Thumbnail should run before heavy processes so houdini does not crash

[SzabadosA]

Problem

We experienced segfault houdini crashes on thumbnail creation, when publishing products. This happens because heavy extractors (in our case the HDA extractor) still block the main thread at the moment when the process moves to the next extractor, which crashes the flipbook tool.

Changes

We change the extractor order to - 0.25 so the thumbnail executes before the HDA extractor, which mitigates the problem

[BigRoy]

Interesting to see this did fix it. Because I wonder what happens between +0.25 and +0.49.

I'd have expected this would needed to be negative like - 0.1 so that it'd run before ExtractROP - assuming that the crash had something to do with the heavy processed occurring from rendering heavy rops in the scene.

Also this plug-in does this check for whether thumbnails are already set on the instance:

        thumbnail = instance.data.get("thumbnailPath")
        if thumbnail:
            # A thumbnail was already set for this instance
            return

We should ensure it doesn't now suddenly run BEFORE anything that we'd expect to otherwise set the thumbnail path - otherwise this one would incorrectly always take precedence.

[SzabadosA]

In our case it failed on HDA extraction, therefor we moved it right in front of the HDA extractor. Do you have any other examples, where you could test this (sth. where you have the feeling the rop extractor fails)?

[MustafaJafar]

ExtractActiveViewThumbnail is only affecting the workfile instance so we should consider only the plugins related to thumbnails and runs through workfile instance. like

• extract_thumbnail_from_source.py

There's another plugin in core but not related to workfile instance.

• extract_thumbnail.py

[MustafaJafar]

In our case it failed on HDA extraction, therefor we moved it right in front of the HDA extractor. Do you have any other examples, where you could test this (sth. where you have the feeling the rop extractor fails)?

How many HDAs were in your scene?

[MustafaJafar]

@SzabadosA could you create an issue for it and link it to this PR?

[SzabadosA]

@SzabadosA could you create an issue for it and link it to this PR?

sure:

#236

[MustafaJafar]

For information.
This order is smaller that the order of a plugin for extracting thumbnail and it runs over workfile instances.

https://github.com/ynput/ayon-core/blob/e420a97543d95bccb5fbf80d220d3ef7a4515670/client/ayon_core/plugins/publish/extract_thumbnail_from_source.py#L36C5-L36C49