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1 WS-Agreement Tutorial Material 2004/09/13 Toshiyuki Nakata NEC Corporation
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WS-Agreement Tutorial Material
2004/09/13
Toshiyuki Nakata
NEC Corporation
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Recent Status Split the spec into two parts
Basic Specification for agreement named Web Services Agreement Specification and Advanced Web Services Agreement Negotiation Specification (WS-AgreementNegotiation)
Graap-WG decided to put priority on discussing WS-Agreement first.
On 25th August WS-Agreement specification was submitted to the GGF editor, on track to enter public comment.
WS-Agreement itself is sort of a frame-work for getting agreements on several different domains. The details of things to be agreed are of course domain-specific and is out of the scope of the WS-Agreement Spec.
Eg. Job-submission using JSDL is a candidate to be used within the frame-work.
Relation to other specification Relies on WS-Addressing Also Relies on WS-ResourceProperties
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Address Map summary ( Old to be updated)
Prefix Namespace
wsag http://www.ggf.org/namespaces/ws-agreement (temporary)
wsa http://schemas.xmlsoap.org/ws/2003/03/addressing
wsbf http://www.ibm.com/xmlns/stdwip/web-services/WS-BaseFaults
wssg http://www.ibm.com/xmlns/stdwip/web-services/WS-ServiceGroup
wsrp http://www.ibm.com/xmlns/stdwip/web-services/WS-ResourceProperties
xs/xsd http://www.w3.org/2001/XMLSchema
xsi http://www.w3.org/2001/XMLSchema-instance
wsdl http://schemas.xmlsoap.org/wsdl/
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Two layer Model
The service layer represents the application-specific layer of business service being provided.
The agreement layer provides a Web service-based interface that can be used to represent and monitor agreements with respect to provisioning of services implemented in the service layer.
An agreement port type, without any operation other than getters for state and metadata of the agreement such as the terms, the context, etc….
An agreement factory exposes an operation for creating an agreement out of an input set of terms. It returns an EPR to an Agreement service. The agreement factory also exposes resource properties such as the templates of offers acceptable for creation of an agreement.
Consumer Provider
create()
foo()Application Instance
Factory
Manager
create()Factory Agreement
Ops:terminate(limits)inspect(query)...
SDEs:
Terms RelatedStatusAgrmts
inspect()
Agreement Layer
Service Layer
Consumer Provider
create()
foo()Application Instance
Factory
Manager
create()Factory Agreement
Ops:terminate(limits)inspect(query)...
SDEs:
Terms RelatedStatusAgrmts
inspect()
Agreement Layer
Service Layer
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Simple Sequnce-1
Agreement Initiator Agreement Provider
Query(wsag:template)
(templates)
CreateAgreement(offer)
(EPR to Agreement1)
Based on the Template create an offer
Decide to agreeTo the offerCreate an agreement
Agreement1At this moment the agreement isObserved. A-I cannot refuse to the Created Agreement
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Simple Sequnce-2
Agreement Initiator Agreement Provider
Query(wsag:template)
(templates)
CreateAgreement(offer)
(Return a Fault)
Based on the Template create an offer
Decide to refuse
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Organization of Agreement
Name: Optional Name Context: Describes ‘meta-data’ of the w
hole Agreement Parites to Agreement Agreement Life-time Template Name Related Agreements
Agreementterms Term Compositor Structure:A scheme to
compose an AND/OR/XOR relationship of the following two elements
Service Description Term: Information needed to instantiate or identify a service to which this agreement pertains
Guarantee Term:Service Levels that the parties are agreeing to.
Agreement Name
Context
Terms Compositor
Service Description Terms
Guarantee Terms
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Agreement Context
/wsag:AgreementContext/AgreementInitiator Agreement Initiator ： （ Requestor ） Can be an URI or wsa:EndpointReference( ＥＰ R)
/wsag:AgreementContext/AgreementProvider Provider Can be an URI or wsa:EndpointReference( ＥＰ R)
/wsag:AgreementContext/ExpirationTime Specifies the time at which this agreement is no longer valid.
/wsag:AgreementContext/TemplateName Specifies the name of the template from which this agreement is created.
/wsag:AgreementContext/RelatedAgreements This element defines a list of related agreements: (Example??)
<wsag:AgreementContext> <wsag:AgreementInitiator>xs:anyURI</wsag:AgreementInitiator> <wsag:AgreementProvider>xs:anyURI</wsag:AgreementProvider> <wsag:ExpirationTime>xs:DateTime</wsag:ExpirationTime> <wsag:TemplateName>xs:string</wsag:templateName> <wsag:RelatedAgreements>...</wsag:RelatedAgreements></wsag:AgreementContext>
Agreement
Context
Terms Compositor
Service Description Terms
Guarantee Terms
PS what is /wsp:Context in page 15?
