VERIFYING THE CORRECT COMPOSITION OF DISTRIBUTED COMPONENTS: FORMALISATION AND TOOL Ludovic Henrio 1, Oleksandra Kulankhina 1,2, Dongqian Liu 3, Eric Madelaine 1,2 1: Univ. of Nice Sophia Antipolis, CNRS, France 2: INRIA – Sophia Antipolis, SCALE team, France 3: East China Normal University, China FOCLASA, 06/09/2014, Rome

Context Grid Component Model: hierarchical components for distributed systems Design and execution environment for GCM: 2 VerCors: design application ADL files Component Factory: Generate components Component Factory: Generate components GCM Compo- nents ProActive: deploy and run components Global objective: ensure correct execution of large-scale distributed applications

Challenges No formal model for GCM architecture No notion of well-formed components in GCM No communication between business logic and control part VerCors tool was not completely implemented 3

Contribution formalisation of GCM component architecture validation constraints that ensure static properties for GCM component assemblies formalisation of the notion of interceptors in GCM implementation of a graphical modeling environment for GCM implementation of architecture validity checks with respect to the proposed formalisation 4

Agenda Motivation and goal Background Formalisation Separation of concerns in GCM architecture Interceptors Constraints and properties Implementation Tool: VerCors Application to the other component models Conclusion and future work 5

Background: Grid Component Model (GCM) 6 Primitive: encapsulates code Composite: contains other components Client interfaces: invoke methods, receive results Server interfaces: serve methods, send results Bindings Hierarchical Distributed Asynchronous

Agenda Motivation and goal Background Formalisation Separation of concerns in GCM architecture Interceptors Constraints and properties Implementation Tool: VerCors Application to the other component models Conclusion and future work 7

Separation of concerns in GCM architecture 8 Content: responsible for business logic Membrane: responsible for control part Functional and non- functional interfaces Business logic and control part can be designed separately

Interceptors: what they are used for? 9 Example: Monitoring and reconfiguration

How do we recognize interceptors chains? 10 all the components are nested inside the membrane all the components have exactly one functional server and one functional client interface The interceptors form a chain the first and the last components of the chain are connected to the composing component

Formalization 11 Architecture Validation Contraints Wellformness Interceptors

Static properties and validation rules (1) 12 Component encapsulation Bindings do not cross the boundaries of the components Correct typing Interfaces connected by bindings have compatible roles Interfaces connected by bindings have compatible methods

Static properties and validation rules (2) 13 Deterministic communications Each client interface is connected to at most one server interface Unique naming Interfaces have unique names inside a container Components have unique names inside a container

Static properties and validation rules (3) 14 Separation of concerns The interfaces connected by a binding should have compatible control levels CL of a functional interface = 1 CL of a non-functional interface = 2 CL is increased by 1 for interfaces of controllers Compatible CLs: either both = 1, or both >1

Static properties and validation rules (4) 15 CL of a functional interface = 1 CL of a non- functional interface = 2 CL is increased by 1 for interfaces of controllers Compatible CL: either = 1, or >

Agenda Motivation and goal Background Formalisation Separation of concerns in GCM architecture Interceptors Constraints and properties Implementation Tool: VerCors Application to the other component models Conclusion and future work 16

Tool: VerCors Based on Obeo Designer Graphical environment for GCM Components and UML Diagrams 17 Produces ADL files, Java classes and Java interfaces Distributed as Eclipse plugins

Static validation in VerCors Check all the constraints specified in the paper Use Acceleo, OCL and Java Services Inform user about the violation of constraints 18

Agenda Motivation and goal Background Formlisation Separation of concerns in GCM architecture Interceptors Constraints and properties Implementation Tool: VerCors Application to the other component models Conclusion and future work 19

Application to the other component models Fractal: would reuse everything except non-functional aspect and interceptors AOKell: would reuse non-functional part and componentized membrane SOFA: hierarchical structure, componentized membrane, “delegation chains” that act like interceptors; would reuse most of our constraints SCA: hierarchical model, would reuse a lot of notions 20

Agenda Motivation and goal Background Formlisation Separation of concerns in GCM architecture Interceptors Constraints and properties Implementation Tool: VerCors Application to the other component models Conclusion and future work 21

Conclusion A formal model for GCM architecture The well-formness properties of GCM components Formalization of interceptors in GCM A graphical specification environment for GCM components modeling and static validation Application to other component models 22

Future work Tool evolution:  Produce behavioral models and model-check them  Generate Java code for UML State Machines Validate other static properties as a prerequesite for the generation of behavior models check compatibility between the State Machines and UML Interfaces 23

Thank you for your attention! Verifying the correct composition of distributed components: Formalisation and Tool Ludovic Henrio, Oleksandra Kulankhina, Dongqian Liu, Eric Madelaine References: Vercors: GCM: F. Baude, D. Caromel, C. Dalmasso, M. Danelutto, V. Getov, L. Henrio, C. Perez: GCM: A Grid Extension to Fractal for Autonomous Distributed Components, in Annals of Telecommunications, Vol. 64, n o 1, jan Francoise Baude, Ludovic Henrio & Cristian Ruz (2014): Programming distributed and adapt- able autonomous components-the GCM/ProActive framework. Software: Practice and Experience, doi: /spe Available at 24

Group communications 1xN communications: multicast 25 Nx1 communications: gathercast