Globus MDS for Developers Mike DArcy Laura Pearlman USC Information Sciences Institute

Globus MDS for Developers

Mike D’ArcyLaura Pearlman

USC Information Sciences Institute

September 11, 2006 MDS for Developers 2

Agenda

Review of MDS services and components Publishing information

Publishing resource properties with the new Resource Property Provider component.

Using ExecutionAggregatorSource to monitor things other than WSRF services

Acting on Information Using the Trigger Service to monitor both WSRF and

non-WSRF services so that user programs may be invoked when specific conditions are detected.

Querying/displaying information Querying the Index Service Using the new TargetedXPath query dialect Producing custom WebMDS views


MDS Services

Index Service Collects information Publishes its data as resource properties

Trigger Service Collects information using the same

mechanism as the Index Service Executes trigger actions when conditions

are met.


Data Flow in MDS

Execution Aggregator Source

Trigger ServiceIndex Service

Resource property requests

Subscription / notiification

Clients: wsrf-query, WebMDS, Java API, C API

Trigger actions

anything

WSRF Service

Query Aggregator Source

WSRF ServiceWith rpProvider

Information Provider

Resource property requests execution


Resource Property Provider

The new RPProvider component provides a modular “plug-in” API for creating Resource Properties from various user-defined input sources.

This mechanism allows for the easy inclusion of custom XML content, represented as a WS-ResourceProperty, into GT4 services with significantly reduced integration overhead.

In many cases, no new code may be required at all. For example, periodically reading a XML file and storing the contents in the IndexService requires no custom coding and minimal configuration.


RPProvider API Basics The goal is the output of XML, bound to a QName that

represents the name of the WS Resource Property that the data will be published as.

This task is handled by 3 sub-components:

Element Producers: perform the generation of the XML data to be used as the resource property value(s).

Element Transforms: optionally perform post-processing and validation on the output of element producers.

Execution Engine: reads configuration and performs the periodic execution of ResourcePropertyProviderTasks, which first executes a specified element producer, and then optionally executes any specified element transform.


RPProvider: Element Producers Element producers are required only to implement the single

method of a Java interface of the form:

public Element getElement(String[] args) throws Exception;

RPProvider comes with a default set of element producers that can be used for a variety of common tasks.

ExternalProcessElementProducer: executes a external process, then attempts to parse the STDOUT stream of that process into a valid XML document.

FileElementProducer: reads data directly from a XML file.

URLElementProducer: reads data by using an HTTP Get request to fetch a XML file.


RPProvider: Element Transforms Element transforms are required only to implement

a single method of a Java interface of the form:

public Object transformElement(Element source, String[] args) throws Exception;

The return type of the transformElement method is expected to be either a DOM Element, or a XML serializable Java bean object generated from WSDL or XSD with Axis WSDL2Java.

RPProvider includes a basic XSLT-based transform for general use, XSLTFileElementTransform, which reads in a XSLT file as specified by arg[0] and applies it to the result element generated by an element producer’s getElement method.


RPProvider: Execution Engine The execution engine of the RPProvider component

is a set of Java classes which handles the creation and periodic execution of Java TimerTasks that generate data by invoking configured Element Producers and Element Transforms.

The execution engine is implemented as a GT4 operation provider. The implementation for the operation provider is contained primarily within the ResourcePropertyProviderCollection.java class.

The execution engine supplies utility classes that implement the ReflectionResourceProperty interface. These classes provide default mechanisms for returning element producer output as either a single value or an array of values.


RPProvider: Execution Engine, continued

Pre-existing Factory and Singleton type services can include the operation provider without code modification by editing the service descriptor in the server-config.wsdd file.

Service resources created at runtime must have support for RPProvider compiled into the code by creating an instance of ResourcePropertyProviderCollection at resource initialization time.


