RE: Version attribute for WSDL

I like the way the discussion is going (including the following emails with 
suggestions how to handle revisions using uri's, etc.) Let's keep it 
simple. Just covering the simple obvious cases will be very helpful.

The one thing I think we need to be very clear on is what we mean by 
phrases like "continues to work with" etc.

It is my belief that we are not making statements about the semantics that 
are implied by describing two services as being related by the "version of" 
relationship. Rather we are allowing the designers to make claims and 
provide assurances about the syntactic evolution of the interface 
types/signatures, i.e. the infrastructure isn't going to fall over when an 
old client using the old signature talks to a newer (compatible) version. 
Essentially we are defining the substitutability rules.

Obviously what the implementation code that lies behind the web service 
facade actually does is not defined in WSDL. In fact, when you get right 
down to it, it is possible that 2 successive uses of the "same" interface 
will use 2 different implementations if the implementations are swapped 
without changing the signatures. We even call those the same version, even 
though what happens may be different.

jeff

At 07:05 AM 2/13/2004, Tom Jordahl wrote:


>I guess I understand the desire to have "real" versioning support in WSDL
>2.0.  I do too. But my proposal came out of the F2F, where we had a long,
>and I believe fruitless, discussion about all of this.
>
>I do not believe we can have a section in our specification about versioning
>and say "if you want versioning, change the namespace".  With a small
>addition to the syntax, we can give users some help in managing change in
>their web services.
>
>I am willing to apply semantics to the version attribute if this group
>thinks that they can move forward in a productive way.  How about these
>changes as a straw man for discussion:
>
>  - The version attribute is part of the infoset (a.k.a. the component model)
>
>  - The version attribute has type xsd:positiveInteger
>
>  - The version attribute has a default value of 1.
>
>  - The version attribute indicates a "minor" revision of the definition or
>    interface. Specifically, a "minor" revision indicates that a client using
>    a WSDL with a version attribute less-than the current value is expected
>    to continue to function.
>
>  - When an interface extends another interface, the version attribute of the
>    interface is NOT inherited - it must be explicitly set on the interface,
>    and if is not, the interface has the default version attribute (1).
>
>Example 1: Version 1 of my interface has two operations. I release a new
>WSDL that adds a third operation, and change the version attribute to 2.
>Clients who are using the previous version of the WSDL continue to function.
>
>Example 2: My WSDL has a purchase order type defined and a target namespace
>of "http://example.org/myservice".  I change my purchase order to include
>several new elements and rename some of the old ones.  Since this change
>will break compatibility, I change the target namespace to
>"http://example.org/myservice/v2".  My service can now easily tell the
>difference between clients that are using the original WSDL and the new one.
>
>
>--
>Tom Jordahl
>Macromedia Server Development
>
>-----Original Message-----
>From: Jeff Mischkinsky [mailto:jeff.mischkinsky@oracle.com]
>Sent: Friday, February 13, 2004 2:56 AM
>To: Tom Jordahl; 'www-ws-desc@w3.org'
>Subject: RE: Version attribute for WSDL
>
>At 12:41 PM 2/12/2004, Tom Jordahl wrote:
>
>
> >David,
> >
> >We wouldn't say anything like this about the version attribute.
> >      "..it has no semantics.."
> >
> >So David can tell his WSDL consumers that he uses this attribute to
>indicate
> >compatible versions of the same WSDL file.  And I can tell my users that
> >version 1 does not equal version 2.  But as WSDL spec authors we don't have
> >to take a stand on how this is done.
> >
> >Isn't that nice?  We don't have to fight about what it means.
>
>and the point of "standardizing" this would be?
>(in this case I'm using the word standardize in its loosest most
>meaningless sense :-)
>
>jeff
>
>
> >--
> >Tom Jordahl
> >Macromedia Server Development
> >
> >-----Original Message-----
> >From: David Orchard [mailto:dorchard@bea.com]
> >Sent: Thursday, February 12, 2004 2:32 PM
> >To: paul.downey@bt.com; vbp@hp.com; tomj@macromedia.com; www-ws-desc@w3.org
> >Subject: RE: Version attribute for WSDL
> >
> >I'm interested in the version attribute for identifying versions within
> >"compatible" definitions.  I would like to have our spec say explicitly
> >that.  I am strongly strongly opposed to using a version attribute for
> >identifying different incompatible versions.  That's what namespaces and
> >URIs are for.
> >
> >Some off-the-cuff suggestions for the wording:
> >
> >"The version attribute identifies a particular version of the definitions,
> >that is compatible with all other versions with the same targetnamespace.
> >It SHOULD not be used to identify incompatible definition versions."
> >
> >Cheers,
> >Dave
> >
> > > -----Original Message-----
> > > From: www-ws-desc-request@w3.org [mailto:www-ws-desc-request@w3.org]On
> > > Behalf Of paul.downey@bt.com
