Files
vllm-dev/vllm/entrypoints/openai/api_server.py
2023-11-30 16:43:13 -08:00

730 lines
29 KiB
Python

# Adapted from
# https://github.com/lm-sys/FastChat/blob/168ccc29d3f7edc50823016105c024fe2282732a/fastchat/serve/openai_api_server.py
import argparse
import asyncio
import codecs
import json
import time
from http import HTTPStatus
from typing import AsyncGenerator, Dict, List, Optional, Tuple, Union
import fastapi
import uvicorn
from fastapi import Request
from fastapi.exceptions import RequestValidationError
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse, StreamingResponse, Response
from vllm.engine.arg_utils import AsyncEngineArgs
from vllm.engine.async_llm_engine import AsyncLLMEngine
from vllm.entrypoints.openai.protocol import (
CompletionRequest, CompletionResponse, CompletionResponseChoice,
CompletionResponseStreamChoice, CompletionStreamResponse,
ChatCompletionRequest, ChatCompletionResponse,
ChatCompletionResponseChoice, ChatCompletionResponseStreamChoice,
ChatCompletionStreamResponse, ChatMessage, DeltaMessage, ErrorResponse,
LogProbs, ModelCard, ModelList, ModelPermission, UsageInfo)
from vllm.logger import init_logger
from vllm.outputs import RequestOutput
from vllm.sampling_params import SamplingParams
from vllm.transformers_utils.tokenizer import get_tokenizer
from vllm.utils import random_uuid
TIMEOUT_KEEP_ALIVE = 5 # seconds
logger = init_logger(__name__)
served_model = None
app = fastapi.FastAPI()
engine = None
response_role = None
def parse_args():
parser = argparse.ArgumentParser(
description="vLLM OpenAI-Compatible RESTful API server.")
parser.add_argument("--host", type=str, default=None, help="host name")
parser.add_argument("--port", type=int, default=8000, help="port number")
parser.add_argument("--allow-credentials",
action="store_true",
help="allow credentials")
parser.add_argument("--allowed-origins",
type=json.loads,
default=["*"],
help="allowed origins")
parser.add_argument("--allowed-methods",
type=json.loads,
default=["*"],
help="allowed methods")
parser.add_argument("--allowed-headers",
type=json.loads,
default=["*"],
help="allowed headers")
parser.add_argument("--served-model-name",
type=str,
default=None,
help="The model name used in the API. If not "
"specified, the model name will be the same as "
"the huggingface name.")
parser.add_argument("--chat-template",
type=str,
default=None,
help="The file path to the chat template, "
"or the template in single-line form "
"for the specified model")
parser.add_argument("--response-role",
type=str,
default="assistant",
help="The role name to return if "
"`request.add_generation_prompt=true`.")
parser = AsyncEngineArgs.add_cli_args(parser)
return parser.parse_args()
def create_error_response(status_code: HTTPStatus,
message: str) -> JSONResponse:
return JSONResponse(ErrorResponse(message=message,
type="invalid_request_error").dict(),
status_code=status_code.value)
def load_chat_template(args, tokenizer):
if args.chat_template is not None:
try:
with open(args.chat_template, "r") as f:
chat_template = f.read()
except OSError:
# If opening a file fails, set chat template to be args to
# ensure we decode so our escape are interpreted correctly
chat_template = codecs.decode(args.chat_template, "unicode_escape")
tokenizer.chat_template = chat_template
logger.info(
f"Using supplied chat template:\n{tokenizer.chat_template}")
elif tokenizer.chat_template is not None:
logger.info(f"Using default chat template:\n{tokenizer.chat_template}")
else:
logger.warning("No chat template provided. Chat API will not work.")
@app.exception_handler(RequestValidationError)
async def validation_exception_handler(_, exc):
return create_error_response(HTTPStatus.BAD_REQUEST, str(exc))
async def check_model(request) -> Optional[JSONResponse]:
if request.model == served_model:
return
ret = create_error_response(
HTTPStatus.NOT_FOUND,
f"The model `{request.model}` does not exist.",
)
return ret
async def check_length(
request: Union[ChatCompletionRequest, CompletionRequest],
prompt: Optional[str] = None,
prompt_ids: Optional[List[int]] = None
) -> Tuple[List[int], Optional[JSONResponse]]:
assert (not (prompt is None and prompt_ids is None)
and not (prompt is not None and prompt_ids is not None)
), "Either prompt or prompt_ids should be provided."