RPProvider: Configuration Adding RPProvider support to a Factory or Singleton service via server-

config.wsdd:

<service name="DefaultIndexService" provider="Handler" use="literal" style="document"> <parameter name="providers" value=

“org.globus.wsrf.impl.servicegroup.ServiceGroupRegistrationProvider org.globus.mds.usefulrp.rpprovider.ResourcePropertyProviderCollection

GetRPProvider GetMRPProvider QueryRPProvider DestroyProvider SetTerminationTimeProvider SubscribeProvider GetCurrentMessageProvider"/>

<parameter name="handlerClass" value="org.globus.axis.providers.RPCProvider"/> <parameter name="scope" value="Application"/> <parameter name="allowedMethods" value="*"/> <parameter name="rpProviderConfigFile"

value="etc/globus_wsrf_mds_usefulrp/gluece-rpprovider-sample-config.xml"/> <parameter name="className" value="org.globus.mds.index.impl.DefaultIndexService"/> <wsdlFile>share/schema/mds/index/index_service.wsdl</wsdlFile> </service>


Adding RPProvider Support to a Resource

Adding RPProvider support directly into a resource implementation class:

ResourcePropertyProviderCollection rpCollection =

new ResourcePropertyProviderCollection (

“path/to/config/file/rpConfig.xml”, // a full path to the configuration file

this.getResourcePropertySet(), // the resource property set to add into

true // initialize immediately after construction

);

Note: This code fragment assumes that the class referred to by the this variable implements the org.globus.wsrf.ResourceProperties interface.


RPProvider usage in GT4

The 4.1.x GRAM ManagedJobFactoryResource uses the latter approach to integrate resource-level RPProvider support for the Fork, PBS, and other GRAM job scheduler factory resources.

A refactored version of the GLUEResourceProperty.java class, based on the RPProvider API, is now used by GT4.1.x GRAM to publish the GLUECE Resource Property.

This newer version of GLUEResourceProperty supports more flexible configuration of the underlying information providers that compose the GLUECE RP for a given scheduler type.

Scheduler providers can now be easily swapped out and replaced with developer versions.


RPProvider: Configuration Sample RPProvider Configuration File Format as defined in rpprovider.xsd

<ns1:ResourcePropertyProviderConfigArray xsi:type="ns1:ResourcePropertyProviderConfigArray" xmlns:ns1="http://mds.globus.org/rpprovider/2005/08" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

<ns1:configArray xsi:type="ns1:resourcePropertyProviderConfig">

<ns1:resourcePropertyName xsi:type="xsd:QName" xmlns:mds="http://mds.globus.org/glue/ce/1.1">mds:GLUECE</ns1:resourcePropertyName>

<ns1:resourcePropertyImpl xsi:type="xsd:string">org.globus.mds.usefulrp.rpprovider.GLUEResourceProperty</ns1:resourcePropertyImpl>

<ns1:resourcePropertyElementProducers xsi:type="ns1:resourcePropertyElementProducerConfig"> <ns1:className xsi:type="xsd:string">org.globus.mds.usefulrp.glue.GangliaElementProducer</ns1:className> <ns1:arguments xsi:type="xsd:string">localhost</ns1:arguments> <ns1:arguments xsi:type="xsd:string">8649</ns1:arguments> <ns1:period xsi:type="xsd:int">300</ns1:period> <ns1:transformClass xsi:type="xsd:string">

org.globus.mds.usefulrp.rpprovider.transforms.GLUEComputeElementTransform</ns1:transformClass> </ns1:resourcePropertyElementProducers>

<ns1:resourcePropertyElementProducers xsi:type="ns1:resourcePropertyElementProducerConfig"> <ns1:className xsi:type="xsd:string">

org.globus.mds.usefulrp.rpprovider.producers.SchedulerInfoElementProducer</ns1:className> <ns1:arguments xsi:type="xsd:string">libexec/globus-scheduler-provider-pbs</ns1:arguments> <ns1:transformClass xsi:type="xsd:string">

org.globus.mds.usefulrp.rpprovider.transforms.GLUESchedulerElementTransform</ns1:transformClass> <ns1:period xsi:type="xsd:int">300</ns1:period> </ns1:resourcePropertyElementProducers>

</ns1:configArray></ns1:ResourcePropertyProviderConfigArray>


RPProvider Example, Overview

Putting it all together: Adding a MOTD Resource Property to the DefaultIndexService

Step 1: Create the MOTD XML file that will contain the value(s) of the resource property.

Step 2: Create a RPProvider configuration file for the MOTD resource property.

Step 3: Configure the DefaultIndexService to use the ResourcePropertyProviderCollection operation provider.

Step 4: Start the container and query the MOTD resource property to verify that things are functional.


