🎁 Adjust Hyrax::DerivativeService.services to Leverage Derivative::Rodeo

[jeremyf]

From the scientist-softserv/adventist_knapsack#406 and building on #218.

Example: Derivatives were pre-processed by the Derivative::Rodeo
Given a <FileSet> (and therefore a Parent Identifier and Original File Name)
And the Derivative::Rodeo has processed the given <FileSet>
When we look for a valid Hyrax::DerivativeService to delegate create_derivatives
Then we should provide a service that can use the files from the rodeo

Example: Derivatives were pre-processed by the Derivative::Rodeo
Given a <FileSet> (and therefore a Parent Identifier and Original File Name)
And the Derivative::Rodeo has not processed the given <FileSet>
When we look for a valid Hyrax::DerivativeService to delegate create_derivatives
Then we should skip the service that can use the files from the rodeo

• Create a new IiifPrint::DerivativeRodeoService class that conforms to the Hyrax::DerivativeService interface (e.g. #valid?, #create_derivatives, etc).
• The new service’s valid method will return true when the associated FileSet has files in the rodeo.
• The new service’s create_derivatives method will take the files in the rodeo and add them as derivatives to the FileSet.

Discussion

As of <2023-04-14 Fri>, the IIIF Print gem is responsible for some of the derivative generation and the remaining derivatives are generated via Hyrax’s Hyrax::FileSetDerivativesService. This is orchestrated by configuring the Hyrax::DerivativeService.services. That configuration is done in IIIF Print’s engine configuration and in the implementation logic of the IiifPrint::PluggableDerivativeService.

By design, the Derivative::Rodeo is envisioned as being able to find and or generate all of the desired derivatives. As of <2023-04-14 Fri> we’re focusing derivative generation on PDFs; in part because that’s the larger group of assets we have for the Adventist ingest.

Those derivatives are:

• Splitting PDF pages so that there’s one image per page
• Creating derivatives of each of those one images
• Perhaps more, but for now this is the focal concern

The default Hyrax service creates the derivatives and assigns them, all as part of a singular derivative process. However, when the rodeo is valid, we will need to know what derivatives to associate with the FileSet.

Note: the current IiifPrint::PluggableDerivativeService may no longer make sense as implemented. However, given that we have implementations that rely on the existing IiifPrint::PluggableDerivativeService we should create a separate derivative service that we can develop and eventually replace (in the default configuration) the PluggableDerivativeService.