[Frontend] Reapply "Factor out code for running uvicorn" (#7095)

vllm/entrypoints/api_server.py

@@ -5,21 +5,23 @@
 We are also not going to accept PRs modifying this file, please
 change `vllm/entrypoints/openai/api_server.py` instead.
 """
-
+import asyncio
 import json
 import ssl
-from typing import AsyncGenerator
+from argparse import Namespace
+from typing import Any, AsyncGenerator, Optional
 
-import uvicorn
 from fastapi import FastAPI, Request
 from fastapi.responses import JSONResponse, Response, StreamingResponse
 
 from vllm.engine.arg_utils import AsyncEngineArgs
 from vllm.engine.async_llm_engine import AsyncLLMEngine
+from vllm.entrypoints.launcher import serve_http
 from vllm.logger import init_logger
 from vllm.sampling_params import SamplingParams
 from vllm.usage.usage_lib import UsageContext
 from vllm.utils import FlexibleArgumentParser, random_uuid
+from vllm.version import __version__ as VLLM_VERSION
 
 logger = init_logger("vllm.entrypoints.api_server")
 
@@ -81,6 +83,53 @@ async def stream_results() -> AsyncGenerator[bytes, None]:
     return JSONResponse(ret)
 
 
+def build_app(args: Namespace) -> FastAPI:
+    global app
+
+    app.root_path = args.root_path
+    return app
+
+
+async def init_app(
+    args: Namespace,
+    llm_engine: Optional[AsyncLLMEngine] = None,
+) -> FastAPI:
+    app = build_app(args)
+
+    global engine
+
+    engine_args = AsyncEngineArgs.from_cli_args(args)
+    engine = (llm_engine
+              if llm_engine is not None else AsyncLLMEngine.from_engine_args(
+                  engine_args, usage_context=UsageContext.API_SERVER))
+
+    return app
+
+
+async def run_server(args: Namespace,
+                     llm_engine: Optional[AsyncLLMEngine] = None,
+                     **uvicorn_kwargs: Any) -> None:
+    logger.info("vLLM API server version %s", VLLM_VERSION)
+    logger.info("args: %s", args)
+
+    app = await init_app(args, llm_engine)
+
+    shutdown_task = await serve_http(
+        app,
+        host=args.host,
+        port=args.port,
+        log_level=args.log_level,
+        timeout_keep_alive=TIMEOUT_KEEP_ALIVE,
+        ssl_keyfile=args.ssl_keyfile,
+        ssl_certfile=args.ssl_certfile,
+        ssl_ca_certs=args.ssl_ca_certs,
+        ssl_cert_reqs=args.ssl_cert_reqs,
+        **uvicorn_kwargs,
+    )
+
+    await shutdown_task
+
+
 if __name__ == "__main__":
     parser = FlexibleArgumentParser()
     parser.add_argument("--host", type=str, default=None)
@@ -105,25 +154,5 @@ async def stream_results() -> AsyncGenerator[bytes, None]:
     parser.add_argument("--log-level", type=str, default="debug")
     parser = AsyncEngineArgs.add_cli_args(parser)
     args = parser.parse_args()
-    engine_args = AsyncEngineArgs.from_cli_args(args)
-    engine = AsyncLLMEngine.from_engine_args(
-        engine_args, usage_context=UsageContext.API_SERVER)
-
-    app.root_path = args.root_path
 
-    logger.info("Available routes are:")
-    for route in app.routes:
-        if not hasattr(route, 'methods'):
-            continue
-        methods = ', '.join(route.methods)
-        logger.info("Route: %s, Methods: %s", route.path, methods)
-
-    uvicorn.run(app,
-                host=args.host,
-                port=args.port,
-                log_level=args.log_level,
-                timeout_keep_alive=TIMEOUT_KEEP_ALIVE,
-                ssl_keyfile=args.ssl_keyfile,
-                ssl_certfile=args.ssl_certfile,
-                ssl_ca_certs=args.ssl_ca_certs,
-                ssl_cert_reqs=args.ssl_cert_reqs)
+    asyncio.run(run_server(args))

vllm/entrypoints/launcher.py

@@ -0,0 +1,46 @@
+import asyncio
+import signal
+from typing import Any
+
+import uvicorn
+from fastapi import FastAPI
+
+from vllm.logger import init_logger
+
+logger = init_logger(__name__)
+
+
+async def serve_http(app: FastAPI, **uvicorn_kwargs: Any):
+    logger.info("Available routes are:")
+    for route in app.routes:
+        methods = getattr(route, "methods", None)
+        path = getattr(route, "path", None)
+
+        if methods is None or path is None:
+            continue
+
+        logger.info("Route: %s, Methods: %s", path, ', '.join(methods))
+
+    config = uvicorn.Config(app, **uvicorn_kwargs)
+    server = uvicorn.Server(config)
+
+    loop = asyncio.get_running_loop()
+
+    server_task = loop.create_task(server.serve())
+
+    def signal_handler() -> None:
+        # prevents the uvicorn signal handler to exit early
+        server_task.cancel()
+
+    async def dummy_shutdown() -> None:
+        pass
+
+    loop.add_signal_handler(signal.SIGINT, signal_handler)
+    loop.add_signal_handler(signal.SIGTERM, signal_handler)
+
+    try:
+        await server_task
+        return dummy_shutdown()
+    except asyncio.CancelledError:
+        logger.info("Gracefully stopping http server")
+        return server.shutdown()

vllm/entrypoints/openai/api_server.py

@@ -2,15 +2,13 @@
 import importlib
 import inspect
 import re
-import signal
+from argparse import Namespace
 from contextlib import asynccontextmanager
 from http import HTTPStatus
 from multiprocessing import Process
 from typing import AsyncIterator, Set
 
