Towards to Compose Cloud Service Flexible Workflow Applications

Semi automatic and semantic composition of workflows from Web and Cloud services is an important challenge in today´s distributed applications. This paper focuses on how to compose and execute flexible workflow applications of Cloud services without considering lower level description of the Cloud environment. To reach this objective, we propose a Model-Driven Approach (MDA) for developing flexible workflow applications from existing Cloud services. The workflows are built on an abstract level with semantic and syntaxic descriptions of services available on the Cloud. To built workflow abstract models, the proposed approach uses BPMN model. As there are particular needs for modelling composed workflows of Cloud services which are not fully captured by traditional workflow modelling, we propose to extend the BPMN notation. These extensions deals with additional information allowing a systematic composition of workflows and containing appropriate data to describe a Cloud service. These data are useful for the execution of the resulting.