import asyncio import multiprocessing import os import sys import threading import traceback import uuid from dataclasses import dataclass from multiprocessing import Queue from multiprocessing.connection import wait from multiprocessing.process import BaseProcess from typing import (Any, Callable, Dict, Generic, List, Optional, TextIO, TypeVar, Union) import vllm.envs as envs from vllm.logger import init_logger logger = init_logger(__name__) T = TypeVar('T') _TERMINATE = "TERMINATE" # sentinel # ANSI color codes CYAN = '\033[1;36m' RESET = '\033[0;0m' JOIN_TIMEOUT_S = 2 mp_method = envs.VLLM_WORKER_MULTIPROC_METHOD mp = multiprocessing.get_context(mp_method) @dataclass class Result(Generic[T]): """Result of task dispatched to worker""" task_id: uuid.UUID value: Optional[T] = None exception: Optional[BaseException] = None class ResultFuture(threading.Event, Generic[T]): """Synchronous future for non-async case""" def __init__(self): super().__init__() self.result: Optional[Result[T]] = None def set_result(self, result: Result[T]): self.result = result self.set() def get(self) -> T: self.wait() assert self.result is not None if self.result.exception is not None: raise self.result.exception return self.result.value # type: ignore[return-value] def _set_future_result(future: Union[ResultFuture, asyncio.Future], result: Result): if isinstance(future, ResultFuture): future.set_result(result) return loop = future.get_loop() if not loop.is_closed(): if result.exception is not None: loop.call_soon_threadsafe(future.set_exception, result.exception) else: loop.call_soon_threadsafe(future.set_result, result.value) class ResultHandler(threading.Thread): """Handle results from all workers (in background thread)""" def __init__(self) -> None: super().__init__(daemon=True) self.result_queue = mp.Queue() self.tasks: Dict[uuid.UUID, Union[ResultFuture, asyncio.Future]] = {} def run(self): for result in iter(self.result_queue.get, _TERMINATE): future = self.tasks.pop(result.task_id) _set_future_result(future, result) # Ensure that all waiters will receive an exception for task_id, future in self.tasks.items(): _set_future_result( future, Result(task_id=task_id, exception=ChildProcessError("worker died"))) def close(self): self.result_queue.put(_TERMINATE) class WorkerMonitor(threading.Thread): """Monitor worker status (in background thread)""" def __init__(self, workers: List['ProcessWorkerWrapper'], result_handler: ResultHandler): super().__init__(daemon=True) self.workers = workers self.result_handler = result_handler self._close = False def run(self) -> None: # Blocks until any worker exits dead_sentinels = wait([w.process.sentinel for w in self.workers]) if not self._close: self._close = True # Kill / cleanup all workers for worker in self.workers: process = worker.process if process.sentinel in dead_sentinels: process.join(JOIN_TIMEOUT_S) if process.exitcode is not None and process.exitcode != 0: logger.error("Worker %s pid %s died, exit code: %s", process.name, process.pid, process.exitcode) # Cleanup any remaining workers logger.info("Killing local vLLM worker processes") for worker in self.workers: worker.kill_worker() # Must be done after worker task queues are all closed self.result_handler.close() for worker in self.workers: worker.process.join(JOIN_TIMEOUT_S) def close(self): if self._close: return self._close = True logger.info("Terminating local vLLM worker processes") for worker in self.workers: worker.terminate_worker() # Must be done after worker task queues are all closed self.result_handler.close() class ProcessWorkerWrapper: """Local process wrapper for vllm.worker.Worker, for handling single-node multi-GPU tensor parallel.""" def __init__(self, result_handler: ResultHandler, worker_factory: Callable[[], Any]) -> None: self._task_queue = mp.Queue() self.result_queue = result_handler.result_queue self.tasks = result_handler.tasks self.process: BaseProcess = mp.Process( # type: ignore[attr-defined] target=_run_worker_process, name="VllmWorkerProcess", kwargs=dict( worker_factory=worker_factory, task_queue=self._task_queue, result_queue=self.result_queue, ), daemon=True) self.process.start() def _enqueue_task(self, future: Union[ResultFuture, asyncio.Future], method: str, args, kwargs): task_id = uuid.uuid4() self.tasks[task_id] = future try: self._task_queue.put((task_id, method, args, kwargs)) except BaseException as e: del self.tasks[task_id] raise ChildProcessError("worker died") from e def execute_method(self, method: str, *args, **kwargs): future: ResultFuture = ResultFuture() self._enqueue_task(future, method, args, kwargs) return future async def execute_method_async(self, method: str, *args, **kwargs): future = asyncio.get_running_loop().create_future() self._enqueue_task(future, method, args, kwargs) return await future def terminate_worker(self): try: self._task_queue.put(_TERMINATE) except ValueError: self.process.kill() self._task_queue.close() def kill_worker(self): self._task_queue.close() self.process.kill() def _run_worker_process( worker_factory: Callable[[], Any], task_queue: Queue, result_queue: Queue, ) -> None: """Worker process event loop""" # Add process-specific prefix to stdout and stderr process_name = mp.current_process().name pid = os.getpid() _add_prefix(sys.stdout, process_name, pid) _add_prefix(sys.stderr, process_name, pid) # Initialize worker worker = worker_factory() del worker_factory # Accept tasks from the engine in task_queue # and return task output in result_queue logger.info("Worker ready; awaiting tasks") try: for items in iter(task_queue.get, _TERMINATE): output = None exception = None task_id, method, args, kwargs = items try: executor = getattr(worker, method) output = executor(*args, **kwargs) except BaseException as e: tb = traceback.format_exc() logger.error( "Exception in worker %s while processing method %s: %s, %s", process_name, method, e, tb) exception = e result_queue.put( Result(task_id=task_id, value=output, exception=exception)) except KeyboardInterrupt: pass except Exception: logger.exception("Worker failed") logger.info("Worker exiting") def _add_prefix(file: TextIO, worker_name: str, pid: int) -> None: """Prepend each output line with process-specific prefix""" prefix = f"{CYAN}({worker_name} pid={pid}){RESET} " file_write = file.write def write_with_prefix(s: str): if not s: return if file.start_new_line: # type: ignore[attr-defined] file_write(prefix) idx = 0 while (next_idx := s.find('\n', idx)) != -1: next_idx += 1 file_write(s[idx:next_idx]) if next_idx == len(s): file.start_new_line = True # type: ignore[attr-defined] return file_write(prefix) idx = next_idx file_write(s[idx:]) file.start_new_line = False # type: ignore[attr-defined] file.start_new_line = True # type: ignore[attr-defined] file.write = write_with_prefix # type: ignore[method-assign]