Blueprint Flow: A Declarative Service Composition Framework for Cloud Applications

Cloud applications provides users with services that can be accessed on demand through the Internet. Fertile service frameworks are considered one of the most critical ingredients for the envisaged benefits so as to further interactions among cloud computing resources and application components. Such foundations should lead to the proliferation of new innovative services and applications. The research community has been exploring the Open Service Gateway initiative's (OSGi) potential as a top candidate for cloud application platforms. Although the current OSGi specification provides some level of support for dynamic service discovery, tracking, and composition, more should be done to be able to adequately address the need for diverse interaction patterns for cloud applications. This paper introduces a novel service framework built upon OSGi platforms that supports a directed-acyclic-graph style composition of constituent services. Given a declarative blueprint of service interconnections and interactions, the framework can find and assemble corresponding component services to form a real application. Our proposal can enable a realistic topology of service component interlinkings beyond linear chaining interactions as supported by the status quo. The design, implementation details, and validation results of our workflow-based service composition framework architecture are discussed in the paper.