[Frontend] Add tokenize/detokenize endpoints (#5054)

tests/entrypoints/test_openai_server.py

@@ -9,6 +9,7 @@ import pytest
 # using Ray for overall ease of process management, parallel requests,
 # and debugging.
 import ray
+import requests
 import torch
 # downloading lora to test lora requests
 from huggingface_hub import snapshot_download
@@ -1366,5 +1367,53 @@ async def test_long_seed(client: openai.AsyncOpenAI):
                 or "less_than_equal" in exc_info.value.message)
 
 
+@pytest.mark.asyncio
+@pytest.mark.parametrize(
+    "model_name",
+    [MODEL_NAME],
+)
+async def test_tokenize(server, client: openai.AsyncOpenAI, model_name: str):
+    base_url = str(client.base_url)[:-3]
+    tokenizer = get_tokenizer(tokenizer_name=MODEL_NAME, tokenizer_mode="fast")
+
+    for add_special in [False, True]:
+        prompt = "This is a test prompt."
+        tokens = tokenizer.encode(prompt, add_special_tokens=add_special)
+
+        response = requests.post(base_url + "/tokenize",
+                                 json={
+                                     "add_special_tokens": add_special,
+                                     "model": model_name,
+                                     "prompt": prompt
+                                 })
+        response.raise_for_status()
+        assert response.json() == {
+            "tokens": tokens,
+            "count": len(tokens),
+            "max_model_len": 8192
+        }
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize(
+    "model_name",
+    [MODEL_NAME],
+)
+async def test_detokenize(server, client: openai.AsyncOpenAI, model_name: str):
+    base_url = str(client.base_url)[:-3]
+    tokenizer = get_tokenizer(tokenizer_name=MODEL_NAME, tokenizer_mode="fast")
+
+    prompt = "This is a test prompt."
+    tokens = tokenizer.encode(prompt, add_special_tokens=False)
+
+    response = requests.post(base_url + "detokenize",
+                             json={
+                                 "model": model_name,
+                                 "tokens": tokens
+                             })
+    response.raise_for_status()
+    assert response.json() == {"prompt": prompt}
+
+
 if __name__ == "__main__":
     pytest.main([__file__])

vllm/entrypoints/openai/api_server.py

@@ -19,10 +19,17 @@ import vllm.envs as envs
 from vllm.engine.arg_utils import AsyncEngineArgs
 from vllm.engine.async_llm_engine import AsyncLLMEngine
 from vllm.entrypoints.openai.cli_args import make_arg_parser
+# yapf conflicts with isort for this block
+# yapf: disable
 from vllm.entrypoints.openai.protocol import (ChatCompletionRequest,
                                               ChatCompletionResponse,
                                               CompletionRequest,
-                                              EmbeddingRequest, ErrorResponse)
+                                              DetokenizeRequest,
+                                              DetokenizeResponse,
+                                              EmbeddingRequest, ErrorResponse,
+                                              TokenizeRequest,
+                                              TokenizeResponse)
+# yapf: enable
 from vllm.entrypoints.openai.serving_chat import OpenAIServingChat
 from vllm.entrypoints.openai.serving_completion import OpenAIServingCompletion
 from vllm.entrypoints.openai.serving_embedding import OpenAIServingEmbedding
@@ -85,6 +92,28 @@ async def health() -> Response:
     return Response(status_code=200)
 
 
+@app.post("/tokenize")
+async def tokenize(request: TokenizeRequest):
+    generator = await openai_serving_completion.create_tokenize(request)
+    if isinstance(generator, ErrorResponse):
+        return JSONResponse(content=generator.model_dump(),
+                            status_code=generator.code)
+    else:
+        assert isinstance(generator, TokenizeResponse)
+        return JSONResponse(content=generator.model_dump())
+
+
+@app.post("/detokenize")
+async def detokenize(request: DetokenizeRequest):
+    generator = await openai_serving_completion.create_detokenize(request)
+    if isinstance(generator, ErrorResponse):
+        return JSONResponse(content=generator.model_dump(),
+                            status_code=generator.code)
+    else:
+        assert isinstance(generator, DetokenizeResponse)
+        return JSONResponse(content=generator.model_dump())
+
+
 @app.get("/v1/models")
 async def show_available_models():
     models = await openai_serving_chat.show_available_models()

