[UNCLASSIFIED]RE: [clug] Web services / SOA reference
Richard
richard_c at tpg.com.au
Fri Dec 16 11:26:25 GMT 2005
Antti.Roppola at brs.gov.au wrote:
>I recently saw a few SOA presentations that were a hommage to the theory that all
>programming problems can be solved by adding another layer of abstraction. The devil
>would seem to be in the detail (boundaries), otherwise all an "Enterprise Services Bus"
>would do is to provide a black-box in which to hide the spaghetti the "before" diagram.
>
>
Well, that's sort of true. I tend to think it's a way of slicing up a
system that you're about to build, rather than explicitly adding cruft.
The thing for me is that you accept a few principles in your development
beforehand (if any of these aren't true, then you can very comfortably
put SOA to one side without further consideration):
a) whatever you build, it will end up as a distributed system of some kind.
b) all distributed systems require IPC.
c) Once we're breaking this problem up into different pieces, we should
make sure we can reuse the pieces when we're done by tightly regulating
the IPC interface, and keeping the calling conventions vendor/language
neutral.
SOA is all about the interface. All other implications of SOA flow from
the idea of a strictly defined, open interface, to generally useful
systems. That's about it. The usual corrollary of "if anyone tries to
make it more complex then they're trying to sell you something" applies
here. There are implications at all stages of the software/project
lifecycle once you start trying to reuse complete systems at a macro level.
For mine, ESB is one of those buzzwords that instantly brands the user
as a poor imitation of a professional. As you've noted, the ESB concept
doesn't bear close scrutiny. I feel ESB's just used by vendors who want
to be a part of the marketing buzz that did surround EAI, and now
surrounds SOA.
For the record, any EAI, that isn't/wasn't SOA is probably crap. IMO ESB
vendors are the try hards from the EAI space. Only BEA /might/ have
claim to something like an "Enterprise Service Bus" - just as soon as
they nail down what it is (and isn't).
Waaaaaaaayyyyyy too many TLAs in here...
Richard
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