Sistema de teste auto-adaptativo baseado em modelo para SOA dinâmico

Orientadores: Eliane Martins, Andrea CeccarelliDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: Arquitetura orientada a serviços (SOA) é um padrão de design popular para implemen- tação de serviços web devido à interoperabilidade, escalabilidade e reuso de soluções de software que promove. Os serviços que usam essa arquitetura precisam operar em um am- biente altamente dinâmico, entretanto quanto mais a complexidade desses serviços cresce menos os métodos tradicionais de validação se mostram viáveis. Aplicações baseadas em arquitetura orientada a serviços podem evoluir e mudar du- rante a execução. Por conta disso testes offline não asseguram completamente o compor- tamento correto de um sistema em tempo de execução. Por essa razão, a necessidade de tecnicas diferentes para validar o comportamento adequado de uma aplicação SOA durante o seu ciclo de vida são necessárias, por isso testes online executados durante o funcionamento serão usados nesse projeto. O objetivo do projeto é de aplicar técnicas de testes baseados em modelos para gerar e executar casos de testes relevantes em aplicações SOA durante seu tempo de execu- ção. Para alcançar esse objetivo uma estrura de teste online autoadaptativa baseada em modelos foi idealizada. Testes baseados em modelos podem ser gerados de maneira offline ou online. Nos testes offline, os casos de teste são gerados antes do sistema entrar em execução. Já nos testes online, os casos de teste são gerados e aplicados concomitantemente, e as saídas produzidas pela aplicação em teste definem o próximo passo a ser realizado. Quando uma evolução é detectada em um serviço monitorado uma atualização no modelo da aplicação alvo é executada, seguido pela geração e execução de casos de testes online. Mais precisamente, quatro componentes foram integrados em um circuito autoadap- tativo: um serviço de monitoramento, um serviço de criação de modelos, um serviço de geração de casos de teste baseado em modelos e um serviço de teste. As caracteristicas da estrutura de teste foram testadas em três cenários que foram executados em uma aplicação SOA orquestrada por BPEL, chamada jSeduite. Este trabalho é um esforço para entender as restrições e limitações de teste de soft- ware para aplicações SOA, e apresenta análises e soluções para alguns dos problemas encontrados durante a pesquisaAbstract: Service Oriented Architecture (SOA) is a popular design pattern to build web services be- cause of the interoperability, scalability, and reuse of software solutions that it promotes. The services using this architecture need to operate in a highly dynamic environment, but as the complexity of these services grows, traditional validation processes become less feasible. SOA applications can evolve and change during their execution, and offline tests do not completely assure the correct behavior of the system during its execution. There- fore there is a need of techniques to validate the proper behaviour of SOA applications during the SOA lifecycle. Because of that, in this project online testing will be used. The project goal is to employ model-based testing techniques to generate and execute relevant test cases to SOA applications during runtime. In order to achieve this goal a self-adaptive model-based online testing framework was designed. Tests based on models can be generated offline and online. Offline test are generated before the system execution. Online tests are generated and performed concomitantly, and the output produced by the application under test defines the next step to be performed. when our solution detects that a monitored service evolves, the model of the target service is updated, and online test case generation and execution is performed. More specifically, four components were integrated in a self-adaptive loop: a mon- itoring service, a model generator service, a model based testing service and a testing platform. The testing framework had its features tested in three scenarios that were performed in a SOA application orchestrated by BPEL, called jSeduite. This work is an effort to understand the constraints and limitations of the software testing on SOA applications, and present analysis and solutions to some of the problems found during the researchMestradoCiência da ComputaçãoMestre em Ciência da ComputaçãoCAPE

Modeling and verification of web service composition based interorganizational workflows

