web services over the grid - wsrf -

Workflows over Grid-based Web servicesGeneral framework and a practical case in structural biology

Web Services over the Grid- WSRF -

Enrique de Andrés Saiz

2/22/2007 Web Services over the Grid 2

Outline

• Generic Web Services problem• Web Services Resource Framework (WSRF)

– WS-Addressing

– Faults

– Declaring WS-Resource properties

– Operations over WS-Resource properties

– WS-Resource lifetime

– Grouping services

• Developing WSRF services– WSRF::Lite

– wsrf4egee


Generic Web Services problem

• Generic Web Services are limited by the timeouts of the servers that hosts them:– It is not possible to run long time operations

• Solution:– Provide asynchronous behavior to the operations of Web Services.

• Requirements:– Any kind of data persistence between invocations to the same instance

of a Web Service.– A way to uniquely identify instances of Web Services.

• Generic Web Services are stateless… they don’t accomplish these requirements.


Example

• Imagine we have a Web Service with operations that:– Require a lot of time to be executed– Require valid credentials to execute them

myOp

OutputsInputs

username

password

……

username

password

username

passwordmyOp_result

Inputs Outputs

…myOp_status

Inputs Outputs

myOp_submit

Inputs

username

password

…

Outputs

id


Example

username

passwordcreateSession

Inputs Outputs

username

password

username

passwordmyOp_result

Inputs Outputs

…id

username

password

…

myOp_submit

Inputs Outputs

myOp_result

Inputs Outputs

…

id

myOp_status

Inputs Outputs


Solving the problem…

• Approach 1:– Your own solution as the previous example.– Problems:

• Using a parameter for identifying the instance of the Web Services.• No very clear how to get data persistence.

• Approach 2:– USING STANDARS.

• WSRF (Web Services Resources Framework) defines a generic framework for modeling and accessing persistent resources using Web Services:– It makes easier the definition and implementation of a service and the

integration and management of multiple services


Outline


– WS-Addressing

– Faults






– wsrf4egee


Web Services Resource Framework, WSRF

• WSRF is an OASIS standard that can be used to implement interoperable stateful web-services.

• WSRF is a set specifications that define what is termed the WS-Resource approach to modeling and managing state in a Web services context.

• WSRF uses the W3C standard WS-Addressing to achieve transport-neutral addressing for web-services.


Web Services Resource Framework, WSRF

• The central element of WSRF standard is the concept of WS-Resource.

• A WS-Resource is the logical entity which stores (persistent) information:– A WS-Resource has defined resource properties:

• A resource property is a piece of information defined as part of the state model of a WS-Resource.

– A WS-Resource can be accessed through defined message exchanges or operations for:

• Accessing resource properties.• Interact with the WS-Resource lifetime.

• A WS-Resource is associated to a Web Service instance.– When creating a new service instance, a new WS-Resource is created.– WSRF uses WS-Addressing specification for uniquely identify a WS-Resource

(or a Web Service instance).• A reference to a WS-Resource is represented by an endpoint reference (EPR).


Example

• We have a shopping carts that store one product (WS-Resource) per cart.• A product (WS-Resource) have defined a set of properties (WS-Resource

Properties):– ProductCode– Description– Quantity– ProductPrice

• It is possible to interact with the properties of the product (Operations over WS-Resource Properties).

• It is possible to delete a shopping cart (Operations over WS-Resource Lifetime).

Simple shopping service example


Using WSRF for the Grid

• One WS-Resource corresponds to one job on the Grid

• WS-Resource properties:– Input data/parameters of the job (or the application executed by the job).– Output data of the job.– Any other data required.

• WS-Resource operations:– Operations over the resource properties.– Operations over the resource lifetime.– Other specific operations for the Grid.

• Grid requirements:– All operations over the Grid must be executed as an authenticated user in the User

Interface.– Operation mode must be asynchronous (edg-job-submit, edg-job-status, edg-jog-get-

output).– It is not necessary to create an asynchronous behavior, only move it from the Grid to the

WSRF services.


