53 lines
1.9 KiB
Python
53 lines
1.9 KiB
Python
# SPDX-License-Identifier: Apache-2.0
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from re import escape as regex_escape
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import llguidance
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from transformers import PreTrainedTokenizerBase
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from vllm.model_executor.guided_decoding.guidance_logits_processors import (
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GuidanceLogitsProcessor)
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from vllm.sampling_params import GuidedDecodingParams
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def get_local_guidance_guided_decoding_logits_processor(
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guided_params: GuidedDecodingParams,
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tokenizer: PreTrainedTokenizerBase) -> GuidanceLogitsProcessor:
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"""
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Given an OpenAI-compatible request, check for guided decoding parameters
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and get the necessary logits processor for the given guide.
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"""
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grm = ""
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any_whitespace = 'disable-any-whitespace' not in \
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guided_params.backend_options()
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if guided_params.json:
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grm = llguidance.LLMatcher.grammar_from_json_schema(
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guided_params.json,
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overrides={"whitespace_pattern": guided_params.whitespace_pattern},
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defaults={
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"whitespace_flexible": any_whitespace,
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})
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elif guided_params.json_object:
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grm = llguidance.LLMatcher.grammar_from_json_schema(
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'{"type": "object"}',
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overrides={"whitespace_pattern": guided_params.whitespace_pattern},
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defaults={
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"whitespace_flexible": any_whitespace,
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})
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elif guided_params.regex:
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grm = llguidance.grammar_from("regex", guided_params.regex)
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elif guided_params.choice:
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# choice just uses regex
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choices = (regex_escape(str(choice))
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for choice in guided_params.choice)
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choices_regex = "(" + "|".join(choices) + ")"
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grm = llguidance.grammar_from("regex", choices_regex)
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elif guided_params.grammar:
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# this supports Lark and GBNF
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grm = llguidance.grammar_from("grammar", guided_params.grammar)
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if grm:
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return GuidanceLogitsProcessor(grm, tokenizer)
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raise ValueError("Unknown guided decoding mode")
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