[Feature] Regex stop condition

[SinanAkkoyun]

Checklist

• 1. If the issue you raised is not a feature but a question, please raise a discussion at https://github.com/sgl-project/sglang/discussions/new/choose Otherwise, it will be closed.
• 2. Please use English, otherwise it will be closed.

Motivation

Hi! This would be awesome, as it would address following problems:

• most custom stopping conditions can be expressed as a regex
• handling custom stopping in a streaming response does not work as quickly as a backend based stopping condition would

(at least in my testing, a NodeJS client (with breaking the AsyncGenerator for await loop) can not stop the SGLang streaming generation the same way it works with the official OpenAI API)

I hope this is easy to implement

Related resources

No response

[merrymercy]

Contribution is welcome!