RPProvider Example, Step 1

Step 1: Create MOTD XML file

Our sample XML file will publish a Message of the Day as a resource property named: {http://mds.globus.org/MOTD}MessageOfTheDay

The motd.xml sample file contains the following data:

<?xml version="1.0" encoding="UTF-8"?>

<motd:MessageOfTheDay xmlns:motd="http://mds.globus.org/MOTD" >

<motd:Message>

The system will be going down for maintenance today at 3:00AM EST for approximately 10 minutes. We apologize for any inconvenience.

</motd:Message>

<motd:LastUpdated> Thu Aug 10 15:05:00 PDT 2006 </motd:LastUpdated>

<motd:UpdatedBy> Ricky Bobby </motd:UpdatedBy>

</motd:MessageOfTheDay>


RPProvider Example, Step 2 Step 2: Create a configuration file for the MOTD resource property

Create the file motd-sample-config.xml in the $GLOBUS_LOCATION/etc/globus_wsrf_mds_index directory.

The MOTD RP configuration file should contain the following data:

<ns1:ResourcePropertyProviderConfigArray xsi:type="ns1:ResourcePropertyProviderConfigArray" xmlns:ns1="http://mds.globus.org/rpprovider/2005/08" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <ns1:configArray xsi:type="ns1:resourcePropertyProviderConfig">

<ns1:resourcePropertyName xsi:type="xsd:QName" xmlns:motd="http://mds.globus.org/MOTD">motd:MessageOfTheDay

</ns1:resourcePropertyName> <ns1:resourcePropertyImpl xsi:type="xsd:string">

org.globus.mds.usefulrp.rpprovider.SingleValueResourcePropertyProvider </ns1:resourcePropertyImpl>

<ns1:resourcePropertyElementProducers xsi:type="ns1:resourcePropertyElementProducerConfig"> <ns1:className xsi:type="xsd:string">

org.globus.mds.usefulrp.rpprovider.producers.FileElementProducer </ns1:className> <ns1:arguments xsi:type="xsd:string"> /full/path/to/motd.xml </ns1:arguments> <ns1:period xsi:type="xsd:int">86400</ns1:period> </ns1:resourcePropertyElementProducers>

</ns1:configArray></ns1:ResourcePropertyProviderConfigArray>


RPProvider Example: Step 3 Step 3: Configure the DefaultIndexService to use the

ResourcePropertyProviderCollection operation provider.

<service name="DefaultIndexService" provider="Handler" use="literal" style="document"> <parameter name="providers" value=

“org.globus.wsrf.impl.servicegroup.ServiceGroupRegistrationProvider org.globus.mds.usefulrp.rpprovider.ResourcePropertyProviderCollection

GetRPProvider GetMRPProvider QueryRPProvider DestroyProvider SetTerminationTimeProvider SubscribeProvider GetCurrentMessageProvider"/>

<parameter name="handlerClass" value="org.globus.axis.providers.RPCProvider"/> <parameter name="scope" value="Application"/> <parameter name="allowedMethods" value="*"/> <parameter name="rpProviderConfigFile"

value="etc/globus_wsrf_mds_index/motd-sample-config.xml"/> <parameter name="className" value="org.globus.mds.index.impl.DefaultIndexService"/> <wsdlFile>share/schema/mds/index/index_service.wsdl</wsdlFile> </service>


RPProvider Example: Step 4 Step 4: Start the container and query the MOTD resource

property to verify that things are functional.

Start container: $GLOBUS_LOCATION/bin/globus-start-container [-nosec]

Issue a GetResourceProperty query: $GLOBUS_LOCATION/bin/wsrf-get-property –s http://localhost:8080/wsrf/services/DefaultIndexService {http://mds.globus.org/MOTD}MessageOfTheDay

The query command output should contain the following data:

<motd:MessageOfTheDay xmlns:motd="http://mds.globus.org/MOTD"> <motd:Message>

The system will be going down for maintenance today at 3:00AM EST for approximately 10 minutes. We apologize for any inconvenience.

</motd:Message> <motd:LastUpdated> Thu Aug 10 15:05:00 PDT 2006 </motd:LastUpdated> <motd:UpdatedBy> Ricky Bobby </motd:UpdatedBy>

</motd:MessageOfTheDay>


ExecutionAggregatorSource

The ExecutionAggregatorSource provides a flexible data ingestion mechanism for WS-MDS Service Groups that are based on the Aggregator Framework. This includes: Index Service Trigger Service

ExecutionAggregatorSource functions by executing an external process and then parsing the process STDOUT stream into a XML file.

