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Static Files

When steps use input files written by you, this must be explicitly stated in plan.py by declaring the human-written files as static files. This informs StepUp that it does not need to wait for other steps whose outputs are the required files.

Example

Example source files: docs/getting_started/static_files/

Create a file limerick.txt with the following contents:

A physicist named Erwin, quite shrewd,
Put a feline in a box rather crude.
With a vial of doom,
And radioactive gloom,
The poor cat's fate, both alive and subdued!

Also create the following plan.py:

#!/usr/bin/env python3
from stepup.core.api import static, step

static("limerick.txt")
step("nl ${inp} > ${out}", inp="limerick.txt", out="numbered.txt")

The static() function declares a static file, i.e. one that you have created.

Make the plan executable and run it with StepUp as follows:

chmod +x plan.py
stepup -n 1

You should get the following output:

  DIRECTOR │ Listening on /tmp/stepup-########/director (StepUp 2.0.4)
   STARTUP │ (Re)initialized boot script
  DIRECTOR │ Launched worker 0
     PHASE │ run
     START │ ./plan.py
   SUCCESS │ ./plan.py
     START │ nl limerick.txt > numbered.txt
   SUCCESS │ nl limerick.txt > numbered.txt
  DIRECTOR │ Trying to delete 0 outdated output(s).
  DIRECTOR │ Stopping workers.
  DIRECTOR │ See you!

As expected, StepUp does not wait for another step to create limerick.txt because the file is static. The file numbered.txt will contain a copy of the limerick with line numbers.

Try the Following

  • Replace gloom by boom in limerick.txt and run stepup -n 1 again. The line numbering is repeated, but the step ./plan.py is skipped as it did not change.

  • Change the order of static() and step() in plan.py and run stepup -n 1 again. This has no apparent effect, but the step is only sent to the worker process after the director is informed that the file limerick.txt is static.

  • Comment out the static() function call and run stepup -n 1 again. StepUp will refuse to execute the line numbering step and will show a warning explaining why.