[dundee] It's soa point, and SFD, and the have soap and rest....

[Rick Moynihan]

2008/10/16 Lee Hughes <toxicnaan at yahoo.co.uk>:
> next, on the list, I've been exposed (in a good way) to soa / soap and rest
> , and  that's not me having a shower and then a snooze. I just wondered if
> anyone else has see this in action in enterprise type networks, it's
> certainly looks interesting. I've always liked the idea of distributed
> services, but the only options in the past have been the evil dcom or even
> eviler Corba. At a guess .net probably this new soap and rest stuff package
> up in Microsoft marketing, but I digress...
>
> soa seems to be a great way of just gluing everything together in the
> enterprise, getting
> some extra millage out of legacy application that won't talk to anything...
> Here's to the enterprise service bus!!!! perhaps!!??

Hey Lee, I'm afraid I'm *way* more _cynical_ about the whole
Web-Services stack.  Now, I've not got any direct experience in
large-scale enterprise deployments; but I have worked on projects
which have had to both provide and use SOAP based services, and it's a
real mess!

People always accuse CORBA of being a real pig, and again I've not got
a significant CORBA background (though again I have developed a few
simple CORBA clients/services in several languages), but I genuinely
believe WS-* hasn't, at least architecturally made any real
improvements to CORBA.  Arguably towards the end, CORBA was getting a
lot better, but by then the mas exodus to web-services had begun.

SOAP however is far from simple, and suffers from a whole host of
problems.  The biggest, ironically is it's massive sprawling
complexity...  I mean to do SOAP properly, you need to be able to
handle and process XML, validate XML-Schema's, and be able to generate
WSDL.  All of these technologies are in my experience poorly defined
and implemented and are unsuited to the problem...  Rather than admit
this though, the WS-* vendors choose to cover up these flaws with yet
more rampant poorly defined standards....  Essentially Microsoft and
IBM reimplemented CORBA on top of an unholy combination of HTTP and
XML, ultimately creating something who's only similarity to the web is
port 80.

REST however seems to be a lot better, and I hold out some hope for it
as unlike WS-Deathstar it doesn't go against the grain of the web.
However it's pretty lacking in tool support, but is pretty simple...
It's benefit is that it's lightweight... However, I suspect some more
complex services will be a little awkward to represent in a RESTfull
way.

In my own opinion, very little has come close to Sun's Jini platform
in this space (See Apache River).  Jini essentially handles the real
issues in distributable service design, such as failure and
self-healing...

It is fault tolerant due to it's implementation of lookup-services,
and leases.  It has tuple-spaces for building workflows between
co-operating services.  It's also network protocol agnostic, meaning
you can implement Jini across a combination of networks

The biggest catch with Jini in this space, is that due to it's use of
mobile code, it requires clients to be able to consume and run Java
class files, whilst services need to publish Java interfaces.  These
shortcomings can be overcome by proxying but it's Java-centricity may
mean it's unsuitable.

Anyway, I think we're still yet to see a good solution in this space;
but there are some interesting component technologies.  I personally
think Messaging Queues hold a lot of promise (preferably without the
XML WS-* bloat).  I'm personally quite keen to take a look at rabbitmq
with JSON messaging, or Amazon's SQS (Simple Queueing Service).



> also, while I was research web services, I can along amazons e2 service?
> seems pretty
> far out, anyone used this, or thinking about using it? A virtual host with
> 160gb of storage, 1.7gb of ram , and the ablity to scale up servers on the
> fly when you need capacity, seems like a crazy idea, but does it work.

Yes, Amazon EC2/S3 and SQS are pretty awesome.  One of my colleagues
raves about EC2, though I myself haven't used it yet.  There were some
limitations to be aware of though, the biggest being data persistence
(though I believe you can now pay a bit more money and get this too).

--
Rick Moynihan
rick.moynihan at gmail.com
http://sourcesmouth.co.uk/