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enginex-mlu370-vllm/vllm-v0.6.2/vllm/entrypoints/openai/tool_parsers/pythonic_tool_parser.py

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2026-02-04 17:22:39 +08:00
import ast
import json
import re
from typing import Any, Sequence, Tuple, Union
from transformers import PreTrainedTokenizerBase
from vllm.entrypoints.openai.protocol import (ChatCompletionRequest,
DeltaFunctionCall, DeltaMessage,
DeltaToolCall,
ExtractedToolCallInformation,
FunctionCall, ToolCall)
from vllm.entrypoints.openai.tool_parsers.abstract_tool_parser import (
ToolParser, ToolParserManager)
from vllm.logger import init_logger
logger = init_logger(__name__)
class _UnexpectedAstError(Exception):
pass
@ToolParserManager.register_module("pythonic")
class PythonicToolParser(ToolParser):
"""
Tool call parser for models that produce tool calls in a pythonic style,
such as Llama 3.2 models.
Used when --enable-auto-tool-choice --tool-call-parser pythonic are all set
"""
# TODO(mdepinet): Possible future improvements:
# 1. Support text + tools separated by either <|python_tag|> or \n\n
# 2. Support tools outside of a list (or separated by a semicolon).
# This depends on item 1 for consistent streaming.
# Neither of these are necessary for e.g. ToolACE, but both would help make
# Llama3.2 models more reliable.
TOOL_CALL_REGEX = re.compile(
r"\[([a-zA-Z]+\w*\(([a-zA-Z]+\w*=.*,\s*)*([a-zA-Z]+\w*=.*\s)?\),\s*)*([a-zA-Z]+\w*\(([a-zA-Z]+\w*=.*,\s*)*([a-zA-Z]+\w*=.*\s*)?\)\s*)+\]",
re.DOTALL)
def __init__(self, tokenizer: PreTrainedTokenizerBase):
super().__init__(tokenizer)
# Rename for readability. This is NOT a tool id.
@property
def current_tool_index(self) -> int:
return self.current_tool_id
@current_tool_index.setter
def current_tool_index(self, value: int) -> None:
self.current_tool_id = value
def extract_tool_calls(
self, model_output: str,
request: ChatCompletionRequest) -> ExtractedToolCallInformation:
"""
Extract the tool calls from a complete model response.
"""
if not (self.TOOL_CALL_REGEX.match(model_output)):
return ExtractedToolCallInformation(tools_called=False,
tool_calls=[],
content=model_output)
try:
module = ast.parse(model_output)
parsed = getattr(module.body[0], "value", None)
if isinstance(parsed, ast.List) and all(
isinstance(e, ast.Call) for e in parsed.elts):
return ExtractedToolCallInformation(
tools_called=True,
tool_calls=[
_handle_single_tool(e) # type: ignore
for e in parsed.elts
],
content=None)
else:
raise _UnexpectedAstError(
"Tool output must be a list of function calls")
except Exception:
logger.exception("Error in extracting tool call from response.")
# Treat as regular text
return ExtractedToolCallInformation(tools_called=False,
tool_calls=[],
content=model_output)
def extract_tool_calls_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],
request: ChatCompletionRequest,
) -> Union[DeltaMessage, None]:
if not current_text.startswith("["):
return DeltaMessage(content=delta_text)
try:
valid_and_added_text = _make_valid_python(current_text)
if valid_and_added_text is None:
return None
valid_text, added_text = valid_and_added_text
module = ast.parse(valid_text)
parsed = getattr(module.body[0], "value", None)
if not isinstance(parsed, ast.List) or not all(
isinstance(e, ast.Call) for e in parsed.elts):
raise _UnexpectedAstError(
"Tool output must be a list of function calls")
tool_calls = [
_handle_single_tool(e) # type: ignore
for e in parsed.elts
]
tool_deltas = []
for index, new_call in enumerate(tool_calls):
if index < self.current_tool_index:
continue
self.current_tool_index = index
if len(self.streamed_args_for_tool) == index:
self.streamed_args_for_tool.append("")
new_call_complete = index < len(
tool_calls) - 1 or ")]" not in added_text
if new_call_complete:
self.current_tool_index += 1
withheld_suffix = (added_text[:-2]
if not new_call_complete else "")
if not new_call_complete and added_text[-2] == ")":
# Function call is incomplete. Withhold the closing bracket.
withheld_suffix = withheld_suffix + "}"
# Strings get single quotes in the model-produced string.
# JSON requires double quotes.
withheld_suffix = withheld_suffix.replace("'", '"')
delta = _compute_tool_delta(self.streamed_args_for_tool[index],
new_call, index, withheld_suffix)
if delta is not None:
tool_deltas.append(delta)
if (delta.function is not None
and delta.function.arguments is not None):
