Support OpenAI API json_schema response format (#1363)

python/sglang/srt/constrained/jump_forward.py

@@ -23,7 +23,6 @@ from collections import defaultdict
 
 import interegular
 import outlines.caching
-from outlines.fsm.json_schema import build_regex_from_schema
 
 from sglang.srt.constrained import (
     FSMInfo,

python/sglang/srt/openai_api/adapter.py

@@ -28,6 +28,13 @@ from fastapi import HTTPException, Request, UploadFile
 from fastapi.responses import JSONResponse, StreamingResponse
 from pydantic import ValidationError
 
+try:
+    from outlines.fsm.json_schema import convert_json_schema_to_str
+except ImportError:
+    # Before outlines 0.0.47, convert_json_schema_to_str is under
+    # outlines.integrations.utils
+    from outlines.integrations.utils import convert_json_schema_to_str
+
 from sglang.srt.conversation import (
     Conversation,
     SeparatorStyle,
@@ -888,22 +895,26 @@ def v1_chat_generate_request(
         return_logprobs.append(request.logprobs)
         logprob_start_lens.append(-1)
         top_logprobs_nums.append(request.top_logprobs)
-        sampling_params_list.append(
-            {
-                "temperature": request.temperature,
-                "max_new_tokens": request.max_tokens,
-                "min_new_tokens": request.min_tokens,
-                "stop": stop,
-                "stop_token_ids": request.stop_token_ids,
-                "top_p": request.top_p,
-                "presence_penalty": request.presence_penalty,
-                "frequency_penalty": request.frequency_penalty,
-                "repetition_penalty": request.repetition_penalty,
-                "regex": request.regex,
-                "json_schema": request.json_schema,
-                "n": request.n,
-            }
-        )
+
+        sampling_params = {
+            "temperature": request.temperature,
+            "max_new_tokens": request.max_tokens,
+            "min_new_tokens": request.min_tokens,
+            "stop": stop,
+            "stop_token_ids": request.stop_token_ids,
+            "top_p": request.top_p,
+            "presence_penalty": request.presence_penalty,
+            "frequency_penalty": request.frequency_penalty,
+            "repetition_penalty": request.repetition_penalty,
+            "regex": request.regex,
+            "n": request.n,
+        }
+        if request.response_format and request.response_format.type == "json_schema":
+            sampling_params["json_schema"] = convert_json_schema_to_str(
+                request.response_format.json_schema.schema_
+            )
+        sampling_params_list.append(sampling_params)
+
         image_data_list.append(image_data)
         modalities_list.extend(modalities)
     if len(all_requests) == 1:

python/sglang/srt/openai_api/protocol.py

@@ -82,6 +82,14 @@ class StreamOptions(BaseModel):
     include_usage: Optional[bool] = False
 
 
+class JsonSchemaResponseFormat(BaseModel):
+    name: str
+    description: Optional[str] = None
+    # use alias to workaround pydantic conflict
+    schema_: Optional[Dict[str, object]] = Field(alias="schema", default=None)
+    strict: Optional[bool] = False
+
+
 class FileRequest(BaseModel):
     # https://platform.openai.com/docs/api-reference/files/create
     file: bytes  # The File object (not file name) to be uploaded
@@ -237,8 +245,8 @@ ChatCompletionMessageParam = Union[
 
 
 class ResponseFormat(BaseModel):
-    # type must be "json_object" or "text"
-    type: Literal["text", "json_object"]
+    type: Literal["text", "json_object", "json_schema"]
+    json_schema: Optional[JsonSchemaResponseFormat] = None
 
 
 class ChatCompletionRequest(BaseModel):
@@ -264,7 +272,6 @@ class ChatCompletionRequest(BaseModel):
 
     # Extra parameters for SRT backend only and will be ignored by OpenAI models.
     regex: Optional[str] = None
-    json_schema: Optional[str] = None
     min_tokens: Optional[int] = 0
     repetition_penalty: Optional[float] = 1.0
     stop_token_ids: Optional[List[int]] = Field(default_factory=list)

test/srt/test_json_constrained.py

@@ -79,7 +79,10 @@ class TestJSONConstrained(unittest.TestCase):
             ],
             temperature=0,
             max_tokens=128,
-            extra_body={"json_schema": self.json_schema},
+            response_format={
+                "type": "json_schema",
+                "json_schema": {"name": "foo", "schema": json.loads(self.json_schema)},
+            },
         )
         text = response.choices[0].message.content