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Subject: RE: [wsbpel] Issue - 72 - ( was RE: [wsbpel] Issue 47 and WS-I BP 1.0)
Ugo,
I think Peter already made a related point, but just to reiterate the idea:
BPEL has nothing to say about what ports are offered when the process is
deployed. The validity of a process definition is really not affected by
how the process gets deployed.
When thinking about interop one has to keep the layering of specs in mind.
At some point WS-I may decide to define a profile that includes BPEL.
Following the natural layering of specs, it should leave all BP 1.0 issues
to WSDL/XSD/SOAP and concentrate on the additional function that BPEL
introduces. The BPEL interop discussion should not be about what ports are
deployed, but about consistently interpreting process behavior, something
we should be able to do that even in deployments that use proprietary
protocols (such as SOAP over MQ.)
This is independent of the fact that to achieve end-to-end WS-I interop at
all levels of the stack you'll need to apply the whole stack of WS-I
profiles.
Paco
"Ugo Corda"
<UCorda@SeeBeyond To: "Furniss, Peter" <Peter.Furniss@choreology.com>, "BPEL OASIS"
.com> <wsbpel@lists.oasis-open.org>
cc:
10/02/2003 01:19 Subject: RE: [wsbpel] Issue - 72 - ( was RE: [wsbpel] Issue 47 and WS-I BP 1.0)
PM
My point is that, for interoperability purposes, a BPEL process should
provide at least one BP-compliant portType/binding/port. In addition to
that, it could provide any other non-compliant elements.
The "at least one" requirement assures that we would not get into the
embarrassing situation where two companies build two brand new BPEL
processes (not talking about legacy Web services here) and still the two
processes would not be able to talk to each other (not too good for BPEL's
reputation ...).
Ugo
-----Original Message-----
From: Furniss, Peter [mailto:Peter.Furniss@choreology.com]
Sent: Thursday, October 02, 2003 10:04 AM
To: Ugo Corda; BPEL OASIS
Subject: RE: [wsbpel] Issue - 72 - ( was RE: [wsbpel] Issue 47 and WS-I BP
1.0)
How on earth is that to be enforced ? Are we considering an abstract case,
a bpel engine, a process script or a particular running instance ? Does a
BPEL script that has one BP-compliant partnerlink become illegal if one day
it's bound (via appropriate WSDL) to MQ ? Must a BPEL engine fault an
attempt to use it to map between a non-BP 1.0 client and a differently
non-BP 1.0 service, mangling between the messages to make them acceptable
to each.
Peter
-----Original Message-----
From: Ugo Corda [mailto:UCorda@SeeBeyond.com]
Sent: 02 October 2003 17:54
To: Furniss, Peter; BPEL OASIS
Subject: RE: [wsbpel] Issue - 72 - ( was RE: [wsbpel] Issue 47 and WS-I BP
1.0)
Please keep in mind that saying that BPEL should offer a BP-compliant
service only means that at least one WSDL port offered by the BPEL process
has to be BPEL-compliant. The BPEL process could provide additional
non-compliant ports and still be considered BP-compliant.
Ugo
-----Original Message-----
From: Furniss, Peter [mailto:Peter.Furniss@choreology.com]
Sent: Thursday, October 02, 2003 2:30 AM
To: BPEL OASIS
Subject: [wsbpel] Issue - 72 - ( was RE: [wsbpel] Issue 47 and WS-I BP
1.0)
I would strongly support Postel's law in general, but I'm not sure it
applies so easily to BPEL.
The detailed content and format of particular messages sent from (be
conservative) or received by (be liberal) a BPEL process are obviously
subject to Postel's law, but that's a matter for the binding and the
involved protocols, and their profiles.
The equivalent for BPEL would first appear to be, as Ron says, be liberal
in the web services you use, conservative in the ones you offer. However,
the use/offer polarity is determined by the WSDL MEP's in use. In the case
of asynchronous relationships, where there are paired port types one-way
operations, there isn't any obvious distinction as to which side is doing
the specifying and which is obediently following it. Even for
request/response patterns, it isn't invariably the case that the server
has freedom to choose (and thus to obey BP 1.0) and the client has to
follow the dictates of the server (whether it obeys BP 1.0 or not), which
is the basis of Postel's law.
For BPEL, or indeed for business protocols in general, which side has the
initiative is probably determined by other features (which side has more
economic clout or more deployed implementation or less intelligent
developers or got there first). Postel's law applies as something like "be
generous in what you demand of others, providing there is unambiguity; be
precise in how you follow the demands of others, even if it doesn't seem
entirely reasonable".
Peter
-----Original Message-----
From: Ron Ten-Hove [mailto:Ronald.Ten-Hove@Sun.COM]
Sent: 01 October 2003 21:48
To: Eckenfels. Bernd
Cc: BPEL OASIS
Subject: Re: [wsbpel] Issue 47 and WS-I BP 1.0
Perhaps we should invoke Postel's law, with respect to basic profile
conformance. To promote interoperability, we should be as permissive as
possible when dealing with (other) web services, but as conformant as
possible when creating our own (BPEL engine provided) web services.
I realize this falls mostly on implementations to worry about, but
the basic profile does contain a lot of restrictions and clarifications
for the "abstract" service model that may be of interest.. The ban on
operation overloading might be slightly simplifying, for example.
Anyway, a quick scan of the BP didn't reveal anything scary to me. It
seems to me that WS-I BP 1.0 compliance will be an implementation worry,
but as a technology that will rely on interoperation of our SOAP
infrastructure, we ought to encourage (but not mandate) BP compliance.