input_ids = prompt_ids if prompt_ids is not None else tokenizer(
prompt).input_ids
token_num = len(input_ids)
if request.max_tokens is None:
request.max_tokens = max_model_len - token_num
if token_num + request.max_tokens > max_model_len:
return input_ids, create_error_response(
HTTPStatus.BAD_REQUEST,
f"This model's maximum context length is {max_model_len} tokens. "
f"However, you requested {request.max_tokens + token_num} tokens "
f"({token_num} in the messages, "
f"{request.max_tokens} in the completion). "
f"Please reduce the length of the messages or completion.",
)
else:
return input_ids, None
@app.get("/health")
async def health() -> Response:
"""Health check."""
return Response(status_code=200)
@app.get("/v1/models")
async def show_available_models():
"""Show available models. Right now we only have one model."""
model_cards = [
ModelCard(id=served_model,
root=served_model,
permission=[ModelPermission()])
]
return ModelList(data=model_cards)
def create_logprobs(
token_ids: List[int],
top_logprobs: Optional[List[Optional[Dict[int, float]]]] = None,
num_output_top_logprobs: Optional[int] = None,
initial_text_offset: int = 0,
) -> LogProbs:
"""Create OpenAI-style logprobs."""
logprobs = LogProbs()
last_token_len = 0
if num_output_top_logprobs:
logprobs.top_logprobs = []
for i, token_id in enumerate(token_ids):
step_top_logprobs = top_logprobs[i]
if step_top_logprobs is not None:
token_logprob = step_top_logprobs[token_id]
else:
token_logprob = None
token = tokenizer.convert_ids_to_tokens(token_id)
logprobs.tokens.append(token)
logprobs.token_logprobs.append(token_logprob)
if len(logprobs.text_offset) == 0:
logprobs.text_offset.append(initial_text_offset)
else:
logprobs.text_offset.append(logprobs.text_offset[-1] +
last_token_len)
last_token_len = len(token)
if num_output_top_logprobs:
logprobs.top_logprobs.append({
tokenizer.convert_ids_to_tokens(i): p
for i, p in step_top_logprobs.items()
} if step_top_logprobs else None)
return logprobs
@app.post("/v1/chat/completions")
async def create_chat_completion(request: ChatCompletionRequest,
raw_request: Request):
"""Completion API similar to OpenAI's API.
See https://platform.openai.com/docs/api-reference/chat/create
for the API specification. This API mimics the OpenAI ChatCompletion API.
NOTE: Currently we do not support the following features:
- function_call (Users should implement this by themselves)
- logit_bias (to be supported by vLLM engine)
"""
error_check_ret = await check_model(request)
if error_check_ret is not None:
return error_check_ret
if request.logit_bias is not None and len(request.logit_bias) > 0:
# TODO: support logit_bias in vLLM engine.
return create_error_response(HTTPStatus.BAD_REQUEST,
"logit_bias is not currently supported")
try:
prompt = tokenizer.apply_chat_template(
conversation=request.messages,
tokenize=False,
add_generation_prompt=request.add_generation_prompt)
except Exception as e:
logger.error(f"Error in applying chat template from request: {str(e)}")
return create_error_response(HTTPStatus.BAD_REQUEST, str(e))
token_ids, error_check_ret = await check_length(request, prompt=prompt)
if error_check_ret is not None:
return error_check_ret
model_name = request.model
request_id = f"cmpl-{random_uuid()}"
created_time = int(time.monotonic())
chunk_object_type = "chat.completion.chunk"
try:
spaces_between_special_tokens = request.spaces_between_special_tokens
sampling_params = SamplingParams(
n=request.n,
presence_penalty=request.presence_penalty,
frequency_penalty=request.frequency_penalty,
temperature=request.temperature,
top_p=request.top_p,
stop=request.stop,
stop_token_ids=request.stop_token_ids,
max_tokens=request.max_tokens,
best_of=request.best_of,
top_k=request.top_k,
ignore_eos=request.ignore_eos,
use_beam_search=request.use_beam_search,
skip_special_tokens=request.skip_special_tokens,
spaces_between_special_tokens=spaces_between_special_tokens,
)
except ValueError as e:
return create_error_response(HTTPStatus.BAD_REQUEST, str(e))
result_generator = engine.generate(prompt, sampling_params, request_id,
token_ids)
def get_role() -> str:
if request.add_generation_prompt:
return response_role
else:
return request.messages[-1]["role"]
async def completion_stream_generator() -> AsyncGenerator[str, None]:
# Send first response for each request.n (index) with the role
role = get_role()
for i in range(request.n):
choice_data = ChatCompletionResponseStreamChoice(
index=i, delta=DeltaMessage(role=role), finish_reason=None)