Simple Hello World Grid WSRF service

username password

stdout

Grid Hello WorldWS-Resource

myName status response

createResource(username, password)

EPR – Resource ID

SetResourceProperty(myName)

submitJob()

GetResourceProperty(status)

collectResults()

GetMultipleResourceProperties(stdout, stderr, response)

Destroy()

stderr

username password

stdout

myName status response

stderr


Outline


– WS-Addressing

– Faults






– wsrf4egee


WS-Addressing

• The key concept in WS-Addressing is the Endpoint Reference (EPR):– An EPR is a URL wrapped by some XML elements which represents the location

of a Web Service:– An EPR allows to include additional information in a SOAP request that helps

uniquely identify a Web Service instance– EPR’s are used by WSRF for representing references to WS-Resources.

• EPR’s vs. URL’s. Why EPR’s are necessary?– Appending something like ?resourceID=123 to the URL is not very SOAP-ish.– It’s better to use additional SOAP headers.

• Web Service specific data is not bound to one specific transport protocol.

• Web Service specific data is all inside the SOAP envelope (not in different levels, one at the transport level and other at SOAP level).


WS-Addressing

• Endpoint Reference format:– wsa:Address

• Specifies the URL that should be used when trying to talk to the Web Service.

– wsa:ReferenceProperties• Encapsulates all Web service-specific data (reference properties), such as a

session identifier, an instance identifier or a resource identifier.

<widget:myLocationEPR>

<wsa:Address>http://localhost/WidgetService</wsa:Address>

<wsa:ReferenceProperties> <widget:resourceID>123</widget:resourceID> </wsa:ReferenceProperties>

</widget:myLocationEPR>


WS-Addressing

• An EPR should be returned at some point of a Web Service:– When creating an instance to the Web Service.

– Asking for a pointer to an instance to the Web Service.

<soap:Envelope...> <soap:Body> <widget:createWidgetResponse...>

<widget:widgetReference> <wsa:Address>http://host/WidgetService</wsa:Address> <wsa:ReferenceProperties> <widget:resourceID>123</widget:resourceID> </wsa:ReferenceProperty> </widget:widgetReference>

</widget:createWidgetResponse> </soap:Body></soap:Envelope>


WS-Addressing

• Subsequent invocations to the instance of a Web Service referred by an EPR must integrate the information of that EPR in the SOAP header:

• wsa:To– SOAP message information header which indicates the target Web Service’s

URL.– It should be the same value as the wsa:Address element of the associated EPR.

<soap:Envelope...>

<soap:Header> <wsa:To> http://host/WidgetService </wsa:To> <widget:resourceID>123</widget:resourceID> </soap:Header>

<soap:Body> ... </soap:Body></soap:Envelope>


WS-Addressing

• Other SOAP message information headers:– wsa:From

• Indicates the EPR of the message's sender.• If the message's receiver needs to send a message back to the endpoint

that sent the message, then it should use this EPR.

– wsa:ReplyTo• Indicates the EPR to where the response message should go.

<wsa:From> <wsa:Address> http://client/myClient </wsa:Address></wsa:From>

<wsa:ReplyTo> <wsa:Address> http://client/myReceiver </wsa:Address></wsa:ReplyTo>


WS-Addressing

• …other SOAP message information headers:– wsa:FaultTo:

• Indicates the EPR to where a fault should go if the response to a message is a SOAP fault.

– wsa:MessageID:• Is a URI that uniquely identifies a message.

– wsa:Action:• Makes reference to the operation that must be carried out.

<wsa:FaultTo> <wsa:Address> http://client/FaultCatcher </wsa:Address></wsa:FaultTo>

<wsa:MessageID>uuid:098765</wsa:MessageID>

<wsa:Action> http://host/widgetOp </wsa:Action>


WS-Addressing

• …other SOAP message information headers:– wsa:RelatesTo:

• Is used on response messages to indicate that it is related to a previously-known message and to define that relationship.

