GT4 WS Core Tutorial Sam Meder Jarek Gawor 6/11/04

Disclaimer l Everything GT4 related is subject to change l Dont expect to be able to do more than prototype with current code

GT 4 WS Core Architecture l Grid Service vs. Web Service + Resource l Operation Providers l Service Properties vs. JNDI Directory l Service State Management vs. Resource State Management l Client side support l Service Data vs. Resource Properties l Notifications l Security

GT3 Grid Service l Implements the OGSI grid service port type u Persistent/Transient lifecycle u Provides operations for l Service lifetime management l Inspecting and changing Service Data

GT4 Web Service + Resource l The service bit is just a plain web service l Resources are managed/discovered via a Resource Home: l ResourceHome implementations provide: u Custom create() methods u Methods that operate on a set of resources

Resource Discovery

Resource Discovery in Practice l The simple case: Counter counter = (Counter) ResourceContext.getResource(); l The complicated case: ResourceContext ctx = null; ResourceHome home = null; ResourceKey key = null; Counter counter = null; try { ctx = ResourceContext.getResourceContext(); home = ctx.getResourceHome(); key = ctx.getResourceKey(); counter = (Counter)home.find(key); } catch (Exception e) { throw new RemoteException("", e); }

GT4 Web Service + Resource l Service and resource in the same object u One resource per service l Service and resource as separate entity u Any number of resources per service

Available Resource Homes l SimpleResourceHome u Basic hash table based implementation l SoftResourceHome u Uses soft references for storing resources l ServiceResourceHome u Service/Resource singleton home l PersistentResourceHome u For use with resources that can be persisted We may introduce a more generic home to replace some of these implementations

Operation Provider Model l Introduced in GT3 u Provides a web service composition framework u Enables reusable components l In GT4 u Any service can be an operation provider u No special interface required u Currently implemented: l Destroy l Set Termination Time l Get Current Message l Notification Consumer l Pause/Resume Subscription l Subscribe l Get/Set Resource Property l Get Multiple Resource Properties l Query Resource Properties

GT3 Service Properties l Allows services to store/checkpoint configuration properties u Flat Table (key, value) u Values can be persisted to deployment descriptor u Works for simple things

GT4 Directory l Uses JNDI code from Apache Tomcat u Hierarchical u Object Factories l Resource Homes l DataSource l Etc. u Entries can be linked u For more information see: doc/jndi-resources-howto.html doc/jndi-resources-howto.html l Note: Configuration file format slightly different

JNDI Examples l Environment entry: <environment name="subscriptionManagerServiceName type="java.lang.String" value="SubscriptionManagerService"/> l Resource Link entry: <resourceLink name="home" target="java:comp/env/notificationConsumerHome"/>

JNDI Examples Continued l Resource entry: <resource name="subscriptionHome" type="org.globus.wsrf.impl.notification.SimpleSubscriptionHome"> factory org.globus.wsrf.tools.jndi.BeanFactory

GT3 Service State Management l Persistent vs. Transient Service u Persistent service - created through container configuration entry u Transient service – created at runtime l Persistent vs. Transient Lifecycle u Persistent – Service can checkpoint and recover properties u Transient – Service Properties are volatile

GT4 Resource State Management l Resource State Management u Will provide implementations for common patterns: l Soft references u Good when state is easily recreated l Persistent Resources l Design your service with scalability in mind u Dont keep long lived references to your resources

Persistent Resources in GT4 l Must implement PersistentResource interface l Must have a default constructor l Must define at least one create() operation l Up to implementation to call store() when appropriate l Currently, can only be used with PersistentResourceHome

Client Side Model l No more Grid Service Handle to Grid Service Reference resolution u Similar step likely in GT4 l Needed for below l Discovery of remote security policy and certificates l Cant really pass WS-A Endpoint References on command line u Factory returns human readable string as well as EPR u Discover EPR via Service Group lookup

Security l Model remains unchanged u Clients will have to set security properties on stub u Service/Resource security policy via deployment descriptor l Security settings will be per resource l New Features in 4.0 u Better GSI Secure Message support l Encryption l Replay Attack Prevention u Flexible Authorization Support l Based on Work in OGSA AuthZ WG u (Rebase on Apache WSS4J code)

GT3 Service Data

GT4 Resource Properties

l Resources implement the Resource Properties interface: l The Resource Property Set manages properties:

GT4 Resource Properties l Every Resource Property implements:

Resource Property Implementations l SimpleResourceProperty u Basic resource property implementation u Stores the resource property values l ReflectionResourceProperty u Relies on reflection to get/set values

GT Query Framework l Supports multiple query dialects u New dialects can be added at runtime u Evaluation engine is chosen using dialect in query

Resource Properties Summary

GT3 Notification l Notifications are coupled to Service Data changes u Flat namespace l Notification interfaces are added via operation providers l Often required one notification sink per subscription u Disambiguation of source