chunk = ChatCompletionStreamResponse(id=request_id,
object=chunk_object_type,
created=created_time,
choices=[choice_data],
model=model_name)
data = chunk.json(exclude_unset=True, ensure_ascii=False)
yield f"data: {data}\n\n"
# Send response to echo the input portion of the last message
if request.echo:
last_msg_content = ""
if request.messages and isinstance(
request.messages, list) and request.messages[-1].get(
"content") and request.messages[-1].get(
"role") == role:
last_msg_content = request.messages[-1]["content"]
if last_msg_content:
for i in range(request.n):
choice_data = ChatCompletionResponseStreamChoice(
index=i,
delta=DeltaMessage(content=last_msg_content),
finish_reason=None)
chunk = ChatCompletionStreamResponse(
id=request_id,
object=chunk_object_type,
created=created_time,
choices=[choice_data],
model=model_name)
data = chunk.json(exclude_unset=True, ensure_ascii=False)
yield f"data: {data}\n\n"
# Send response for each token for each request.n (index)
previous_texts = [""] * request.n
previous_num_tokens = [0] * request.n
finish_reason_sent = [False] * request.n
async for res in result_generator:
res: RequestOutput
for output in res.outputs:
i = output.index
if finish_reason_sent[i]:
continue
if output.finish_reason is None:
# Send token-by-token response for each request.n
delta_text = output.text[len(previous_texts[i]):]
previous_texts[i] = output.text
completion_tokens = len(output.token_ids)
previous_num_tokens[i] = completion_tokens
choice_data = ChatCompletionResponseStreamChoice(
index=i,
delta=DeltaMessage(content=delta_text),
finish_reason=None)
chunk = ChatCompletionStreamResponse(
id=request_id,
object=chunk_object_type,
created=created_time,
choices=[choice_data],
model=model_name)
data = chunk.json(exclude_unset=True, ensure_ascii=False)
yield f"data: {data}\n\n"
else:
# Send the finish response for each request.n only once
prompt_tokens = len(res.prompt_token_ids)
final_usage = UsageInfo(
prompt_tokens=prompt_tokens,
completion_tokens=completion_tokens,
total_tokens=prompt_tokens + completion_tokens,
)
choice_data = ChatCompletionResponseStreamChoice(
index=i, delta=[], finish_reason=output.finish_reason)
chunk = ChatCompletionStreamResponse(
id=request_id,
object=chunk_object_type,
created=created_time,
choices=[choice_data],
model=model_name)
if final_usage is not None:
chunk.usage = final_usage
data = chunk.json(exclude_unset=True,
exclude_none=True,
ensure_ascii=False)
yield f"data: {data}\n\n"
finish_reason_sent[i] = True
# Send the final done message after all response.n are finished
yield "data: [DONE]\n\n"
async def completion_full_generator():
final_res: RequestOutput = None
async for res in result_generator:
if await raw_request.is_disconnected():
# Abort the request if the client disconnects.
await engine.abort(request_id)
return create_error_response(HTTPStatus.BAD_REQUEST,
"Client disconnected")
final_res = res
assert final_res is not None
choices = []
role = get_role()
for output in final_res.outputs:
choice_data = ChatCompletionResponseChoice(
index=output.index,
message=ChatMessage(role=role, content=output.text),
finish_reason=output.finish_reason,
)
choices.append(choice_data)
if request.echo:
last_msg_content = ""
if request.messages and isinstance(
request.messages, list) and request.messages[-1].get(
"content") and request.messages[-1].get(
"role") == role:
last_msg_content = request.messages[-1]["content"]
for choice in choices:
full_message = last_msg_content + choice.message.content
choice.message.content = full_message
num_prompt_tokens = len(final_res.prompt_token_ids)
num_generated_tokens = sum(
len(output.token_ids) for output in final_res.outputs)
usage = UsageInfo(
prompt_tokens=num_prompt_tokens,
completion_tokens=num_generated_tokens,
total_tokens=num_prompt_tokens + num_generated_tokens,
)
response = ChatCompletionResponse(
id=request_id,
created=created_time,
model=model_name,
choices=choices,
usage=usage,
)
return response
# Streaming response
if request.stream:
return StreamingResponse(completion_stream_generator(),
media_type="text/event-stream")
else:
return await completion_full_generator()
@app.post("/v1/completions")
async def create_completion(request: CompletionRequest, raw_request: Request):
"""Completion API similar to OpenAI's API.
See https://platform.openai.com/docs/api-reference/completions/create
for the API specification. This API mimics the OpenAI Completion API.