self.streamed_args_for_tool[
index] += delta.function.arguments
# HACK: serving_chat.py inspects the internal state of tool parsers
# when determining it's final streaming delta, automatically
# adding autocompleted JSON.
# These two lines avoid that nonsense while ensuring finish_reason
# is set to tool_calls when at least one tool is called.
if tool_deltas and not self.prev_tool_call_arr:
self.prev_tool_call_arr = [{"arguments": {}}]
if tool_deltas:
return DeltaMessage(tool_calls=tool_deltas)
elif not added_text and self.current_tool_id > 0:
# Return an empty DeltaMessage once the tool calls are all done
# so that finish_reason gets set.
return DeltaMessage(content='')
else:
return None
except Exception:
logger.exception("Error trying to handle streaming tool call.")
logger.debug(
"Skipping chunk as a result of tool streaming extraction "
"error")
return None
def _get_parameter_value(val: ast.expr) -> Any:
if isinstance(val, ast.Constant):
return val.value
elif isinstance(val, ast.Dict):
if not all(isinstance(k, ast.Constant) for k in val.keys):
raise _UnexpectedAstError(
"Dict tool call arguments must have literal keys")
return {
k.value: _get_parameter_value(v) # type: ignore
for k, v in zip(val.keys, val.values)
}
elif isinstance(val, ast.List):
return [_get_parameter_value(v) for v in val.elts]
else:
raise _UnexpectedAstError("Tool call arguments must be literals")
def _handle_single_tool(call: ast.Call) -> ToolCall:
if not isinstance(call.func, ast.Name):
raise _UnexpectedAstError("Invalid tool call name")
function_name = call.func.id
arguments = {}
for keyword in call.keywords:
arguments[keyword.arg] = _get_parameter_value(keyword.value)
return ToolCall(type="function",
function=FunctionCall(name=function_name,
arguments=json.dumps(arguments)))
def _make_valid_python(text: str) -> Union[Tuple[str, str], None]:
bracket_stack = []
for index, char in enumerate(text):
if char in {"[", "(", "{"}:
bracket_stack.append(char)
elif char == "]":
if not bracket_stack or bracket_stack.pop() != "[":
raise _UnexpectedAstError("Mismatched square brackets")
elif char == ")":
if not bracket_stack or bracket_stack.pop() != "(":
raise _UnexpectedAstError("Mismatched parentheses")
elif char == "}":
if not bracket_stack or bracket_stack.pop() != "{":
raise _UnexpectedAstError("Mismatched curly braces")
elif char in {"'", '"'}:
if bracket_stack and bracket_stack[-1] == char:
if index > 0 and text[index - 1] == "\\":
# Treat an escaped quote as a regular character
pass
else:
bracket_stack.pop()
elif bracket_stack and bracket_stack[-1] in {"'", '"'}:
# Double quote within a single quote string or vice versa.
pass
else:
bracket_stack.append(char)
text = text.rstrip()
if text.endswith("=") or text.endswith(":"):
# Since we have no type information for this property/parameter value,
# we can't fill in a valid value.
return None
if bracket_stack and bracket_stack[-1] == "{":
trailing_dict_text = text[:text.rfind("{")]
num_keys = trailing_dict_text.count(":")
num_values = trailing_dict_text.count(",")
if num_keys <= num_values:
return None # Incomplete property name within parameter value
if bracket_stack and bracket_stack[-1] == "(":
trailing_params_text = text[:text.rfind("(")]
num_full_param_names = trailing_params_text.count("=")
num_full_param_values = trailing_params_text.count(",")
if num_full_param_names <= num_full_param_values:
return None # Incomplete parameter name
if text.endswith(","):
text = text[:-1]
if bracket_stack and bracket_stack[-1] == "[" and not text.endswith(
"[") and not text.endswith(")"):
return None # Incomplete function name
added_text = ""
for char in reversed(bracket_stack):
if char == "[":
added_text += "]"
elif char == "(":
added_text += ")"
elif char == "{":
added_text += "}"
elif char == "'":
added_text += "'"
elif char == '"':
added_text += '"'
return text + added_text, added_text
def _compute_tool_delta(previously_sent_args: str, new_call: ToolCall,
index: int,
withheld_suffix: str) -> Union[DeltaToolCall, None]:
new_call_args = new_call.function.arguments
if withheld_suffix:
assert new_call_args.endswith(withheld_suffix)
new_call_args = new_call_args[:-len(withheld_suffix)]
if not previously_sent_args:
return DeltaToolCall(id=new_call.id,
index=index,
function=DeltaFunctionCall(
name=new_call.function.name,
arguments=new_call_args,
))
arg_diff = new_call_args[len(previously_sent_args):]
return DeltaToolCall(
id="", index=index, function=DeltaFunctionCall(
arguments=arg_diff)) if arg_diff else None