RE: [ws-caf] Mt Everest and WS-CF

["Furniss, Peter" <Peter.Furniss@choreology.com>]

Mark,

> > But you can get them to understand your own ad-hoc overload of the
> > ws-context identifier ?
> >
> > Do you accept that they will have to implement something
> you define ?
> > You seem to think WS-Context alone will do it, but it has no
> > semantics.
> 
> Peter, that is incorrect. Maybe there is a problem with the
> text describing this, but I thought we were quite clear in 
> the 0.2 draft that a context identifier represents an 
> activity which represents a set of related invocations on 
> (potentially a number of different) Web services. As such, by 
> itself it does have implied semantics: correlation of 
> invocations. This is precisely what Jim, Savas and the WS-GAF 
> document defined last September (I think). As such, 
> WS-Context is useful by itself.

What does correlation cause to happen ? Something has its behaviour
modified by the presence of the WS-Context header or there wasn't any
point in sending it. Stating that a context identifier labels the
invocations in an activity means nothing unless the activity itself has
some  attributes that are known among the implementations.


Another way of expressing this:

a) A SOAP implementation allows access to the headers, and has no
constraints on the headers - they can be inspected and walked through as
xml constructs. (as infoset or raw, as you please - infoset only if it
can find the schema) Is it an implementation of basic WS-Context ?

b) The implementation is modified to recognise WS-Context headers, and
offers an additional internal api that gives access to them via
thread-local storage. No deployed application uses this new api. Is it
an implementation of basic WS-Context ?

c) the implementation is modified such that if it receives a WS-Context,
and the mustPropagate flag is true, and the processing resulting from
the received message causes any outbound soap messages, the WS-Context
header is copied unchanged to that. Is it now an implementatioan of
basic WS-Context ?

d) An application using a) or b) includes the context identifier in its
access logs, but does nothing else. Is it now an implementation of basic
WS-Context ?


I'm not sure what else can be done with just WS-Context alone - and even
d) seems to have some understanding of a specification in addtion to
WS-Context itself. Anything more (like recognising it as a WS-CF context
and registering with the coordinator, or adding stuff to it) would
clearly be implementation of a WS-Context-using protocol, not of
WS-Context alone.


Peter