Deployable Self-contained Workflow Models.

Service composition is a popular approach for building software applications from several individual services. Using imperative workflow technologies, service compositions can be specified as workflow models comprising activities that are implemented, e.g., by service calls or scripts. While scripts are typically included in the workflow model itself and can be executed directly by the workflow engine, the required services must be deployed in a separate step. Moreover, to enable their invocation, an additional step is required to configure the workflow model regarding the endpoints of the deployed services, i.e., IP-address, port, etc. However, a manual deployment of services and configuration of the workflow model are complex, time-consuming, and error-prone tasks. In this paper, we present an approach that enables defining service compositions in a self-contained manner using imperative workflow technology. For this, the workflow models can be packaged with all necessary deployment models and software artifacts that implement the required services. As a result, the service deployment in the target environment where the workflow is executed as well as the configuration of the workflow with the endpoint information of the services can be automated completely. We validate the technical feasibility of our approach by a prototypical implementation based on the TOSCA standard and OpenTOSCA.