[Feature] Support "strict" in function calling (#4310)

python/sglang/srt/openai_api/adapter.py

@@ -20,7 +20,7 @@ import os
 import time
 import uuid
 from http import HTTPStatus
-from typing import Dict, List
+from typing import Any, Dict, List, Set
 
 from fastapi import HTTPException, Request, UploadFile
 from fastapi.responses import ORJSONResponse, StreamingResponse
@@ -38,7 +38,7 @@ from sglang.srt.conversation import (
     generate_embedding_convs,
     register_conv_template,
 )
-from sglang.srt.function_call_parser import TOOLS_TAG_LIST, FunctionCallParser
+from sglang.srt.function_call_parser import FunctionCallParser
 from sglang.srt.managers.io_struct import EmbeddingReqInput, GenerateReqInput
 from sglang.srt.openai_api.protocol import (
     BatchRequest,
@@ -915,6 +915,7 @@ def v1_chat_generate_request(
         #  - image_data: None or a list of image strings (URLs or base64 strings).
         #  - audio_data: None or a list of audio strings (URLs).
         #    None skips any image processing in GenerateReqInput.
+        strict_tag = None
         if not isinstance(request.messages, str):
             # Apply chat template and its stop strings.
             tools = None
@@ -929,6 +930,10 @@ def v1_chat_generate_request(
                 else:
                     tools = [item.function.model_dump() for item in request.tools]
 
+                tool_call_parser = tokenizer_manager.server_args.tool_call_parser
+                parser = FunctionCallParser(request.tools, tool_call_parser)
+                strict_tag = parser.get_structure_tag()
+
             if chat_template_name is None:
                 openai_compatible_messages = []
                 for message in request.messages:
@@ -1036,6 +1041,22 @@ def v1_chat_generate_request(
             sampling_params["structural_tag"] = convert_json_schema_to_str(
                 request.response_format.model_dump(by_alias=True)
             )
+
+        if strict_tag is not None:
+            if (
+                sampling_params.get("regex")
+                or sampling_params.get("ebnf")
+                or sampling_params.get("structural_tag")
+                or sampling_params.get("json_schema")
+            ):
+                logger.warning(
+                    "Constrained decoding is not compatible with tool calls."
+                )
+            else:
+                sampling_params["structural_tag"] = convert_json_schema_to_str(
+                    strict_tag.model_dump(by_alias=True)
+                )
+
         sampling_params_list.append(sampling_params)
 
         image_data_list.append(image_data)

python/sglang/srt/openai_api/protocol.py

@@ -287,6 +287,7 @@ class Function(BaseModel):
     description: Optional[str] = Field(default=None, examples=[None])
     name: Optional[str] = None
     parameters: Optional[object] = None
+    strict: bool = False
 
 
 class Tool(BaseModel):