GT4 Notification l Main change: Notifications are no longer coupled to service data u Parallel code structure u Hierarchy of topics u Topic can represent anything you want l Default notification consumer (sink) service per hosting environment u Individual sinks are represented by resources l Default subscription manager service per hosting environment u Subscriptions are resources l Still uses operation providers model

GT4 Notification Overview

GT4 Notification Interfaces

l Topic List Accessor u Allows for different TopicList implementations u Usually implemented by a Resource l Topic List u List of root topics l Topic u Represents a topic u May have child topics

GT4 Notification Interfaces l Topic Listener u Interface for propagating Topic changes u Used to connect subscriptions to topics\ u Used for creating the topics RP l Subscription u Interface to subscription state

Current Topic Implementations l SimpleTopic u Your basic no-frills implementation l ResourcePropertyTopic u Creates a topic from a object that implements the Resource Property Interface

Topic Expression Framework l Similar to Query Engine l You will also need to register dialect with Axis

GT4 Threads and Timers l Based on J2EE APIs proposed by IBM & BEA u Royalty free u More information at ibm.com/developerworks/java/library/j -commonj-sdowmt/ l WorkManager & Timer interfaces u Using thread/timer pools u Container provides default WorkManager and Timer objects via JNDI lookup l Replaces SweeperPool in GT3

Timer Example l Get the TimeManager and schedule: Context initialContext = new InitialContext(); TimerManager timerManager = (TimerManager) initialContext.lookup(WSRFConstants.DEFAULT_TIMER); timerManager.schedule(new TerminationTimerListener(), period, period); l Each timer task needs to implement TimerListener: protected class TerminationTimerListener implements TimerListener { public void timerExpired(Timer timer) { … }

WorkManager Example l Get the WorkManager and schedule: Context initialContext = new InitialContext(); WorkManager workManager = (WorkManager) initialContext.lookup(WSRFConstants.DEFAULT_WORK_MANAGER); WorkItem item1 = workManager.schedule(work1); l Each work task needs to implement Work: private class TestWork implements Work { public void release() { … } public void run() { … }

Base Faults l You should define your service faults l Helper API (FaultHelper) u Methods for populating and inspecting Base Faults l Currently have a handler that fills in some of the fields (timestamp etc.)

GT3 vs. GT4 Summary l What has fundamentally changed: u No long lived address anymore (GSH) u doc/literal (GT4) instead of wrapped/literal u Decoupled notification framework Not that much

Counter Service II: The Revenge l What is required to implement a new service? u WSDL u Service u Resource u Resource Home u Client u Configuration

Counter Service Interaction

The Code: WSDL <xsd:schema targetNamespace=" xmlns:tns=" xmlns:xsd=" … <xsd:element ref="tns:Value" minOccurs="1" maxOccurs="1"/>

The Code - WSDL <portType name="CounterPortType" gtwsdl:implements="wsnt:NotificationProducer wsrl:ImmediateResourceTermination" wsrp:ResourceProperties ="tns:CounterRP">

The Code: Service public _createCounterResponse createCounter(_createCounterRequest request) throws RemoteException { ResourceContext ctx = null; CounterHome home = null; ResourceKey key = null; try { ctx = ResourceContext.getResourceContext(); home = (CounterHome) ctx.getResourceHome(); key = home.create(); } catch(RemoteException e) { throw e; } catch(Exception e) { throw new RemoteException("", e); }

The Code: Service EndpointReferenceType epr = null; try { epr = AddressingUtils.createEndpointReference(ctx, key); } catch(Exception e) { throw new RemoteException("", e); } _createCounterResponse response = new _createCounterResponse(); response.setEndpointReference(epr); return response; }

The Code: Service public int add(int arg0) throws RemoteException { Object resource = null; try { resource = ResourceContext.getResourceContext().getResource(); } catch(RemoteException e) { throw e; } catch(Exception e) { throw new RemoteException("", e); } Counter counter = (Counter) resource; int result = counter.getValue(); result += arg0; counter.setValue(result); return result; }

The Code: Resource public class PersistentCounter extends Counter implements RemoveCallback, PersistentResource, ResourceLifetime { public void setValue(int value) { super.setValue(value); try { store(); } catch (Exception e) { throw new RuntimeException(e.getMessage()); } public void setTerminationTime(Calendar time) { super.setTerminationTime(time); try { store(); } catch (Exception e) { throw new RuntimeException(e.getMessage()); }

The Code: Resource /** * User-defined function. * the resource key */ public Object create() throws Exception { Object key = super.create(); store(); return key; }

/** * Called when activating a Counter resource by PersistentResourceHome */ public void load(ResourceKey key) throws ResourceException { File file = getKeyAsFile(key.getValue()); if (!file.exists()) { throw new NoSuchResourceException(); } FileInputStream fis = null; int value = 0; try { fis = new FileInputStream(file); ObjectInputStream ois = new ObjectInputStream(fis); value = ois.readInt(); this.terminationTime = (Calendar)ois.readObject(); } catch (Exception e) { throw new ResourceException("Failed to load resource", e); } finally { if (fis != null) { try { fis.close(); } catch (Exception ee) {} } initialize(key.getValue()); this.value.set(0, new Integer(value)); }