Interorganisationale Workflows sind Arbeitsabläufe, welche die Grenzen einer Organisation verlassen und einen Rahmen für Kooperationen der verschiedenen autonomen Organisationen zur Verfügung stellen. Ein wichtiger Punkt für den Entwurf solcher Workflows ist die Balance zwischen Offenheit und Abgrenzung, wobei erstere für Kooperationen und letztere die für den Schutz von Know-how benötigt wird. Workflow Sichten stellen ein effizientes Werkzeug für diesen Zweck zur Verfügung. Durch Offenlegung von bestimmten Teilen eines Prozesses, können Organisationen sowohl kooperieren als auch das Know-how schützen. Diese Dissertation präsentiert nun eine Methode für die korrekte Konstruktion von Workflow Sichten. Es wird angenommen, dass Organisationen Web Service orientierte Technologien zur Modellierung und Implementierung von interorganisationalen Workflows verwenden. Die Anwendung von Web Services bietet Organisationen viele Vorteile. Den eigentlichen Mehrwert von Web Services stellt aber die Kompositionsfähigkeit dar. Verfügbare Web Services können dadurch von anderen Choreographien und Orchestrationen (wieder-)verwendet werden. Die Notwendigkeit der Implementierung von Systemen von Null weg kann minimiert werden. Die zentralen Anforderungen sind einerseits eine Architektur mit adäquatem Potential, andererseits die Verifikation der Korrektheit. Diese Dissertation präsentiert nun eine Architektur zur Modellierung von Web Service Composition basierten interorganisationalen Workflows, genannt föderierte Choreographien, die verglichen mit anderen Architekturen verschiedene Vorteile anbieten. Darüber hinaus werden Algorithmen und Techniken zur Verifikation der strukturellen und temporalen Korrektheit vorgestellt. Strukturelle Korrektheit prüft, ob die Strukturen der beteiligten Prozesse zusammenpassen. Temporale Korrektheit überprüft, ob ein interorganisationaler Workflow, der aus mehreren Choreographien und Orchestrationen besteht hinsichtlich der lokalen und globalen Bedingungen fehlerfrei ist. Mit Hilfe dieser Techniken kann die strukturelle und temporale Konformität des Modells zur Designzeit überprüft werden. Falls das Modell nicht strukturell oder temporal konform ist, können nötige Änderungen durchgeführt werden, sodass die korrekte Ausführung zur Laufzeit garantiert werden kann. Die Überprüfung der Konformität zur Designzeit reduziert die Prozesskosten vor allem wegen den folgenden zwei Gründen: Erstens, die entdeckten Fehler zur Designzeit sind normalerweise billiger als jene, die zur Laufzeit entdeckt werden und zweitens, Fehlerbehandlungsmechanismen können verhindert werden, die wiederum Zusatzkosten verursachen. Zusätzlich zu der vorgestellten Architektur wird eine allgemeinere Architektur zusammen mit den passenden Konformitätsprüfungsalgorithmen präsentiert. Der Ansatz ist Platform- und sprachunabhängig und die Algorithmen sind verteilt.Interorganizational workflows are workflows that cross the boundaries of a single organization and provide a framework for cooperation of different autonomous organizations. An important issue when designing such workflows is the balance between the openness needed for cooperation and the privacy needed for protection of business know-how. Workflow views provide an efficient tool for this aim. By exposure of only selected parts of a process, organizations can both cooperate and protect their business logic. This dissertation presents a technique for a correct construction of workflow views. It is assumed that organizations and partners use web services and web service related technology to model and implement interorganizational workflows. Application of web services offers several advantages for organizations. The real surplus of web services is their capability of being composed to more complex systems. Available web services can be reused by other choreographies and orchestrations and the need for development of new systems from scratch can be minimized. The essential requirements are on the one hand an architecture with adequate capabilities and on the other hand, verification of correctness. This dissertation proposes an architecture for modeling web service composition based interorganizational workflows, called \emph{federated choreographies}, that provides several advantages compared to existing proposals. Moreover, algorithms and techniques for verification of structural and temporal correctness of interorganizational workflows are proposed. Structural conformance checks if the structures of the involved processes match. Temporal conformance checks if an interorganizational workflow composed of choreographies and orchestrations is temporally error-free with respect to local and global temporal constraints. The proposed algorithms can be applied for checking the structural and temporal conformance of the federated choreographies at design-time. If the model is not structurally or temporally conformant, necessary modifications can be done such that the correct execution of the flow at run-time can be guaranteed. The conformance checking at design time reduces the cost of process because of two reasons: first, errors detected at design time are normally cheaper than those detected at run time and second, exception handling mechanisms can be avoided which are, in turn, coupled with additional costs. In addition to the proposed architecture, a more general architecture together with the conformance checking algorithms and techniques for interorganizational workflows are presented. The presented approach is language and platform independent and algorithms work in a distributed manner

Automated Realistic Test Input Generation and Cost Reduction in Service-centric System Testing

