docs: explain different connection string formats in the docstring

[kanenorman]

Related Issues

• fixes Bug/Workaround/feature proposal : DBString Parsing in PgvectorDocumentStore #928

Proposed Changes:

Allow user to provide connection parameters as a dictionary of individual arguments

How did you test it?

• Ran existing test
• Updated existing test
• Added unit test for to_dict() and from_dict()

Notes for the reviewer

This PR is labeled as a feature rather than a bug because the underlying library, rather than Haystack itself, contains the bug.

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:.

[davidsbatista]

thanks @kanenorman for your contribution! I just left a few minor comments

[anakin87]

@kanenorman I am sorry to step in after you have worked on this PR.

I think that the original issue proposes an acceptable workaround for the problem. (I tried it and it also works on default use cases)

After some discussion, we think that it is better to explain the possible connection string formats in the docstring instead of introducing a new init parameter, which might complicate the API and make future maintenance more difficult.

Therefore, my proposal is to:

• remove the connection_param_kwargs init parameter
• make the connection_string docstring more comprehensive, including an example like this: "host=HOST port=PORT dbname=DBNAME user=USER password=PASSWORD".

[kanenorman]

No problem @anakin87! Thank you for stepping in. I reverted the changes and enhanced the docstrings in the latest commit.

[anakin87]

Thanks!