versioning services. Indeed,
it’s very hard to write XML Schemas that version well – it’s a defect of the
schema for schemas itself, not just a vendor gap (though it is that
too). So, our ESB gives us an opportunity to buffer our development
teams against the thrash in the enterprise
beyond.
Services are often
delivered in “one size fits all” format. An ESB is a chance for us, as
one of many lines of business, to tailor that service to our own ends, adding
caching or applying security and visibility restrictions. This goes to
Steve’s point about needing to assume that buses are >1 in
number.
The ESB lets us
forward responsibility for certain kinds of complexity. If an enterprise
service only provides a SOAP/HTTP interface, we can put an ESB service in
front of it that does guaranteed delivery using JMS and then let the ESB be
responsible for getting it through to the less-reliable
interface.
The ESB is the
natural place to implement fan-out of parallel service calls.
Multithreaded programming is hard enough that we don’t want most developers
doing it. Doing this sort of thing in the ESB lets it provide “value
add” aggregating services that the enterprise will not
cover.
Looking into my
crystal ball, I think the next big push in this arena will be to virtualize
ESBs. Today, our ESB is a network-addressable endpoint with SLAs and the
whole shooting match. In a heterogeneous computing environment we’ll
always need that to some extent, but it is reasonable to ask why we’d continue
to incur the cost of network indirection for the ESB when we can just
co-deploy. Perhaps with the rise of ‘utility computing’ that will just
“happen” in infrastructure and we won’t have to think about
it.
Eric
Friedman
Wells Fargo Private Client
Services Architecture
From: Jones,
Steve G [mailto:]
Sent: Monday, December 05, 2005 3:33
PM
To:
Subject: [soa-blueprints] The Myth of
ESB... is it a blueprint or a pattern...
A question to the group
Back in the old “Enterprise
Application Integration” days the vendors pushed a model which had either a
single broker in the middle, or a bus in the middle. The common element
was always that “one” thing in the centre. We are now seeing the same
thing with ESB, the concept of a single bus (product) that rules the
enterprise. With EAI one of the biggest challenges was that product
centric view of the world which led to organisations being left with “legacy”
EAI which is as much of an issue as the applications it was meant to make easy
to access (any Monk programmers out there?).
So what my strawman is to this
group (and as the Soalogic thing evolves its quite important) is that concept
of bus federation is essential to an SOA Blueprint, you must assume that there
will be multiple busses, potentially at all levels, these may use similar
technology (even identical) but the principles of federation should be the
default for a well formed SOA. Now is this a pattern or a blueprint, and
if a blueprint where should it be considered. My viewpoint is that there
needs to be an official counterpoint to the vendor view that takes a Lord of
the Rings (one ESB to find them all and in the darkness bind them) approach to
delivery. The best ESB is the one that assumes it isn’t the only thing
around.
Steve
___________________________________________________________
Steve Jones | Capgemini
CTO, Application Development
Transformation
T +44 870 906 7026| 700 7026|
www.capgemini.com
m:
txt: +44 (0) 7891157026
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