Service-centric System Testing (ScST) is more challenging than testing traditional software due to the complexity of service technologies and the limitations that are imposed by the SOA environment. One of the most important problems in ScST is the problem of realistic test data generation. Realistic test data is often generated manually or using an existing source, thus it is hard to automate and laborious to generate. One of the limitations that makes ScST challenging is the cost associated with invoking services during testing process. This thesis aims to provide solutions to the aforementioned problems, automated realistic input generation and cost reduction in ScST. To address automation in realistic test data generation, the concept of Service-centric Test Data Generation (ScTDG) is presented, in which existing services used as realistic data sources. ScTDG minimises the need for tester input and dependence on existing data sources by automatically generating service compositions that can generate the required test data. In experimental analysis, our approach achieved between 93% and 100% success rates in generating realistic data while state-of-the-art automated test data generation achieved only between 2% and 34%. The thesis addresses cost concerns at test data generation level by enabling data source selection in ScTDG. Source selection in ScTDG has many dimensions such as cost, reliability and availability. This thesis formulates this problem as an optimisation problem and presents a multi-objective characterisation of service selection in ScTDG, aiming to reduce the cost of test data generation. A cost-aware pareto optimal test suite minimisation approach addressing testing cost concerns during test execution is also presented. The approach adapts traditional multi-objective minimisation approaches to ScST domain by formulating ScST concerns, such as invocation cost and test case reliability. In experimental analysis, the approach achieved reductions between 69% and 98.6% in monetary cost of service invocations during testin

Process mining : conformance and extension

Today’s business processes are realized by a complex sequence of tasks that are performed throughout an organization, often involving people from different departments and multiple IT systems. For example, an insurance company has a process to handle insurance claims for their clients, and a hospital has processes to diagnose and treat patients. Because there are many activities performed by different people throughout the organization, there is a lack of transparency about how exactly these processes are executed. However, understanding the process reality (the "as is" process) is the first necessary step to save cost, increase quality, or ensure compliance. The field of process mining aims to assist in creating process transparency by automatically analyzing processes based on existing IT data. Most processes are supported by IT systems nowadays. For example, Enterprise Resource Planning (ERP) systems such as SAP log all transaction information, and Customer Relationship Management (CRM) systems are used to keep track of all interactions with customers. Process mining techniques use these low-level log data (so-called event logs) to automatically generate process maps that visualize the process reality from different perspectives. For example, it is possible to automatically create process models that describe the causal dependencies between activities in the process. So far, process mining research has mostly focused on the discovery aspect (i.e., the extraction of models from event logs). This dissertation broadens the field of process mining to include the aspect of conformance and extension. Conformance aims at the detection of deviations from documented procedures by comparing the real process (as recorded in the event log) with an existing model that describes the assumed or intended process. Conformance is relevant for two reasons: 1. Most organizations document their processes in some form. For example, process models are created manually to understand and improve the process, comply with regulations, or for certification purposes. In the presence of existing models, it is often more important to point out the deviations from these existing models than to discover completely new models. Discrepancies emerge because business processes change, or because the models did not accurately reflect the real process in the first place (due to the manual and subjective creation of these models). If the existing models do not correspond to the actual processes, then they have little value. 2. Automatically discovered process models typically do not completely "fit" the event logs from which they were created. These discrepancies are due to noise and/or limitations of the used discovery techniques. Furthermore, in the context of complex and diverse process environments the discovered models often need to be simplified to obtain useful insights. Therefore, it is crucial to be able to check how much a discovered process model actually represents the real process. Conformance techniques can be used to quantify the representativeness of a mined model before drawing further conclusions. They thus constitute an important quality measurement to effectively use process discovery techniques in a practical setting. Once one is confident in the quality of an existing or discovered model, extension aims at the enrichment of these models by the integration of additional characteristics such as time, cost, or resource utilization. By extracting aditional information from an event log and projecting it onto an existing model, bottlenecks can be highlighted and correlations with other process perspectives can be identified. Such an integrated view on the process is needed to understand root causes for potential problems and actually make process improvements. Furthermore, extension techniques can be used to create integrated simulation models from event logs that resemble the real process more closely than manually created simulation models. In Part II of this thesis, we provide a comprehensive framework for the conformance checking of process models. First, we identify the evaluation dimensions fitness, decision/generalization, and structure as the relevant conformance dimensions.We develop several Petri-net based approaches to measure conformance in these dimensions and describe five case studies in which we successfully applied these conformance checking techniques to real and artificial examples. Furthermore, we provide a detailed literature review of related conformance measurement approaches (Chapter 4). Then, we study existing model evaluation approaches from the field of data mining. We develop three data mining-inspired evaluation approaches for discovered process models, one based on Cross Validation (CV), one based on the Minimal Description Length (MDL) principle, and one using methods based on Hidden Markov Models (HMMs). We conclude that process model evaluation faces similar yet different challenges compared to traditional data mining. Additional challenges emerge from the sequential nature of the data and the higher-level process models, which include concurrent dynamic behavior (Chapter 5). Finally, we point out current shortcomings and identify general challenges for conformance checking techniques. These challenges relate to the applicability of the conformance metric, the metric quality, and the bridging of different process modeling languages. We develop a flexible, language-independent conformance checking approach that provides a starting point to effectively address these challenges (Chapter 6). In Part III, we develop a concrete extension approach, provide a general model for process extensions, and apply our approach for the creation of simulation models. First, we develop a Petri-net based decision mining approach that aims at the discovery of decision rules at process choice points based on data attributes in the event log. While we leverage classification techniques from the data mining domain to actually infer the rules, we identify the challenges that relate to the initial formulation of the learning problem from a process perspective. We develop a simple approach to partially overcome these challenges, and we apply it in a case study (Chapter 7). Then, we develop a general model for process extensions to create integrated models including process, data, time, and resource perspective.We develop a concrete representation based on Coloured Petri-nets (CPNs) to implement and deploy this model for simulation purposes (Chapter 8). Finally, we evaluate the quality of automatically discovered simulation models in two case studies and extend our approach to allow for operational decision making by incorporating the current process state as a non-empty starting point in the simulation (Chapter 9). Chapter 10 concludes this thesis with a detailed summary of the contributions and a list of limitations and future challenges. The work presented in this dissertation is supported and accompanied by concrete implementations, which have been integrated in the ProM and ProMimport frameworks. Appendix A provides a comprehensive overview about the functionality of the developed software. The results presented in this dissertation have been presented in more than twenty peer-reviewed scientific publications, including several high-quality journals

