Self-supervising BPEL Processes

Service compositions suffer changes in their partner services. Even if the composition does not change, its behavior may evolve over time and become incorrect. Such changes cannot be fully foreseen through prerelease validation, but impose a shift in the quality assessment activities. Provided functionality and quality of service must be continuously probed while the application executes, and the application itself must be able to take corrective actions to preserve its dependability and robustness. We propose the idea of self-supervising BPEL processes, that is, special-purpose compositions that assess their behavior and react through user-defined rules. Supervision consists of monitoring and recovery. The former checks the system's execution to see whether everything is proceeding as planned, while the latter attempts to fix any anomalies. The paper introduces two languages for defining monitoring and recovery and explains how to use them to enrich BPEL processes with self-supervision capabilities. Supervision is treated as a cross-cutting concern that is only blended at runtime, allowing different stakeholders to adopt different strategies with no impact on the actual business logic. The paper also presents a supervision-aware runtime framework for executing the enriched processes, and briefly discusses the results of in-lab experiments and of a first evaluation with industrial partners

A coordination protocol for user-customisable cloud policy monitoring

Cloud computing will see a increasing demand for end-user customisation and personalisation of multi-tenant cloud service offerings. Combined with an identified need to address QoS and governance aspects in cloud computing, a need to provide user-customised QoS and governance policy management and monitoring as part of an SLA management infrastructure for clouds arises. We propose a user-customisable policy definition solution that can be enforced in multi-tenant cloud offerings through an automated instrumentation and monitoring technique. We in particular allow service processes that are run by cloud and SaaS providers to be made policy-aware in a transparent way

Comprehensive Monitor-Oriented Compensation Programming

Compensation programming is typically used in the programming of web service compositions whose correct implementation is crucial due to their handling of security-critical activities such as financial transactions. While traditional exception handling depends on the state of the system at the moment of failure, compensation programming is significantly more challenging and dynamic because it is dependent on the runtime execution flow - with the history of behaviour of the system at the moment of failure affecting how to apply compensation. To address this dynamic element, we propose the use of runtime monitors to facilitate compensation programming, with monitors enabling the modeller to be able to implicitly reason in terms of the runtime control flow, thus separating the concerns of system building and compensation modelling. Our approach is instantiated into an architecture and shown to be applicable to a case study.Comment: In Proceedings FESCA 2014, arXiv:1404.043

Service-Oriented Dynamic Software Product Lines

An operational example of controls in a smart home demonstrates the potential of a solution that combines the Common Variability Language and a dynamic extension of the Business Process Execution Language to address the need to manage software system variability at runtime

Customized Infrastructures for Monitoring Business Processes

Process enactment technology provides native tools and add-ons for monitoring, such as APIs and monitoring consoles, which are usually highly entangled with the underlying process enactment logic and not customizable by process users. In such a case, all users access the same set of monitoring data and functions and process management resources may be allocated for monitoring concerns not of interest for users. In this context, we present a model and a tool for customized process monitoring infrastructures executing on top of existing process enactment technology. The model classifies the options about monitoring over which the preferences of process users may diverge. The tool implements the proposed model, generating customized process monitoring infrastructures embedding the business logic of the monitoring options chosen by process users

Automated runtime recovery for QoS-based service composition

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Facing uncertainty in web service compositions

© 2013 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works[EN] Web service compositions run in complex computing infrastructures where arising events may affect the quality of the system. However, crucial Web service compositions cannot be stopped to apply changes to deal with problematic events. Therefore, the trend is moving towards context-aware Web service compositions, which use context information as a basis for autonomic changes. Under the closed-world assumption, the context and possible adaptations are fully known at design time. Nevertheless, it is difficult to foresee all the possible situations arising in uncertain contexts. In this paper, we leverage models at runtime to guide the dynamic evolution of context-aware Web service compositions to deal with unexpected events in the open world. In order to manage uncertainty, a model that abstracts the Web service composition, self-evolves to preserve requirements. The evolved model guides changes in the underlying WS-BPEL composition schema. A prototype and an evaluation demonstrate the feasibility of our approach.This work has been developed with the support of MICINN under the project everyWare TIN2010-18011 and co-financed with ERDF.Alférez, GH.; Pelechano Ferragud, V. (2013). Facing uncertainty in web service compositions. En Web Services (ICWS), 2013 IEEE 20th International Conference on. IEEE Computer Society. 219-226. https://doi.org/10.1109/ICWS.2013.38S21922

A robust client-driven distributed service localisation architecture

The fundamental purpose of service-oriented computing is the ability to quickly provide software resources to global users. The main aim of service localisation is to provide a method for facilitating the internationalisation and localisation of software services by allowing them to be adapted to different locales. We address lingual localisation by providing a service interface translation using the latest web services technology to adapt services to different languages and currency conversion as an example of regulatory localisation by using real-time data provided by the European Central Bank. Units and Regulatory Localisations are performed by a conversion mapping, which we have generated for a subset of locales. The aim is to investigate a standardised view on the localisation of services by using runtime and middleware services to deploy a localisation implementation. We apply traditional software localisation ideas to service interfaces. Our contribution is a localisation platform consisting of a conceptual model classifying localisation concerns and the definition of a number of specific platform services. The architecture in which this localisation technique is client-centric in a way that it allows the localisation to be controlled and managed by the client, ultimately providing more personalisation and trust. It also addresses robustness concerns by enabling a fault-tolerant architecture for third-party service localisation in a distributed setting

A distributed architecture for policy-customisable multi-tenant Processes-as-a-Service

Service-based business processes are often developed and deployed by single organizations. In distributed, shared resource environments like the cloud on the other hand, consumers share resources owned by cloud providers. %Higher levels of resource sharing gives more economy of scale for providers in the software-as-a-service (SaaS) or business process-as-a-service (BPaaS) space. This requires multi-tenancy capability for service processes that provides customized behaviour for on shared process implementations to meet the varying needs of different process consumers as tenants of the process resource. In this paper, we define a distributed multi-tenant architecture for BPEL processes provided as a service. A single-version BPEL process is deployed by a provider and offered for all process consumers, combined with a customization and management functionality to create a unique experience for different consumers (process tenants). We provide two core components: a policy model for consumers to express customization/business requirements of service processes and a coordination framework for policy enforcement between consumers and providers to achieve on-the-fly customization of service processes