sglang0.4.5.post1/python/sglang/srt/function_call_parser.py

630 lines
23 KiB
Python

import json
import logging
import re
from abc import ABC, abstractmethod
from dataclasses import dataclass
from json import JSONDecodeError, JSONDecoder
from typing import Any, Callable, Dict, List, Optional, Set, Tuple, Type
import partial_json_parser
from partial_json_parser.core.exceptions import MalformedJSON
from partial_json_parser.core.options import Allow
from pydantic import BaseModel
from sglang.srt.openai_api.protocol import (
StructuralTagResponseFormat,
StructuresResponseFormat,
Tool,
)
logger = logging.getLogger(__name__)
TOOLS_TAG_LIST = [
"<|plugin|>",
"<function=",
"<tool_call>",
"<|python_tag|>",
"[TOOL_CALLS]",
]
class ToolCallItem(BaseModel):
"""Simple encapsulation of the parsed ToolCall result for easier usage in streaming contexts."""
tool_index: int
name: Optional[str] = None
parameters: str # JSON string
def _find_common_prefix(s1: str, s2: str) -> str:
prefix = ""
min_length = min(len(s1), len(s2))
for i in range(0, min_length):
if s1[i] == s2[i]:
prefix += s1[i]
else:
break
return prefix
def _partial_json_loads(input_str: str, flags: Allow) -> Tuple[Any, int]:
try:
return (partial_json_parser.loads(input_str, flags), len(input_str))
except JSONDecodeError as e:
if "Extra data" in e.msg:
dec = JSONDecoder()
return dec.raw_decode(input_str)
raise
def _is_complete_json(input_str: str) -> bool:
try:
json.loads(input_str)
return True
except JSONDecodeError:
return False
class StreamingParseResult:
"""Result of streaming incremental parsing."""
def __init__(
self, normal_text: str = "", calls: Optional[List[ToolCallItem]] = None
):
self.normal_text = normal_text
self.calls = calls or []
@dataclass
class StructureInfo:
begin: str
end: str
trigger: str
_GetInfoFunc = Callable[[str], StructureInfo]
"""
helper alias of function
ususally it is a function that takes a name string and returns a StructureInfo object,
which can be used to construct a structural_tag object
"""
class BaseFormatDetector(ABC):
"""Base class providing two sets of interfaces: one-time and streaming incremental."""
def __init__(self):
# initialize properties used for state when parsing tool calls in
self._buffer = ""
# streaming mode
self.prev_tool_call_arr: List[Dict] = []
self.current_tool_id: int = -1
self.current_tool_name_sent: bool = False
self.streamed_args_for_tool: List[str] = (
[]
) # map what has been streamed for each tool so far to a list
self.bot_token = ""
self.eot_token = ""
def parse_base_json(self, action: Any, tools: List[Tool]) -> List[ToolCallItem]:
tool_indices = {
tool.function.name: i for i, tool in enumerate(tools) if tool.function.name
}
if not isinstance(action, list):
action = [action]
results = []
for act in action:
name = act.get("name")
if name and name in tool_indices:
results.append(
ToolCallItem(
tool_index=tool_indices[name],
name=name,
parameters=json.dumps(
act.get("parameters") or act.get("arguments", {}),
ensure_ascii=False,
),
)
)
else:
logger.warning(f"Model attempted to call undefined function: {name}")
return results
@abstractmethod
def detect_and_parse(self, text: str, tools: List[Tool]) -> StreamingParseResult:
"""
Parses the text in one go. Returns success=True if the format matches, otherwise False.
Note that leftover_text here represents "content that this parser will not consume further".
"""
action = json.loads(text)
return StreamingParseResult(calls=self.parse_base_json(action, tools))
def parse_streaming_increment(
self, new_text: str, tools: List[Tool]
) -> StreamingParseResult:
"""
Streaming incremental parsing with tool validation.
