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Subject: RE: [ws-rx] i021 proposal
Sanjay, Perhaps I did not express my discomfort on (B) well and why I prefer a restricted semantics to apply to "in" messages only. I do not think that the general use case is really thought out well hence my hesistation. I am in favor of applying the assertion at message subject but I hesitate its use with outbound messages when there are multiple messages in an MEP (inbound and outbound) and we allow attachment to individual messages due to complexity. Lets consider the specific cases: (a) There is an operation which has only output message(s) in it. This use case can easily be handled with endpoint message policy subject and does not require message policy subject. No problem there. (b) There is an operation which is input/output, your typical request response. Lets assume that we allow that the assertion applies to outbound message in a request response. Here are the questions that come to my mind. -- How would this use case interact with CS/CSR since RM kicks in on the outbound message? -- what would be the requirement on the sender of the message wrt to specific the respective WS-Addressing headers? Take your typical use of WS-Addressing most folks would assume that request/response would map to sync request-response where replyTo would be anonymous (HTTP response). (Am I hearing i061 but it is out of scope for inbound messages or not? :-)) I fear that the assertion would not really work well with RM if RM only applies to the outbound message only which applies to the HTTP response in this case. (c) There is a complicated MEP with multiple in/out messages where we allow some of the messages to have RM assertions and some others do not. This is a rather complicated use case. Endpoint policy subject is simple since it governs both input and output messages. If there is granularity needed to cover at the message level, we should allow them at the input message level only where the RMD can assert its requirements for the incoming messages and RMS can initiate the protocol. If we leave the assertion at the inbound message only, it is implied that a clearly demarcated interaction with this party (hence RMD) would require RM engagement and the sender of the message accepts this fact. Otherwise, I fear that we need to clarify the roles and responsibility of client and/or RMS for case (b) and (c) well in order to proceed. "Redesign your abstract layer in order to suit RM requirements" so that cases (b) and (c) never occur may be a recommendation we can make, but I do not see that part of the proposals. This option implies WSDL-last kind of design as well. If this is what we would be promoting, we should be clear about it. Hope this clarifies where I am coming from, --umit > -----Original Message----- > From: Patil, Sanjay > Sent: Monday, Feb 13, 2006 6:22 AM > To: Yalcinalp, Umit; 'Paul Fremantle' > Cc: 'wsrx' > Subject: RE: [ws-rx] i021 proposal > > > Just to kick the i021 discussion further (this issue has an > amazing characteristic of moving very fast in multiple > direction, typically away from the center of gravity and > always needs some impetus :) ... > > How about saying that -- > A> RM Policy assertion applies one-way (inbound messages only) > B> RM Policy assertion can be applied at various > granularities - service/port/binding/operation/message. > Attachment at higher granularity overrides attachment at lower level. > C> EPR based techniques may also be used to assert the RM > behavior of outbound messages of a Service. Specifying the > precise syntax of how RM Policy assertion can appear in an > EPR and how the policies in an EPR interact with the static > policies of the endpoints (both ends) is outside the scope of this TC. > > If there is consensus on the above semantic, I believe that > Paul's last proposal can be easily tweaked to reflect the same. > > Please comment and let us continue hashing out this issue > further on the mailing list (data point: this issue is close > to 8 months old now!). > > -- Sanjay > > > -----Original Message----- > > From: Yalcinalp, Umit > > Sent: Thursday, Feb 09, 2006 18:43 PM > > To: Paul Fremantle; Patil, Sanjay > > Cc: wsrx > > Subject: RE: [ws-rx] i021 proposal > > > > > > > > > -----Original Message----- > > > From: Paul Fremantle [mailto:paul@wso2.com] > > > Sent: Thursday, Feb 09, 2006 3:04 AM > > > To: Patil, Sanjay > > > Cc: wsrx > > > Subject: Re: [ws-rx] i021 proposal > > > > > > Sanjay > > > > > > You are right. The proposal isn't yet fully clear on the > meaning of > > > attaching WS-RM to a message or operation. > > > > > > > That is not the real issue, see below. > > > > > How about if the following text was added, before the EPR text. > > > > > > Attaching the RM assertion to a specific wsdl:input, > > wsdl:output, or > > > wsdl:fault construct indicates that the RM protocol MUST be > > used when > > > sending that message (or MAY if the assertion is marked optional). > > > Attaching the RM assertion to a specific wsdl:operation construct > > > indicates that the RM protocol MUST be used for all > > messages (whether > > > input, output or fault) related to the operation(or MAY if > > > the assertion > > > is marked optional). > > > Attaching the RM assertion to a specific wsdl:binding construct > > > indicates that the RM protocol MUST be used for all > > messages (whether > > > input, output or fault) related to the binding (or MAY if the > > > assertion > > > is marked optional). > > > Attaching the RM assertion to a specific wsdl:port construct > > > indicates > > > that the RM protocol MUST be used for all messages > (whether input, > > > output or fault) related to the port (or MAY if the assertion > > > is marked > > > optional). > > > Attaching the RM assertion to a specific wsdl:service construct > > > indicates that the RM protocol MUST be used for all > > messages (whether > > > input, output or fault) related to the service (or MAY if the > > > assertion > > > is marked optional). > > > > > > You are also right about the EPR. I would recommend > making the EPR > > > policy override the WSDL policy, but once again I think this > > > is an issue > > > with the overall WS-Policy Framework (i.e. a general Policy > > > issue not a > > > specific RX issue). > > > > > > > I must agree that there is an issue which is beyond WS-RX > > here, but not really about WS-Policy per se but metadata that > > is contained within an EPR in general. EPR may have metadata > > that mimics WSDL constructs in addition to policy assertions. > > > > EPR policy and WSDL policy may conflict and EPR may be stale. > > We punted on this in the WS-Addressing wg. We left the > > question to be answered using an unspecified lifecycle > > definition of the EPR or retrieval mechanisms, such as WS-MEX > > that will help in resolving this issue. Therefore, I am not > > sure it is a good idea recommend making the EPR policy > > override the WSDL policy. Let me ask this. Can we guarantee > > that the EPR will never be stale within an WS-RM context? > > > > Further, is the EPR policy about the EPR itself or the > > endpoint that it represents? > > I have heard different answers to this last question > > depending on whom I talked to. Can the EPR metadata contain > > both type of policy? By design, it is possible. It is a bucket... > > > > I think we should punt on overriding just like WS-A. > > > > > > > Thanks for your comments, > > > > Thanks for the proposal. This is pretty much what I was > > suggesting as well in my email [1] for using message level > > subject but it appears that you want to allow outbound or > > fault messages as well. I need to think about the consequence > > of this a bit further, so I do not think that Sanjay's > > question is really answered by the text you added wrt to > > applying the RM assertion to outbound messages. > > > > It seems to me if it would be cleaner to leave the one-way > > policy assertion at the input message only, so that for the > > "outbound messages" the receiving end's policy assertion > > would apply. I am thinking in terms reconciling the policies > > of RMS and RMD at both ends (including extensibility). I > > think binding/operation/input message should be sufficient > > and is simpler. > > > > > > > > Paul > > > > --umit > > > > [1] > > http://www.oasis-open.org/apps/org/workgroup/ws-rx/email/archi > > ves/200602/msg00027.html > > > > > > Patil, Sanjay wrote: > > > > Comments inline ... > > > > > > > > > > > >> -----Original