Python Hooks

You can use Python hook files to do some custom scripting.

In order to find the hook files the file name must match exactly. Please see list below.
The example scripts can be found here:
https://github.com/das-element/resources/tree/main/scripts/hooks/examples

The software follows this order looking for Python Hook files.

1. directory defined in the $DASELEMENT_HOOKS environment variable

2. directory defined in the $DASELEMENT_RESOURCES/scripts/hooks environment variable

3. your local .das-element folder (for Linux: ~/.das-element/scripts/hooks or for Windows %homepath%/.das-element/scripts/hooks)

The result data needs to be JSON serializable.
For example convert pathlib Path to string → str(Path('/some/path/file.exr'))

Pre Render Hook

The input is the resolver data dictionary which will be used to resolve the path pattern. You can modify it here before the transcoding task gets processed.

You will need to return the same dictionary with your changes included.

In the example below, in order to resolve a path pattern like <custom.dependecy> you need to add some value for the custom data. If that is not provided the resolve would otherwise fail if you re-render the proxies and there is no main task to provide the dependency which we normally would get from the post render hook after sending the task to the render farm.

Link to example script:

https://github.com/das-element/resources/blob/main/scripts/hooks/examples/deadline/pre_render.py

Post Render Hook

The input is the output of the process called by the custom command task.

You will have to return a Dictionary which will be added as custom to the resolver data and can later be accessed in the Path Builder. return {'dependency': job_id} can later be resolved with <custom.dependency>

Link to example script:

https://github.com/das-element/resources/blob/main/scripts/hooks/examples/deadline/post_render.py

Pre Ingest Load

This hook can be used to parse the file paths to set tags and the category from the file path before the items are loaded into the ingest list. These tags and the category will automatically populate the ingest list items.

The input is a List of Dictionaries and the same has to be returned from the function.

Link to example script:

https://github.com/das-element/resources/blob/main/scripts/hooks/examples/ingest/pre_ingest_load.py

Pre Export

This hook can be used to edit, reformat or add additional values to the export from the library elements.

Tip: use this hook to create a CSV file that you can import into Shotgrid

The input is a List of Dictionaries and the same has to be returned from the function.

Link to example script:

https://github.com/das-element/resources/blob/main/scripts/hooks/examples/shotgrid/pre_export.py

Troubleshooting

Print inside python file

To output data to the console when customizing the hook files use a print statement inside the main function. The input args will be a list of data.

To get a better idea what’s happening inside the hook files you can follow these steps:

1. inside the Python hook file you can add print statements

   CODE

   print(item)
   print(item['path'])

2. start a terminal/command prompt

3. activate the debug mode - set the environment variable

   CODE

   # Linux/MacOS
   export DASELEMENT_LOG_LEVEL=debug
   # Windows
   set DASELEMENT_LOG_LEVEL=debug

4. now run the software via the command line

   CODE

   # Linux
   /opt/das-element-1.2.1/das-element-1.2.1
   
   # MacOS
   /Applications/das-element-1.2.1.app/Contents/MacOS/das-element-1.2.1
   
   # Windows
   "C:\Program Files\das element\das element 1.2.1\das element 1.2.1.exe"

5. If you make changes to the hook file you will need to restart the application to re-read these changes

Example for pre_load_ingest.py

import logging

def main(*args):
    items = args[0]

    logging.warning('This is a warning!') # <- use the default logging module

    for item in items:
      print(item) # <- this print() will be output to the console
    return items

if __name__ == '__main__':
    main(sys.argv[1:])