-import fastapi
-import uvicorn
-from fastapi import APIRouter, Request
+from fastapi import APIRouter, FastAPI, Request
 from fastapi.exceptions import RequestValidationError
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.responses import JSONResponse, Response, StreamingResponse
@@ -22,6 +20,7 @@
 from vllm.engine.arg_utils import AsyncEngineArgs
 from vllm.engine.async_llm_engine import AsyncLLMEngine
 from vllm.engine.protocol import AsyncEngineClient
+from vllm.entrypoints.launcher import serve_http
 from vllm.entrypoints.logger import RequestLogger
 from vllm.entrypoints.openai.cli_args import make_arg_parser
 # yapf conflicts with isort for this block
@@ -71,7 +70,7 @@ def model_is_embedding(model_name: str) -> bool:
 
 
 @asynccontextmanager
-async def lifespan(app: fastapi.FastAPI):
+async def lifespan(app: FastAPI):
 
     async def _force_log():
         while True:
@@ -135,7 +134,7 @@ async def build_async_engine_client(args) -> AsyncIterator[AsyncEngineClient]:
 router = APIRouter()
 
 
-def mount_metrics(app: fastapi.FastAPI):
+def mount_metrics(app: FastAPI):
     # Add prometheus asgi middleware to route /metrics requests
     metrics_route = Mount("/metrics", make_asgi_app())
     # Workaround for 307 Redirect for /metrics
@@ -225,8 +224,8 @@ async def create_embedding(request: EmbeddingRequest, raw_request: Request):
         return JSONResponse(content=generator.model_dump())
 
 
-def build_app(args):
-    app = fastapi.FastAPI(lifespan=lifespan)
+def build_app(args: Namespace) -> FastAPI:
+    app = FastAPI(lifespan=lifespan)
     app.include_router(router)
     app.root_path = args.root_path
 
@@ -274,11 +273,10 @@ async def authentication(request: Request, call_next):
     return app
 
 
-async def build_server(
+async def init_app(
     async_engine_client: AsyncEngineClient,
-    args,
-    **uvicorn_kwargs,
-) -> uvicorn.Server:
+    args: Namespace,
+) -> FastAPI:
     app = build_app(args)
 
     if args.served_model_name is not None:
@@ -334,62 +332,31 @@ async def build_server(
     )
     app.root_path = args.root_path
 
-    logger.info("Available routes are:")
-    for route in app.routes:
-        if not hasattr(route, 'methods'):
-            continue
-        methods = ', '.join(route.methods)
-        logger.info("Route: %s, Methods: %s", route.path, methods)
-
-    config = uvicorn.Config(
-        app,
-        host=args.host,
-        port=args.port,
-        log_level=args.uvicorn_log_level,
-        timeout_keep_alive=TIMEOUT_KEEP_ALIVE,
-        ssl_keyfile=args.ssl_keyfile,
-        ssl_certfile=args.ssl_certfile,
-        ssl_ca_certs=args.ssl_ca_certs,
-        ssl_cert_reqs=args.ssl_cert_reqs,
-        **uvicorn_kwargs,
-    )
-
-    return uvicorn.Server(config)
+    return app
 
 
 async def run_server(args, **uvicorn_kwargs) -> None:
     logger.info("vLLM API server version %s", VLLM_VERSION)
     logger.info("args: %s", args)
 
-    shutdown_task = None
     async with build_async_engine_client(args) as async_engine_client:
-
-        server = await build_server(
-            async_engine_client,
-            args,
+        app = await init_app(async_engine_client, args)
+
+        shutdown_task = await serve_http(
+            app,
+            host=args.host,
+            port=args.port,
+            log_level=args.uvicorn_log_level,
+            timeout_keep_alive=TIMEOUT_KEEP_ALIVE,
+            ssl_keyfile=args.ssl_keyfile,
+            ssl_certfile=args.ssl_certfile,
+            ssl_ca_certs=args.ssl_ca_certs,
+            ssl_cert_reqs=args.ssl_cert_reqs,
             **uvicorn_kwargs,
         )
 
-        loop = asyncio.get_running_loop()
-
-        server_task = loop.create_task(server.serve())
-
-        def signal_handler() -> None:
-            # prevents the uvicorn signal handler to exit early
-            server_task.cancel()
-
-        loop.add_signal_handler(signal.SIGINT, signal_handler)
-        loop.add_signal_handler(signal.SIGTERM, signal_handler)
-
-        try:
-            await server_task
-        except asyncio.CancelledError:
-            logger.info("Gracefully stopping http server")
-            shutdown_task = server.shutdown()
-
-    if shutdown_task:
-        # NB: Await server shutdown only after the backend context is exited
-        await shutdown_task
+    # NB: Await server shutdown only after the backend context is exited
+    await shutdown_task
 
 
 if __name__ == "__main__":
@@ -399,4 +366,5 @@ def signal_handler() -> None:
         description="vLLM OpenAI-Compatible RESTful API server.")
     parser = make_arg_parser(parser)
     args = parser.parse_args()
+
     asyncio.run(run_server(args))