• In all of the headers that either contain an Address element or are, like the To header, an address themselves, you can use a special anonymous URI:– http://schemas.xmlsoap.org/ws/2003/03/addressing/role/anonymous

– Indicates that there is no real endpoint available for this address.

<wsa:RelatesTo RelationshipType="wsa:Response"> uuid:098765</wsa:RelatesTo>


Outline


– WS-Addressing

– Faults






– wsrf4egee


Base faults

• WSRF defines a set of rules for exchanging faults messages through WS-BaseFaults specification.

• WS-BaseFaults defines a XML schema type for a base fault.

• The base fault has the following syntax:

<BaseFault> {any}* <Timestamp>xsd:dateTime</Timestamp> <OriginatorReference> wsa:EndpointReferenceType </OriginatorReference> ? <ErrorCode dialect="anyURI">xsd:anyType</ErrorCode> ? <Description>xsd:string</Description> * <FaultCause>{any}</FaultCause> ?</BaseFault>


Faults

• All faults must use the following URI inside the wsa:Action – http://docs.oasis-open.org/wsrf/fault

• A WSRF service supports the following base faults:– ResourceUnknownFault

• The resource identified in the message is not known to the Web service.

– ResourceUnavailableFault • The resource identified in the message is unavailable.


Faults

Example SOAP 1.1 Encoding of a Base Fault


Outline


– WS-Addressing

– Faults






– wsrf4egee


Declaring WS-Resource Properties

• One characteristic of a WS-Resource is the set of properties associated with the resource.

• The definition of the properties of a WS-Resource MAY be declared as part of a Web Service interface:– The declaration of the WS-Resource’s properties represents a

projection of a view of the WS-Resource’s state.

– This projection is defined in terms of a resource properties document:

• The resource properties document definition is associated with a Web service WSDL portType in the following manner:<wsdl:defintions …> <wsdl:portType … wsrf-rp:ResourceProperties=”xsd:QName”? … > …</wsdl:portType>


Declaring Resource Properties

WSDL example


Outline


– WS-Addressing

– Faults






– wsrf4egee


Operations over WS-Resource Properties

• WSFR defines a standard set of message exchanges or operations that allow a requestor to query or update the property values of a WS-Resource:– GetResourcePropertyDocument (optional)

– GetResourceProperty (mandatory)

– GetMultipleResourceProperties (optional)

– QueryResourceProperties (optional)

– PutResourcePropertyDocument (optional)

– SetResourceProperties (optional)

– InsertResourceProperties (optional)

– UpdateResourceProperties (optional)

– DeleteResourceProperties (optional)


GetResourcePropertyDocument

• Allows a requestor to retrieve the values of all resource properties associated with the WS-Resource.

• Request:– wsa:Action=http://docs.oasis-open.org/wsrf/rpw-2/

GetResourcePropertyDocument/GetResourcePropertyDocumentRequest

• Response:– wsa:Action=http://docs.oasis-open.org/wsrf/rpw-2/

GetResourcePropertyDocument/GetResourcePropertyDocumentResponse

• Faults:– Generic WS-Resource faults.

<wsrf-rp:GetResourcePropertyDocument />

<wsrf-rp:GetResourcePropertyDocumentResponse> {any}</wsrf-rp:GetResourcePropertyDocumentResponse>


GetResourcePropertyDocument

ResponseResource properties document

Request


GetResourceProperty

• Allows a requestor to retrieve the value of a single resource property of a WS-Resource.

