Quality of Service Conflict During Web Service Monitoring: A Case Study

AbstractWeb services have become one of the most used technologies in service-oriented systems. Its popularity is due to its property to adapt to any context. As a consequence of the increasing number of Web services on the Internet and its important role in many applications today, Web service quality has become a crucial requirement and demanded by service consumers. Terms of quality levels are written between service providers and service consumers to ensure a degree of quality. The use of monitoring tools to control service quality levels is very important. Quality attributes suffer variations in their values during runtime, this is produced by many factors such as a memory leak, deadlock, race data, inconsistent data, etc. However, sometimes monitoring tools can impact negatively affecting the quality of service when they are not properly used and configured, producing possible conflicts between quality attributes. This paper aims to show the impact of monitoring tools over service quality, two of the most important quality attributes – performance and accuracy – were chosen to be monitored. A case study is conducted to present and evaluate the relationship between performance and accuracy over a Web service. As a result, conflict is found between performance and accuracy, where performance was the most affected, because it presented a degradation in its quality level during monitoring

Robustness testing of a reliable infrastructure for web service-based architectures

Orientador: Eliane MartinsDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: Os sistemas baseados em serviços Web estão suscetíveis a diversos tipos de falhas, entre elas, as causadas pelo ambiente em que operam, a Internet, que está sujeita a sofrer com problemas como, atrasos de entrega de mensagem, queda de conexão, mensagens inválidas entre outros. Para que estas falhas não causem um problema maior para quem está interagindo com o serviço Web, existem soluções, como é o caso do Archmeds, que fornece uma infraestrutura confiável que melhora a confiabilidade e disponibilidade dos sistemas baseados em serviços Web. Mas, para o Archmeds ser uma solução confiável, ele também deve ser testado, pois ele também é um sistema que está sujeito a ter defeitos. Por isso, este trabalho propõe uma abordagem para teste de robustez no Archmeds e para isso, contou com o desenvolvimento de uma ferramenta de injeção de falhas chamada WSInject, que utiliza falhas de comunicação e dados de entrada inválidos nos parâmetros das chamadas aos serviços. Com isso espera-se emular as falhas do ambiente real de operação dos serviços Web e revelar os defeitos do sistema sob teste. Este trabalho também levou em conta que o Archmeds é uma composição de serviços Web, por isso também propõe uma abordagem para testar composições de serviços. Com os resultados deste estudo de caso, espera-se que esta abordagem de teste de robustez possa ser reutilizada para outros sistemas baseados em serviços WebAbstract: Web service-based systems are subject to different types of faults, among them, the ones caused by the environment in which they work, which is the Internet. These faults could be problems like delay of message, connection loss, invalid message request, and others. To avoid that these faults do not become a bigger problem for the clients who are interacting with the Web service, a solution can be the use of a reliable infrastructure, like Archmeds, to increases the reliability and availability of the Web-service-based systems. Although Archmeds is a solution with the aim to increase the reliability of Web services, it is also subject to faults and for this reason, it should also be tested. This work proposes an approach to test the robustness of Archmeds and to reach this goal, a fault injection tool, called WSInject, was developed. It uses communication faults and invalid inputs into services calls. In order to reveal the failures, these faults aim to emulate the real ones that affect the Web services in the real operational environment. This work also took into account that Archmeds is a Web service composition and for this reason, it was created an approach to test it. With the results of this case study, it is expected that this approach can be adapted to others applications based in Web services technologyMestradoCiência da ComputaçãoMestre em Ciência da Computaçã

A fault injection tool for testing web services composition

International audienceWeb Services are increasingly becoming the standard for both Web-based commercial application as well as distributed scientific projects. Given the prominence of this technology, test methods and tools are required to ensure that robust systems are deployed. Testing is required not only to uncover existing problems but also to provide users with tools and metrics to compare similar solutions. In this paper, we propose WSInject, a fault injection tool for testing Web Services. WSInject is a script-driven fault injector able to inject both interface and communication faults. Unlike other Web Service fault injectors, WSInject allows users to combine several types of fault in one injection statement and is able to handle either single or composed services. We also present the results of preliminary experiments on a case study and show some revealed failure