Desynchronizable Choreographies

50 %
50 %
Information about Desynchronizable Choreographies
Technology

Published on December 6, 2008

Author: gero.decker

Source: slideshare.net

Non-desynchronizable Service Choreographies Gero Decker 1 , Alistair Barros 2 , Frank Michael Kraft 3 , Niels Lohmann 4 1 Hasso-Plattner-Institute, Potsdam, Germany 2 SAP Research, Brisbane, Australia 3 SAP AG, Walldorf, Germany 4 University of Rostock, Germany

Agenda Modeling service choreographies Synchronous / asynchronous communication Desynchronizability Resolution strategies Conclusion

Modeling service choreographies

Synchronous / asynchronous communication

Desynchronizability

Resolution strategies

Conclusion

Service Choreographies Inter-organizational integration requires interaction contracts Defined set of interactions Defined document structures / message types Defined interaction behavior: constraints and obligations Choreographies as behavioral specification for services Starting point for adapting existing services Starting point for implementing new services

Inter-organizational integration requires interaction contracts

Defined set of interactions

Defined document structures / message types

Defined interaction behavior: constraints and obligations

Choreographies as behavioral specification for services

Starting point for adapting existing services

Starting point for implementing new services

Modeling Choreographies Interconnection Modeling

Modeling Choreographies Interconnection Modeling incompatible loops definition of process instantiation incompatible branching structures incompatible sequence flow abstraction level = messages

Modeling Choreographies Interaction Modeling atomic interactions decision ownership global control flow dependencies complex interactions global loops process instantiation unspecified

Modeling Choreographies BPMN, BPEL4Chor Send and receive as separate steps (asynchronous) Let’s Dance, WS-CDL BPMN 2.0 Send and receive in one step (synchronous) Interconnection Models Interaction Models

BPMN, BPEL4Chor

Send and receive as separate steps (asynchronous)

Let’s Dance, WS-CDL

BPMN 2.0

Send and receive in one step (synchronous)

Modeling Choreographies

Modeling Choreographies Does this choreography make sense in an asynchronous world?

Modeling Choreographies Synchronous vs. Asynchronous Assumes asynchronous communication Assumes synchronous communication Desynchronized Net Interaction Petri net

Assumes asynchronous communication

Assumes synchronous communication

Studying the Desynchronized Net Deadlock

Desynchronized Net Desynchronizability Observable behavior model (role Z) Interaction Model Observable behavior model (role A) … Role projection Role projection Interconnection Has final markings Must weakly terminate Must be realizable Final markings are generated Check for weak termination

Desynchronized Net

Interaction Model

Has final markings

Must weakly terminate

Must be realizable

Final markings are generated

Check for weak termination

Desynchronizability Location of conflict transitions The interaction model weakly terminates and is realizable  There exist choreography instances that end in final markings  Those transitions can be identified that lead to a deadlock “ Conflict transitions”

The interaction model

weakly terminates and

is realizable

 There exist choreography instances that end in final markings

 Those transitions can be identified that lead to a deadlock

“ Conflict transitions”

Tooling Desynchronizability in IPNs http://oryx-editor.org

http://oryx-editor.org

Tooling Desynchronizability in IPNs http://oryx-editor.org

http://oryx-editor.org

Tooling Desynchronizability in BPMN 2.0 http://oryx-editor.org

http://oryx-editor.org

Tooling Desynchronizability in BPMN 2.0 http://oryx-editor.org

http://oryx-editor.org

Resolution Strategies in Practice (1/2) Not a solution: Removing the possibility of cancellation Solution 1: Precedence Agreement on precedence relationships at design-time Assumption: the services will notice that conflicting messages are present Predefined behavior upon conflicting messages a. Singular Interaction Partner Precedence b. Type-based Precedence between Multiple Interactions c. Situation-based Precedence between Multiple Interactions

Not a solution: Removing the possibility of cancellation

Solution 1: Precedence

Agreement on precedence relationships at design-time

Assumption: the services will notice that conflicting messages are present

Predefined behavior upon conflicting messages

a. Singular Interaction Partner Precedence

b. Type-based Precedence between Multiple Interactions

c. Situation-based Precedence between Multiple Interactions

Resolution Strategies in Practice (2/2) Solution 2: Precedence with Decision Precedence relationships define who has the right to decide on the outcome upon conflicting messages Solution 3: Allowing Individual Decisions Upon conflicting messages each service decides how to handle this and tells the other services about the decision Main problem: contradicting decisions Solution 4: Negotiation of Outcome Upon conflicting messages the conversation is suspended and a negotiation phase starts

Solution 2: Precedence with Decision

Precedence relationships define who has the right to decide on the outcome upon conflicting messages

Solution 3: Allowing Individual Decisions

Upon conflicting messages each service decides how to handle this and tells the other services about the decision

Main problem: contradicting decisions

Solution 4: Negotiation of Outcome

Upon conflicting messages the conversation is suspended and a negotiation phase starts

Summary & Outlook Interaction modeling eases choreography modeling (but hides the challenges of asynchronous communication) Desynchronizability checking detects and locates errors Resolution strategies have business impact  must be chosen on a business level! Future work Formalization of resolution strategies Declarative integration of resolution strategies

Interaction modeling eases choreography modeling (but hides the challenges of asynchronous communication)

Desynchronizability checking detects and locates errors

Resolution strategies have business impact  must be chosen on a business level!

Future work

Formalization of resolution strategies

Declarative integration of resolution strategies

Questions? Mail [email_address] Tool http://oryx-editor.org Blog http://bpmn.info

Mail [email_address]

Tool http://oryx-editor.org

Blog http://bpmn.info

Add a comment

Related presentations

Related pages

Non-desynchronizable Service Choreographies - BPT · WebHome

Non-desynchronizable Service Choreographies Gero Decker1, Alistair Barros2, Frank Michael Kraft3, and Niels Lohmann4 1 Hasso-Plattner-Institute, University ...
Read more

Non-desynchronizable Service Choreographies

Aus dem eBook: Service-Oriented Computing – ICSOC 2008 von Gero Decker, Alistair Barros, Frank Michael Kraft, Niels Lohmann: A precise definition of ...
Read more

Non-desynchronizable Service Choreographies

Schriften / Publications: Non-desynchronizable Service Choreographies. Gero Decker, Alistair Barros, Frank Michael Kraft, and Niels Lohmann. Non ...
Read more

Non-desynchronizable Service Choreographies. (PDF Download ...

Page 1. Non-desynchronizable Service Choreographies Gero Decker1, Alistair Barros2, Frank Michael Kraft3, and Niels Lohmann4 1Hasso-Plattner-Institute ...
Read more

CiteSeerX — Non-desynchronizable Service Choreographies

CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): A precise definition of interaction behavior between services is a ...
Read more

Non-desynchronizable service choreographies

Non-desynchronizable service choreographies . By Gero Decker, Alistair P. Barros, Frank Kraft and Niels Lohmann. Abstract.
Read more

Non-desynchronizable Service Choreographies - Springer

A precise definition of interaction behavior between services is a prerequisite for successful business-to-business integration. Service choreographies ...
Read more

Non-desynchronizable service choreographies | QUT ePrints

Decker, Gero, Barros, Alistair P., Kraft, Frank, & Lohmann, Niels (2008) Non-desynchronizable service choreographies. In Bouguettaya, Athman ...
Read more

Non-desynchronizable Service Choreographies | Frank ...

Co-authoring with Gero Decker, Alistair Barros and Niels Lohmann we published the paper “Non-desynchronizable Service Choreographies” on the 6th ...
Read more