• Request:– wsa:Action=http://docs.oasis-open.org/wsrf/rpw-2/GetResourceProperty/

GetResourcePropertyRequest

• Response:– wsa:Action=http://docs.oasis-open.org/wsrf/rpw-2/GetResourceProperty/

GetResourcePropertyResponse

<wsrf-rp:GetResourceProperty> QName</wsrf-rp:GetResourceProperty>

<wsrf-rp:GetResourcePropertyResponse> {any}*</wsrf-rp:GetResourcePropertyResponse>


GetResourceProperty


– InvalidResourcePropertyQNameFault:• The QName in the request message did not correspond to a resource

property element of the WS-Resource referred to in the request message.


GetResourceProperty

Request

Response


GetMultipleResourceProperties

• Allows a requestor to retrieve the values of multiple resource properties of a WS-Resource.


GetMultipleResourceProperties/GetMultipleResourcePropertiesRequest


GetMultipleResourceProperties/GetMultipleResourcePropertiesResponse

<wsrf-rp:GetMultipleResourceProperties> <wsrf-rp:ResourceProperty>QName <wsrf-rp:ResourceProperty>+</wsrf-rp:GetMultipleResourceProperties>

<wsrf-rp:GetMultipleResourcePropertiesResponse> {any}*</wsrf-rp:GetMultipleResourcePropertiesResponse>




– InvalidResourcePropertyQNameFault:• One or more of the QNames in the request message did not correspond to a

resource property element of the WS-Resource referred to in the request message.



ResponseRequest


QueryResourceProperties

• Allows a requestor to query the resource properties document of a WS-Resource using a query expression such as XPath.

– Supporting XPath dialect is mandatory:• http://www.w3.org/TR/1999/REC-xpath-19991116

• Request:– wsa:Action=http://docs.oasis-open.org/wsrf/rpw-2/QueryResourceProperties/

QueryResourcePropertiesRequest

• Response:– wsa:Action=http://docs.oasis-open.org/wsrf/rpw-2/QueryResourceProperties/

QueryResourcePropertiesResponse

<wsrf-rp:QueryResourceProperties> <wsrf-rp:QueryExpression Dialect=”xsd:anyURI”> xsd:any </wsrf-rp:QueryExpression></wsrf-rp:QueryResourceProperties>

<wsrf-rp:QueryResourcePropertiesResponse> {any}</wsrf-rp:QueryResourcePropertiesResponse>




– UnknownQueryExpressionDialectFault• The given QueryExpression has a dialect that is unknown to the Web

service.

– InvalidQueryExpressionFault• The given QueryExpression is not valid within the QueryExpression

language identified by the dialect attribute.



Request

Response


PutResourcePropertyDocument

• Allows a requestor to completely replace the values of a WS-Resource’s properties with an entirely new resource property document.


PutResourcePropertyDocument/PutResourcePropertyDocumentRequest


PutResourcePropertyDocument/PutResourcePropertyDocumentResponse

<wsrf-rp:PutResourcePropertyDocument> {any}</wsrf-rp:PutResourcePropertyDocument>

<wsrf-rp:PutResourcePropertyDocumentResponse> {any} ?</wsrf-rp:PutResourcePropertyDocumentResponse>




– UnableToPutResourcePropertyDocumentFault• The WS-Resource was unable to complete the processing of the

PutResourcePropertyDocument for some reason.



Response

Request


SetResourceProperties

• Allows the processing of a single request message to make multiple changes to the resource properties document.

• Types of changes:

– Insert:• wherein a new resource property element is inserted into the resource

properties document

– Update:• wherein existing resource property element(s) are modified

– Delete:• wherein existing resource property element(s) are removed



• Request:– wsa:Action=http://docs.oasis-open.org/wsrf/rpw-2/SetResourceProperties/

SetResourcePropertiesRequest

• Response:– wsa:Action=http://docs.oasis-open.org/wsrf/rpw-2/SetResourceProperties/

SetResourcePropertiesResponse

<wsrf-rp:SetResourceProperties>[ <wsrf-rp:Insert > {any}* </wsrf-rp:Insert> |

<wsrf-rp:Update > {any}* </wsrf-rp:Update> | <wsrf-rp:Delete ResourceProperty=”QName” /> ]+</wsrf-rp:SetResourceProperties>

<wsrf-rp:SetResourcePropertiesResponse></wsrf-rp:SetResourcePropertiesResponse>




– InvalidModificationFault• The contents of the SetResourceProperties request component cause the

resource properties document to no longer be able to validate.

