In this section we provide a detailed step by step guide on using the VePS provenance framework for collecting the provenance on a demo example. The example consists of two Axis2 services named, ‘Fahrenheit2Celsius’ and ‘Celsius2Kelvin.’ The ‘Fahrenheit2Celsius’ service takes as input, temperature in Fahrenheit and converts it into Celsius. Whereas, the ‘Celsius2Kelvin’ service converts the temperature from Celsius into Kelvin scale.
Follow the following steps to create a workflow, execute it, and explore the provenance captured by the VePS provenance framework.
Download the Fahrenheit2Celsius.aar.
Download the Celsius2Kelvin.aar.
Deploy the downloaded services into your Tomcat (that is, copy the ‘aar’ files into your-axis2-location/WEB-INF/services directory).
Compose a workflow of these two services in your favorite workflow composition/execution language directly or you can use some visual workflow composition tool to compose the workflow.
Submit the composed workflow for execution into workflow enactment engine(the engine must support, the enactment of Axis2 services).
Once the workflow execution is completed and you get the results, start the ‘XAMPP’ and using your browser go to the http://localhost/veps-gui/index.php. This starts the web interface of the VePS provenance framework. It provides two basic functionalities: (i) Provenance explorer and (ii) Workflow parameters significance measurement (ACO4PS).
The ‘Provenance Explorer’ offers the following functionalities:
Generate BPEL: This reproduces the workflow executed, using the Business Process Execution Language (BPEL).
Visualize Workflow: This visualizes the workflow, including details about the ‘partnerLinks’ and methods exposed by the services.
Generate Report: This produces a summary of the workflow services, their execution time, and parameters.
View XML: It provides a view of the actual provenance data captured in XML format.
The ‘ACO4PS’ determines the workflow parameters significance using the following sequential steps:
Parameters: It takes as input the total number of parameters in a workflow from the user.
Cost: It takes the range of individual parameters as input and calculates the cost of parameters.
Profit: It calculates the profit of the workflow parameters.
Display: It applies the proposed Ant Colony Optimization for Parameters Significance (ACO4PS) algorithms and displays the results in tabular format.