NOTE: Currently we do not support the following features:
- suffix (the language models we currently support do not support
suffix)
- logit_bias (to be supported by vLLM engine)
"""
error_check_ret = await check_model(request)
if error_check_ret is not None:
return error_check_ret
# OpenAI API supports echoing the prompt when max_tokens is 0.
echo_without_generation = request.echo and request.max_tokens == 0
if request.suffix is not None:
# The language models we currently support do not support suffix.
return create_error_response(HTTPStatus.BAD_REQUEST,
"suffix is not currently supported")
if request.logit_bias is not None and len(request.logit_bias) > 0:
# TODO: support logit_bias in vLLM engine.
return create_error_response(HTTPStatus.BAD_REQUEST,
"logit_bias is not currently supported")
model_name = request.model
request_id = f"cmpl-{random_uuid()}"
use_token_ids = False
if isinstance(request.prompt, list):
if len(request.prompt) == 0:
return create_error_response(HTTPStatus.BAD_REQUEST,
"please provide at least one prompt")
first_element = request.prompt[0]
if isinstance(first_element, int):
use_token_ids = True
prompt = request.prompt
elif isinstance(first_element, (str, list)):
# TODO: handles multiple prompt case in list[list[int]]
if len(request.prompt) > 1:
return create_error_response(
HTTPStatus.BAD_REQUEST,
"multiple prompts in a batch is not currently supported")
use_token_ids = not isinstance(first_element, str)
prompt = request.prompt[0]
else:
prompt = request.prompt
if use_token_ids:
_, error_check_ret = await check_length(request, prompt_ids=prompt)
else:
token_ids, error_check_ret = await check_length(request, prompt=prompt)
if error_check_ret is not None:
return error_check_ret
created_time = int(time.monotonic())
try:
spaces_between_special_tokens = request.spaces_between_special_tokens
sampling_params = SamplingParams(
n=request.n,
best_of=request.best_of,
presence_penalty=request.presence_penalty,
frequency_penalty=request.frequency_penalty,
temperature=request.temperature,
top_p=request.top_p,
top_k=request.top_k,
stop=request.stop,
stop_token_ids=request.stop_token_ids,
ignore_eos=request.ignore_eos,
max_tokens=request.max_tokens
if not echo_without_generation else 1,
logprobs=request.logprobs,
use_beam_search=request.use_beam_search,
prompt_logprobs=request.logprobs if request.echo else None,
skip_special_tokens=request.skip_special_tokens,
spaces_between_special_tokens=spaces_between_special_tokens,
)
except ValueError as e:
return create_error_response(HTTPStatus.BAD_REQUEST, str(e))
if use_token_ids:
result_generator = engine.generate(None,
sampling_params,
request_id,
prompt_token_ids=prompt)
else:
result_generator = engine.generate(prompt, sampling_params, request_id,
token_ids)
# Similar to the OpenAI API, when n != best_of, we do not stream the
# results. In addition, we do not stream the results when use beam search.
stream = (request.stream
and (request.best_of is None or request.n == request.best_of)
and not request.use_beam_search)
def create_stream_response_json(
index: int,
text: str,
logprobs: Optional[LogProbs] = None,
finish_reason: Optional[str] = None,
usage: Optional[UsageInfo] = None,
) -> str:
choice_data = CompletionResponseStreamChoice(
index=index,
text=text,
logprobs=logprobs,
finish_reason=finish_reason,
)
response = CompletionStreamResponse(
id=request_id,
created=created_time,
model=model_name,
choices=[choice_data],
)
if usage is not None:
response.usage = usage
response_json = response.json(exclude_unset=True, ensure_ascii=False)
return response_json
async def completion_stream_generator() -> AsyncGenerator[str, None]:
previous_texts = [""] * request.n
previous_num_tokens = [0] * request.n
has_echoed = [False] * request.n
async for res in result_generator:
res: RequestOutput
for output in res.outputs:
i = output.index
delta_text = output.text[len(previous_texts[i]):]
token_ids = output.token_ids[previous_num_tokens[i]:]
top_logprobs = output.logprobs[previous_num_tokens[i]:]
offsets = len(previous_texts[i])
if request.echo and not has_echoed[i]:
if not echo_without_generation:
delta_text = res.prompt + delta_text
token_ids = res.prompt_token_ids + token_ids
top_logprobs = res.prompt_logprobs + top_logprobs
else:
delta_text = res.prompt