> > > Sent: Thursday, February 12, 2004 9:02 AM
> > > To: vbp@hp.com; tomj@macromedia.com; www-ws-desc@w3.org
> > > Subject: RE: Version attribute for WSDL
> > >
> > >
> > >
> > > I believe the version value is useful information for when the
> > > interface has been compatibly changed within the same namespace.
> > >
> > > +1 Tom's proposal, i can't see any harm and it could be useful
> > > as a building block for a mechanism for relating an interface
> > > version to other versions, akin to the 'previous', 'this' and
> > > 'latest' version URLs on W3C publications.
> > >
> > > Paul
> > >
> > >
> > > -----Original Message-----
> > > From: www-ws-desc-request@w3.org [mailto:www-ws-desc-request@w3.org]On
> > > Behalf Of Vambenepe, William N
> > > Sent: 12 February 2004 16:53
> > > To: Tom Jordahl; www-ws-desc@w3.org
> > > Subject: RE: Version attribute for WSDL
> > >
> > >
> > >
> > >
> > > Thanks Tom for the proposal. I could live with this attribute on
> > > <definitions> but I really don't like it on <interface>. As Glen
> > > eloquently explained at the F2F, a different interface should use a
> > > different QName. What does it mean for a binding to reference an
> > > interface if there are dozens of "versions" of this interface. Can I
> > > have a binding for only a certain version of an interface? I know we
> > > don't have to answer this since we "define no semantic" but
> > > that doesn't
> > > make the problem go away.
> > >
> > > William
> > >
> > >
> > > > -----Original Message-----
> > > > From: www-ws-desc-request@w3.org
> > > > [mailto:www-ws-desc-request@w3.org] On Behalf Of Tom Jordahl
> > > > Sent: Thursday, February 12, 2004 6:13 AM
> > > > To: 'www-ws-desc@w3.org'
> > > > Subject: Version attribute for WSDL
> > > >
> > > >
> > > >
> > > >
> > > > In fulfillment of my action item received at the January F2F,
> > > > here is a
> > > > proposal to add a version attribute to WSDL to aid in the
> > > > versioning of WSDL
> > > > documents and interfaces.
> > > >
> > > > I propose that an attribute with the name "version" be added to the
> > > > <definitions> element of WSDL.  This attribute is for user
> > > > convenience, and
> > > > the specification would define no semantics for it,
> > > > specifically the value
> > > > of this attribute would NOT be included in the infoset.
> > > > However, it is
> > > > expected that WSDL authors and consumers can use this
> > > attribute, when
> > > > present, to differentiate between different revisions of a
> > > > WSDL document.
> > > >
> > > > Example:
> > > >
> > > > <definitions version="1" targetNamespace=http://sample.org/>
> > > > ...
> > > > </definitions>
> > > >
> > > > This proposal is modeled after the version attribute of XML
> > > > Schema, see
> > > > section 3.15.2 in Part 1 of the XML Schema specification:
> > > >   http://www.w3.org/TR/xmlschema-1/#Schemas
> > > >
> > > > In our specification, section 2.1.2 would be updated to
> > > > include the new
> > > > attribute:
> > > >
> > > > 2.1.2 XML Representation of Definitions Component
> > > >
> > > > <definitions
> > > >       targetNamespace="xs:anyURI"
> > > >       version = "xs:token"? >
> > > >   <documentation />?
> > > >   [ <import /> | <include /> ]*
> > > >   <types />?
> > > >   [ <interface /> | <binding /> | <service /> ]*
> > > > </definitions>
> > > >
> > > >
> > > > Additionally, I propose that a similar version attribute be
> > > > added to the
> > > > <interface> element of WSDL. This attribute would mirror the
> > > > definitions
> > > > attribute.  Again, this would be for user convenience, and
> > > > the specification
> > > > would define no semantics for it, specifically the value of
> > > > this attribute
> > > > would NOT be included in the infoset.  WSDL authors and
> > > > consumers could use
> > > > this attribute, when present, to differentiate between
> > > > different revisions
> > > > of an interface.  In particular, this would enable a consumer of the
> > > > document to know explicitly when an interface they are using
> > > > has changed.
> > > >
> > > > Example:
> > > > <definitions>
> > > >   <interface name="myInterface" version="alpha17">
> > > >     ...
> > > >   </interface>
> > > > </definitions>
> > > >
> > > >
> > > > 2.2.2 XML Representation of Interface Component
> > > > <definitions>
> > > >   <interface
> > > >         name="xs:NCName"
> > > >         extends="list of xs:QName"?
> > > >         styleDefault="xs:anyURI"?
> > > >         version = "xs:token"? >
> > > >     <documentation />?
> > > >     [ <operation /> | <feature /> | <property /> ]*
> > > >   </interface>
> > > > </definitions>
> > > >
> > > >
> > > > --
> > > > Tom Jordahl
> > > > Macromedia Server Development
> > > >
> > > >
> > >
> > >
>
>Jeff Mischkinsky                      jeff.mischkinsky@oracle.com
>Consulting Member Technical Staff     +1(650)506-1975
>Director, Web Services Standards      500 Oracle Parkway M/S 4OP9
>Oracle Corporation                    Redwood Shores, CA 94065

Jeff Mischkinsky                      jeff.mischkinsky@oracle.com
Consulting Member Technical Staff     +1(650)506-1975
Director, Web Services Standards      500 Oracle Parkway M/S 4OP9
Oracle Corporation                    Redwood Shores, CA 94065

Received on Friday, 13 February 2004 17:31:16 UTC