Re: [sca-bindings] Issue 126: proposal to add support for ws-addr (v1)

[Mike Edwards <mike_edwards@uk.ibm.com>]

Folks,

I'd first like to thank Anish for the
work he has done on the proposal document.

However, after thinking more about this
issue and discussing it within IBM, I have reached the
conclusion that there is not much point
in requiring support of WS-Policy without having some
concrete policies that are required
to be supported by any binding.ws implementation.

I'm afraid that I don't think that the
WS-Addressing assertion or the WS-Callback assertion 
qualify.  I believe that both are
optional.

As a result, at the moment, I see no
concrete assertions which force the requirement to support WS-Policy.

I think that we should Close with No
Action Issue 126 and bring something like it back in the future
if we ever decide to add mandatory support
for one or more assertions (eg security related assertions).



Yours,  Mike.

Strategist - Emerging Technologies, SCA & SDO.
Co Chair OASIS SCA Assembly TC.
IBM Hursley Park, Mail Point 146, Winchester, SO21 2JN, Great Britain.
Phone & FAX: +44-1962-818014    Mobile: +44-7802-467431  
Email:  mike_edwards@uk.ibm.com

From:	Eric Johnson <eric@tibco.com>
To:	Anish Karmarkar <Anish.Karmarkar@oracle.com>
Cc:	OASIS Bindings <sca-bindings@lists.oasis-open.org>
Date:	06/05/2010 01:56
Subject:	Re: [sca-bindings] Issue 126: proposal to add support for ws-addr (v1)

---

I've not looked at the specific proposal yet, but my skepticism
persists.

Just because we're unable to to test a proposal to mandate something, we've
gone down the path of:

• Mandating support for WS-Addressing
• Mandating support for EPR where we used to just suggest it.
• Mandating support for the WS-Policy indication that flags the use of WS-Addressing
• Mandating support of the protocol assertion for the protocol when support is there

... all around an issue where
we all seem to agree that the use cases are unclear.  My design instincts
are screaming "feature creep!"  All of this nets out to
an implementation needing to recognize the WS-Addressing assertion in a
concrete referenced WSDL, and then using the support that we've now mandated. 
It doesn't actually reveal much about actual support for the underlying
concern - WS-Policy.  The above set of mandates does reveal the ability
to recognize XML elements in a particular scenario and not barf them up,
but that's about it.

WS-Policy is a particular XML-based expression of a model for policies
- a "platform dependent model" (PDM) in UML terms.  SCA
intents come close to being a "platform independent model" for
policy requirements as I've seen.  

Without a mandate to use WS-Policy, implementers can happily punt on correlating
between the two, and hopefully avoid complexity for themselves and their
customers by always generating one (the PDM) from the other (PIM). 
In fact, the way to generate the PDM from the PIM is to define the mechanism
that does the one-way translation.  In mandating WS-Policy, we might
make it necessary for implementations to think about having a bi-directional
model between the two, where (a) it might not make sense, and (b) it may
actually be more confusing to the end-user than simply giving an implementation
the freedom to say "I don't understand how to do what you're asking
me."

Does anyone actually have implementation experience that suggests that
this particular mandate works?  If so, I will happily hear the details
and how they work, and be quiet.  Otherwise, I think we're going to
far with 126.

-Eric

On 05/05/2010 01:09 PM, Anish Karmarkar wrote: 
Attached. 

The proposal uses cd03-rev4 as the basis (with changes accepted). The relevant
changes are confined to section 2.10 (new section) and section 6.4. Do
note that Mike & I had taken a joint AI to produce a complete proposal
for issue 126. The attached doc adds support for ws-addr but not for ws-policy.

I have made one change that was not discussed on previous calls or on the
ML: when the callback protocol is supported I had made changes that require
the runtime to support the callback protocol policy assertion. Since this
proposal is about requiring ws-policy, I thought it made a lot of sense
to mandate support for the protocol assertion when the protocol is supported.

If this (or something like this) is accepted, I think we should make the
endpointReference element mandatory (currently it is a SHOULD). Especially,
since the UPA issue resolution means that it would be the same element
defined in ws-address. But on the last call, someone expressed preference
to deal with this separately. I'll raise an issue related to that if/when
126 is resolved. 

Mike: I know this proposal doesn't give you a lot of time to add ws-policy
support before the bindings call. Please let me know if you don't have
time and I can try and add that later this evening/tonight (my time). 

Thanks. 

-Anish 
-- 


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