Une approche déclarative pour la gestion de la qualité de service dans les compositions de service

The advent of Service Oriented Architectures tends to promote a new kind of software architecture where services, exposing features accessible through highly standardized protocols, are composed in aloosely coupled way. In such a context, where services are likely to be replaced or used by a large numberof clients, the notion of Quality of Service (QoS), which focuses on the quality of the relationship between a service and its customers, becomes a key challenge. QoS deals with multiple concerns suchas security, reliability, performance (response time or availability), or even the cost of the service. Although much work has been carried out in the field of service composition, in particular leading to the elaboration of the BPEL4WS standard, the challenge of QoS management in service compositions still lacks flexible and reusable solutions offering a suitable level of abstraction.This thesis aims to ease QoS management in service compositions through a better separation of concerns. For this purpose, we designed QoSL4BP, a domain-specific language which allows QoS policy specification on service compositions. Such policies handle QoS constraints and mechanisms, both at pre-deployment time and runtime, by use of a limited set of high level primitives. By encapsulating the expertise of QoS management domain and by offering a high level expressivity, the QoSL4BP language enables an easy, flexible and reusable specification of both QoS contracts management and QoS related mechanisms implementation. This language is executed by our ORQOS platform, which cooperates ina non-intrusive way with orchestration engines. Thus, at pre-deployment time, the ORQOS platform performs service planning depending on services QoS offers and on the QoS requirements in QoSL4BPpolicies. At runtime, the QoSL4BP policies make it possible to react to QoS variations and to enact QoS management related mechanisms. Two scenarii, belonging to telecommunications and medical domains, validate our approach.L'avènement des architectures orientées service tend à promouvoir un style d'architecture logicielle où des services, exposant des fonctionnalités accessibles à l'aide de protocoles hautement standardisés sont composés avec un couplage lâche. Dans un tel contexte où les services sont aisément amenés à être remplacés ou utilisés par un grand nombre d'utilisateurs, la notion de Qualité de Service (QdS), qui s'intéresse à la qualité de la relation entre un service et ses clients, constitue un enjeu majeur. La QdS regroupe diverses préoccupations telles que la sécurité, la garantie de livraison, la performance (temps de réponse ou accessibilité) ou encore le coût. Bien qu'il existe déjà d'importants travaux autour des compositions de services, qui ont notamment permis l'élaboration du standard BPEL4WS, le problème de la gestion de la QdS dans les compositions de services manque de solution flexible, réutilisable et offrant un degré d'abstraction approprié.L'objectif de cette thèse est de faciliter la gestion de la QdS dans les compositions de services en s'appuyant sur une meilleure séparation des préoccupations. Pour cela nous proposons QoSL4BP, un langage dédié qui permet la spécification de politiques de QdS à l'échelle des compositions de services. Ces politiques gèrent des contraintes et des mécanismes de QdS statiquement et dynamiquement à l'aide d'un ensemble limité de primitives de haut niveau. En encapsulant l'expertise liée au domaine de la gestion de QdS et en offrant une expressivité de haut niveau, le langage QoSL4BP permet une spécification aisée, flexible et réutilisable de la gestion des contrats de QdS et des mécanismes liés à la QdS. Ce langage est mis en œuvre par notre plateforme ORQOS qui coopère de manière non intrusive avec les moteurs d'orchestration. Ainsi, au moment du déploiement d'une composition de services, ORQOS sélectionne les services de la composition, selon leurs offres de QdS et les exigences spécifiées dans les politiques QoSL4BP. A l'exécution, les politiques QoSL4BP permettent de réagir aux variations de QdS et de mettre en œuvre des mécanismes liés à la gestion de QdS. Deux scénarii, appartenant respectivement aux domaines des télécommunications et du médical, permettent de valider l'approche proposée

Standards and Web Services: some concrete limitations

International audienc

A pragmatic use of Contracts and aspects to gain in adaptability and reusability

National audienc

A concrete solution for Web Services adaptability using policies and aspects

International audienc

Une approche déclarative pour la gestion de la qualité de service dans les compositions de services

PARIS-MINES ParisTech (751062310) / SudocSudocFranceF

A Declarative Approach for QoS-Aware Web Service Compositions

International audienceWhile BPEL language has emerged to allow the specification of Web Service compositions from a functional point of view, it is still left to the architects to find proper means to handle the Quality of Service (QoS) concerns of their compositions. Typically, they use ad-hoc technical solutions, at the message level, that significantly reduce flexibility and require costly developments. In this paper, we propose a policy-based language aiming to provide expressivity for QoS behavioural logic specification in Web Service orchestrations, as well as a non-intrusive platform in charge of its execution both at pre-deployment time and at runtime

QoS Policies for Business Processes in Service Oriented Architectures

International audienceThe advent of Service Oriented Architectures tends to promote a new kind of software architecture where services, exposing features accessible through highly standardized protocols, are composed in a loose coupling way. In such a context, where services are likely to be replaced or used by a large number of clients, the notion of Quality of Service (QoS), which focuses on the quality of the relationship between a service and its customers, becomes a key challenge. This paper aims to ease QoS management in service compositions through a better separation of concerns. For this purpose, we designed QoSL4BP, a domain-specific language which allows QoS policies specification for business processes. More specifically, the QoSL4BP language is designed to allow an architect to specify QoS constraints and mechanisms over parts of BPEL compositions. This language is executed by our ORQOS platform which cooperates in a non-intrusive way with orchestration engines. At pre-deployment time, ORQOS platform performs service planning depending on services QoS offers and on the QoS requirements in QoSL4BP policies. At runtime, QoSL4BP policies allow to react to QoS variations and to enact QoS management related mechanisms

QoS Policies for Business Processes in Service Oriented Architectures

International audienceThe advent of Service Oriented Architectures tends to promote a new kind of software architecture where services, exposing features accessible through highly standardized protocols, are composed in a loose coupling way. In such a context, where services are likely to be replaced or used by a large number of clients, the notion of Quality of Service (QoS), which focuses on the quality of the relationship between a service and its customers, becomes a key challenge. This paper aims to ease QoS management in service compositions through a better separation of concerns. For this purpose, we designed QoSL4BP, a domain-specific language which allows QoS policies specification for business processes. More specifically, the QoSL4BP language is designed to allow an architect to specify QoS constraints and mechanisms over parts of BPEL compositions. This language is executed by our ORQOS platform which cooperates in a non-intrusive way with orchestration engines. At pre-deployment time, ORQOS platform performs service planning depending on services QoS offers and on the QoS requirements in QoSL4BP policies. At runtime, QoSL4BP policies allow to react to QoS variations and to enact QoS management related mechanisms

A Declarative Approach for QoS-Aware Web Service Compositions

International audienceWhile BPEL language has emerged to allow the specification of Web Service compositions from a functional point of view, it is still left to the architects to find proper means to handle the Quality of Service (QoS) concerns of their compositions. Typically, they use ad-hoc technical solutions, at the message level, that significantly reduce flexibility and require costly developments. In this paper, we propose a policy-based language aiming to provide expressivity for QoS behavioural logic specification in Web Service orchestrations, as well as a non-intrusive platform in charge of its execution both at pre-deployment time and at runtime