"""
# Append new text to buffer
self._buffer += new_text
current_text = self._buffer
if not (self.bot_token in current_text or current_text.startswith("{")):
self._buffer = ""
if self.eot_token in new_text:
new_text = new_text.replace(self.eot_token, "")
return StreamingParseResult(normal_text=new_text)
# Build tool indices if not already built
if not hasattr(self, "_tool_indices"):
self._tool_indices = {
tool.function.name: i
for i, tool in enumerate(tools)
if tool.function and tool.function.name
}
flags = Allow.ALL if self.current_tool_name_sent else Allow.ALL & ~Allow.STR
try:
tool_call_arr = []
is_complete = []
try:
start_idx = (
len(self.bot_token)
if current_text.startswith(self.bot_token)
else 0
)
while start_idx < len(current_text):
(obj, end_idx) = _partial_json_loads(
current_text[start_idx:], flags
)
is_complete.append(
_is_complete_json(current_text[start_idx : start_idx + end_idx])
)
start_idx += end_idx + len("; ")
# Validate tool name if present
if "name" in obj and obj["name"] not in self._tool_indices:
# Invalid tool name - reset state
self._buffer = ""
self.current_tool_id = -1
self.current_tool_name_sent = False
if self.streamed_args_for_tool:
self.streamed_args_for_tool.pop()
return StreamingParseResult()
# Handle parameters/arguments consistency
if "parameters" in obj:
assert (
"arguments" not in obj
), "model generated both parameters and arguments"
obj["arguments"] = obj["parameters"]
tool_call_arr.append(obj)
except MalformedJSON:
return StreamingParseResult()
if len(tool_call_arr) == 0:
return StreamingParseResult()
current_tool_call: Dict = (
tool_call_arr[self.current_tool_id] if len(tool_call_arr) > 0 else {}
)
# Handle new tool in array
if len(tool_call_arr) > 0 and len(tool_call_arr) > self.current_tool_id + 1:
if self.current_tool_id >= 0:
cur_arguments = current_tool_call.get("arguments")
if cur_arguments:
cur_args_json = json.dumps(cur_arguments)
sent = len(self.streamed_args_for_tool[self.current_tool_id])
argument_diff = cur_args_json[sent:]
res = StreamingParseResult(
calls=[
ToolCallItem(
tool_index=self.current_tool_id,
name="",
parameters=argument_diff,
)
],
)
self.streamed_args_for_tool[
self.current_tool_id
] += argument_diff
else:
res = StreamingParseResult()
else:
res = StreamingParseResult()
self.current_tool_id = len(tool_call_arr) - 1
self.current_tool_name_sent = False
self.streamed_args_for_tool.append("")
return res
# Handle tool name
elif not self.current_tool_name_sent:
function_name = current_tool_call.get("name")
if function_name and function_name in self._tool_indices:
res = StreamingParseResult(
calls=[
ToolCallItem(
tool_index=self._tool_indices[function_name],
name=function_name,
parameters="",
)
],
)
self.current_tool_name_sent = True
else:
res = StreamingParseResult()
# Handle streaming arguments
else:
cur_arguments = current_tool_call.get("arguments")
res = StreamingParseResult()
if cur_arguments:
sent = len(self.streamed_args_for_tool[self.current_tool_id])
cur_args_json = json.dumps(cur_arguments)
prev_arguments = self.prev_tool_call_arr[self.current_tool_id].get(
"arguments"
)
argument_diff = None
if is_complete[self.current_tool_id]:
argument_diff = cur_args_json[sent:]
self._buffer = ""
self.prev_tool_call_arr[self.current_tool_id].clear()
self.current_tool_name_sent = False
self.streamed_args_for_tool[self.current_tool_id] = ""
elif prev_arguments:
prev_args_json = json.dumps(prev_arguments)
if cur_args_json != prev_args_json:
prefix = _find_common_prefix(prev_args_json, cur_args_json)
argument_diff = prefix[sent:]
if argument_diff is not None:
res = StreamingParseResult(
calls=[
ToolCallItem(
tool_index=self.current_tool_id,
parameters=argument_diff,
)
],
)
if not is_complete[self.current_tool_id]:
self.streamed_args_for_tool[
self.current_tool_id
] += argument_diff
self.prev_tool_call_arr = tool_call_arr
return res
except Exception as e:
logger.error(f"Error in parse_streaming_increment: {e}")
return StreamingParseResult()
@abstractmethod
def has_tool_call(self, text: str) -> bool:
raise NotImplementedError()
@abstractmethod
def structure_info(self) -> _GetInfoFunc:
raise NotImplementedError()
class Qwen25Detector(BaseFormatDetector):
"""
Detector for Qwen 2.5 models.
Assumes function call format:
<tool_call>{"name":"xxx", "arguments":{...}}</tool_call>
"""
def __init__(self):
"""
Initializes the detector with necessary state variables.
"""
super().__init__()
self.bot_token = "<tool_call>"
self.eot_token = "</tool_call>"
def has_tool_call(self, text: str) -> bool:
"""Check if the text contains a Qwen 2.5 format tool call."""
return self.bot_token in text
def detect_and_parse(self, text: str, tools: List[Tool]) -> StreamingParseResult:
"""
One-time parsing: Detects and parses tool calls in the provided text.
:param text: The complete text to parse.
:param tools: List of available tools.
:return: ParseResult indicating success or failure, consumed text, leftover text, and parsed calls.
