Enhancement: Workfile Templates add events, plugin discovery, run script and build from published workfile

[BigRoy]

Changelog Description

• Implement an event-system for the Workfile Templates Builder
• Add plug-in registry/discovery so plug-ins can be registered dynamically instead of requiring to be defined in the Host class
• Maya: Add Run Script plugin, Add Assign Look plugin, Add Build from Publisher Workfile loader and some refactoring
• Change in behavior: This may fix a bug where previously placeholders may sometimes load only one subset when it should have loaded more. It could thus influence the loading behavior on existing templates, see here.
• And some cosmetics

Additional info

Events

• Allow partial functions registered with the Event System already implemented in develop
• Add OrderedEventSystem already implemented in develop
• Implement event system into Workfile Template Builder

Plug-in discovery

• Allow workfile template plug-ins to be dynamically registered and discovered -- todo: this might be good as a separate PR to this PR to implement already for all hosts.

Other

• Allow running build template - even if current context doesn't match - if all required arguments are passed along

Maya

• Refactor maya workfile template load placeholder plugin
  • Cleanup code by re-using more library functions
  • Register plug-in as plug-in path for dynamic reloads
  • Allow storing more complex data, e.g. EnumDef with multiselection=True
  • Reorder into outliner to next to placeholder locator
• Add Run Python Script workfile template plugin
• Add assign look placeholder
• Add Loader to explicitly use any published workfile as workfile template
  • Sort of a start for issue Enhancement: Workfile template builder using publishes instead of direct filepath #5135
• Add Reorder help utilities to maya lib, since it made code easier for the Load Placeholder for maya.

---

Also see this comment here describing what might be other todos to investigate or discuss.

Testing notes:

1. Create and build maya workfile templates (basically existing templates should continue to work)
2. Make sure workfile templates in Nuke and After Effects still behave as intended (basically existing templates should continue to work)
3. The Run Python Script Placeholder in Maya should work (including 'ordering' it with the order attribute)
4. The Assign Look Placeholder in Maya should work - any contents inside the placeholder should get shaders assigned, even if e,g. the loaded content is itself loaded from a placeholder.
5. Ordering in Maya outliner should be preserved for placeholders, also when "keep placeholders" is enabled.

[BigRoy]

For context, this plug-in:

Runs as:

On populate
On depth iteration finished
<openpype.lib.events.Event object at 0x0000020A103A51E0>
On build finished
{'depth': 1, 'placeholders_by_scene_id': {'|maya_runscript': < PlaceholderItem |maya_runscript >}}

[BigRoy]

@ClementHector could this be of interest to you for some test runs? But maybe @mre7a and @friquette have a say as well.

[iLLiCiTiT]

I like this TODO and I think it should be separated PR, merged before this one.

[BigRoy]

How would you like to name the dedicated function for it?

register_workfile_template_builder_placeholder_plugin_path

Seems a bit too verbose haha.

[BigRoy]

@iLLiCiTiT any naming preference on this? I can take a look at creating a separate PR for this then.

[tokejepsen]

Could we resolve the merge conflicts before any testing?

I would also suggest maybe splitting this into smaller PRs.

[BigRoy]

@tokejepsen Resolved the conflicts - should be testable again. Some features have become available in develop already which already takes quite a bit of complexity out of this PR. And I've updated the PR description for that as well - and marked one todo there that would be nice to implement outside of this PR which then makes the diff of this PR smaller in scope as well.

I've refactored usage of partial to weakref_partial @iLLiCiTiT - this was the intended use case, right? It's basically this commit: 27b89ed

[tokejepsen]

Lots of cool stuff here for the workfile builder!

I think there is a lot to test on this PR, so could you update the testing notes with different cases we should look for?

For example I see the plugins look assigner and run python script.

[BigRoy]

Added testing notes to PR description - is this sufficient?

[tokejepsen]

I think there is bugfix in this PR as well.

I've got two subsets of family model. In current develop it'll only bring in 1 model subset main, but testing this PR and it brings in both; main and unique subsets.

[BigRoy]

I think there is bugfix in this PR as well.

I've got two subsets of family model. In current develop it'll only bring in 1 model subset main, but testing this PR and it brings in both; main and unique subsets.

Could very well be - there's also some fixes in how it orders things in the outliner, etc. I just 'patched' as I hit issues while testing and implementing whilst keeping in mind in the code 'original behavior' but just fixing Maya code issues that I knew could have edge cases where it failed.

So it's hoping I didn't actually break another thing! ;)

[tokejepsen]

So it's hoping I didn't actually break another thing! ;)

Could we update the description, just so we are clear on release what might happen for studios updating. I think it's correct behaviour but studios might be used to a single subset being loaded. Unless the original intent was 1 subset per placeholder?

[BigRoy]

Unless the original intent was 1 subset per placeholder?

As far as I know the placeholder design of Workfile Templates was always designed to behave like that.

[mkolar]

Because we're splitting OpenPype into ayon-core and individual host addons, this PR would have to be re-created to target one of those.

We're closing it down, but we'll he happy for a new PR to ynput/ayon-core or the host addon repository once it's up.