– UnableToModifyResourcePropertyFault• A resource property identified by one of the SetResourceProperties request

components is read-only.

– InvalidResourcePropertyQNameFault• A resource property QName does not identify a resource property.

– SetResourcePropertyRequestFailedFault• One or more components of the SetResourceProperties request failed.



• Any fault message indicating a failure during the update of the resource properties document must also indicate whether the document was restored or not by using the ResourcePropertyChangeFailure element of the fault:– Indicates the resource property element change associated with the

fault.

– Indicates if the resource property document as a whole was restored

<wsrf-rp:ResourcePropertyChangeFailure Restored=xsd:boolean?> <wsrf-rp:CurrentValue>{any}*</wsrf-rp:CurrentValue> ? <wsrf-rp:RequestedValue>{any}*</wsrf-rp:RequestedValue> ?</wsrf-rp:ResourcePropertyChangeFailure>



Request

Change failure

Response


InsertResourceProperties

• Request the insertion of one or more element values of a single resource property into the resource properties document of a WS-Resource.

• Request:– wsa:Action=http://docs.oasis-open.org/wsrf/rpw-2/InsertResourceProperties/

InsertResourcePropertiesRequest.

• Response:– wsa:Action=http://docs.oasis-open.org/wsrf/rpw-2/InsertResourceProperties/

InsertResourcePropertiesResponse.

<wsrf-rp:InsertResourceProperties> <wsrf-rp:Insert> {any}* </wsrf-rp:Insert></wsrf-rp:InsertResourceProperties>

<wsrf-rp:InsertResourcePropertiesResponse></wsrf-rp:InsertResourcePropertiesResponse>



• Faults:– Generic WS-Resource faults.– InvalidModificationFault

• The contents of the InsertResourceProperties request component cause the resource properties document to no longer be able to validate.

– UnableToModifyResourcePropertyFault• A resource property identified by the InsertResourceProperties request is not

modifiable.


– InsertResourcePropertiesRequestFailedFault• The InsertResourceProperties request failed for some reason.

– Use the ResourcePropertyChangeFailure element of the fault if failure during the update.



Request

Response


UpdateResourceProperties

• It requests the replacement of all the element values of a single resource property in the resource properties document of a WS-Resource with a new set of values.

• Request:– wsa:action=http://docs.oasis-open.org/wsrf/rpw-2/UpdateResourceProperties/

UpdateResourcePropertiesRequest

• Response:– wsa:action=http://docs.oasis-open.org/wsrf/rpw-2/UpdateResourceProperties/

UpdateResourcePropertiesResponse

<wsrf-rp:UpdateResourceProperties> <wsrf-rp:Update> {any}* </wsrf-rp:Update></wsrf-rp:UpdateResourceProperties>

<wsrf-rp:UpdateResourcePropertiesResponse></wsrf-rp:UpdateResourcePropertiesResponse>



• Faults:– Generic WS-Resource faults.– InvalidModificationFault

• The contents of the UpdateResourceProperties request component cause the resource properties document to no longer be able to validate.

– UnableToModifyResourcePropertyFault• A resource property identified by the updateResourceProperties request is

not modifiable.


– UpdateResourcePropertiesRequestFailedFault• The UpdateResourceProperties request failed for some reason.




RequestResponse


DeleteResourceProperties

• Allows a requestor to remove all values of a resource property of a WS-Resource.