"""
idx = text.find(self.bot_token)
normal_text = text[:idx].strip() if idx != -1 else text
if self.bot_token not in text:
return StreamingParseResult(normal_text=normal_text, calls=[])
pattern = rf"{self.bot_token}(.*?){self.eot_token}"
match_result_list = re.findall(pattern, text, re.DOTALL)
calls = []
for match_result in match_result_list:
match_result = json.loads(match_result)
calls.extend(self.parse_base_json(match_result, tools))
return StreamingParseResult(normal_text=normal_text, calls=calls)
def structure_info(self) -> _GetInfoFunc:
return lambda name: StructureInfo(
begin='<tool_call>{"name":"' + name + '", "arguments":',
end="}</tool_call>",
trigger="<tool_call>",
)
class MistralDetector(BaseFormatDetector):
"""
Detector for Mistral models.
Assumes function call format:
<|action_start|><|plugin|>{"name":"xxx", "arguments":{...}}<|action_end|>
"""
def __init__(self):
"""
Initializes the detector with necessary state variables.
"""
super().__init__()
self.bot_token = "[TOOL_CALLS] ["
self.tool_call_regex = re.compile(r"\[{.*}\]", re.DOTALL)
def has_tool_call(self, text: str) -> bool:
"""Check if the text contains a Mistral format tool call."""
return self.bot_token in text
def _clean_text(self, text: str) -> str:
"""
clean text to only leave ''[TOOL_CALLS] [{"name": xxx, "arguments": {xxx}}]'
for example,
text = '[TOOL_CALLS] [{"name": "get_current_weather", "arguments": {"location": "Boston, MA", "unit": "fahrenheit"}}]\n\nToday\'s weather in Boston is :{function call result} (in Fahrenheit)\n\nIf you prefer Celsius, please let me know.'
return '[TOOL_CALLS] [{"name": "get_current_weather", "arguments": {"location": "Boston, MA", "unit": "fahrenheit"}}]'
The key pattern is [TOOL_CALLS] [...]
"""
find_results = re.findall(r"\[TOOL_CALLS\] \[.*?\]", text, re.DOTALL)
if len(find_results) > 0:
return find_results[0]
else:
return ""
def detect_and_parse(self, text: str, tools: List[Tool]) -> StreamingParseResult:
"""
One-time parsing: Detects and parses tool calls in the provided text.
:param text: The complete text to parse.
:param tools: List of available tools.
:return: ParseResult indicating success or failure, consumed text, leftover text, and parsed calls.
"""
idx = text.find(self.bot_token)
normal_text = text[:idx].strip() if idx != -1 else text
text = self._clean_text(text)
tool_content = text.replace("[TOOL_CALLS]", "").strip()
raw_tool_calls = self.tool_call_regex.findall(tool_content)
calls = []
if len(raw_tool_calls) > 0:
raw_tool_call = raw_tool_calls[0]
function_call_arr = json.loads(raw_tool_call)
for match_result in function_call_arr:
calls.extend(self.parse_base_json(match_result, tools))
return StreamingParseResult(normal_text=normal_text, calls=calls)
def structure_info(self) -> _GetInfoFunc:
return lambda name: StructureInfo(
begin='[TOOL_CALLS] [{"name":"' + name + '", "arguments":',
end="}]",
trigger="[TOOL_CALLS]",
)
class Llama32Detector(BaseFormatDetector):
"""
Detector for Llama 3.2 models.
Assumes function call format:
<|python_tag|>{"name":"xxx", "arguments":{...}}
"""
def __init__(self):
super().__init__()
self.bot_token = "<|python_tag|>"
def has_tool_call(self, text: str) -> bool:
"""Check if the text contains a Llama 3.2 format tool call."""
# depending on the prompt format the Llama model may or may not
# prefix the output with the <|python_tag|> token
return "<|python_tag|>" in text or text.startswith("{")
def detect_and_parse(self, text: str, tools: List[Tool]) -> StreamingParseResult:
"""Parse function calls from text, handling multiple JSON objects."""