vllm/entrypoints/openai/protocol.py

@@ -699,3 +699,24 @@ class BatchRequestOutput(OpenAIBaseModel):
     # For requests that failed with a non-HTTP error, this will contain more
     # information on the cause of the failure.
     error: Optional[Any]
+
+
+class TokenizeRequest(OpenAIBaseModel):
+    model: str
+    prompt: str
+    add_special_tokens: bool = Field(default=True)
+
+
+class TokenizeResponse(OpenAIBaseModel):
+    tokens: List[int]
+    count: int
+    max_model_len: int
+
+
+class DetokenizeRequest(OpenAIBaseModel):
+    model: str
+    tokens: List[int]
+
+
+class DetokenizeResponse(OpenAIBaseModel):
+    prompt: str

vllm/entrypoints/openai/serving_completion.py

@@ -16,7 +16,11 @@ from vllm.entrypoints.openai.protocol import (CompletionLogProbs,
                                               CompletionResponseChoice,
                                               CompletionResponseStreamChoice,
                                               CompletionStreamResponse,
-                                              UsageInfo)
+                                              DetokenizeRequest,
+                                              DetokenizeResponse,
+                                              TokenizeRequest,
+                                              TokenizeResponse, UsageInfo)
+# yapf: enable
 from vllm.entrypoints.openai.serving_engine import (LoRAModulePath,
                                                     OpenAIServing)
 from vllm.logger import init_logger
@@ -442,3 +446,29 @@ class OpenAIServingCompletion(OpenAIServing):
             tokens=out_tokens,
             top_logprobs=out_top_logprobs,
         )
+
+    async def create_tokenize(self,
+                              request: TokenizeRequest) -> TokenizeResponse:
+        error_check_ret = await self._check_model(request)
+        if error_check_ret is not None:
+            return error_check_ret
+
+        (input_ids, input_text) = self._validate_prompt_and_tokenize(
+            request,
+            prompt=request.prompt,
+            add_special_tokens=request.add_special_tokens)
+
+        return TokenizeResponse(tokens=input_ids,
+                                count=len(input_ids),
+                                max_model_len=self.max_model_len)
+
+    async def create_detokenize(
+            self, request: DetokenizeRequest) -> DetokenizeResponse:
+        error_check_ret = await self._check_model(request)
+        if error_check_ret is not None:
+            return error_check_ret
+
+        (input_ids, input_text) = self._validate_prompt_and_tokenize(
+            request, prompt_ids=request.tokens)
+
+        return DetokenizeResponse(prompt=input_text)

vllm/entrypoints/openai/serving_engine.py

@@ -10,9 +10,10 @@ from vllm.config import ModelConfig
 from vllm.engine.async_llm_engine import AsyncLLMEngine
 from vllm.entrypoints.openai.protocol import (ChatCompletionRequest,
                                               CompletionRequest,
+                                              DetokenizeRequest,
                                               EmbeddingRequest, ErrorResponse,
                                               ModelCard, ModelList,
-                                              ModelPermission)
+                                              ModelPermission, TokenizeRequest)
 from vllm.logger import init_logger
 from vllm.lora.request import LoRARequest
 from vllm.sequence import Logprob
@@ -99,8 +100,9 @@ class OpenAIServing:
         return json_str
 
     async def _check_model(
-        self, request: Union[CompletionRequest, ChatCompletionRequest,
-                             EmbeddingRequest]
+        self, request: Union[ChatCompletionRequest, CompletionRequest,
+                             DetokenizeRequest, EmbeddingRequest,
+                             TokenizeRequest]
     ) -> Optional[ErrorResponse]:
         if request.model in self.served_model_names:
             return None
@@ -126,7 +128,8 @@ class OpenAIServing:
     def _validate_prompt_and_tokenize(
             self,
             request: Union[ChatCompletionRequest, CompletionRequest,
-                           EmbeddingRequest],
+                           DetokenizeRequest, EmbeddingRequest,
+                           TokenizeRequest],
             prompt: Optional[str] = None,
             prompt_ids: Optional[List[int]] = None,
             truncate_prompt_tokens: Optional[Annotated[int,
@@ -174,6 +177,11 @@ class OpenAIServing:
                     f"generation. Please reduce the length of the input.", )
             return input_ids, input_text
 
+        # Note: TokenizeRequest and DetokenizeRequest doesn't have max_tokens
+        # and does not require model context length validation
+        if isinstance(request, (TokenizeRequest, DetokenizeRequest)):
+            return input_ids, input_text
+
         if request.max_tokens is None:
             if token_num >= self.max_model_len:
                 raise ValueError(