Hope this all makes sense.
[Jones,
Steve G] Definitely makes sense, to me this is why the mixed mode (and the
concept of hierarchy of IT and business) should be the norm, so policy can
both be delegated upwards “You say who can call me” and downwards “Thou shalt
record everything”. So both service container and bus must be able
to exchange policy and manage policy enforcement. I think I’m agreeing
with you, I just thought it was a good topic for debate as the “single bus”
model is often pushed by vendors, in a similar way to the “one EAI” solution
was 5 years ago.
[Marchant, Dan
R.] Maybe even one object
broker...
On Nov 22, 2005, at 4:54 AM, Jones, Steve G
wrote:
One question on Meta-data from a blueprints
perspective, do we feel that
Meta-data resides with the service or with the
bus? This isn't an
esoteric
debate, it's about how services are deployed and
managed. One view is
that
the service has all of the policy elements and does
the all the management
and adherence, this is the full autonomous view of the
world. The
other
side is that the service just provides functionality
and it is the
enterprise (the bus) that defines and enforces
policy. One other way
I've
seen work successfully is where the service has the
policy for its minimal
state of operation, while the bus contains the policy
related to actual
interactions.
In this last case the ability of the bus is only
to
strengthen contracts and add them rather than being
able to over-ride.
I've tended to use the later case as it fits with a
hierarchy pretty well.
But is it the blueprints going to provide examples of
multiple types of
policy management approaches or stick to a single
recommended best practice?
-----Original Message-----
Sent: 21 November 2005 19:51
Subject: RE: [soa-blueprints]
WS-TX
Agree.
The descriptive metadata for all entities involved in
SOA,
e.g. content as well as services, should adequately
describe that
entity so a user (both providers and consumers) knows
what the entity
is, when it is applicable, and how to apply it. Context is
obviously
a big part because the details of what is described
may change with
I would also add that there may be options to include
some of the
work done in the WS-CAF TC for
context.
It is not as rich as it should be but feedback to that
group might
-----Original Message-----
Sent: Monday, November 21, 2005 10:24
AM
Subject: Re: [soa-blueprints]
WS-TX
I would expect the service metadata to include, or
more likely
prominently link to, representations of policies under
which the
service wishes to perform. Per the SOA-RM, policies represent
a
"wish list" for the service, where some items may be
negotiable and
some not.
Establishing the "execution context" is the mechanism
by
which provider and consumer policies are aligned and
conflicts
resolved;
it may be thought of as a negotiation of
policies
resulting in a contract between the parties. A service
invocation
becomes possible and may occur within an established
execution
context.
The transaction semantics would not be changed, but
some
level of semantic mediation may be necessary in the
process of
creating the contract, including documenting what
mediation has occurred.
At 12:28 PM 11/21/2005, John Harby
wrote:
I joined the WS-Transactions TC and attended their F2F
last week.
Although I don't think we have the sort of
liason
requirements that we may have in other SOA related
TCs, the notion
of SOAs and services did come up in the discussion.
One particular
example was compensation (e.g. in a rollback
scenario), certain
services may be compensatable and others may not. It
wasn't too
certain whether this property should be expressed in
the service
metadata or some policies. It was extremely
undesirable to that
group for the transaction semantics or protocol to be
modified though.
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