The result XML file is stored as the value of the Content ResourceProperty for the ServiceGroupEntry resource that is created when the Service Group Add operation is invoked against the service.


ExecutionAggregatorSource Example

Prerequisite: Install the GridFTP information provider Ensure that the information provider file gridftp-banner.pl is located

in the following directory: $GLOBUS_LOCATION/libexec/aggrexec

Step 1: Enable the usage of gridftp-banner.pl by editing the executableMappings field of the AggregatorConfiguration block of the jndi-config.xml file for the Index or Trigger.

$GLOBUS_LOCATION/etc/globus_wsrf_mds_index/jndi-config.xml $GLOBUS_LOCATION/etc/globus_wsrf_mds_trigger/jndi-config.xml

Step 2: Create or modify a mds-servicegroup-add registration file to contain the instructions to run the GridFTP information provider periodically against a specifed GridFTP server address.


ExecutionAggregatorSource Example, continued

Configuring the Index and Trigger services to use ExecutionAggregatorSource to monitor GridFTP

Step 3: Start the container and run the mds-servicegroup-add program to register a new service group entry that will run the GridFTP information provider.

Step 4: Issue a wsrf-query to check the status of the provider:

$GLOBUS_LOCATION/bin/wsrf-query –s http://myhost:8080/wsrf/services/DefaultIndexService


ExecutionAggregatorSource Example: Step 1

Step 1: Enable execution of gridftp-banner.pl For security reasons, all executable programs used by the

ExecutionAggregatorSource must be enumerated by the adminstrator of the Globus installation prior to starting the container.

The administrator is required to map a logical “probe name” to the physical filename of the information provider. Furthermore, the information provider executable file must by located in $GLOBUS_LOCATION/libexec/aggrexec (or symlinked from that location).

In this case, edit the AggregatorConfiguration block of the service jndi-config.xml as follows:

<resource name="configuration" type="org.globus.mds.aggregator.impl.AggregatorConfiguration">

… <parameter>

<name>executableMappings</name> <value> gridftp-info=gridftp-banner.pl, aggr-test=aggregator-exec-test.sh, pingexec=example-ping-exec </value>

</parameter> …

</resource>



Step 2: Create or modify a mds-servicegroup-add registration file for the GridFTP information provider

<ServiceGroupRegistrationsxmlns="http://mds.globus.org/servicegroup/client" xmlns:sgc="http://mds.globus.org/servicegroup/client" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance“ xmlns:wsa=“http://schemas.xmlsoap.org/ws/2004/03/addressing” xmlns:agg="http://mds.globus.org/aggregator/types">

<defaultServiceGroupEPR> <wsa:Address>https://yourhost:8443/wsrf/services/DefaultIndexService</wsa:Address> </defaultServiceGroupEPR>

<ServiceGroupRegistrationParameters xmlns="http://mds.globus.org/servicegroup/client" >

<RegistrantEPR xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:wsa=“http://schemas.xmlsoap.org/ws/2004/03/addressing” xmlns:agg="http://mds.globus.org/aggregator/types">

<wsa:Address>ftp://yourhost:2811</wsa:Address> </RegistrantEPR>

<RefreshIntervalSecs>600</RefreshIntervalSecs>

<Content xsi:type="agg:AggregatorContent" xmlns:agg="http://mds.globus.org/aggregator/types"> <agg:AggregatorConfig xsi:type="agg:AggregatorConfig"> <agg:ExecutionPollType> <agg:PollIntervalMillis>60000</agg:PollIntervalMillis> <agg:ProbeName>gridftp-info</agg:ProbeName> </agg:ExecutionPollType> </agg:AggregatorConfig> <agg:AggregatorData/> </Content>

</ServiceGroupRegistrationParameters> </ServiceGroupRegistrations>



Step 3: Start the container and run the mds-servicegroup-add program to register a new service group entry that will run the GridFTP information provider.

