Distributed Enforcement of Service Choreographies

Modern service-oriented systems are often built by reusing, and composing together, existing services distributed over the Internet. Service choreography is a possible form of service composition whose goal is to specify the interactions among participant services from a global perspective. In this paper, we formalize a method for the distributed and automated enforcement of service choreographies, and prove its correctness with respect to the realization of the specified choreography. The formalized method is implemented as part of a model-based tool chain released to support the development of choreography-based systems within the EU CHOReOS project. We illustrate our method at work on a distributed social proximity network scenario.Comment: In Proceedings FOCLASA 2014, arXiv:1502.0315

On the Automated Synthesis of Enterprise Integration Patterns to Adapt Choreography-based Distributed Systems

The Future Internet is becoming a reality, providing a large-scale computing environments where a virtually infinite number of available services can be composed so to fit users' needs. Modern service-oriented applications will be more and more often built by reusing and assembling distributed services. A key enabler for this vision is then the ability to automatically compose and dynamically coordinate software services. Service choreographies are an emergent Service Engineering (SE) approach to compose together and coordinate services in a distributed way. When mismatching third-party services are to be composed, obtaining the distributed coordination and adaptation logic required to suitably realize a choreography is a non-trivial and error prone task. Automatic support is then needed. In this direction, this paper leverages previous work on the automatic synthesis of choreography-based systems, and describes our preliminary steps towards exploiting Enterprise Integration Patterns to deal with a form of choreography adaptation.Comment: In Proceedings FOCLASA 2015, arXiv:1512.0694

thematic series on verification and composition for the internet of services and things

Abstract ■■■ The Internet of Services and Things is characterized as a distributed computing environment that will be populated by a large number of software services and things. Within this context, software systems will increasingly be built by reusing and composing together software services and things distributed over the Internet. This calls for new integration paradigms and patterns, formal composition theories, integration architectures, as well as flexible and dynamic composition and verification mechanisms. In particular, service- and thing-based systems pose new challenges for software composition and verification techniques, due to changing requirements, emerging behaviors, uncertainty, and dynamicity

Towards a connector algebra

Abstract. Interoperability of heterogeneous networked systems has yet to reach the maturity required by ubiquitous computing due to the technology-dependent nature of solutions. The Connect Integrated Project attempts to develop a novel network infrastructure to allow heterogeneous networked systems to freely communicate with one another by synthesising the required connectors on-the-fly. A key objective of Connect is to build a comprehensive theory of composable connectors, by devising an algebra for rigorously characterising complex interaction protocols in order to support automated reasoning. With this aim in mind, we formalise a high-level algebra for reasoning about protocol mismatches. Basic mismatches can be solved by suitably defined primitives, while complex mismatches can be settled by composition operators that build connectors out of simpler ones. The semantics of the algebra is given in terms of Interface Automata, and an example in the domain of instant messaging is used to illustrate how the algebra can characterise the interaction behaviour of a connector for mediating protocols

A Software Exoskeleton to Protect and Support Citizen's Ethics and Privacy in the Digital World

Citizens of the digital world are threatened. The digital systems that surround them are increasingly able to make autonomous decisions over and above them and on their behalf. They feel that their moral rights, as well as the social, economic, and political spheres, can be affected by the behavior of such systems. Although unavoidable, the digital world is becoming uncomfortable and potentially hostile to its users as human beings and as citizens. Notwithstanding the introduction of the GDPR and of initiatives to establish criteria on software transparency and accountability, users feel vulnerable and unprotected. In this paper, we present EXOSOUL, an overarching research framework that aims at building a software a personalized exoskeleton that enhances and protects users by mediating their interactions with the digital world according to their own ethics of actions and privacy of data. The exoskeleton disallows or adapts the interactions that would result in unacceptable or morally wrong behaviors according to the ethics and privacy preferences of the users. With their software shield, users will feel empowered and in control, and more in the balance of forces with the other actors of the digital world. To reach the breakthrough result of automatically building a personalized exoskeleton, EXOSOUL identifies multidisciplinary challenges never touched before: 1) defining the scope for and inferring citizen's ethical preferences; 2) treating privacy as an ethical dimension managed through the disruptive notion of active data; and 3) automatically synthesizing ethical actuators, i.e., connector components that mediate the interaction between the user and the digital world to enforce her ethical preferences. In this paper, we discuss the research challenges of EXOSOUL in terms of their feasibility and risks