• Request:– wsa:Action=http://docs.oasis-open.org/wsrf/rpw-2/DeleteResourceProperties/

DeleteResourcePropertiesRequest

• Response:– wsa:Action=http://docs.oasis-open.org/wsrf/rpw-2/DeleteResourceProperties/

DeleteResourcePropertiesResponse

<wsrf-rp:DeleteResourceProperties> <wsrf-rp:Delete ResourceProperty=”QName” /></wsrf-rp:DeleteResourceProperties>

<wsrf-rp:DeleteResourcePropertiesResponse></wsrf-rp:DeleteResourcePropertiesResponse>



• Faults:– Generic WS-Resource faults.– InvalidModificationFault:

• The contents of the DeleteResourceProperties request component cause the resource properties document to no longer be able to validate.

– UnableToModifyResourcePropertyFault:• A resource property identified by the DeleteResourceProperties request is

not modifiable.

– InvalidResourcePropertyQNameFault:• A resource property QName does not identify a resource property.

– DeleteResourcePropertiesRequestFailedFault:• One or more components of the DeleteResourceProperties request failed.




RequestResponse


Outline


– WS-Addressing

– Faults






– wsrf4egee


WS-Resource Lifetime

• WS-Resource lifetime defines the message exchanges needed for destroying a WS-Resource.– Normally, a service requestor’s interest in a WS-Resource is for some

period of time - rarely is it indefinite.

• WS-Resource lifetime also defines the required resource properties that may be used to inspect and monitor the lifetime of a WS-Resource.

• WS-Resources support:– Immediate destruction.

– Scheduled destruction after a period of time.


WS-Resource immediate destruction

• Immediate destruction of a resource may be provided by the Destroy operation:

– Request:• wsa:Action=http://docs.oasis-open.org/wsrf/rlw-2

/ImmediateResourceTermination/DestroyRequest

– Response:• wsa:Action=http://docs.oasis-open.org/wsrf/rlw-2/ImmediateResourceTermination/

DestroyResponse

• Faults:– Generic WS-Resource faults.– ResourceNotDestroyedFault

• The WS-Resource could not be destroyed for some reason.

<wsrf-rl:Destroy/>

<wsrf-rl:DestroyResponse />


WS-Resource immediate destruction example

Request Response


WS-Resource scheduled destruction

• It may be provided the destruction of a WS-Resource after a period of time (scheduled destruction):– WS-Resource has associated a termination time.

• Scheduled destruction requires:– TerminationTime resource property.

– CurrentTime resource property.

– SetTerminationTime operation.


SetTerminationTime

• Request:– wsa:Action=http://docs.oasis-open.org/wsrf/rlw-2/

ScheduledResourceTermination/SetTerminationTimeRequest

• Response:– wsa:Action=http://docs.oasis-open.org/wsrf/rlw-2/

ScheduledResourceTermination/SetTerminationTimeResponse

<wsrf-rl:SetTerminationTime> [<wsrf-rl:RequestedTerminationTime xsi:nil=”xsd:boolean”?> xsd:dateTime </wsrf-rl:RequestedTerminationTime>] | [<wsrf-rl:RequestedLifetimeDuration> xsd:duration </wsrf-rl:RequestedLifetimeDuration>] </wsrf-rl:SetTerminationTime>

<wsrf-rl:SetTerminationTimeResponse> <wsrf-rl:NewTerminationTime xsi:nil=”xsd:boolean”?> xsd:dateTime </wsrf-rl:NewTerminationTime> <wsrf-rl:CurrentTime> xsd:dateTime </wsrf-rl:CurrentTime> <wsrf-rl:SetTerminationTimeResponse>


SetTerminationTime


– UnableToSetTerminationTimeFault • The request for termination time could not be changed for some reason.

– TerminationTimeChangeRejectedFault • In the case where a WS-Resource is willing to update its TerminationTime.


SetTerminationTime example

RequestResponse


Outline


– WS-Addressing

– Faults






– wsrf4egee


Grouping services

• WSRF allows creating groups of services (WSRF services or not WSRF services).