Start container:

$GLOBUS_LOCATION/bin/globus-start-container -nosec

Run mds-servicegroup-add:

$GLOBUS_LOCATION/bin/mds-servicegroup-add my-gridftp-registration.xml


ExecutionAggregatorSource Example: step 4

Step 4: Issue a wsrf-query to check the status of the information provider:

Query: $GLOBUS_LOCATION/bin/wsrf-query –s http://myhost:8080/wsrf/services/DefaultIndexService

"//*[ local-name()='Address' and contains(.,'ftp://wiggum.mcs.anl.gov:2811') ]/../..//*[ local-name()='AggregatorData' ] "

Query Output:

<ns11:AggregatorData xmlns:ns11="http://mds.globus.org/aggregator/types"> <test xmlns:mds="http://www.globus.org/namespaces/2006/8/mds" xmlns=""> <reporter> <name>./gridftp-banner.pl</name> <url>skynet-login</url> </reporter>

<target> <name>GridFTP</name> <url>ftp://wiggum.mcs.anl.gov:2811</url> </target>

<result> <status>UP</status> <comment applyTransform="true"> <![CDATA[ 220 GridFTP Server wiggum.mcs.anl.gov 2.0 (gcc32dbg, 1114447190-1) ready. ]]> </comment> </result> </test></ns11:AggregatorData>


ExecutionAggregatorSource: Conclusion

Useful for Non-WSRF Services

Developers can implement their own information providers using ExecutionAggregatorSource in a similar manner.

Benefits of this approach:

Information modeled as ServiceGroupEntry content.

WS-Lifetime interfaces used to manage information lifetime for each ServiceGroupEntry resource.

WSRF and Non-WSRF Service information can co-exist in the same Service Group, in this case, the DefaultIndexService.


Trigger Service Using the Trigger Service to monitor other services so that

user programs may be invoked when specific conditions are detected.

The Trigger Service may be used to monitor the results of data aggregation operations for both WSRF and Non-WSRF services.

The Trigger Service can be configured to probe information directly, or can also be configured to probe summary information from another service already aggregating information, such as the IndexService.

This example will show how to use the DefaultTriggerService to monitor the DefaultIndexService in order to detect and trigger a status notification email when a GridFTP service (as described in the previous section) goes down.


Trigger Service: Configuration Configuring the container’s DefaultTriggerService:

Step 1: Enable the email action script that will be used by the DefaultTriggerService.

Step 2: Edit the email action script to specify the addressee and optional event description.

Step 3: Edit the registration file that will be used with mds-servicegroup-add that will be used to register the trigger configuration to the DefaultTriggerService.

Step 4: Run the mds-servicegroup-add command to register and activate the trigger and query the DefaultTriggerService for status about the trigger state.


Trigger Service Example: Step 1 Step 1: Enable the email action script that will be used by

the DefaultTriggerService Like the ExecutionAggregatorSource, for security reasons all trigger action

scripts used by the TriggerService must be enumerated by the administrator of the Globus installation prior to starting the container.

The administrator is required to map a logical “action name” to the physical filename of the executable trigger action. Furthermore, the information provider executable file must by located in the following directory: $GLOBUS_LOCATION/libexec/trigger

In this case, edit the TriggerConfiguration block of the Trigger Service jndi-config.xml as follows:

<resource name="configuration" type="org.globus.mds.aggregator.impl.AggregatorConfiguration">

… <parameter> <name>executableMappings</name> <value>email-trigger=email-trigger.sh, test-trigger=test-trigger-action.sh, glue-trigger=glue-trigger-action.sh,

echo-trigger=echo-trigger-action.sh</value> </parameter>

… </resource>


Trigger Service Example, Step 2 Step 2: Edit the email action script to specify the

addressee and optional event description.

Create a file called email-trigger.sh file in $GLOBUS_LOCATION/libexec/trigger

NOTE: Make sure the file has permissions allowing it to be executed by the user account that the container process will run as.

The following file can be used as a template for those systems that have the mailx program installed.

#!/bin/sh

[email protected]=SUBJECT="Your event has been triggered"DATE=`date '+20%y-%m-%d'`MSG="The GridFTP server at ftp://wiggum.mcs.anl.gov:2811 is down."

echo "$MSG" | mailx -s "$SUBJECT" $CC $TO

cat <<FIN<?xml version="1.0" encoding="UTF-8"?><TriggerAction> <message>$SUBJECT</message> <status>DOWN</status> <time>$DATE</time></TriggerAction>FIN


Trigger Service Example, Step 3 Step 3: Edit the registration file that will be used with mds-

servicegroup-add that will be used to register the trigger configuration to the DefaultTriggerService.