Modeling of application- and middleware-layer interaction protocols

The CONNECT Integrated Project aims at enabling continuous composition of networked systems to respond to the evolution of functionalities provided to and required from the networked environment. CONNECT aims at dropping the interoperability barrier by adopting a revolutionary approach to the seamless networking of digital systems, that is, synthesizing on-the-fly the connectors via which networked systems communicate. The resulting emergent connectors are effectively synthesized according to the behavioral semantics of application- down to middleware-layer protocols run by the interacting parties. The role of work package WP3 is to devise automated and compositional approaches to connector synthesis, which can be performed at run-time. Given the respective interaction behavior of networked systems, we want to synthesize the behavior of the connector(s) needed for them to interact. These connectors serve as mediators of the networked systems' interaction at both application and middleware layers. In this deliverable, we set the scene for a formal theory of the automated synthesis of application- and middleware-layer protocol mediators. We formally characterize mediating connectors between mismatching application-layer protocols by rigorously defining the necessary conditions that must hold for protocols to be mediated. The outcome of this formalization is the definition of two relationships between heterogenous protocols: matching and mapping. The former is concerned with checking whether a mediator letting two protocols interoperate exists or not. The latter concerns the algorithm that should be executed to synthesize the required mediator. Furthermore, we analyze the different dimensions of interoperability at the middleware layer and exploit this analysis to formalize existing solutions to middleware-layer interoperability. Since the work on application-layer mediator synthesis is based on the assumption that a model of the interaction protocol for a networked system is dynamically discovered, we finally present an approach, based on data-flow analysis and testing, for the automated elicitation of application-layer protocols from software implementations. This approach presents similarities, but also several differences, with the work of work package WP4 (protocol learning). Furthermore, it allowed us to proceed in parallel with the work of WP4 and to state the requirements that the learning approaches have to satisfy to enable mediator synthesis. For this reason, we keep this work separate from the work on protocol learning and discuss it in this deliverable. All the approaches mentioned above are applied to several examples and scenarios

Dynamic connector synthesis: revised prototype implementation

The CONNECT Integrated Project aims at enabling continuous composition of Networked Systems (NSs) to respond to the evolution of functionalities provided to and required from the networked environment. CONNECT aims at dropping the interoperability barrier by adopting a revolutionary approach to the seamless networking of digital systems, that is, synthesizing on-the-fly the connectors via which networked systems communicate. The resulting emergent connectors are effectively synthesized according to the behavioral semantics of application- down to middleware-layer protocols run by the interacting parties

Reasoning about and Harmonizing the Interaction Behavior of Networked Systems at Application- and Middleware- Layer

The CONNECT Integrated Project aims at enabling continuous composition of networked systems to respond to the evolution of functionalities provided to and required from the networked environment. CONNECT aims at dropping the interoperability barrier by adopting a revolutionary approach to the seamless networking of digital systems, that is, synthesizing on-the-fly the connectors via which networked systems communicate. The resulting emergent connectors are effectively synthesized according to the behavioral semantics of application- down to middleware-layer protocols run by the interacting parties. The role of work package WP3 is to devise automated and compositional approaches to connector synthesis, which can be performed at run-time. Given the respective interaction behavior of networked systems, we want to synthesize the behavior of the connector(s) needed for them to interact. These connectors serve as mediators of the networked systems' interaction at both application and middleware layers. During the project's first year, the work of WP3 led us to achieve the following preliminary results: the formalization of matching and mapping relationships for application-layer interaction protocols; the definition of the corresponding mediator generation algorithm; the analysis of the interoperability problems, and related solutions, that can occur at middleware-layer; and a model-driven approach to the automated elicitation of application-layer protocols from software implementations. All these achievements have been reported in Deliverable D3.1: "Modeling of application- and middleware-layer interaction protocols". In this deliverable, we go a step forward with respect to some of the previous achievements by delivering a unified process, and related artefacts, for the automated synthesis of mediators at both application and middleware layers, code-generation techniques to generate the actual code that implements a synthesized mediator, and a preliminary integration of QoS management in the synthesis process. During year 2, all the work has been validated through its application to several scenarios, in particular as part of WP1 and WP6. By selecting one of them as common scenario, in this deliverable, we also show the different methods/techniques at work on the scenario. All the steps of the devised synthesis process are described in detail and applied to the selected common scenario

Initial CONNECT Architecture

Interoperability remains a fundamental challenge when connecting heterogeneous systems which encounter and spontaneously communicate with one another in pervasive computing environments. This challenge is exasperated by the highly heterogeneous technologies employed by each of the interacting parties, i.e., in terms of hardware, operating system, middleware protocols, and application protocols. The key aim of the CONNECT project is to drop this heterogeneity barrier and achieve universal interoperability. Here we report on the development of the overall CONNECT architecture that will underpin this solution; in this respect, we present the following contributions: i) an elicitation of interoperability requirements from a set of pervasive computing scenarios, ii) a survey of existing solutions to interoperability, iii) an initial view of the CONNECT architecture, and iv) a series of experiments to provide initial validation of the architecture