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enginex-bi_150-vllm/reasoning/abs_reasoning_parsers.py

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2026-03-05 18:06:10 +08:00
# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
import importlib
import os
from abc import abstractmethod
from collections.abc import Callable, Sequence
from functools import cached_property
from typing import TYPE_CHECKING, Any
from vllm.entrypoints.tool_server import ToolServer
from vllm.logger import init_logger
from vllm.utils.collection_utils import is_list_of
from vllm.utils.import_utils import import_from_path
if TYPE_CHECKING:
from vllm.entrypoints.openai.protocol import (
ChatCompletionRequest,
DeltaMessage,
ResponsesRequest,
)
from vllm.transformers_utils.tokenizer import AnyTokenizer
else:
ChatCompletionRequest = Any
DeltaMessage = Any
ResponsesRequest = Any
AnyTokenizer = Any
logger = init_logger(__name__)
class ReasoningParser:
"""
Abstract reasoning parser class that should not be used directly.
Provided and methods should be used in derived classes.
It is used to extract reasoning content from the model output.
"""
def __init__(self, tokenizer: AnyTokenizer, *args, **kwargs):
self.model_tokenizer = tokenizer
@cached_property
def vocab(self) -> dict[str, int]:
# NOTE: Only PreTrainedTokenizerFast is guaranteed to have .vocab
# whereas all tokenizers have .get_vocab()
return self.model_tokenizer.get_vocab()
@abstractmethod
def is_reasoning_end(self, input_ids: list[int]) -> bool:
"""
Check if the reasoning content ends in the input_ids.
It is used in structured engines like `xgrammar` to check if the
reasoning content ends in the model output.
Parameters:
input_ids: list[int]
The input_ids of the model output.
Returns:
bool
True if the reasoning content ends in the input_ids.
"""
@abstractmethod
def extract_content_ids(self, input_ids: list[int]) -> list[int]:
"""
Extract content token ids from the input_ids.
Parameters:
input_ids: list[int]
The input_ids of the model output.
Returns:
list[int]
The extracted content from the input_ids.
"""
@abstractmethod
def extract_reasoning(
self,
model_output: str,
request: ChatCompletionRequest | ResponsesRequest,
) -> tuple[str | None, str | None]:
"""
Extract reasoning content from a complete model-generated string.
Used for non-streaming responses where we have the entire model response
available before sending to the client.
Parameters:
model_output: str
The model-generated string to extract reasoning content from.
request: ChatCompletionRequest
The request object that was used to generate the model_output.
Returns:
tuple[Optional[str], Optional[str]]
A tuple containing the reasoning content and the content.
"""
@abstractmethod
def extract_reasoning_streaming(
self,
previous_text: str,
current_text: str,
delta_text: str,
previous_token_ids: Sequence[int],
current_token_ids: Sequence[int],
delta_token_ids: Sequence[int],
) -> DeltaMessage | None:
"""
Instance method that should be implemented for extracting reasoning
from an incomplete response; for use when handling reasoning calls and
streaming. Has to be an instance method because it requires state -
the current tokens/diffs, but also the information about what has
previously been parsed and extracted (see constructor)
"""
def prepare_structured_tag(
self,
original_tag: str | None,
tool_server: ToolServer | None,
) -> str:
"""
Instance method that is implemented for preparing the structured tag
Otherwise, None is returned
"""
return None
class ReasoningParserManager:
"""
Central registry for ReasoningParser implementations.
Supports two registration modes:
- Eager registration via `register_module`
- Lazy registration via `register_lazy_module`
Each reasoning parser must inherit from `ReasoningParser`.
"""
reasoning_parsers: dict[str, type[ReasoningParser]] = {}
lazy_parsers: dict[str, tuple[str, str]] = {} # name -> (module_path, class_name)
@classmethod
def get_reasoning_parser(cls, name: str) -> type[ReasoningParser]:
"""
Retrieve a registered or lazily registered ReasoningParser class.