token_ids = res.prompt_token_ids
top_logprobs = res.prompt_logprobs
has_echoed[i] = True
if request.logprobs is not None:
logprobs = create_logprobs(
token_ids=token_ids,
top_logprobs=top_logprobs,
num_output_top_logprobs=request.logprobs,
initial_text_offset=offsets,
)
else:
logprobs = None
previous_texts[i] = output.text
previous_num_tokens[i] = len(output.token_ids)
finish_reason = output.finish_reason
response_json = create_stream_response_json(
index=i,
text=delta_text,
logprobs=logprobs,
finish_reason=finish_reason,
)
yield f"data: {response_json}\n\n"
if output.finish_reason is not None:
logprobs = (LogProbs()
if request.logprobs is not None else None)
prompt_tokens = len(res.prompt_token_ids)
completion_tokens = len(output.token_ids)
final_usage = UsageInfo(
prompt_tokens=prompt_tokens,
completion_tokens=completion_tokens,
total_tokens=prompt_tokens + completion_tokens,
)
response_json = create_stream_response_json(
index=i,
text="",
logprobs=logprobs,
finish_reason=output.finish_reason,
usage=final_usage,
)
yield f"data: {response_json}\n\n"
yield "data: [DONE]\n\n"
# Streaming response
if stream:
return StreamingResponse(completion_stream_generator(),
media_type="text/event-stream")
# Non-streaming response
final_res: RequestOutput = None
async for res in result_generator:
if await raw_request.is_disconnected():
# Abort the request if the client disconnects.
await engine.abort(request_id)
return create_error_response(HTTPStatus.BAD_REQUEST,
"Client disconnected")
final_res = res
assert final_res is not None
choices = []
prompt_token_ids = final_res.prompt_token_ids
prompt_logprobs = final_res.prompt_logprobs
prompt_text = final_res.prompt
for output in final_res.outputs:
if request.logprobs is not None:
if not echo_without_generation:
token_ids = output.token_ids
top_logprobs = output.logprobs
if request.echo:
token_ids = prompt_token_ids + token_ids
top_logprobs = prompt_logprobs + top_logprobs
else:
token_ids = prompt_token_ids
top_logprobs = prompt_logprobs
logprobs = create_logprobs(
token_ids=token_ids,
top_logprobs=top_logprobs,
num_output_top_logprobs=request.logprobs,
)
else:
logprobs = None
if not echo_without_generation:
output_text = output.text
if request.echo:
output_text = prompt_text + output_text
else:
output_text = prompt_text
choice_data = CompletionResponseChoice(
index=output.index,
text=output_text,
logprobs=logprobs,
finish_reason=output.finish_reason,
)
choices.append(choice_data)
num_prompt_tokens = len(final_res.prompt_token_ids)
num_generated_tokens = sum(
len(output.token_ids) for output in final_res.outputs)
usage = UsageInfo(
prompt_tokens=num_prompt_tokens,
completion_tokens=num_generated_tokens,
total_tokens=num_prompt_tokens + num_generated_tokens,
)
response = CompletionResponse(
id=request_id,
created=created_time,
model=model_name,
choices=choices,
usage=usage,
)
if request.stream:
# When user requests streaming but we don't stream, we still need to
# return a streaming response with a single event.
response_json = response.json(ensure_ascii=False)
async def fake_stream_generator() -> AsyncGenerator[str, None]:
yield f"data: {response_json}\n\n"
yield "data: [DONE]\n\n"
return StreamingResponse(fake_stream_generator(),
media_type="text/event-stream")
return response
if __name__ == "__main__":
args = parse_args()
app.add_middleware(
CORSMiddleware,
allow_origins=args.allowed_origins,
allow_credentials=args.allow_credentials,
allow_methods=args.allowed_methods,
allow_headers=args.allowed_headers,
)
logger.info(f"args: {args}")
if args.served_model_name is not None:
served_model = args.served_model_name
else:
served_model = args.model
response_role = args.response_role
engine_args = AsyncEngineArgs.from_cli_args(args)
engine = AsyncLLMEngine.from_engine_args(engine_args)
engine_model_config = asyncio.run(engine.get_model_config())
max_model_len = engine_model_config.max_model_len
# A separate tokenizer to map token IDs to strings.
tokenizer = get_tokenizer(
engine_model_config.tokenizer,
tokenizer_mode=engine_model_config.tokenizer_mode,
trust_remote_code=engine_model_config.trust_remote_code)
load_chat_template(args, tokenizer)
uvicorn.run(app,
host=args.host,
port=args.port,
log_level="info",
timeout_keep_alive=TIMEOUT_KEEP_ALIVE)