Fig. 1.

Overview of Watchdog. a Modules are defined in an XSD format that describes the command to be executed and valid parameters. All modules together represent the software library that can be used in workflows and can be extended by defining new modules. b A workflow is defined in an XML format and consists of tasks that depend on each other. Among others, the XML format allows setting environment variables, defining different executors in the settings part of the workflow and processing replicate data in a straightforward way. cWatchdog parses the workflow, creates the corresponding tasks, executes them and verifies whether execution of each task terminated successfully or not. d Email notification (optional) and log files combined with either the GUI or a simple web-interface allow monitoring the execution of the workflow and intervening if necessary, e.g. by restarting tasks with modified parameters