• A group of services could be interpreted as:– A collection of services.– A directory of services.– A registry of services.– …

• Concepts about group of services:– Member: is a web service that belongs to a group of services.– ServiceGroup: is a web service that is a collection of web services.– ServiceGroupEntry: is an entry in a ServiceGroup that associates a

Member with that ServiceGroup.


Grouping services

• A ServiceGroup service may be extended as a ServiceGroupRegistration service, which allows adding new entries (associated to members) to the group of services.

• A service group has associated ServiceGroupEntry’s, one for each member in the group of services.


ServiceGroup

• MembershipContentRule optional property:

– Specifies rules that members of the ServiceGroup must accomplish.

– MemberInterface: interface (portType) that a member must be available.

– ContentElements: property QNames that a ServiceGroupEntry must provide to be part of the ServiceGroup.

• Entry property:– ServiceGroupEntryEPR– MemberServiceEPR– Content: resource property

document of the member


ServiceGroupRegistration

• Extends Service Group with the Add operation for including new members to a group of services:

Request Response


ServiceGroupRegistration

• Add faults:– Generic WS-Resource.

– ContentCreationFailedFault:• The operation was unable to create a valid Content element.

– UnsupportedMemberInterfaceFault:• The member service referred to by the MemberEPR argument is not

conformant with the MembershipContentRule.

– AddRefusedFault:• The ServiceGroupRegistration refused to create a new entry for the member

service based the semantics of the ServiceGroupRegistration.


ServiceGroupEntry

• There is one ServiceGroupEntry for each member of the group of services.

• Resource properties:– ServiceGroupEPR

– MemerEPR

– Content

– The same values as the elements inside Add operation of ServiceGroupRegistration.

– The same values as the elements available into the Content of the Entry property of ServiceGroup.


Outline


– WS-Addressing

– Faults






– wsrf4egee


Developing WSRF services

• Apache WSRF (Java)• WSRF.NET• WSRF::Lite (Perl)• Globus Java WS Core• Globus Python Core


WSRF::Lite

• Open source Perl implementation of WSRF.

• Successor of OGSI::Lite, a Perl implementation of OGSI.

• WSRF::Lite provides support for the following Web Service Specifications:

– WS-Addressing.– WS-ResourceProperties.– WS-ResourceLifetimes.– WS-BaseFaults.– WS-ServiceGroups.– WS-Security.


WSRF::Lite

• Based on SOAP::Lite, the Web services module for Perl.

• The state of a WS-Resource can be managed in the following ways:– A process to manage the state of a WS-Resource.– A process to manage the state of several WS-Resources– A file to store the state between calls to the WS-Resource.

• fault-tolerant

• Provides:– Container scripts:

• Plain HTTP container• HTTP over Secure Sockets Layer container

– Uses X.509 certificates for mutual authentication between client and server.(it is possible to user a Web server, such as Apache, as container)

– Perl classes for developing WSRF services– Client scripts:

• Invoke standard WSRF operations.


wsrf4egee

• Tool that provides server and client utilities for deploying WSRF compliant services which send jobs to the EGEE Grid.

• Provides:– a base Perl class that can be easily extended for deploying this kind of

services

– a set of client scripts for invoking that services.

• Based on WSRF::Lite Perl module.

• Not yet publicly available

Workflows over Grid-based Web servicesGeneral framework and a practical case in structural biology

References


References

• OASIS Web Services Resource Framework (WSRF) TC – http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=wsrf

• The hidden impact of WS-Addressing on SOAP– http://www-128.ibm.com/developerworks/webservices/library/ws-

address.html

• Globus WSRF– http://www.globus.org/wsrf/

• WSRF::Lite– http://www.sve.man.ac.uk/Research/AtoZ/ILCT

• Apache WebServices - Apache WSRF– http://ws.apache.org/wsrf/index.html

• WSRF.NET– http://www.cs.virginia.edu/~gsw2c/wsrf.net.html

web services over the grid - wsrf -

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