Feature/function calling update (#2700)

Co-authored-by: Mingyuan Ma <mamingyuan2001@berkeley.edu>
Co-authored-by: Chayenne <zhaochen20@outlook.com>
Co-authored-by: shuaills <shishuaiuoe@gmail.com>

python/sglang/srt/managers/io_struct.py

@@ -17,7 +17,7 @@ processes (TokenizerManager, DetokenizerManager, Controller).
 """
 
 import uuid
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 from enum import Enum
 from typing import Dict, List, Optional, Union
 
@@ -540,3 +540,27 @@ class CloseSessionReqInput:
 class OpenSessionReqOutput:
     session_id: Optional[str]
     success: bool
+
+
+@dataclass
+class Function:
+    description: Optional[str] = None
+    name: Optional[str] = None
+    parameters: Optional[object] = None
+
+
+@dataclass
+class Tool:
+    function: Function
+    type: Optional[str] = "function"
+
+
+@dataclass
+class FunctionCallReqInput:
+    text: str  # The text to parse.
+    tools: List[Tool] = field(
+        default_factory=list
+    )  # A list of available function tools (name, parameters, etc.).
+    tool_call_parser: Optional[str] = (
+        None  # Specify the parser type, e.g. 'llama3', 'qwen25', or 'mistral'. If not specified, tries all.
+    )