Issue 34 - Proposal for vote

[Ron Ten-Hove <Ronald.Ten-Hove@Sun.COM>]

    [resend; the  proposal is unchanged . This is just to move the issue state forward according to protocol]

Summary

WS-BPEL Issue 34 concerns the inappropriate dependency of the WS-BPEL specification on a proprietary specification, namely WS-Addressing (henceforth WSA). WS-BPEL uses WSA to provide a vocabulary for describing endpoint references.

It is proposed that the use of WSA-defined variables be replaced with opaque variables. Variables of this opaque type will provide specified data to provide endpoint reference information, but the specifics are left to implementations.

Problem

The use of WSA is inappropriate; it is a proprietary specification, closed (therefore unstable), difficult if not impossible to license (given its dependencies on other proprietary specifications). WSA is also only defined for SOAP, making it binding specific, which is inappropriate given that the TC has consistently avoided including binding-specific requirements (e.g., the decision to not incorporate WS-I Basic Profile 1.0).

WSA is used within WS-BPEL to provide an XML vocabulary for providing endpoint references. This is required mainly to provide a mechanism for dynamic partner link resolution. There are no open standards available that provide such a vocabulary (although the W3C has published the WS-Message Delivery specification as a submitted note.)

Proposal

The incorporation of WSA by WS-BPEL should be eliminated. Endpoint references should be made opaque (i.e., anyType from XML Schema 1.0): the XML type of abstract message parts that provide endpoint should be opaque to WS-BPEL, and undefined by WS-BPEL other than some general requirements (listed below).

Implementations of WS-BPEL will need to provide support for one (or more) endpoint description vocabularies. Provision for interoperability of separate implementations is important, but is outside the scope of the WS-BPEL TC in this issue.

It is anticipated that standards setting organizations will eventually provide standard endpoint description vocabularies, and that future versions of WS-BPEL will incorporate them while preserving backwards compatibility with this initial version of the WS-BPEL.

Endpoint Reference Requirements

The opaque endpoint reference type MUST provide the following:

• A representation of addressing information needed by transport protocols that can be used by implementation-specific bindings to resolve to a communications endpoint.

• Support for two distinct address types, mappable to the “myRole” and “partnerRole” values of the partnerLink attribute of the <assign> <to> element.