<?xml version="1.0" encoding="UTF-8" ?><ServiceGroupRegistrations> <defaultServiceGroupEPR><wsa:Address>http://localhost:8080/wsrf/services/DefaultTriggerService</wsa:Address></defaultServiceGroupEPR> <ServiceGroupRegistrationParameters> <RegistrantEPR xmlns:wsa="http://schemas.xmlsoap.org/ws/2004/03/addressing"> <wsa:Address>http://localhost:8080/wsrf/services/DefaultIndexService</wsa:Address> </RegistrantEPR> <RefreshIntervalSecs>600</RefreshIntervalSecs> <Content xsi:type="agg:AggregatorContent" xmlns:agg="http://mds.globus.org/aggregator/types"> <agg:AggregatorConfig xsi:type="agg:AggregatorConfig"> <agg:GetMultipleResourcePropertiesPollType xmlns:wssg="http://docs.oasis-open.org/wsrf/2004/06/wsrf-WS-ServiceGroup-1.2-draft-01.xsd"> <agg:PollIntervalMillis>150000</agg:PollIntervalMillis> <agg:ResourcePropertyNames> wssg:Entry </agg:ResourcePropertyNames> </agg:GetMultipleResourcePropertiesPollType>

<trigger:TriggerRuleType> <trigger:matchingRule> //test[target/url='ftp://wiggum.mcs.anl.gov:2811' and result/status='DOWN'] </trigger:matchingRule> <trigger:actionScript>email-trigger</trigger:actionScript> <trigger:minimumFiringInterval>86400</trigger:minimumFiringInterval> <trigger:minimumMatchTime>300</trigger:minimumMatchTime> <trigger:enableFilteredActionScriptInput>true</trigger:enableFilteredActionScriptInput> <trigger:disableUnmodifiedActionScriptInput>true</trigger:disableUnmodifiedActionScriptInput> </trigger:TriggerRuleType>

</agg:AggregatorConfig> <agg:AggregatorData/> </Content> </ServiceGroupRegistrationParameters></ServiceGroupRegistrations>


Trigger Service Example, Step 4 Step 4: Run the mds-servicegroup-add command to

register and activate the trigger and query the DefaultTriggerService for status about the trigger state. Run mds-servicegroup-add using the email trigger

registration file. Query the DefaultTriggerService for the trigger state:

wsrf-query -s http://localhost:8080/wsrf/services/DefaultTriggerService "//*[local-name()='TriggerStatusArray'] “

Sample Query Output:<ns13:TriggerStatusArray xmlns:ns13="http://mds.globus.org/2004/08/trigger/types"> <ns13:triggerStatus> <ns13:triggerID>07b3f440-3710-11db-bf4d-89fc4ea14c8f</ns13:triggerID> <ns13:matchingRule>//test[target/url='ftp://wiggum.mcs.anl.gov:2815' and result/status='DOWN']</ns13:matchingRule> <ns13:conditionTrueSince>2006-08-29T03:40:52.575Z</ns13:conditionTrueSince> <ns13:actionFiredAt>2006-08-29T03:41:52.668Z</ns13:actionFiredAt> <ns13:ruleLastCheckedAt>2006-08-29T03:41:52.564Z</ns13:ruleLastCheckedAt> <ns13:actionOutput> <TriggerAction xmlns=""> <message>Your event has been triggered</message> <status>DOWN</status> <time>2006-08-28</time> </TriggerAction> </ns13:actionOutput> <ns13:statusInfo>The trigger action was executed successfully</ns13:statusInfo> </ns13:triggerStatus></ns13:TriggerStatusArray>


Querying the Index Service

Standard QueryResourceProperties WSRF request takes a dialect and a query expression

GT4 supports the standard xpath dialect: Examples:

/ - returns entire xml tree //glue:Cluster returns all elements of that type

Limitations: can’t specify namespace mappings (e.g., can’t guarantee that “glue” will be recognized in second example)

Workaround: use xpath functions like local-name //*[local-name()='Cluster']


QueryResourceProperties Overview

1. Set up a porttype object. Server address security options

2. Create query arguments. dialect query

3. Run query request


Set Up the Porttype ObjectString myURL =

“https://myhost:8443/wsrf/services/DefaultIndexService”EndpointReferenceType endpoint = new EndpointReferenceType();endpoint.setAddress(new AttributedURI(myURL));

