Moving Forward

Having successfully established running installation of DALiuGE applications, it is now possible to begin testing a new workflow!

To continue working on a new workflow, it is recommended to take the following steps:

  • EAGLE: The editor provides three sets of interactive tutorials in-browser. It is highly recommended you follow those tutorials. Go to https://eagle.icrar.org and navigate to the Help > Tutorials section on the navigation bar to review them.

  • dlg_paletteGen: This allows you to create and load Python modules as Palettes into EAGLE, and begin creating workflows directly from Python classes, methods, and functions.

“Hello DALiuGE”

Having followed the tutorials above, as with all programming related tutorials, we encourage you to try out a simple “Hello, World” example using a BashShellAppDROP and FileDROP.

To do this, you will need to:

  1. Create a new graph

  2. Create a BashShellAppDROP component on the EAGLE Graph Canvas

  3. Click on the BashShellAppDrop and open the Fields Table

  4. In the command row, add the following to the value column: echo "Hello, World" > {output}

  5. In the Fields Table, click Add Parameter and give it the name output, and value demo.txt

  • Note: This is using our string-substituion approach ; the parameter name output and the string inside the braces ({}) need to match.

  • Note: The demo.txt could also have been used as part of the command line directly; however, this would fix the name of the file to demo.txt which can be a problem if we want to scale the workflow (more on this in further tutorials).

  1. In the Use As column, click on the drop-down menu for the output attribute and select OutputPort

  2. This should create an OutputPort on the BashShellAppDROP; add an output FileDROP to the BashShellAppDROP by clicking on the new port and dragging, then selecting Built-In Components -> File

  3. Save the graph, either to a repository or locally (EAGLE will not let you translate without saving).

  4. Start the daliuge-translator and daliuge-engine applications based on your current environment.

  5. Click on the Translate button, which should open a new tab to show the translated workflow .

  6. From this tab, click on the Deploy button, which will run the workflow on your locally running DROPManagers.

  7. If all is successful, you will be able to see a file created in your DALiuGE workspace (/home/dlg/workspace by default.).

  8. Open the most recent session directory, and check the output in demo.txt