Actes des Sixièmes journées nationales du Groupement De Recherche CNRS du Génie de la Programmation et du Logiciel

National audienceCe document contient les actes des Sixièmes journées nationales du Groupement De Recherche CNRS du Génie de la Programmation et du Logiciel (GDR GPL) s'étant déroulées au CNAM à Paris du 11 au 13 juin 2014. Les contributions présentées dans ce document ont été sélectionnées par les différents groupes de travail du GDR. Il s'agit de résumés, de nouvelles versions, de posters et de démonstrations qui correspondent à des travaux qui ont déjà été validés par les comités de programmes d'autres conférences et revues et dont les droits appartiennent exclusivement à leurs auteurs

Engineering framework for service-oriented automation systems

Tese de doutoramento. Engenharia Informática. Universidade do Porto. Faculdade de Engenharia. 201

Recovery within long running transactions

As computer systems continue to grow in complexity, the possibilities of failure increase. At the same time, the increase in computer system pervasiveness in day-to-day activities brought along increased expectations on their reliability. This has led to the need for effective and automatic error recovery techniques to resolve failures. Transactions enable the handling of failure propagation over concurrent systems due to dependencies, restoring the system to the point before the failure occurred. However, in various settings, especially when interacting with the real world, reversal is not possible. The notion of compensations has been long advocated as a way of addressing this issue, through the specification of activities which can be executed to undo partial transactions. Still, there is no accepted standard theory; the literature offers a plethora of distinct formalisms and approaches. In this survey, we review the compensations from a theoretical point of view by: (i) giving a historic account of the evolution of compensating transactions; (ii) delineating and describing a number of design options involved; (iii) presenting a number of formalisms found in the literature, exposing similarities and differences; (iv) comparing formal notions of compensation correctness; (v) giving insights regarding the application of compensations in practice; and (vi) discussing current and future research trends in the area.peer-reviewe

Interim research assessment 2003-2005 - Computer Science

This report primarily serves as a source of information for the 2007 Interim Research Assessment Committee for Computer Science at the three technical universities in the Netherlands. The report also provides information for others interested in our research activities