-Ron
Eckenfels. Bernd wrote:
Hello Ugo,
I think it is not good to speak about violation if an
implementation is able to communicate with an larger number of
systems.
Perhaps we should chnage this: "conformant BPEL engines must be
able to provide and consume Web Services according to BP 1.0a
specification. Engine should not provide Web Services with HTTP
SOAP binding other than BP1.0 conformant.
Actually I see the point of requiring BP1.0 support as a
conformance rule, but I dont see a point of restricting engines to
that, even if it applies.
Mit freundlichen Grüßen
Bernd Eckenfels
Chief Architect
--
SEEBURGER AG - Edisonstr.1 , D-75015 Bretten, Germany
Fax: +49 (0)7252 96-2400 - Phone: +49 (0)7252 96-1256
mailto:b.eckenfels@seeburger.de - http://www.seeburger.de
-----Original Message-----
From: Ugo Corda [mailto:UCorda@SeeBeyond.com]
Sent: Wednesday, October 01, 2003 8:28 PM
To: Satish Thatte; Prasad Yendluri; Eckenfels. Bernd
Cc: BPEL OASIS
Subject: RE: [wsbpel] Issue 47 and WS-I BP 1.0
Right, RPC literal would be fine, but RPC encoded would be in
violation.
-----Original Message-----
From: Satish Thatte [mailto:satisht@microsoft.com]
Sent: Wednesday, October 01, 2003 11:23 AM
To: Ugo Corda; Prasad Yendluri; Eckenfels. Bernd
Cc: BPEL OASIS
Subject: RE: [wsbpel] Issue 47 and WS-I BP 1.0
So for instance the RPC encoded services bound to SOAP/HTTP
would be in the “in scope but in violation” category?
From: Ugo Corda [mailto:UCorda@SeeBeyond.com]
Sent: Wednesday, October 01, 2003 11:18 AM
To: Satish Thatte; Prasad Yendluri; Eckenfels. Bernd
Cc: BPEL OASIS
Subject: RE: [wsbpel] Issue 47 and WS-I BP 1.0
Let me clarify point 4 (sorry, I mislabeled it as 3) in
relation to point 1.
I think we should distinguish services that are not compliant
with BP 1.0 from those that are simply out of scope for BP
1.0.
If I have a Web service that is not bound to SOAP/HTTP, then
I would say it is out of scope for BP 1.0, so it's OK for
BPEL to interact with it.
My point 4 is about services that are within the scope of BP
1.0 and still do not comply with its requirements.
Ugo
-----Original Message-----
From: Satish Thatte [mailto:satisht@microsoft.com]
Sent: Wednesday, October 01, 2003 11:09 AM
To: Ugo Corda; Prasad Yendluri
Cc: BPEL OASIS
Subject: RE: [wsbpel] Issue 47 and WS-I BP 1.0
I doubt that we can mandate BPEL to be used with BP 1.0
compliant services only especially given the answer to 1
assuming it is correct, and given that there are many
services today that are not compliant (e.g., RPC encoded
ones).
From: Ugo Corda [mailto:UCorda@SeeBeyond.com]
Sent: Wednesday, October 01, 2003 10:55 AM
To: Satish Thatte; Prasad Yendluri
Cc: BPEL OASIS
Subject: RE: [wsbpel] Issue 47 and WS-I BP 1.0
I see a few separate issues/questions connected to the
relationship of BP 1.0 and BPEL.
1- Would BP 1.0 be restricting BPEL to the point that some
of BPEL's functionality would not be available?
I cannot think of any such restriction off the top of my
head.
2- Would the fact that BP 1.0 only addresses the SOAP/HTTP
binding imply that also BPEL should be limited to that type
of binding?
I don't think that anybody would imply that.
3- Should a BPEL process be offered as a Web service that is
BP 1.0 compliant?
My answer would be yes.
3- Would it be fair to limit BPEL use to interacting with BP
1.0 compliant Web services only?
My personal answer would be yes. But I am a member of WS-I,
and I understand other people might have different answers.
Ugo
-----Original Message-----
From: Satish Thatte [mailto:satisht@microsoft.com]
Sent: Wednesday, October 01, 2003 10:39 AM
To: Prasad Yendluri
Cc: BPEL OASIS
Subject: RE: [wsbpel] Issue 47 and WS-I BP 1.0
For the benefit of the non-expert could post a salient
example please? Specifically, a BPEL usage pattern that
would not work if BP 1.0 is followed but would work if any
WSDL 1.1 portType is allowed. In other words, is BP 1.0 a
restriction on the WSDL artifacts we use or potentially on
BPEL itself?
From: Prasad Yendluri [mailto:pyendluri@webmethods.com]
Sent: Wednesday, October 01, 2003 10:11 AM
To: Satish Thatte
Cc: BPEL OASIS
Subject: Re: [wsbpel] Issue 47 and WS-I BP 1.0
The sections 5.5 and 5.6 in the basic profile (
http://www.ws-i.org/Profiles/Basic/2003-08/BasicProfile-1.0
a.htm) are devoted to binding aspects but, several major
sections including section 4, other sections of 5 address
abstract aspects of WSDL, which is a pretty large portion.
All those are applicable BPEL IMO.
Prasad
Satish Thatte wrote:
Most of the BP 1.0 directives are binding related. BP also
forbids outbound operations which BPEL does not use. Can
someone identify a directive in BP 1.0 that actually affects
BPEL?
Satish
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