If the parser is lazily registered, it will be imported and cached
on first access.
Raises:
KeyError: if no parser is found under the given name.
"""
if name in cls.reasoning_parsers:
return cls.reasoning_parsers[name]
if name in cls.lazy_parsers:
return cls._load_lazy_parser(name)
raise KeyError(f"Reasoning parser '{name}' not found.")
@classmethod
def list_registered(cls) -> list[str]:
"""Return names of all eagerly and lazily registered reasoning parsers."""
return sorted(set(cls.reasoning_parsers.keys()) | set(cls.lazy_parsers.keys()))
@classmethod
def _load_lazy_parser(cls, name: str) -> type[ReasoningParser]:
"""Import and register a lazily loaded reasoning parser."""
module_path, class_name = cls.lazy_parsers[name]
try:
mod = importlib.import_module(module_path)
parser_cls = getattr(mod, class_name)
if not issubclass(parser_cls, ReasoningParser):
raise TypeError(
f"{class_name} in {module_path} is not a ReasoningParser subclass."
)
cls.reasoning_parsers[name] = parser_cls # cache
return parser_cls
except Exception as e:
logger.exception(
"Failed to import lazy reasoning parser '%s' from %s: %s",
name,
module_path,
e,
)
raise
@classmethod
def _register_module(
cls,
module: type[ReasoningParser],
module_name: str | list[str] | None = None,
force: bool = True,
) -> None:
"""Register a ReasoningParser class immediately."""
if not issubclass(module, ReasoningParser):
raise TypeError(
f"module must be subclass of ReasoningParser, but got {type(module)}"
)
if module_name is None:
module_names = [module.__name__]
elif isinstance(module_name, str):
module_names = [module_name]
elif is_list_of(module_name, str):
module_names = module_name
else:
raise TypeError("module_name must be str, list[str], or None.")
for name in module_names:
if not force and name in cls.reasoning_parsers:
existed = cls.reasoning_parsers[name]
raise KeyError(f"{name} is already registered at {existed.__module__}")
cls.reasoning_parsers[name] = module
@classmethod
def register_lazy_module(cls, name: str, module_path: str, class_name: str) -> None:
"""
Register a lazy module mapping for delayed import.
Example:
ReasoningParserManager.register_lazy_module(
name="qwen3",
module_path="vllm.reasoning.parsers.qwen3_reasoning_parser",
class_name="Qwen3ReasoningParser",
)
"""
cls.lazy_parsers[name] = (module_path, class_name)
@classmethod
def register_module(
cls,
name: str | list[str] | None = None,
force: bool = True,
module: type[ReasoningParser] | None = None,
) -> (
type[ReasoningParser] | Callable[[type[ReasoningParser]], type[ReasoningParser]]
):
"""
Register module with the given name or name list. it can be used as a
decoder(with module as None) or normal function(with module as not
None).
"""
if not isinstance(force, bool):
raise TypeError(f"force must be a boolean, but got {type(force)}")
# Immediate registration (explicit call)
if module is not None:
cls._register_module(module=module, module_name=name, force=force)
return module
# Decorator usage
def _decorator(obj: type[ReasoningParser]) -> type[ReasoningParser]:
module_path = obj.__module__
class_name = obj.__name__
if isinstance(name, str):
names = [name]
elif is_list_of(name, str):
names = name
else:
names = [class_name]
for n in names:
cls.lazy_parsers[n] = (module_path, class_name)
return obj
return _decorator
@classmethod
def import_reasoning_parser(cls, plugin_path: str) -> None:
"""
Import a user-defined reasoning parser by the path
of the reasoning parser define file.
"""
module_name = os.path.splitext(os.path.basename(plugin_path))[0]
try:
import_from_path(module_name, plugin_path)
except Exception:
logger.exception(
"Failed to load module '%s' from %s.", module_name, plugin_path
)
return