Message----- > > > >> From: Paul Fremantle [mailto:paul@wso2.com] > > > >> Sent: Thursday, Feb 09, 2006 1:43 AM > > > >> To: wsrx > > > >> Subject: [ws-rx] i021 proposal > > > >> > > > >> Proposal regarding issue 021. I'm not quite sure this is > > > >> right yet, so I > > > >> would appreciate feedback from the Policy experts. > > > >> > > > >> Based on CDII > > > >> > > > >> Delete 142-154 section 2.3 and replace with. > > > >> > > > >> 2.3 Assertion Attachment > > > >> > > > >> The RM assertion can have Service, Endpoint, Operation > > or Message > > > >> Endpoint Policy Subjects [WS-PolicyAttachment]. > > > >> > > > >> WS-PolicyAttachment [WS-PolicyAttachment] defines both > > > abstract and > > > >> concrete attachment points in WSDL [WSDL1.1]. Because the > > > RM policy > > > >> assertion specifies a concrete behaviour, it MUST NOT be > > > attached to > > > >> abstract constructs: > > > >> > > > >> * wsdl:portType > > > >> * wsdl:portType/wsdl:operation > > > >> * wsdl:portType/wsdl:operation/wsdl:input > > > >> * wsdl:portType/wsdl:operation/wsdl:output > > > >> * wsdl:portType/wsdl:operation/wsdl:fault > > > >> * wsdl:message > > > >> > > > >> The RM policy assertion MAY be attached to the following > > constructs > > > >> * wsdl:service > > > >> * wsdl:port > > > >> * wsdl:binding. > > > >> * wsdl:binding/wsdl:operation > > > >> * wsdl:binding/wsdl:operation/wsdl:input > > > >> * wsdl:binding/wsdl:operation/wsdl:output > > > >> * wsdl:binding/wsdl:operation/wsdl:fault > > > >> > > > >> If the RM assertion is attached to the wsdl:service > > > >> construct, it MUST > > > >> be considered to apply to all the wsdl:port's referenced in > > > >> the binding. > > > >> If the RM assertion is attached to the wsdl:port construct, > > > >> it MUST be > > > >> considered to apply to all the wsdl:binding's referenced > > > in the port. > > > >> If the RM assertion is attached to the wsdl:binding > > > >> construct, it MUST > > > >> be considered to apply to all the wsdl:operation's > > > referenced in the > > > >> binding. > > > >> If the RM assertion is attached to the wsdl:operation > > > >> construct, it MUST > > > >> be considered to apply to all the wsdl:input's, > > wsdl:output's and > > > >> wsdl:fault's referenced in the operation. > > > >> > > > > It seems like your proposal allows for attachment of RM > > > assertion at the > > > > message level. In that case, wouldn't you also want to > specify the > > > > behavior when the RM assertion is directly attached to the > > > wsdl:input, > > > > wsdl:output or wsdl:fault constructs? Or is that > semantic somehow > > > > derived from the above? I think the main question of the > > > issue i021 is > > > > whether and how does RM assertion apply to the outbound > > (I hate this > > > > term) messages of an endpoint, and I don't see a clear > > > answer to that > > > > question in this proposal. > > > > > > > > There should also be statements for handling the case where RM > > > > assertions are attached to multiple subjects within the > > same scope. > > > > > > > > > > > >> WS-Addressing allows for policy assertions to be > > included within an > > > >> EndpointReference. Per section 2.2 above, the presence of this > > > >> policy assertion in an EPR specifies the level of support for > > > >> WS-ReliableMessaging offered by that endpoint. > > > >> > > > > Since the previous text regarding the WSDL attachment of RM > > > assertion > > > > covers the behavior of outbound messages also, there may > > possibly be > > > > conflicts when both the techniques of associating policies (WSDL > > > > attachment and EPR inclusion) are used. > > > > > > > > -- Sanjay > > > > > > > > > > > >> Paul > > > >> > > > >> -- > > > >> > > > >> Paul Fremantle > > > >> VP/Technology, WSO2 and OASIS WS-RX TC Co-chair > > > >> > > > >> http://bloglines.com/blog/paulfremantle > > > >> paul@wso2.com > > > >> > > > >> "Oxygenating the Web Service Platform", www.wso2.com > > > >> > > > >> > > > >> > > > > > > -- > > > > > > Paul Fremantle > > > VP/Technology, WSO2 and OASIS WS-RX TC Co-chair > > > > > > http://bloglines.com/blog/paulfremantle > > > paul@wso2.com > > > > > > "Oxygenating the Web Service Platform", www.wso2.com > > > > > > > > >
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