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Unstructured-IO / unstructured

Open source libraries and APIs to build custom preprocessing pipelines for labeling, training, or production machine learning pipelines.
https://www.unstructured.io/
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legacy office doc type conversion is not thread-safe in a container setup with Rocky Linux (potentially in general) #3763

Open cwang opened 3 weeks ago

cwang commented 3 weeks ago

Describe the bug

The convert_office_doc function used to convert file types such as ppt and doc to their modern equivalents (pptx and docx respectively for example) is NOT thread safe as in the subprocess spun in a thread would randomly return exit code 1 without doing actual conversion via soffice in a container setup with Rocky Linux base images.

See https://github.com/Unstructured-IO/unstructured/blob/340a07f18b6e4df47fe8365c636e9328657a520d/unstructured/partition/common/common.py#L256

To Reproduce Take a bundle of legacy office docs such as a few .doc and a few .ppt files, and call partition function in a thread pool setup, to see that randomly one of the doc would fail to get converted (therefore the whole partition function for that file fails). BUT it's definitely not always one file but can be any legacy file in that pack of documents, which suggests to me it's not a file issue but a threading with subprocess issue.

Expected behavior The legacy to modern office file conversion should always work despite threading or not.

Screenshots N/A

Environment Info I've tested with a wide range of Rocky base images + Python 3.10/3.11/3.12 for this issue.

Additional context My workaround is to always do sequential processing among a pack of documents, by picking out all the legacy office docs and put them in a single thread to be processed sequentially. It's not ideal but maybe it should be mentioned in the OSS docs if no fix is coming any time soon?

scanny commented 3 weeks ago

@cwang A couple questions:

  1. Is there any clue as to the cause of the failure? Like some message that occurs? Or does it just silently fail?
  2. How does the multi-threading arise? Is that something you add? How do you accomplish the single-threading that avoids the problem?
cwang commented 3 weeks ago
  1. Is there any clue as to the cause of the failure? Like some message that occurs? Or does it just silently fail?

What I think happened is running threads in a threadpoolexecutor and when more than one threads (running concurrently) calling subprocess(), some of them failed with blank message and exit code 1.

  1. How does the multi-threading arise? Is that something you add? How do you accomplish the single-threading that avoids the problem?

Yes we built a system on top of partition function call for office docs, and the only way we can avoid this happening is demonstrated below:

Given a batch of docs: a.pdf, b.pdf, c.pdf and p.doc, q.ppt As we know the fact that: both .doc and .ppt calls the convert_office_doc function mentioned above that calls subprocess() Then running processing using 5 threads concurrently in a thread pool would always result in one legacy office doc (sometimes p.doc other times q.ppt) not being partitioned because of the exit code 1 from subprocess() call; However using 4 threads and sequentially processing p.dpc and q.ppt in a single thread while the other 3 threads processing 3 pdf files concurrently would make sure every file is processed successfully. It also explains why tests don't usually caught this kind of errors because they tend to be ran sequentially or even in a parallel testing scenario, it's less unlikely you run these conversion tasks exactly at the same time.

Hope it helps and happy to explain in more details.

scanny commented 3 weeks ago

The soffice command actually loads the LibreOffice application. On my Mac I can see the application icon pop up in the dock when running soffice and then disappear after the conversion is completed. I suspect that's where this particular thread-safety problem lies. You might try running it with multiprocessing rather than multithreading to see if that remedies the situation.

scanny commented 3 weeks ago

Changing to enhancement because I don't believe thread-safety is a promised behavior.

cwang commented 3 weeks ago

Right call to re-classify this as an improvement because it's usage scenario dependent.

Also multiprocessing is a good suggestion however it's a different topic as in why multiprocessing with unstructured isn't easy in within a container, at least that's what I saw in our production environment, mostly because of the heaviness of stuff like Tesseract.

Thanks @scanny!