Support for guided decoding for offline LLM

[kevinbu233]

FILL IN THE PR DESCRIPTION HERE

Added support for guided decoding (JSON, regex, choice) on offline interface that is raised in issue #3536 . A refactor of #4130

FIX #3536
FIX #7030

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[DarkLight1337]

Thanks for implementing this! Left a few comments.

Also, it would be a good idea to implement this for AsyncLLMEngine so we can move the guided decoding logic out of the OpenAI server.

[roG0d]

Hi, I've been tracked the guided decoding with CFG for vLLM this past week. I found this PR that points exactly to what I'm looking for.

To be on the same page: it's true that vLLM supports grammar but just with requests related to OpenAI Compatible Server?

If that's so, I would like to help and try bringing this feature forward.

[DarkLight1337]

LGTM now. You just have to run format.sh to appease the linter.

[DarkLight1337]

Hi, I've been tracked the guided decoding with CFG for vLLM this past week. I found this PR that points exactly to what I'm looking for.

To be on the same page: it's true that vLLM supports grammar but just with requests related to OpenAI Compatible Server?

Yes, this PR just extends the existing functionality to offline LLM class.

If that's so, I would like to help and try bringing this feature forward.

The PR is basically complete already, thanks for offering help though!

[rkooo567]

QQ: should we deprecate logit processor API and pass the string to sampling parameter instead?

[DarkLight1337]

QQ: should we deprecate logit processor API and pass the string to sampling parameter instead?

Could you elaborate on that? Not sure how would that work.

[stas00]

@kevinbu233, can this be merged? I think there are quite a few of us who have been waiting for this feature since many moons. Thank you!

[simon-mo]

/ready

[stas00]

Thank you for the quick merge!

[han-steve]

Can we add a docstring for the guided_options_request param here? It's pretty hard to discover this option on the documentation.