if "<|python_tag|>" not in text and not text.startswith("{"):
return StreamingParseResult(normal_text=text, calls=[])
if "<|python_tag|>" in text:
normal_text, action_text = text.split("<|python_tag|>")
else:
normal_text, action_text = "", text
# Split by semicolon and process each part
json_parts = [part.strip() for part in action_text.split(";") if part.strip()]
all_actions = []
for part in json_parts:
try:
# Parse each individual JSON object
action = json.loads(part)
all_actions.append(action)
except json.JSONDecodeError as e:
logger.warning(f"Failed to parse JSON part: {part}")
logger.warning(f"JSON parse error: {str(e)}")
continue
calls = []
# Only process if we found valid JSON objects
if all_actions:
calls = self.parse_base_json(all_actions, tools)
return StreamingParseResult(normal_text=normal_text, calls=calls)
def structure_info(self) -> _GetInfoFunc:
return lambda name: StructureInfo(
begin='<|python_tag|>{"name":"' + name + '", "arguments":',
end="}",
trigger="<|python_tag|>",
)
class MultiFormatParser:
def __init__(self, detectors: List[BaseFormatDetector]):
"""
:param detectors: A series of available Detector instances passed in
"""
self.detectors = detectors
def parse_once(
self, text: str, tools: List[Tool]
) -> Tuple[str, list[ToolCallItem]]:
"""
One-time parsing: Loop through detectors until there are no new matches or text is exhausted
Return: (final_text, all_calls)
- final_text: The remaining text after parsing that was not consumed by any Detector (can be treated as normal text)
- all_calls: All calls parsed by the Detectors
"""
final_calls = []
final_normal_text = text
for detector in self.detectors:
parsed_result = detector.detect_and_parse(text, tools)
tool_call_list = parsed_result.calls
if len(tool_call_list) > 0: # parsed successfully
final_calls = tool_call_list
final_normal_text = parsed_result.normal_text
break
# leftover_text is the normal text not consumed by any Detector
return final_normal_text, final_calls
def parse_streaming_increment(
self, new_text: str, tools: List[Tool]
) -> Tuple[str, list[ToolCallItem]]:
"""
Streaming incremental parsing: Feed new_text to each detector's parse_streaming_increment
and merge their produced normal_text/calls to return.
(The logic here can be "priority-based" or "parallel parsing" based on your needs)
"""
final_normal_text = ""
final_calls = []
for detector in self.detectors:
sp_result = detector.parse_streaming_increment(new_text, tools)
# Merge normal_text and calls
# If one sp_result contains result call, this should be a successful parse
# If one sp_result only contains normal_text, this can either be a successful
# parse or it is not using the desired parsing tool.
if sp_result.normal_text:
final_normal_text = sp_result.normal_text
if sp_result.calls:
final_calls.extend(sp_result.calls)
final_normal_text = sp_result.normal_text
break
return final_normal_text, final_calls
class FunctionCallParser:
"""
In streaming scenarios, each time new_text is received, it calls multi_format_parser.parse_streaming_increment
and returns the resulting normal_text and calls to the upper layer (or SSE).
"""
ToolCallParserEnum: Dict[str, Type[BaseFormatDetector]] = {
"llama3": Llama32Detector,
"qwen25": Qwen25Detector,
"mistral": MistralDetector,
}
def __init__(self, tools: List[Tool], tool_call_parser: str):
detectors = []
if tool_call_parser:
detector_class = self.ToolCallParserEnum.get(tool_call_parser)
if detector_class:
detectors.append(detector_class())
else:
raise ValueError(f"Unsupported tool_call_parser: {tool_call_parser}")
else:
raise ValueError("Tool Call Parser Not Given!")
self.multi_format_parser = MultiFormatParser(detectors)
self.tools = tools
def has_tool_call(self, text: str) -> bool:
"""
Check if the given text contains a tool call in the format supported by this parser.
This delegates to the detector's implementation.
:param text: The text to check for tool calls
:return: True if the text contains a tool call, False otherwise
"""
# Check all detectors in the multi_format_parser
for detector in self.multi_format_parser.detectors:
if detector.has_tool_call(text):
return True
return False
def parse_non_stream(self, full_text: str) -> Tuple[str, list[ToolCallItem]]:
"""
Non-streaming call: one-time parsing
"""
full_normal_text, calls = self.multi_format_parser.parse_once(
full_text, self.tools
)
return full_normal_text, calls
def parse_stream_chunk(self, chunk_text: str) -> Tuple[str, list[ToolCallItem]]:
"""
Streaming call: incremental parsing
"""
normal_text, calls = self.multi_format_parser.parse_streaming_increment(
chunk_text, self.tools
)
return normal_text, calls
def structure_infos(self) -> List[_GetInfoFunc]:
"""
Returns a list of structure_info functions for each detector
"""
return [
detector.structure_info() for detector in self.multi_format_parser.detectors
]
def get_structure_tag(self) -> StructuralTagResponseFormat:
tool_structures: List[StructuresResponseFormat] = list()
tool_trigger_set: Set[str] = set()
for wrapper in self.structure_infos():
for tool in self.tools:
function = tool.function
name = function.name
assert name is not None
info = wrapper(name)
# accept all if not strict, otherwise only accept the schema
schema = function.parameters if function.strict else {}
tool_structures.append(
StructuresResponseFormat(
begin=info.begin,
schema=schema, # type: ignore
end=info.end,
)
)
tool_trigger_set.add(info.trigger)
return StructuralTagResponseFormat(
type="structural_tag",
structures=tool_structures,
triggers=list(tool_trigger_set),
)