[GRAAP-WG] Problems of WS-Agreement Specification

[Tianchao Li]

*Hello,
*

*
while I am currently working on an implementation of WS-Agreement on 
Globus Toolkit 4, I found some potential problems with the current 
specification.*

*Many of them are minor issues, but some can be important. I have 
documented those I have found up to now and sending it to the mail list 
so that we have a chance to improve it in the next draft.
*

*best regards,*

*Tianchao Li*

*LRR, Technische Universitaet Muenchen, Germany
*

==========================================================

1. non symmetric names

TerminateRequest <-> TerminateResponse (operation input/output)

TerminateInputMessage <-> TerminateOuputMessage (input/output message)
TerminateInput <-> TerminateResponse (input/output element)

recommendation:

(1) A simple choice:

TerminateResponse should be modified to TerminateOutput to be consistent 
with the other definitions.

This will force the input and output type of the service method to be 
TerminateInput and Terminate output, which is a little bit strange to me.

(2) A better choice:

TerminateInput <-> TerminateOutput (operation input/output)

TerminateInputMessage <-> TerminateOuputMessage (input/output message)
TerminateRequest <-> TerminateResponse (input/output element)

2. Agreement Template Property of Agreement Factory and Pending 
Agreement Factory Service

The agreement factory has a property of agreement template. However, the 
agreement template retrieval should be regarded as a part of the 
resource negotiation process to accommodate the different modes of 
negotiation. For example, the service provider might post their 
agreement template in a category (index) service as advertisement.

This might also cause security problems. For example, the service 
provider might want to provide different templates for different 
clients, or restrict certain clients to access template at all.

recommendation:

do not define the agreement template property in agreement factory and 
pending agreement factory service.

Instead, move the derivation of agreement template to the layer of 
agreement negotiation.

3. Separation of Agreement port type and agreement status port type

The agreement port type and status port type is separated in the current 
specification. I understand that this is mainly to separate the resource 
properties that are related with agreement definition and agreement status.

However, the current specification does not define the link between the 
agreement resource property and agreement status resource property 
explicitly.

The AgreementFactory and PendingAgreementFactory service only creates 
agreement and how the agreement status is created is not specified.

recommendation:
We have different choices:

(1) merge agreement and agreement status port type

(2) modify AgreementFactory and PendingAgreementFactory portType

(3) specify the relation more explicitly in the documentation

4. Inconsistent name conventions

Resource parameters and message names are sometimes big camel case and 
some times lower camel case. For example: agreementProperties is used 
with first character in lower case.

recommendation:

make them consistent.

5. rejectAgreementInput/Ouput with type AgreementAcceptanceInputType and 
AgreementAcceptanceOutputType . This is a littlble bit confusing name, 
as in the Java program, object with type AgreementAcceptanceInputType 
and AgreementAcceptanceOutputType will be used for rejectAgreement.

Recommendation:

Improve the schema definition by using type extensions.

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