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Example of usage of related Agreements:
Would really like to embed something like one shown below, but I am not confident whether this is valid or not..
ASP Provider
1)Agreement Offer
Site A
Site B
Site C
Site D
Site E
<wsag:context><wsag:RelatedAgreements>
<wsag:RelatedAgreement wsag:Name=“basic”＞(Contents/pointers for offer to agreement1)(cf.nextpage)
<wsag:AgreementEPR><empty>
</wsag:AgreementEPR></wsag:RelatedAgreement><wsag:RelatedAgreement “ wsag:Name=“ext1”>
(Contents / pointers for offer to agreement2)(cf. nex page)<wsag:AgreementEPR>
<empty></wsag:AgreementEPR>
</wsag:RelatedAgreement></wsag:RelatedAgreements></wsag:context>
2)Agr
eem
ent O
ffer
Agreement1
Accept & Create
3)EPR of A
greement1
2)Agreement Offer
3)Fault4)Agreement Offer
Agreement2
Accept & Create
EPR of Agreement12
Agreement3 <wsag:RelatedAgreements><wsag:RelatedAgreement >(Contents/pointers for offer to agreement1)（cf. next page)<wsag:AgreementEPR>
<EPR of Agreement1></wsag:AgreementEPR>
</wsag:RelatedAgreement><wsag:RelatedAgreement >(Contents/pointers for offer to agreement2) (cf. next page)
<wsag:AgreementEPR><EPR of Agreement2 >
</wsag:AgreementEPR> </wsag:RelatedAgreement>
</wsag:AgreementEPR> </wsag:RelatedAgreements>
Create 5)EPR of Agreement3
GGJM
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Term Composite Structure
/wsag:Terms/wsag:All (or wsag:OneOrMore, or wsag:ExactlyOne) This is a logical AND (or OR, o
r XOR) operator of type wsag:TermCompositorType
The rest see next page
<wsag:Terms> <wsag:All> wsag:TermCompositorType </wsag:All> |
<wsag:OneOrMore> wsag:TermCompositorType </wsag:OneOrMore> | <wsag:ExactlyOne> wsag:TermCompositorType </wsag:ExactlyOne> | {<wsag:ServiceDescriptionTerm> wsag:ServiceDescriptionTermT
ype </wsag:ServiceDescriptionTer
m> | <wsag:ServiceReference> wsag:ServiceReferenceType </wsag:ServiceReference> | <wsag:ServiceProperties> wsag:ServicePropertiesType </wsag:ServiceProperties> | <wsag:GuaranteeTerm> wsag:GuaranteeTermType </wsag:GuaranteeTerm> } * </wsag:Terms>
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Individual types Service description terms
are a fundamental component of an agreement: the agreement is about the service(s) - existing or not - described by the service description terms.
ServiceReference provides means for an agreement to
simply refer to the existing service instance
ServiceProperties are used to define measurable and
exposed properties associated with a service, such as response time and throughput.
GuaranteeTerm define the assurance on service quality,
associated with the service described by the service definition terms.
{ <wsag:ServiceDescriptionTe
rm> wsag:ServiceDescriptionTer
mType </wsag:ServiceDescriptionT
erm> | <wsag:ServiceReference> wsag:ServiceReferenceType </wsag:ServiceReference> | <wsag:ServiceProperties> wsag:ServicePropertiesType </wsag:ServiceProperties> | <wsag:GuaranteeTerm> wsag:GuaranteeTermType </wsag:GuaranteeTerm> } *
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Service Description Terms
Service description terms (SDTs) are a fundamental component of an agreement: the agreement is about the service(s) - existing or not - described by the service description terms.
May be domain specific Contains three parts
• The name of the ServiceDescriptionTerm.• The name of the service being described partially or fully by the
domain-specific part of this service description term. This allows for semantic grouping of service description terms that may not be structurally grouped together in the agreement.
• A domain-specific description of the offered or required functionality. This element MAY completely describe the service it is about, or it MAY do so only partially.
Agreement
Context
Terms Compositor
Service Description Terms
Guarantee Terms
<wsag:ServiceDescriptionTerm wsag:Name=”xs:NCName” wsag:ServiceName=”xs:NCName”> <xsd:any> … </xsd:any></wsag:ServiceDescriptionTerm>
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Example of a Service description Term
<wsag:All> <wsag:ServiceDescriptionTerm wsag:Name=“executable1" wsag:Servi
ceName=“a1> <job:executable> /usr/local/job1 </job:executable> </wsag:ServiceDescriptionTerm> <wsag:ServiceDescriptionTerm wsag:Name="numberOfCPUs1" wsag:Ser
viceName=“a1"> <job:numberOfCPUs>32</job:numberOfCPUs> </wsag:ServiceDescriptionTerm> <wsag:ServiceDescriptionTerm wsag:Name="memoryPerCPU1“ wsag:Ser
viceName=“a1"> <job:realMemorySize>200</job:realMemorySize> </wsag:ServiceDescriptionTerm> </wsag:All>
Specifies a job whose executable is /usr/local/job1 with 32 CPUs and Memory size of 200 (MB?)Please note the usage of Service Name to aggregate several SDT’s.
