Policy-driven DevelopmentLeveraging Rich Services to Empower Stakeholders

Barry Demchak (bdemchak@ucsd.edu) & Ingolf KrügerCalifornia Institute for Telecommunications and Information Technology, San Diego Division

Problem

Cyberinfrastructure (CI)† † context• 100s of stakeholders (e.g., producers,

consumers, operators, etc.)• Stakeholders opt in only when CI

satisfies their requirements• Requirements frequently change &

often mis-implemented• CIs have long delivery times

Consequence• More stakeholders requirement

churn, even longer delivery timesContradiction

• More stakeholders fewer stakeholders opt in∴ lower likelihood CI will satisfy community requirements

Result• CI underserves stakeholders

Solution

CI as scaffolding supporting:• basic data and control flows• high availability & reliability• scalability (bandwidth/storage/…)

Policy definition/execution• stakeholder authorable• injected directly into CI• constrains/augments data & control

flows

Challenges

Requirement elicitation• Enable stakeholders to articulate

requirements as policies• Enable complex/compound policies

Policy enactment• Refine policies into executable code• Compose and coordinate policy

executionPolicy deployment

• Verify completeness/correctness• Maintain system consistency

This material is based upon work supported by the National Institutes of HealthUnder Grant No 1U01CA130771-01 (Project PALMS: Kevin Patrick, PI)

and the National Science Foundation under Grant No CNS-0932403

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† †Cyberinfrastructures (CI) f

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†PALMS ReferencesPhysical Activity Location Measurement System to understand where activity-related energy expenditure occurs in humans as a function of time and space. Harvests data from wearable devices on small and large scales, provides framework for research and analysis, and has ultimate goal of discovering methods for engineering better health.

An Internet-based research computing environment that supports data acquisition, data storage, data management, data integration, data mining, data visualization, and other computing and information processing services. Different stakeholders produce, consume, manage, and govern a CI, and their requirements must be simultaneously met or else the integrity of the CI degrades.

1. J. Juerjens. Security Systems Development with UML. Springer-Verlag Berlin Heidelberg, 2003.2. T. Lodderstedt, D. Basin, and J. Doser. SecureUML: A UML-Based Modeling Language for Model-Driven Security. Proceedings

of the 5th International Conference on The Unified Modeling Language. pp426-441. Springer Verlag, 2002.3. M. Arrott, B. Demchak, V. Ermagan, C. Farcas, E. Farcas, I. H. Krüger, and M. Menarini. Rich Services: The Integration Piece

of the SOA Puzzle. In Proceedings of the IEEE International Conference on Web Services (ICWS), Salt Lake City, Utah, USA. IEEE, Jul. 2007, pp. 176-183.

4. A. Bhattacharjee and R. Shyamasundar. Activity Diagrams: A Formal Framework to Model Business Processes and Code Generation. Journal of Object Technology. Vol 8, No 1, Jan 2009.

5. M. Fowler. Domain-Specific Languages. Boston, MA: Addison-Wesley, Pearson Education, Inc. Sept 2010.6. K. Jensen and L. Kristensen. Coloured Petri Nets: Modeling and Validation of Concurrent Systems. Berlin: Springer-Verlag.

2009.

Techniques

Model-driven engineering• Stakeholders specify policies

directly1,2 on workflow models (UML Activity Diagrams4) using visual Domain Specific Language (DSL5)

• Refinement follows Rich Service3 decomposition & logical/deployment transformation

• Policies specify alternate workflows & data flow transformations

• Model checking using CPN Tools6

Service Oriented Architecture-based execution & deployment• Leverage standard patterns3:

strategy, messaging, routing, & composite pattern

• Leverage role-based interaction, choreography & interceptor techniques

PALMS† Case Study

Sensor Data Data Storage Calculations Visualization

Overall Requirements

Register with Study Add to Device ListUser, Dev

List Devices Select Device Add to StudyUser, DevUser User,

Devs

Create Study Add Device

Return Error

1: Only RA can add device

2: User ∈ {“RA”}

3: User ∈ {“RA”} è normal flow, else error flow

PALMS-CIService Data Connector

User

Access Policies

Study

GlobalDeviceListStudy

Service Data Connector

StudyDeviceList

3a. Constraint finally expressed as interceptor on data flow

1.Stakeholder expresses constraint on high level workflow activity 2.Constraint is re-

expressed in each workflow refinement

Conditional replacement of data flow or control flowA Policy is …

Refinement Driven by …Rich Service

Decomposition

3b. Policy executed by Interceptor

OK

Study GlobalDeviceList

AddDeviceToStudy

User PALMS-CI

AddStudyOK

GetAvailDevices

AvailDeviceList

AddDeviceToStudy

OK

Select Device

StudyDeviceList

AddDeviceToStudy

OK

GetAvailDevices

AvailDeviceList