hf_transformers_utils.py

"""
Copyright 2023-2024 SGLang Team
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
"""

"""Utilities for Huggingface Transformers."""

import contextlib
import functools
import json
import os
import warnings
from typing import AbstractSet, Collection, Dict, List, Literal, Optional, Type, Union

from huggingface_hub import snapshot_download
from transformers import (
    AutoConfig,
    AutoProcessor,
    AutoTokenizer,
    PretrainedConfig,
    PreTrainedTokenizer,
    PreTrainedTokenizerFast,
)

try:
    from vllm.transformers_utils.configs import ChatGLMConfig, DbrxConfig

    from sglang.srt.configs import ExaoneConfig

    _CONFIG_REGISTRY: Dict[str, Type[PretrainedConfig]] = {
        ChatGLMConfig.model_type: ChatGLMConfig,
        DbrxConfig.model_type: DbrxConfig,
        ExaoneConfig.model_type: ExaoneConfig,
    }
except ImportError:
    # We want this file to run without vllm dependency
    _CONFIG_REGISTRY: Dict[str, Type[PretrainedConfig]] = {}

for name, cls in _CONFIG_REGISTRY.items():
    with contextlib.suppress(ValueError):
        AutoConfig.register(name, cls)


def download_from_hf(model_path: str):
    if os.path.exists(model_path):
        return model_path

    return snapshot_download(model_path, allow_patterns=["*.json", "*.bin", "*.model"])


def get_config(
    model: str,
    trust_remote_code: bool,
    revision: Optional[str] = None,
    model_override_args: Optional[dict] = None,
):
    config = AutoConfig.from_pretrained(
        model, trust_remote_code=trust_remote_code, revision=revision
    )
    if config.model_type in _CONFIG_REGISTRY:
        config_class = _CONFIG_REGISTRY[config.model_type]
        config = config_class.from_pretrained(model, revision=revision)
    if model_override_args:
        config.update(model_override_args)
    return config


# Models don't use the same configuration key for determining the maximum
# context length.  Store them here so we can sanely check them.
# NOTE: The ordering here is important. Some models have two of these and we
# have a preference for which value gets used.
CONTEXT_LENGTH_KEYS = [
    "max_sequence_length",
    "seq_length",
    "max_position_embeddings",
    "max_seq_len",
    "model_max_length",
]


def get_context_length(config):
    """Get the context length of a model from a huggingface model configs."""
    rope_scaling = getattr(config, "rope_scaling", None)
    if rope_scaling:
        rope_scaling_factor = config.rope_scaling["factor"]
        if "original_max_position_embeddings" in rope_scaling:
            rope_scaling_factor = 1
        if config.rope_scaling.get("rope_type", None) == "llama3":
            rope_scaling_factor = 1
    else:
        rope_scaling_factor = 1

    for key in CONTEXT_LENGTH_KEYS:
        val = getattr(config, key, None)
        if val is not None:
            return int(rope_scaling_factor * val)
    return 2048


# A fast LLaMA tokenizer with the pre-processed `tokenizer.json` file.
_FAST_LLAMA_TOKENIZER = "hf-internal-testing/llama-tokenizer"


def get_tokenizer(
    tokenizer_name: str,
    *args,
    tokenizer_mode: str = "auto",
    trust_remote_code: bool = False,
    tokenizer_revision: Optional[str] = None,
    **kwargs,
) -> Union[PreTrainedTokenizer, PreTrainedTokenizerFast]:
    """Gets a tokenizer for the given model name via Huggingface."""
    if tokenizer_mode == "slow":
        if kwargs.get("use_fast", False):
            raise ValueError("Cannot use the fast tokenizer in slow tokenizer mode.")
        kwargs["use_fast"] = False

    try:
        tokenizer = AutoTokenizer.from_pretrained(
            tokenizer_name,
            *args,
            trust_remote_code=trust_remote_code,
            tokenizer_revision=tokenizer_revision,
            **kwargs,
        )
    except TypeError as e:
        # The LLaMA tokenizer causes a protobuf error in some environments.
        err_msg = (
            "Failed to load the tokenizer. If you are using a LLaMA V1 model "
            f"consider using '{_FAST_LLAMA_TOKENIZER}' instead of the "
            "original tokenizer."
        )
        raise RuntimeError(err_msg) from e
    except ValueError as e:
        # If the error pertains to the tokenizer class not existing or not
        # currently being imported, suggest using the --trust-remote-code flag.
        if not trust_remote_code and (
            "does not exist or is not currently imported." in str(e)
            or "requires you to execute the tokenizer file" in str(e)
        ):
            err_msg = (
                "Failed to load the tokenizer. If the tokenizer is a custom "
                "tokenizer not yet available in the HuggingFace transformers "
                "library, consider setting `trust_remote_code=True` in LLM "
                "or using the `--trust-remote-code` flag in the CLI."
            )
            raise RuntimeError(err_msg) from e
        else:
            raise e

    if not isinstance(tokenizer, PreTrainedTokenizerFast):
        warnings.warn(
            "Using a slow tokenizer. This might cause a significant "
            "slowdown. Consider using a fast tokenizer instead."
        )
    return tokenizer


def get_processor(
    tokenizer_name: str,
    *args,
    tokenizer_mode: str = "auto",
    trust_remote_code: bool = False,
    tokenizer_revision: Optional[str] = None,
    **kwargs,
):
    processor = AutoProcessor.from_pretrained(
        tokenizer_name,
        *args,
        trust_remote_code=trust_remote_code,
        tokenizer_revision=tokenizer_revision,
        **kwargs,
    )
    return processor