Steve Graham WS-Notification Technical Overview OASIS WS-Notification TC F2F Thursday, April 29th, 2004

Steve Graham [email protected]

WS-NotificationTechnical OverviewOASIS WS-Notification TC F2F

Thursday, April 29th, 2004

© 2004 IBM Corporation 2

WS-Notification Family of documents and specifications Brings enterprise quality publish and subscribe

messaging to Web services• Loosely coupled, asynchronous messaging in a Web services context

WS Notification exploits WS Resource framework and other Web services technologies

Direct and Brokered notification Topics and Topic Spaces


Requirements Must support resource-constrained devices Must support both direct and brokered Notification Must permit transformation and aggregation of Topics Must provide runtime metadata In addition, must allow for: WS-Notification must be independent of binding-level

details Must allow for Message Oriented Middleware

implementations Must allow for federation of brokers Relationship to other WS-* specifications


Non Goals Defining the format of notification payloads: Defining any Events or NotificationMessages Defining the mapping between Situations and

NotificationMessages Defining the means by which NotificationProducers

and NotificationBrokers are discovered by subscribers

Defining the specific policy language to be used to govern specifics of the notification message exchange between the NotificationProducer and the NotificationConsumer


WS-Notification Family of Documents WS-Notification is a family of documents:

• Publish-Subscribe for Web services– Whitepaper describing roles, concepts, terms, etc.

• Base Notification– Basic interfaces: Producer, Consumer, Subscription

• Topics– Topics and TopicSpaces model in XML– Topic Expression Dialects

• Brokered Notification– Mechanisms of Publish and the Broker role

Authored by:• CA, Fujitsu, Globus, HP, IBM

+ Akamai, SAP, Sonic, Tibco


Status of WS-Notification Specification announced on January 20, 2004

• http://www-106.ibm.com/developerworks/webservices/library/ws-notification/

Public feedback session February 24 Specifications updated March 5

• Factored into 4 documents OASIS TC call for participation March 9 Interoperability “fest” April 21 First meeting of OASIS TC April 29


Terminology and Concepts Situation NotificationMessage Notification NotificationProducer NotificationConsumer Subscription SubscriptionManager Subscriber

Topic Topic Space Topic Tree NotificationBroker Publisher PublisherRegistration PublisherRegistrationMana

ger Demand-based Publisher


Consumer

Producer

Subscriber

WS-Notification: Base Notification

subscribe

subscribe

S

notify

EPR

Defines the Basis for the family Direct notification: Three primary roles Subscriber deals directly with the

producer of the Notifications• indicates interest in a particular

“Topic” by issuing a “subscribe” request

An EPR to the subscription is returned

Producer is responsible fordetecting situation and creating the notification

Subscriptions that matchreceive the notification


Base Message Exchange Pattern

Subscriber NotificationProducer NotificationConsumer

Subscribe

wsa:EndpointReference

Notify


WS-Base Notification Defines the Web services interfaces for

NotificationProducers and NotificationConsumers• It includes standard message exchanges • along with operational requirements expected of

them. This is the base specification on which the other

WS-Notification specification documents depend. Direct, point to point, notification

• WS-Base Notification • Publish-Subscribe Notification for Web Services


WS-Base Notification InterfacesNotificationConsumer

Notify()

NotificationProducerTopics : wsnot:TopicExpressionFixedTopicSet : xsd:booleanDialects : xsd:anyURI

Subscribe()GetCurrentMessage()

wsrp:ResourceProperties wsrl:ResourceLifetime

SubscriptionManagerConsumerReference : wsa:EndpointReferenceTopics : wsnot:TopicExpressionUseNotify : xsd:booleanPrecondition : wsrp:QueryExpressionSelector : wsrp:QueryExpressionSubscriptionPolicy : wsp:PolicyCreationTime : xsd:dateTime

PauseSubscription()ResumeSubscription()


Notification Consumer: Notify

<wsnt:Notify> <wsnt:NotificationMessage> <wsnt:Topic dialect=”xsd:anyURI”> {any} </wsnt:Topic> <wsnt:ProducerReference>? wsa:EndpointReference </wsnt:ProducerReference> <wsnt:Message>xsd:any</wsnt:Message> <wsnt:NotificationMessage>+</wsnt:Notify>


Notification Producer: Resource Properties MUST support required WS-ResourceProperties

message exchanges<xsd:element name=”Topics” type=”wsnt:TopicExpressionType” minOccurs=”0” maxOccurs=”unbounded” />

<xsd:element name=”FixedTopicSet” type=”xsd:boolean” minOccurs=”1” maxOccurs=”1” />

<xsd:element name=”TopicExpressionDialects” type=”xsd:anyURI” minOccurs=”1” maxOccurs=”unbounded” />


Notification Producer:: Subscribe More on Subscribe Request

Returns EPR to a Subscription WS-Resource

<wsnt:Subscribe> <wsnt:ConsumerReference>EPR </wsnt: ConsumerReference> <wsnt:TopicExpression dialect=“URI”/> <wsnt:UseNotify> xsd:boolean </wsnt:UseNotify>? <wsnt:Precondition> wsrp:QueryExpression </Precondition>? <wsnt:Selector> wsrp:QueryExpression </wsnt:Selector>? <wsnt:SubscriptionPolicy> any </wsnt:SubscriptionPolicy>? <wsnt:InitialTerminationTime> xsd:dateTime </wsnt:InitialTerminationTime>?</wsnt: Subscribe>


NotificationProducer::GetCurrentMessage

<wsnt:GetCurrentMessage> <wsnt:Topic dialect=”xsd:anyURI”>{any}</wsnt:Topic></wsnt:GetCurrentMessage>

<wsnt:GetCurrentMessageResponse> {any}</wsnt:GetCurrentMessageResponse>


SubscriptionManager Resource Properties<xsd:element name=”ConsumerReference” type=”wsa:EndpointReferenceType” minOccurs=”1” maxOccurs=”1” />

<xsd:element name=”TopicExpression” type=”wsnt:TopicExpressionType” minOccurs=”1” maxOccurs=”1” />

<xsd:element name=”UseNotify” type=”xsd:boolean” minOccurs=”1” maxOccurs=”1” />

<xsd:element name=”Precondition” type=”wsrp:QueryExpressionType” minOccurs=”0” maxOccurs=”1” />

<xsd:element name=”Selector” type=”wsrp:QueryExpressionType” minOccurs=”0” maxOccurs=”1” />

<xsd:element name=”SubscriptionPolicy” type=”xsd:anyType” minOccurs=”0” maxOccurs=”1” />

<xsd:element name=”CreationTime” type=”xsd:dateTime” minOccurs=”0” maxOccurs=”1” />


SubscriptionManager Operations MUST support the required WS-

ResourceProperties message exchanges MUST support the message exchanges defined for

immediate and scheduled destruction

<wsnt:PauseSubscription/><wsnt:PauseSubscriptionResponse />

<wsnt:ResumeSubscription/><wsnt:ResumeSubscriptionResponse/>