WSResourcePropertiesServiceAddressingLocator locator = new WSResourcePropertiesServiceAddressingLocator();QueryResourceProperties_PortType port;try { port = locator.getQueryResourcePropertiesPort(endpoint);} catch (ServiceException e) { // Do something.}

((Stub)port)._setProperty( Constants.GSI_ANONYMOUS, Boolean.TRUE);


Create Query Arguments (XPath)String queryString = “/”;QueryExpressionType query = new QueryExpressionType();try { query.setDialect(WSRFConstants.XPATH_1_DIALECT);} catch (MalformedURIException e) { // Do something.}query.setValue(queryString);

QueryResourceProperties_Element request = new QueryResourceProperties_Element();request.setQueryExpression(query);


Run Query

QueryResourcePropertiesResponse response;

try {

response = port.queryResourceProperties(request);

} catch (RemoteException e) {

// Do something.

}

// response is an array of MessageElement

System.out.println(

AnyHelper.toSingleString(response));


targetedXPath

GT4.1.x has a new dialect, targetedXPath XPath dialect is still there

Allows the user to specify namespace mappings for use in queries

Usage is the same as with the XPath dialect, except that setting up the query args is different


Create Query Arguments (targetedXPath)

TargetedXPathQueryType targetedQuery = new TargetedXPathQueryType();NamespaceMappingType nsMap[] = new NamespaceMappingType[1];nsMap[0] = new NamespaceMappingType();nsMap[0].setMappedName(“glue”);nsMap[0].setNamespace( new URI(“http://mds.globus.org/glue/ce/1.1”));targetedQuery.setNamespaceMappings(nsMap);targetedQuery.setQueryString(“//glue:Cluster”);QueryExpressionType query = new QueryExpressionType();try { query.setDialect(TargetedXPathConstants.TARGETED_XPATH_DIALECT);} catch (MalformedURIException e) { // Do something.}query.setValue(targetedQuery);


WebMDS


WebMDS: How it Works

Web Browser

Web Form

WebMDS

plugin plugin

XSL Transform

IndexService

HTMLOutput

Resource property query

HTTP query with form

arguments


WebMDS and HTML Forms

For a URL like http://myhost:8080/webmds/webmds?info=indexinfo

“info” arg tells WebMDS where to get data Looks for “indexinfo” file in WebMDS conf

directory “info” is the only mandatory argument Optional “xsl” arg tells WebMDS where to

get the XSL transform Uses same config mechanism as “info” arg

Other arguments are available


WebMDS Plugins

Resource Property Plugin Performs resource property queries Can be configured to accept an EPR argument.

Implemented by “openEndedQuery” conf file

Can be configured to query a specific EPR Implemented by “indexinfo” conf file

File Plugin Reads a file Useful for getting XML transforms Also used for testing


WebMDS openEndedQuery

<WebmdsConfig> <description> Resource property query of the local default index service </description> <className>org.globus...NodeXmlSource</className> <parameter> <name>class</name> <value>org.globus...ResourcePropertyQueryNodeSource</value> </parameter> <parameter> <name>allowUserEndpoints</name> <value>true</value> </parameter></WebmdsConfig>


WebMDS Resource Property Plugin<WebmdsConfig>

<description>

Resource property query of the local default index service

</description>

<className>org.globus...xmlDomNode.NodeXmlSource</className>

<parameter>

<name>class</name>

<value>org.globus.mds...ResourcePropertyQueryNodeSource</value>

</parameter>

<parameter>

<name>endpoint</name>

<value>

https://127.0.0.1:8443/wsrf/services/DefaultIndexService

</value>

</parameter>

</WebmdsConfig>


WebMDS File Plugin

<WebmdsConfig> <description> XSL file to show service group summary information </description> <className>org.globus...FileXmlSource</className> <suitableForXSL>true</suitableForXSL> <parameter> <name>file</name> <value>xslfiles/servicegrouptable.xsl</value> </parameter></WebmdsConfig>


Implementing a New XSL Transform

1. Write an XSL transform

2. Create a config file in $GLOBUS_LOCATION/lib/webmds/conf

3. Use a web browser to test the transform


WebMDS – Write an XSL Transform

XSL is documented at http://www.w3.org/TR/xslt

There are many examples of XSL transforms in $GLOBUS_LOCATION/lib/webmds/xslfiles

