[LLM] vLLM: Add api_server entrypoint (#9783)

Add vllm.entrypoints.api_server for benchmark_serving.py in vllm.

python/llm/src/bigdl/llm/vllm/entrypoints/api_server.py

@@ -0,0 +1,123 @@
+#
+# Copyright 2016 The BigDL Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# Some parts of this file is adapted from
+# https://github.com/vllm-project/vllm/blob/v0.2.1.post1/vllm/entrypoints/api_server.py
+# which is licensed under Apache License 2.0
+#
+# Copyright 2023 The vLLM team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import argparse
+import json
+from typing import AsyncGenerator
+
+from fastapi import FastAPI, Request
+from fastapi.responses import JSONResponse, Response, StreamingResponse
+import uvicorn
+
+from bigdl.llm.vllm.engine.arg_utils import AsyncEngineArgs
+from bigdl.llm.vllm.engine.async_llm_engine import AsyncLLMEngine
+from bigdl.llm.vllm.sampling_params import SamplingParams
+from bigdl.llm.vllm.utils import random_uuid
+
+TIMEOUT_KEEP_ALIVE = 5  # seconds.
+TIMEOUT_TO_PREVENT_DEADLOCK = 1  # seconds.
+app = FastAPI()
+engine = None
+
+
+@app.get("/health")
+async def health() -> Response:
+    """Health check."""
+    return Response(status_code=200)
+
+
+@app.post("/generate")
+async def generate(request: Request) -> Response:
+    """Generate completion for the request.
+
+    The request should be a JSON object with the following fields:
+    - prompt: the prompt to use for the generation.
+    - stream: whether to stream the results or not.
+    - other fields: the sampling parameters (See `SamplingParams` for details).
+    """
+    request_dict = await request.json()
+    prompt = request_dict.pop("prompt")
+    stream = request_dict.pop("stream", False)
+    sampling_params = SamplingParams(**request_dict)
+    request_id = random_uuid()
+
+    results_generator = engine.generate(prompt, sampling_params, request_id)
+
+    # Streaming case
+    async def stream_results() -> AsyncGenerator[bytes, None]:
+        async for request_output in results_generator:
+            prompt = request_output.prompt
+            text_outputs = [
+                prompt + output.text for output in request_output.outputs
+            ]
+            ret = {"text": text_outputs}
+            yield (json.dumps(ret) + "\0").encode("utf-8")
+
+    if stream:
+        return StreamingResponse(stream_results())
+
+    # Non-streaming case
+    final_output = None
+    async for request_output in results_generator:
+        if await request.is_disconnected():
+            # Abort the request if the client disconnects.
+            await engine.abort(request_id)
+            return Response(status_code=499)
+        final_output = request_output
+
+    assert final_output is not None  # noqa
+    prompt = final_output.prompt
+    text_outputs = [prompt + output.text for output in final_output.outputs]
+    ret = {"text": text_outputs}
+    return JSONResponse(ret)
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--host", type=str, default=None)
+    parser.add_argument("--port", type=int, default=8000)
+    parser.add_argument("--ssl-keyfile", type=str, default=None)
+    parser.add_argument("--ssl-certfile", type=str, default=None)
+    parser = AsyncEngineArgs.add_cli_args(parser)
+    args = parser.parse_args()
+
+    engine_args = AsyncEngineArgs.from_cli_args(args)
+    engine = AsyncLLMEngine.from_engine_args(engine_args)
+
+    uvicorn.run(app,
+                host=args.host,
+                port=args.port,
+                log_level="debug",
+                timeout_keep_alive=TIMEOUT_KEEP_ALIVE,
+                ssl_keyfile=args.ssl_keyfile,
+                ssl_certfile=args.ssl_certfile)