Introduction

The GRIA Workflow Service is based on the Freefluo workflow enactment engine. Freefluo is a task orchestration tool and interpreter for executing workflows. A workflow describes a graph of executable steps and also describes how data and control should be passed between steps at runtime.

This release includes a J2EE web application (WAR) that can be deployed along side an existing GRIA 4.2.0 Services installation. The web application includes web-based administration tools for configuration and deployment of workflows that have been authored using Taverna. Deployment of the web application exposes a SOAP web service that clients can use to execute workflows in a similar manner to which they can execute a GRIA job in a workflow.

The Freefluo web service utilises the secure web service infrastructure of GRIA. WS Security is used for message integrity and Process based access control (PBAC) for managing dynamic authorisations.

Architecture

Figure 1 shows how the Freefluo web service relates to other components. A GRIA services administrator can use Taverna to compose a workflow that aggregates GRIA jobs and data transfer operations and other workflows. For example the administrator of GRIA 1 may compose a workflow of GRIA services and workflows hosted at its site (not shown) in addition to GRIA jobs and workflows provided by another GRIA service provider (GRIA 2). Deployment of this workflow to the Freefluo GRIA Service at GRIA 1 makes it available to its clients. Thus, clients of GRIA 1 can use the workflow as a single step in their own workflows, without concern for its implementation.

Figure 1 System architecture

Related components

GRIA documentation and software downloads are available from the GRIA homepage. Taverna information and user documentation can be found at the Taverna project site.

GRIA Workflow Plugins version 1.0.0 has been released along with this distribution and is needed for use with Taverna to author workflows that can be deployed to a GRIA Workflow Service instance.