OASIS Mailing List ArchivesView the OASIS mailing list archive below
or browse/search using MarkMail.


Help: OASIS Mailing Lists Help | MarkMail Help

wsbpel message

[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]

Subject: Issue - R45 - BPEL partner link assignments (revisit issue R13)

The TC reviewed this public comment at the Jan 24 meeting and decided to close the associated issue, R45, with no change to the spec.  The email below provides further explanation beyond the discussion that has already taken place in email associated with issue R13.  
Regards, Diane
IBM  Emerging Internet Software Standards
(919)254-7221 or 8-444-7221, Mobile: 919-624-5123, Fax 845-491-5709

----- Forwarded by Diane Jordan/Raleigh/IBM on 01/25/2007 05:20 PM -----
Dieter Koenig1/Germany/IBM@IBMDE

01/25/2007 08:55 AM

Diane Jordan/Raleigh/IBM@IBMUS
Fw: [wsbpel] Issue - R45 - BPEL partner link assignments (revisit issue R13)

Hi Diane, the primary rationale for closing this issue is that the submitter connects two concepts that are in fact independent:

(1) The example shows inbound message activities (receive, similar for onMessage and onEvent), their corresponding synchronous responses (reply), and process-internal correlations (messageExchange) -- for such inbound request-response operations, only the *myRole* side of a partnerLink is relevant. The WS-BPEL runtime has to take care of correlating the response to the inbound request, and the partnerRole side of a partner link is not involved at all. WS-BPEL makes no assumptions about protocols and bindings. In particular, the notion of automatically assigning (e.g. WS-Addressing wsa:replyTo) Endpoint References to partner links is out of scope of the specification. Even if an implementation chooses to support this behavior, it has nothing to do with delivering a response of a request-response operation back to the caller. Having said that, the submitter's point 1. is not an issue.

(2) For partner link assignments, only the *partnerRole* side of a partner link is relevant and used for outbound calls only (invoke). The partnerRole is either (a) initialized at deployment time, (b) set by out-of-scope means, or (c) explicitly assigned inside the process.  The lifecycle of a partner link is the same as the lifecycle of the scope declaring the partner link. Once assigned, the EPR value remains unchanged until the partner link goes out of scope, unless again overridden as described in (b) or (c) above. Again, the partnerRole, independent of its initialization or lifetime, is never used for reply activities.

Hope this helps!
Kind Regards
Dieter König Mail: dieterkoenig@de.ibm.com IBM Deutschland Entwicklung GmbH
Senior Technical Staff Member Tel (office): (+49) 7031-16-3426 Schönaicher Strasse 220
Architect, Business Process Choreographer Fax (office): (+49) 7031-16-4890 71032 Böblingen
Member, Technical Expert Council Tel (home office): (+49) 7032-201464 Germany

----- Forwarded by Dieter Koenig1/Germany/IBM on 25.01.2007 13:42 -----
ws-bpel issues list editor <peter.furniss@irisfinancialsolutions.com>

24.01.2007 13:02
Please respond to

[wsbpel] Issue - R45 - BPEL partner link assignments (revisit issue R13)

This issue has been added to the wsbpel issue list with a status of "received". The status will be changed to "open" if a motion to open the issue is proposed and that motion is approved by the TC. A motion could also be proposed to close it without further consideration. Otherwise it will remain as "received".

The issues list is posted as a Technical Committee document to the OASIS WSBPEL TC pages on a regular basis. The current edition, as a TC document, is the most recent version of the document entitled in the "Issues" folder of the WSBPEL TC document list - the next posting as a TC document will include this issue. The list editor's working copy, which will normally include an issue when it is announced, is available at this constant URL.
Issue - R45 - BPEL partner link assignments (revisit issue R13)

Status: received
Date added:
23 Jan 2007
Public comment
Andi Abes, 15 Jan 2007 (public comment list)
Date submitted:
15 Jan 2007
Andi Abes
WS-BPEL 2.0 second public review text
This is an attempt to crystallize the one of the many issues raised in the first public review, originally referenced in
issue R13 : BPEL partner link assignments

Consider the same use case as in the original email exchange:

1. Receive PartnerLinkA, Operation1, messageExchange=First
2. Receive PartnerLinkA, Operation1, messageExchange=Second

    ... some work (a) ...

3. Reply PartnerLinkA, Operation1, messageExchange=First
4. Reply PartnerLinkA, Operation1, messageExchange=Second

    ... some work (b) ...

In the original issue, there was an implied assumption that any reference to the partner link EPR relies on some engine capability - and mandates some transport specific behavior.

While this is true, there should be a portable way of representing a simple behavior such as logging the source of the request - in a generic way (using an serf for example) - without any reliance on a particular transport or its capability. For example, the service ref might encode the TCP connection information (the 5 tuple) or the WSA address or any other identity the engine supports.

There are 2 areas not defined by the spec which would make this use case, and other's like it, non-portable:
1.        The spec allows assignments from a partner link, so "some work (a)" could be an assign from PartnerLinkA. But considering that messageExchange First and messageExchange Second might have been invoked by different entities (i.e. different synchronous TCP connections), the assign activity does not provide enough information (e.g. message exchange) to allow for portable operation. Each engine implementation is free to have its own interpretation - or even to reject this since there's no definite way to disambiguate the 2 originating entities.
2.        The spec does require the engine to keep track of each open IMA, with enough information to deliver a reply to the appropriate request. A bpel process can assign from an initialized partner link. Considering an assign performed after a reply has been sent ("some work b") - is the partner link still considered initialized? The spec does not address this issue.

The 2 points above suggest that for portability of BPEL processes, message exchange attribute should be included on the partner link form of Assign. The same considerations apply to Invoke activities.
Submitter's proposal:

The requested changes are:

Note that the above changes do not impose any new demands on an engine - they require the engine maintain some identity for the originator of a message, but does not impose any semantics on it. In fact, service-ref already defines a container for such identities.
23 Jan 2007 - new issue

To comment on this issue (including whether it should be accepted), please follow-up to this announcement on the wsbpel@lists.oasis-open.org list (replying to this message should automatically send your message to that list), or ensure the subject line as you send it starts "Issue - R45 - [anything]" or is a reply to such a message. If you want to formally propose a resolution to an open issue, please start the subject line "Issue - R45 - Proposed resolution", without any Re: or similar.

To add a new issue, see the issues procedures document

[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]