Sync from v0.13

vllm/entrypoints/launcher.py

@@ -0,0 +1,175 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+import asyncio
+import signal
+import socket
+from http import HTTPStatus
+from typing import Any
+
+import uvicorn
+from fastapi import FastAPI, Request, Response
+
+from vllm import envs
+from vllm.engine.protocol import EngineClient
+from vllm.entrypoints.constants import (
+    H11_MAX_HEADER_COUNT_DEFAULT,
+    H11_MAX_INCOMPLETE_EVENT_SIZE_DEFAULT,
+)
+from vllm.entrypoints.ssl import SSLCertRefresher
+from vllm.logger import init_logger
+from vllm.utils.network_utils import find_process_using_port
+from vllm.v1.engine.exceptions import EngineDeadError, EngineGenerateError
+
+logger = init_logger(__name__)
+
+
+async def serve_http(
+    app: FastAPI,
+    sock: socket.socket | None,
+    enable_ssl_refresh: bool = False,
+    **uvicorn_kwargs: Any,
+):
+    """
+    Start a FastAPI app using Uvicorn, with support for custom Uvicorn config
+    options.  Supports http header limits via h11_max_incomplete_event_size and
+    h11_max_header_count.
+    """
+    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))
+
+    # Extract header limit options if present
+    h11_max_incomplete_event_size = uvicorn_kwargs.pop(
+        "h11_max_incomplete_event_size", None
+    )
+    h11_max_header_count = uvicorn_kwargs.pop("h11_max_header_count", None)
+
+    # Set safe defaults if not provided
+    if h11_max_incomplete_event_size is None:
+        h11_max_incomplete_event_size = H11_MAX_INCOMPLETE_EVENT_SIZE_DEFAULT
+    if h11_max_header_count is None:
+        h11_max_header_count = H11_MAX_HEADER_COUNT_DEFAULT
+
+    config = uvicorn.Config(app, **uvicorn_kwargs)
+    # Set header limits
+    config.h11_max_incomplete_event_size = h11_max_incomplete_event_size
+    config.h11_max_header_count = h11_max_header_count
+    config.load()
+    server = uvicorn.Server(config)
+    _add_shutdown_handlers(app, server)
+
+    loop = asyncio.get_running_loop()
+
+    watchdog_task = loop.create_task(watchdog_loop(server, app.state.engine_client))
+    server_task = loop.create_task(server.serve(sockets=[sock] if sock else None))
+
+    ssl_cert_refresher = (
+        None
+        if not enable_ssl_refresh
+        else SSLCertRefresher(
+            ssl_context=config.ssl,
+            key_path=config.ssl_keyfile,
+            cert_path=config.ssl_certfile,
+            ca_path=config.ssl_ca_certs,
+        )
+    )
+
+    def signal_handler() -> None:
+        # prevents the uvicorn signal handler to exit early
+        server_task.cancel()
+        watchdog_task.cancel()
+        if ssl_cert_refresher:
+            ssl_cert_refresher.stop()
+
+    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:
+        port = uvicorn_kwargs["port"]
+        process = find_process_using_port(port)
+        if process is not None:
+            logger.warning(
+                "port %s is used by process %s launched with command:\n%s",
+                port,
+                process,
+                " ".join(process.cmdline()),
+            )
+        logger.info("Shutting down FastAPI HTTP server.")
+        return server.shutdown()
+    finally:
+        watchdog_task.cancel()
+
+
+async def watchdog_loop(server: uvicorn.Server, engine: EngineClient):
+    """
+    # Watchdog task that runs in the background, checking
+    # for error state in the engine. Needed to trigger shutdown
+    # if an exception arises is StreamingResponse() generator.
+    """
+    VLLM_WATCHDOG_TIME_S = 5.0
+    while True:
+        await asyncio.sleep(VLLM_WATCHDOG_TIME_S)
+        terminate_if_errored(server, engine)
+
+
+def terminate_if_errored(server: uvicorn.Server, engine: EngineClient):
+    """
+    See discussions here on shutting down a uvicorn server
+    https://github.com/encode/uvicorn/discussions/1103
+    In this case we cannot await the server shutdown here
+    because handler must first return to close the connection
+    for this request.
+    """
+    engine_errored = engine.errored and not engine.is_running
+    if not envs.VLLM_KEEP_ALIVE_ON_ENGINE_DEATH and engine_errored:
+        server.should_exit = True
+
+
+def _add_shutdown_handlers(app: FastAPI, server: uvicorn.Server) -> None:
+    """
+    VLLM V1 AsyncLLM catches exceptions and returns
+    only two types: EngineGenerateError and EngineDeadError.
+
+    EngineGenerateError is raised by the per request generate()
+    method. This error could be request specific (and therefore
+    recoverable - e.g. if there is an error in input processing).
+
+    EngineDeadError is raised by the background output_handler
+    method. This error is global and therefore not recoverable.
+
+    We register these @app.exception_handlers to return nice
+    responses to the end user if they occur and shut down if needed.
+    See https://fastapi.tiangolo.com/tutorial/handling-errors/
+    for more details on how exception handlers work.
+
+    If an exception is encountered in a StreamingResponse
+    generator, the exception is not raised, since we already sent
+    a 200 status. Rather, we send an error message as the next chunk.
+    Since the exception is not raised, this means that the server
+    will not automatically shut down. Instead, we use the watchdog
+    background task for check for errored state.
+    """
+
+    @app.exception_handler(RuntimeError)
+    @app.exception_handler(EngineDeadError)
+    @app.exception_handler(EngineGenerateError)
+    async def runtime_exception_handler(request: Request, __):
+        terminate_if_errored(
+            server=server,
+            engine=request.app.state.engine_client,
+        )
+
+        return Response(status_code=HTTPStatus.INTERNAL_SERVER_ERROR)