"""JupyterLab Server process handler""" # Copyright (c) Jupyter Development Team. # Distributed under the terms of the Modified BSD License. from __future__ import annotations import atexit import logging import os import re import signal import subprocess import sys import threading import time import weakref from logging import Logger from shutil import which as _which from typing import Any from tornado import gen try: import pty except ImportError: pty = None # type:ignore[assignment] if sys.platform == "win32": list2cmdline = subprocess.list2cmdline else: def list2cmdline(cmd_list: list[str]) -> str: """Shim for list2cmdline on posix.""" import shlex return " ".join(map(shlex.quote, cmd_list)) def which(command: str, env: dict[str, str] | None = None) -> str: """Get the full path to a command. Parameters ---------- command: str The command name or path. env: dict, optional The environment variables, defaults to `os.environ`. """ env = env or os.environ # type:ignore[assignment] path = env.get("PATH") or os.defpath # type:ignore[union-attr] command_with_path = _which(command, path=path) # Allow nodejs as an alias to node. if command == "node" and not command_with_path: command = "nodejs" command_with_path = _which("nodejs", path=path) if not command_with_path: if command in ["nodejs", "node", "npm"]: msg = "Please install Node.js and npm before continuing installation. You may be able to install Node.js from your package manager, from conda, or directly from the Node.js website (https://nodejs.org)." raise ValueError(msg) raise ValueError("The command was not found or was not " + "executable: %s." % command) return os.path.abspath(command_with_path) class Process: """A wrapper for a child process.""" _procs: weakref.WeakSet = weakref.WeakSet() _pool = None def __init__( self, cmd: list[str], logger: Logger | None = None, cwd: str | None = None, kill_event: threading.Event | None = None, env: dict[str, str] | None = None, quiet: bool = False, ) -> None: """Start a subprocess that can be run asynchronously. Parameters ---------- cmd: list The command to run. logger: :class:`~logger.Logger`, optional The logger instance. cwd: string, optional The cwd of the process. env: dict, optional The environment for the process. kill_event: :class:`~threading.Event`, optional An event used to kill the process operation. quiet: bool, optional Whether to suppress output. """ if not isinstance(cmd, (list, tuple)): msg = "Command must be given as a list" # type:ignore[unreachable] raise ValueError(msg) if kill_event and kill_event.is_set(): msg = "Process aborted" raise ValueError(msg) self.logger = logger or self.get_log() self._last_line = "" if not quiet: self.logger.info("> %s", list2cmdline(cmd)) self.cmd = cmd kwargs = {} if quiet: kwargs["stdout"] = subprocess.DEVNULL self.proc = self._create_process(cwd=cwd, env=env, **kwargs) self._kill_event = kill_event or threading.Event() Process._procs.add(self) def terminate(self) -> int: """Terminate the process and return the exit code.""" proc = self.proc # Kill the process. if proc.poll() is None: os.kill(proc.pid, signal.SIGTERM) # Wait for the process to close. try: proc.wait(timeout=2.0) except subprocess.TimeoutExpired: if os.name == "nt": # noqa: SIM108 sig = signal.SIGBREAK # type:ignore[attr-defined] else: sig = signal.SIGKILL if proc.poll() is None: os.kill(proc.pid, sig) finally: if self in Process._procs: Process._procs.remove(self) return proc.wait() def wait(self) -> int: """Wait for the process to finish. Returns ------- The process exit code. """ proc = self.proc kill_event = self._kill_event while proc.poll() is None: if kill_event.is_set(): self.terminate() msg = "Process was aborted" raise ValueError(msg) time.sleep(1.0) return self.terminate() @gen.coroutine def wait_async(self) -> Any: """Asynchronously wait for the process to finish.""" proc = self.proc kill_event = self._kill_event while proc.poll() is None: if kill_event.is_set(): self.terminate() msg = "Process was aborted" raise ValueError(msg) yield gen.sleep(1.0) raise gen.Return(self.terminate()) def _create_process(self, **kwargs: Any) -> subprocess.Popen[str]: """Create the process.""" cmd = list(self.cmd) kwargs.setdefault("stderr", subprocess.STDOUT) cmd[0] = which(cmd[0], kwargs.get("env")) if os.name == "nt": kwargs["shell"] = True return subprocess.Popen(cmd, **kwargs) # noqa: S603 @classmethod def _cleanup(cls: type[Process]) -> None: """Clean up the started subprocesses at exit.""" for proc in list(cls._procs): proc.terminate() def get_log(self) -> Logger: """Get our logger.""" if hasattr(self, "logger") and self.logger is not None: return self.logger # fallback logger self.logger = logging.getLogger("jupyterlab") self.logger.setLevel(logging.INFO) return self.logger class WatchHelper(Process): """A process helper for a watch process.""" def __init__( self, cmd: list[str], startup_regex: str, logger: Logger | None = None, cwd: str | None = None, kill_event: threading.Event | None = None, env: dict[str, str] | None = None, ) -> None: """Initialize the process helper. Parameters ---------- cmd: list The command to run. startup_regex: string The regex to wait for at startup. logger: :class:`~logger.Logger`, optional The logger instance. cwd: string, optional The cwd of the process. env: dict, optional The environment for the process. kill_event: callable, optional A function to call to check if we should abort. """ super().__init__(cmd, logger=logger, cwd=cwd, kill_event=kill_event, env=env) if pty is None: self._stdout = self.proc.stdout # type:ignore[unreachable] while 1: line = self._stdout.readline().decode("utf-8") # type:ignore[has-type] if not line: msg = "Process ended improperly" raise RuntimeError(msg) print(line.rstrip()) if re.match(startup_regex, line): break self._read_thread = threading.Thread(target=self._read_incoming, daemon=True) self._read_thread.start() def terminate(self) -> int: """Terminate the process.""" proc = self.proc if proc.poll() is None: if os.name != "nt": # Kill the process group if we started a new session. os.killpg(os.getpgid(proc.pid), signal.SIGTERM) else: os.kill(proc.pid, signal.SIGTERM) # Wait for the process to close. try: proc.wait() finally: if self in Process._procs: Process._procs.remove(self) return proc.returncode def _read_incoming(self) -> None: """Run in a thread to read stdout and print""" fileno = self._stdout.fileno() # type:ignore[has-type] while 1: try: buf = os.read(fileno, 1024) except OSError as e: self.logger.debug("Read incoming error %s", e) return if not buf: return print(buf.decode("utf-8"), end="") def _create_process(self, **kwargs: Any) -> subprocess.Popen[str]: """Create the watcher helper process.""" kwargs["bufsize"] = 0 if pty is not None: master, slave = pty.openpty() kwargs["stderr"] = kwargs["stdout"] = slave kwargs["start_new_session"] = True self._stdout = os.fdopen(master, "rb") # type:ignore[has-type] else: kwargs["stdout"] = subprocess.PIPE # type:ignore[unreachable] if os.name == "nt": startupinfo = subprocess.STARTUPINFO() startupinfo.dwFlags |= subprocess.STARTF_USESHOWWINDOW kwargs["startupinfo"] = startupinfo kwargs["creationflags"] = subprocess.CREATE_NEW_PROCESS_GROUP kwargs["shell"] = True return super()._create_process(**kwargs) # Register the cleanup handler. atexit.register(Process._cleanup)