Install the transform in $GLOBUS_LOCATION/lib/webmds/xslfiles/local For purposes of this example, call the file

“mytransform.xsl”


WebMDS – Configure an XSL Transform

Create a config file in $GLOBUS_LOCATION/lib/webmds/conf For this example, call the file “mytransform”

<WebmdsConfig> <description> XSL file to implement my custom transform </description> <className>org.globus...FileXmlSource</className> <suitableForXSL>true</suitableForXSL> <parameter> <name>file</name> <value>xslfiles/local/mytransform.xsl</value> </parameter></WebmdsConfig>


WebMDS – Test Your XSL Transform

Use “mytransform” as the “xsl” argument in an HTML form or URL http://myhost:8080/webmds/webmds?

info=indexinfo&xsl=mytransform


WebMDS – Adding Summary Info to Service Group Summary

The Service Group summary view (“xsl=servicegroupxsl”) has a summary line for each entry in the Index.

The format of the summary data is based on the data type GRAM data contains the number of queues,

RFT data includes the number of files transferred, etc.

For unrecognized types, only the type name and EPR are reported


WebMDS – Adding Summary Datato Service Group Summary, continued

To tell the service group summary transform how to deal with a new data type, edit the file sgtypes.xsl in $GLOBUS_LOCATION/lib/webmds/xslfiles/local

Define a transform that will produce a suitable summary line for your type

See examples in the directory $GLOBUS_LOCATION/lib/webmds/xslfiles/sgtypes

The transform should act on a service group entry that contains content of your type

Fortunately, there’s a template… If you have several custom types, you may want to

define them in separate files and have sgtypes.xsl include them.


WebMDS – sgtypes.xsl<xsl:template match="wssg:Entry[wssg:Content/ag:AggregatorData/myns:MyType]" mode="rows" xmlns:myns="http://www.myhome.org/path/to/my/namespace"> <tr valign="top"> <th>MyLabel</th> <xsl:call-template name="MemberEPRtoTD" /> <td> Summary data, which probably has one or more select statements of the form <xsl:value-of select="./wssg:Content/ag:AggregatorData/my/data“/> </td> <td> <xsl:apply-templates mode="DetailLink"/> </td> </tr></xsl:template>


How to Contribute

Join the mailing lists and offer your thoughts! [email protected] [email protected] [email protected]

Offer to contribute your information providers, higher level services, or WebMDS XSL transforms

If you’ve got a complementary monitoring system – think about being an Incubator project (contact [email protected], or come to the talk on Thursday)


Meet the Developers Session at Globus Alliance Booth (152A-P7)

September 12

8:00am - 9:00am "Java WS Core and Security (C, Java)" -- Olle Mulmo, Jarek Gawor, Rachana Anantakrishnan

11:30am -12:30pm "RLS" -- Rob Schuler, Ann Chervenak12:30pm -1:30pm "MDS" -- Mike D‘Arcy, Laura Pearlman3:00pm - 4:00pm ”Resource Management (GRAM, Virtual Workspaces and Dynamic Accounts)" – Stu Martin, Peter Lane, Tim Freeman, Kate Keahey6:00pm - 7:00pm "C WS Core" -- Joe Bester7:00pm - 8:00pm "Python WS Core" -- Joshua Boverhof

September 13

8:00am - 9:00am "GridShib" -- Von Welch, Ton Scavo, Tim Freeman

11:30am - 12:30pm "GT Installation and Administration" -- Charles Bacon12:30pm - 1:30pm "MyProxy" -- Jim Basney3:00pm - 4:00pm "GridFTP, XIO, RFT" -- John Bresnahan, Ravi Madduri

COME CELEBRATE WITH US!

In appreciation of your support of all things Globus over the past decade, you are cordially invited to the Globus 10th Birthday Party.

When: Monday, September 11, 2006 - 7:00pm, immediately following Ian Foster’s Globus State of the Union Keynote.

Where: The convention center concourse, in the center of the GlobusWORLD / GridWorld conference activity.

What: Food, drinks, music, friends and lots of fun!

Documents

Globus MDS for Developers Mike DArcy Laura Pearlman USC Information Sciences Institute