Matt,
Well almost.
I've always viewed this as a directed search via
classification and
taxonomy tools - with linking and
switching.
There is in fact a good example of this approach in
the OASIS BCM
specifications.
So once you initiate a search for what you need -
you actually enter
a directed response tree with agent smarts - to get
you to the right
place - via prompts / decisions / selections - from
what the registry
knows about the domain you are
querying.
That probably all sits neatly above the middleware
glue you are
probably talking about - but is vital in ensuring
the right 'docking'
occurs.
DW.
----- Original Message -----
Sent: Sunday, April 18, 2004 11:47
AM
Subject: [regrep] service discovery,
finding an object's registry with only an ID...
With ebR being the backbone for our version of what Service
Oriented Architecture is, it will become increasingly important to make
resolution of registry services something that can be done with absolutely no
initial software configuration.
Many years ago, the internet community
realized that /etc/hosts or lmhosts files would not be a scalable way of
aliasing services and making applications impervious to hardware change and
movement. DNS was born as a result of that. Now, I cannot imaging the internet
without DNS.
Fairly recently, some people at Apple Computer published
an Internet Draft, titled "DNS-Based Service Discovery" (DNS-SD). Its goal is
to define an interoperable way to find out about things in the application
layer from DNS. DNS-SD words with standard unicast DNS, so that means the well
established, tested and deployed DNS resolver libraries on every platform can
be leveraged for service discovery. DNS-SD relies on SRV and TXT records. To
find registry services in a given domain, a query against SRV records may be
made. Extended info about how to build a registry URL would be embedded into a
TXT record.
Sample Session
Step 1: SRV query ->
_ebr._tcp.adobe.com Response: 0..n PTR records
Step 2: Given
returned PTR records, select one. Not sure if there should be a selection
criteria.
Step 3: Interrogate TXT record from selected PTR to obtain
HTTP-binding info. TXT record may contain stuff
like: Hostname=foo.adobe.com, Port=9080,
HBindPrefix=/ebxml-registry/http-binding
Step 4: Do something
against the registry.
The session above illustrates more of an
'intra/extranet' model of finding a certain type of service. It would be
possible to use a central DNS service to allow applications to resolve
UUID/IDs into fully qualified URIs,
e.g.
urn:dnssd:oasis:ADBE:6677-999-888j-jhhh
The reason for
sending this message to this list is to solicit interest in this concept. If
others are interested, I would like to prepare some sort of proposal for the
3.0 timeframe.
Comments?
___________________________/bigger>/color> Matthew
MacKenzie /bigger>Senior
Architect IDBU Server Solutions Adobe Systems Canada
Inc. http://www.adobe.com/products/server/ mattm@adobe.com +1 (506)
871.5409/smaller>/color>
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