Meandre Workbench

Data-Intensive Technologies and Applications,!National Center for Supercomputing Applications, !

University of Illinois at Urbana-Champaign

Boris Capitanu capitanu@ncsa.uiuc.edu

The SEASR project and its Meandre infrastructure!are sponsored by The Andrew W. Mellon Foundation

What is it?

•  Visual programming environment Thankfully, no code writing skills are required.

•  Provides a mechanism to create and execute flows

•  Built on top of GWT (Google Web Toolkit) – accessible from all major browsers

Getting Started

•  Fire up your favorite browser and connect If you installed the Workbench on your local machine, use http://localhost:1712 to access it, otherwise replace “localhost” with the correct address of the computer where the Workbench is running at.

•  Log in

The Workbench

The Workbench

The Workspace

•  used as a main staging area for building / editing flows

The Output Panel

The Details Panel The Repository

Panel

The Workspace

Components can be dragged into this region from the “Components” panel and interconnected to create flows.

The Flow Toolbar

•  Provides access to frequently used functions o  save flows o  remove components o  control flow execution

Saving a Flow

Required metadata: -  Name -  Base URL

Separate tags with commas

Removing Components

Two ways:

1. Select the component and click “Remove” on the toolbar

2. Right-click the component you want to remove and select “Remove”

Controlling Flow Execution

Executes the current flow loaded in the Workspace. Any output from the flow will be displayed in the Output panel. If the flow contains interactive components, they will be displayed automatically.

Run Flow

Important: Please be sure to set your browser to allow pop-ups from the Workbench, otherwise the web interactive components will not display!

Stop Flow Sends a request to the Meandre server to abort the currently executing flow. May take a while – the server waits for components to finish their current operation.

The Repository Panel

Three sections: - Components - Flows - Locations

Searching is supported

Display is customizable

Components

•  Software units that are designed to accomplish a particular task •  May have inputs, outputs, and properties

Components with properties can be identified by a symbol appearing in the lower left-hand side of a component icon.

Flows

A Flow is essentially an application — a group of components connected together to perform a certain task

Click on the Flows tab in the Repository panel to view the flows in your Workbench.

Double click on a flow to load that flow into the Workspace.

Locations

Adding a repository location causes all the components and flows hosted at that location to be imported in the user’s private repository on the server

You can find a list of available repository locations at http://www.seasr.org/documentation

Removing a location also removes the associated components and flows from the server.

The Details Panel

Shows the properties and description of a selected component or flow

Properties

Description

For components, the Description displays information about the component function.

For flows, the Description displays information about the flow and the components it contains and their property values.

The Output Panel

Displays output and error messages generated by the Workbench

Using the Workspace

Placing Components The first step in building a flow is to choose components from the Repository panel and place them into the Workspace. To place a component, click on the Components section in the Repository panel and drag the desired component over into the Workspace area.

Note: A flow must have at least one component with no inputs to be able to be executed by the Meandre server.

Selecting Components Components can be selected by single clicking on them in the Workspace. When a component is selected, other selected items are deselected. While selected, a component can be moved about the Workspace or deleted. A selected component (or flow) can be unselected by using CTRL+click on that component (or flow).

Using the Workspace Labeling Components

Editing the component label only changes the name of the component in the given flow. The label must remain unique among the other component labels in the flow. The label can be edited by single-clicking on it and entering the desired text. Pressing ESC while editing a label cancels the labeling operation and restores the original label.

Connecting and Disconnecting Components To make a connection, click on the output port of the desired source component (the port you clicked will be colored red), and then click on the input port to which you wish to connect. You should now have a line connecting the output and input port. If, after selecting a port, you wish to cancel the operation, simply clicking the same port again will unselect it.

The ports of two components should only be connected if their data types are compatible with one another. Any errors resulting from data incompatibilities will occur at runtime.

To remove a connection, simply right-click one of the ports and select “Disconnect” from the context menu. Alternatively, you can remove groups of ports by right-clicking the component and selecting the appropriate menu option.

Using the Workspace Connecting and Disconnecting Components

A component’s output port may only be connected to one input port. However, a component’s input port may be connected to several different output ports. This could be useful when you are retrieving the same data format from multiple components.

The connection line is highlighted if the user hovers over an input or output port. This is useful for verifying connections in a complex flow. When hovering over a component port, the description of that port is also briefly displayed.

Questions / comments?