fix: Move potential nltk download to warm_up

[sjrl]

Related Issues

• fixes #issue-number

Proposed Changes:

Move the download of the NLTK files to the warm up method. In general we try to use warm_up to house expensive operations and also calls to the internet.

Also specifically the validation service we use in dC requires initializing a pipeline which we do in a threaded way to speed things up. This creates the requirement that components init methods need to be thread safe. The download of the punkt files isn't thread safe which does cause thread locking to occur in the validation service.

How did you test it?

updated tests

Notes for the reviewer

Checklist

• I have read the contributors guidelines and the code of conduct
• I have updated the related issue with new insights and changes
• I added unit tests and updated the docstrings
• I've used one of the conventional commit types for my PR title: fix:, feat:, build:, chore:, ci:, docs:, style:, refactor:, perf:, test: and added ! in case the PR includes breaking changes.
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• I ran pre-commit hooks and fixed any issue

[coveralls]

Pull Request Test Coverage Report for Build 12398909766

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

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Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 10 unchanged lines in 5 files lost coverage.
• Overall coverage increased (+0.2%) to 90.644%

---

Files with Coverage Reduction	New Missed Lines	%
components/generators/openai_utils.py	1	83.33%
components/preprocessors/document_splitter.py	1	99.51%
components/generators/chat/hugging_face_api.py	2	97.67%
dataclasses/chat_message.py	2	98.69%
components/preprocessors/nltk_document_splitter.py	4	96.72%

Totals
Change from base Build 12353137414:	0.2%
Covered Lines:	8303
Relevant Lines:	9160

---

💛 - Coveralls

[wochinge]

🙌🏻

[julian-risch]

LGTM! 👍

@bilgeyucel tutorial 42 will break when this PR gets merged. We just need to add a splitter.warm_up() call. In cookbooks, I expect only this notebooks/rag_fastembed.ipynb to fail.

@sjrl I had a look at deserialization methods and noticed that DocumentSplitter and NLTKDocumentSplitter differ in how they treat splitting function. I will open a separate issue about adding a to_dict to NLTKDocumentSplitter, sth like:

    @classmethod
    def from_dict(cls, data: Dict[str, Any]) -> "NLTKDocumentSplitter":
        """
        Deserializes the component from a dictionary.
        """
        init_params = data.get("init_parameters", {})

        splitting_function = init_params.get("splitting_function", None)
        if splitting_function:
            init_params["splitting_function"] = deserialize_callable(splitting_function)

        return default_from_dict(cls, data)