mistral.py

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
from concurrent.futures import ThreadPoolExecutor
from typing import Any

from vllm.config import ModelConfig
from vllm.entrypoints.chat_utils import (
    ChatCompletionMessageParam,
    ConversationMessage,
    parse_chat_messages,
    parse_chat_messages_async,
)
from vllm.inputs import EmbedsPrompt, TextPrompt, TokensPrompt
from vllm.logger import init_logger
from vllm.tokenizers import cached_get_tokenizer
from vllm.tokenizers.mistral import MistralTokenizer
from vllm.utils.async_utils import make_async

from .params import ChatParams
from .protocol import RendererLike

logger = init_logger(__name__)


def safe_apply_chat_template(
    tokenizer: MistralTokenizer,
    messages: list[ChatCompletionMessageParam],
    **kwargs,
) -> str | list[int]:
    from mistral_common.exceptions import MistralCommonException

    try:
        return tokenizer.apply_chat_template(messages, **kwargs)
    # mistral-common uses assert statements to stop processing of input
    # if input does not comply with the expected format.
    # We convert those assertion errors to ValueErrors so they can be
    # properly caught in the preprocessing_input step
    except (AssertionError, MistralCommonException) as e:
        raise ValueError(str(e)) from e

    # External library exceptions can sometimes occur despite the framework's
    # internal exception management capabilities.
    except Exception as e:
        # Log and report any library-related exceptions for further
        # investigation.
        logger.exception(
            "An error occurred in `mistral_common` while applying chat template"
        )
        raise ValueError(str(e)) from e


class MistralRenderer(RendererLike):
    @classmethod
    def from_config(
        cls,
        config: ModelConfig,
        tokenizer_kwargs: dict[str, Any],
    ) -> "RendererLike":
        return cls(config, tokenizer_kwargs)

    def __init__(
        self,
        config: ModelConfig,
        tokenizer_kwargs: dict[str, Any],
    ) -> None:
        super().__init__()

        self.config = config

        if config.skip_tokenizer_init:
            tokenizer = None
        else:
            tokenizer = cached_get_tokenizer(
                tokenizer_cls=MistralTokenizer,
                **tokenizer_kwargs,
            )

        self._tokenizer = tokenizer

        self._apply_chat_template_executor = ThreadPoolExecutor(max_workers=1)
        self._apply_chat_template_async = make_async(
            safe_apply_chat_template, executor=self._apply_chat_template_executor
        )

    @property
    def tokenizer(self) -> MistralTokenizer | None:
        return self._tokenizer

    def get_tokenizer(self) -> MistralTokenizer:
        tokenizer = self.tokenizer
        if tokenizer is None:
            raise ValueError("Tokenizer not available when `skip_tokenizer_init=True`")

        return tokenizer

    def render_messages(
        self,
        messages: list[ChatCompletionMessageParam],
        params: ChatParams,
    ) -> tuple[list[ConversationMessage], TextPrompt | TokensPrompt | EmbedsPrompt]:
        tokenizer = self.get_tokenizer()
        conversation, mm_data, mm_uuids = parse_chat_messages(
            messages,
            self.config,
            content_format="string",
        )

        prompt_raw = safe_apply_chat_template(
            tokenizer,
            messages,
            **params.get_apply_chat_template_kwargs(),
        )

        prompt = self.render_completion(prompt_raw)
        if mm_data is not None:
            prompt["multi_modal_data"] = mm_data
        if mm_uuids is not None:
            prompt["multi_modal_uuids"] = mm_uuids

        return conversation, prompt

    async def render_messages_async(
        self,
        messages: list[ChatCompletionMessageParam],
        params: ChatParams,
    ) -> tuple[list[ConversationMessage], TextPrompt | TokensPrompt | EmbedsPrompt]:
        tokenizer = self.get_tokenizer()
        conversation, mm_data, mm_uuids = await parse_chat_messages_async(
            messages,
            self.config,
            content_format="string",
        )

        prompt_raw = await self._apply_chat_template_async(
            tokenizer,
            messages,
            **params.get_apply_chat_template_kwargs(),
        )

        prompt = self.render_completion(prompt_raw)
        if mm_data is not None:
            prompt["multi_modal_data"] = mm_data
        if mm_uuids is not None:
            prompt["multi_modal_uuids"] = mm_uuids

        return conversation, prompt