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Service compositionService composition

Roberto Lucchijoint work with

Anders Friis-Christensen, Michael Lutz and Nicole Ostlaender

European Commission – DG Joint Research CentreSpatial Data Infrastructure Unit

Ispra, Italy

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OutlineOutline

• ORCHESTRA

• Service chaining and Service Chain Access Service

• Pilot

• Control flow and data flow patterns

• Related issues

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ORCHESTRA – GoalsORCHESTRA – Goals

• Develop and test interoperable software architecture for risk management applications– specify interoperable risk management services – input to standardisation (OGC, ISO, CEN…)

• Role JRC–IES:– Technical supervisor – Pilot development within two application areas

(forest fires and flooding)

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ORCHESTRA pilot: Pan-European Assessment ORCHESTRA pilot: Pan-European Assessment of Natural Hazardsof Natural Hazards

• Implement distributed geo-processing for– Forest Fire Risk analysis– (Flood) Damage assessment

• by chaining existing ORCHESTRA (SOAP) services – Feature Access Service (FAS)– Map Access Service (MAS)– Processing Service (PS)

• in a new (risk specific) service executing the workflow

FAS OGC WFS

MAS OGC WMS

PS OGC WPS

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Service Chaining in ORCHESTRAService Chaining in ORCHESTRA

• ISO 19119 Opaque chaining (aggregate services)– Hide the business logic– Service chain instance functionalities can be re-used

• Service chain descriptions based on BPEL• Usage of the Service Chain Access Service (SCAS) for

– Managing service chain descriptions – Deploying the service chain instances in ORCHESTRA Service

Networks• SCAS provides a means to:

– getServiceChain: Get a service chain description – createServiceChain: Create a new service chain instance based on a

chain description– deleteServiceChain: Delete service chain instances– getCapabilities

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Register the createdservice chain instance

CreateServiceChain request• Chain Description (M) : MyChain• Catalogue endpoint (O) : CatUrl

MyChain

Catalogue

SCAS client

SCAS

MyChain Workflow Description

Height Difference

Store

Zonal Rating

FFRADA

<entry …><entry …><entry …><entry …>

<entry …><entry …><entry …><entry …>

Deploy

ORCHESTRA Services Network

<entry …>

SCAS: Creating new service chainsSCAS: Creating new service chains

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SCAS: get service chain descriptionSCAS: get service chain description

• The operation getServiceChain (ID) provides MetaInformation on the chain and a link to the service chain description

getServiceChain Sample response

• Requesting existing service chain descriptions can be used to:– Re-deploy in different ORCHESTRA service networks– Modify existing workflows (use new services, different techniques)

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ScenarioScenario- Forest Fires -- Forest Fires -

Pilot Application – Thematic FocusPilot Application – Thematic Focus

• Assessing natural hazards and related risks

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Pilot Application – Requirement AnalysisPilot Application – Requirement Analysis• End users: Domain experts in the context of forest fires

conducting policy support towards various EC DGs• Functionalities:

– Interoperable access to heterogeneous MS fire records– Harmonisation of heterogeneous data into a common schema – Flexible and distributed Forest Fire Hazard and Risk mapping

• Measures– Forest fire frequency: number of forest

fires aggregated by administrative unit– Forest fire density: forest fire

frequency normalised by area– Forest fire risk: forest fire density

classified into risk classes

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cd Data Model

ForestFireRegistration_Common

+ fireID: char+ dateAl: char+ timeAl: char+ timeIn: char+ dateIn: char+ dateEx: char+ timeEx: char+ codeCom: char+ nuts3: char+ nameCom: char+ tba: char+ fba: char+ nfba: char+ cause: char

Pilot Application – Conceptual LevelPilot Application – Conceptual Level1. Access

– Fire records from EU Member States– Schema mapping

2. Spatial and temporal aggregation– Based on Administrative Units– Or based on European Grid

3. Analysis – Fire frequency – Fire density– Fire risk classes

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Distributed Geoprocessing – ApproachDistributed Geoprocessing – Approach

• Identify the processing tasks required to produce the requested analysis information

• Define workflows producing the required information

• Provide workflows execution as OT-Risk-Specific Services– implemented using opaque chaining (via BPEL)– the client applications use one single service

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Distributed Geoprocessing – Processing TasksDistributed Geoprocessing – Processing Tasks

• Forest Fire Frequency– Spatial Join of Forest Fire Points with NUTS polygons– Counting joined points per NUTS polygon

Join and Aggregation service

• Forest Fire Density– Normalizing Forest Fire Frequency by area of NUTS polygons

Normalisation service

• Forest Fire Risk– Classifying risk based on forest fire density per NUTS polygon into

risk classes

Classification service

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(1) retrieve forestfire features

(2) retrieve admin.unit features

(3) aggregate forestfire features

by admin. units

(4) normalisefeatures by area

(5) classify features

(6) render featuresin a map

MS2 forest fireregistration

FAS-X

Mapping Rules toCommon Schema

uses

MS1 forest fireregistration

accesses

Administrative units

FAS

accesses

Join & Aggregation

Service

Classification Service

Processing Services

ClassificationRules

uses

Normalisation Service

MAS

SymbologyRules

uses

PEUNHA Client

(0) provide execution parameters

Forest Fire Risk

Assessment

MAS = Map Access Service

FAS = Feature Access Service

FAS-X = Translating FAS

Client

OA Info-Structure Service

OT Support Service

OT Risk Specific Service

Distributed Geoprocessing in the Pilot ApplicationDistributed Geoprocessing in the Pilot Application

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Forest Fire Risk Assessment ServiceForest Fire Risk Assessment Service

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Control and data flow patternsControl and data flow patterns• We also invetigated different chaining patterns and data

passing modalities

Centralized control flow data passed by value

Cascaded control flow(e.g. WPS)

Centralized control flow and data passed by value =separation of control and data flow BPEL + storage functionalities

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Final remarks and open issuesFinal remarks and open issues

• No standard service chain interface– High flexibility, but complicates

• clients development• service chain re-usability (and discovery)

• Service chains conformance – getCapabilities: is it mandatory?

• What kind of data reference mechanism?– URL

• WPS and WCS 1.1 can store results and return a URL – getResourceByID (OWS Common 1.1.0)

• Alternative interaction modalities– Asynchronous invocation of service chains

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Extra slidesExtra slides

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Forest FireRisk Analysis

Damageassessment

The ORCHESTRA Service Types and The ORCHESTRA Service Types and TaxonomyTaxonomy

OT support service

OA support service

OA info-structure service

OT risk specific services

Catalogue FASMAS

PSMap AlgebraPS

Classification

PSJoin & Aggreg.

FAS OGC WFSMAS OGC WMSPS OGC WPS

Obtained by chaining ORCHESTRA services

SCAS