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Service reference: To be added
Any good examples?
<wsag:All> <wsag:ServiceDescriptionTerm wsag:Name="WSDLInterface" wsag:ServiceName="BankingService">
<sdtc:WSDLReference> http://www.foo.org/interfaces/bank.wsdl </sdtc:WSDLReference>
</wsag:ServiceDescriptionTerm><wsag:ServiceDescriptionTerm
wsag:Name="WebAccess" wsag:ServiceName="BankingService">
<sdtc:URLPrefixDefinition> http://www.foo.org/bank </sdtc:URLPrefixDefinition> </wsag:ServiceDescriptionTerm></wsag:All>
Extracted from Page 58 Should change ServiceDescriptionTerm To ServiceReference??
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Service Properties
Sorry ran out of time will translate/update the rest tomorrow.
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変数宣言：
<wsag:Variable name=”xsd:NCName” metric=”xsd:QName”> …</wsag:Variable>
例えば
<wsag:Variable name=”numberOfNodes”> /wsag:Agreement/job:JobDescription</wsag:Variable>
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Guarantee Term
サービス品質の規定に関する記述 最小のＣＰＵ数、メモリ容量、実行時間保証する終了時間
など 以下の 3 項からなるものの繰り返し
QualifyingCondition: サービスレベルを保障するための前提条件
• 例：サービスを提供する時間（月ー金の定時内） ServiceLevelObjective: 満たすべきサービスレベル
• 応答時間何秒以内とか BusinessValueList: 保障に関するより高度なビジネスレベ
ルの項目• 費用• 罰則規定 など
Agreement
Context
Terms Compositor
Service Description Terms
Guarantee Terms
<wsag:GuaranteeTerm> <wsag:QualityingCondition>…</wsag:QualifyingCondition>? <wsag:ServiceLevelObjective>…</wsag:ServiceLevelObjective> <wsag:BusinessValueList>…</wsag:BusinessValueList></wsag:GuaranteeTerm>
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Business Value..<wsag:BusinessValueList><wsag:Importance> xsd:integer </wsag:Importance
>?<wsag:Penalty> </wsag:Penalty>? <wsag:Reward> </wsag:Reward>? <wsag:BusinessValue> … </wsag:BusinessValue>
*</wsag:BusinessValue>
<wsag:Penalty> <wsag:AssesmentInterval> <wsag:TimeInterval>xsd:duration</wsag:TimeInterval> | <wsag:Count>xsd:positiveInteger</wsag:Count> </wsag:AssesmentInterval> <wsag:ValueUnit>xsd:string</wsag:ValueUnit>? <wsag:ValueExpr>xsd:any</wsag:ValueExpr></wsag:Penalty>
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Agreement Template
Agreementを生成するためにクライエントは Agreement Factoryに、Agreement Templateに基づいたAgreement生成提案を行う。
Agreement TemplateはAgreement Factoryにより予め、周知されている。
Agreement templateは Agreementと同じような構造を有するが、更に Agreement Creation Constraintを付加して、合意を得るための条件を指定することが可能である。
Agreement Template
Context
Terms Compositor
Agreement Creation Constraints
Service Description Terms
Guarantee Terms
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Agreement Constraintの構成
任意個の offer Itemと Constraintからなる。
Offer Item ：名前、指定する Itemの場所、制限値で指定する
<wsag:template>…
<wsag:CreationConstraints> ? <wsag:Item>…</wsag:Item> * <wsag:Constraint>…</wsag:Constraint> * </wsag:CreationConstraints>
Agreement Template
Context
Terms Compositor
Agreement Creation Constraints
Service Description Terms
Guarantee Terms
<wsag:Item name=”xsd:NCName” location=”xsd:string”> <restriction> xsd:simpleRestrictionModel <restriction> ? </wsag:Item>
Constraint ： 任意の制限条件が記述可能 Xquery を使うことも
<wsag:Constraint/> <wsag:XQueryXConstraint> <wsag:Expression> … </wsag:Expression> </wsag:XQueryXConstraint>
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PortType
<wsag:createAgreementInput> <initiatorAgreementEPR> EPR1 </initiatorAgreementEPR> ? <offer> ... </offer> </wsag:createAgreementInput>
生成時の Input
<wsag:createAgreementResponse> <createdAgreementEPR> EPR2 </createdAgreementEPR> </wsag:createAgreementResponse>
結果
テンプレートを元に指定された offer