The Code: Resource public void store() throws ResourceException { FileOutputStream fos = null; try { fos = new FileOutputStream(getKeyAsFile(this.key)); ObjectOutputStream oos = new ObjectOutputStream(fos); oos.writeInt(((Integer) this.value.get(0)).intValue()); oos.writeObject(this.terminationTime); } catch (Exception e) { throw new ResourceException("Failed to store resource", e); } finally { if (fos != null) { try { fos.close(); } catch (Exception ee) {} }

The Code: Resource private static File getKeyAsFile(Object key) throws InvalidResourceKeyException { if (key instanceof Integer) { return new File(key.toString()); } else { throw new InvalidResourceKeyException(); } public void remove() throws ResourceException { File f = getKeyAsFile(this.key); f.delete(); }

The Code: Resource Home public class CounterHome extends PersistentResourceHome { static Log logger = LogFactory.getLog(CounterHome.class.getName()); public ResourceKey create() throws Exception { Counter counter = (Counter)createNewInstance(); counter.create(); ResourceKey key = new SimpleResourceKey(keyTypeName, counter.getID()); this.resources.put(key, counter); return key; }

The Code: Configuration <resource name="home" type="org.globus.wsrf.samples.counter.CounterHome"> factory org.globus.wsrf.tools.jndi.BeanFactory resourceClass org.globus.wsrf.samples.counter.PersistentCounter resourceKeyName { resourceKeyType java.lang.Integer

The Code: Configuration <deployment name="defaultServerConfig" xmlns=" xmlns:java=" xmlns:xsd=" <service name="CounterService" provider="Handler" use="literal" style="document"> <parameter name="allowedMethodsClass" value="com.counter.CounterPortType"/> <parameter name="handlerClass" value="org.globus.axis.providers.RPCProvider"/> <parameter name="className" value="org.globus.wsrf.samples.counter.CounterService"/> share/schema/core/samples/counter/counter_service.wsdl <parameter name="providers" value=" DestroyProvider SetTerminationTimeProvider GetRPProvider SubscribeProvider GetCurrentMessageProvider"/>

The Code: Client public class CounterClient implements NotifyCallback { public static void main(String [] args) { CounterServiceAddressingLocator locator = new CounterServiceAddressingLocator(); NotificationConsumerManager consumer = null; try { EndpointReferenceType endpoint = new EndpointReferenceType(); endpoint.setAddress( new Address( " CounterPortType port = locator.getCounterPortTypePort(endpoint); // Create counter resource _createCounterResponse createResponse = port.createCounter(new _createCounter()); endpoint = createResponse.getEndpointReference(); port = locator.getCounterPortTypePort(endpoint); _Subscribe request = new _Subscribe(); request.setUseNotify(Boolean.TRUE);

The Code: Client // Create client side notification consumer consumer = NotificationConsumerManager.getInstance(); consumer.startListening(); EndpointReferenceType consumerEPR = consumer.createNotificationConsumer(new CounterClient()); request.setConsumerReference(consumerEPR); TopicExpressionType topicExpression = new TopicExpressionType(); topicExpression.setDialect(WSRFConstants.SIMPLE_TOPIC_DIALECT); topicExpression.setValue(Counter.VALUE); request.setTopicExpression(topicExpression); // Subscribe to value port.subscribe(request);

The Code: Client // Add 3 port.add(3); // Sleep so we actually get the notification Thread.sleep(5000); // Get the value RP _GetResourcePropertyResponse getRPResponse = port.getResourceProperty(Counter.VALUE); System.out.println("Counter has value: " + getRPResponse.get_any()[0].getValue()); // Destroy the counter resource port.destroy(new _Destroy()); } catch(Exception e) { e.printStackTrace(); } finally { if (consumer != null) { try { consumer.stopListening(); } catch (Exception ee) {} }

The Code: Client // Notification callback public void deliver( List topicPath, EndpointReferenceType producer, Object message) { ResourcePropertyValueChangeNotificationType changeMessage = ((ResourcePropertyValueChangeNotificationElementType) message). getResourcePropertyValueChangeNotification(); if(changeMessage != null) { System.out.println("Got notification with value: " + changeMessage.getNewValue().get_any()[0].getValue()); }

What is still missing? l GT3 Compatibility Layer l More Helper APIs l Performance Work l Lots of examples l Lots of polish l Service Group

Take A Look l Anonymous CVS: u cvs \ packages \ login u When asked for a password, please enter your . u cvs \ packages \ checkout \ wsrf u unset GLOBUS_LOCATION ; cd wsrf ; ant all u Installation will end up in wsrf/install u Take a look at test services in wsrf/java/core/test/interop