Function start_ray_process

python/ray/_private/services.py:883–1109

Start one of the Ray processes. TODO(rkn): We need to figure out how these commands interact. For example, it may only make sense to start a process in gdb if we also start it in tmux. Similarly, certain combinations probably don't make sense, like simultaneously running the process

(
    command: List[str],
    process_type: str,
    fate_share: bool,
    env_updates: Optional[dict] = None,
    cwd: Optional[str] = None,
    use_valgrind: bool = False,
    use_gdb: bool = False,
    use_valgrind_profiler: bool = False,
    use_perftools_profiler: bool = False,
    use_tmux: bool = False,
    stdout_file: Optional[IO[AnyStr]] = None,
    stderr_file: Optional[IO[AnyStr]] = None,
    pipe_stdin: bool = False,
)

def start_ray_process(
    command: List[str],
    process_type: str,
    fate_share: bool,
    env_updates: Optional[dict] = None,
    cwd: Optional[str] = None,
    use_valgrind: bool = False,
    use_gdb: bool = False,
    use_valgrind_profiler: bool = False,
    use_perftools_profiler: bool = False,
    use_tmux: bool = False,
    stdout_file: Optional[IO[AnyStr]] = None,
    stderr_file: Optional[IO[AnyStr]] = None,
    pipe_stdin: bool = False,
):
    """Start one of the Ray processes.

    TODO(rkn): We need to figure out how these commands interact. For example,
    it may only make sense to start a process in gdb if we also start it in
    tmux. Similarly, certain combinations probably don't make sense, like
    simultaneously running the process in valgrind and the profiler.

    Args:
        command: The command to use to start the Ray process.
        process_type: The type of the process that is being started
            (e.g., "raylet").
        fate_share: If true, the child will be killed if its parent (us) dies.
            True must only be passed after detection of this functionality.
        env_updates: A dictionary of additional environment variables to
            run the command with (in addition to the caller's environment
            variables).
        cwd: The directory to run the process in.
        use_valgrind: True if we should start the process in valgrind.
        use_gdb: True if we should start the process in gdb.
        use_valgrind_profiler: True if we should start the process in
            the valgrind profiler.
        use_perftools_profiler: True if we should profile the process
            using perftools.
        use_tmux: True if we should start the process in tmux.
        stdout_file: A file handle opened for writing to redirect stdout to. If
            no redirection should happen, then this should be None.
        stderr_file: A file handle opened for writing to redirect stderr to. If
            no redirection should happen, then this should be None.
        pipe_stdin: If true, subprocess.PIPE will be passed to the process as
            stdin.

    Returns:
        Information about the process that was started including a handle to
            the process that was started.
    """
    # Detect which flags are set through environment variables.
    valgrind_env_var = f"RAY_{process_type.upper()}_VALGRIND"
    if os.environ.get(valgrind_env_var) == "1":
        logger.info("Detected environment variable '%s'.", valgrind_env_var)
        use_valgrind = True
    valgrind_profiler_env_var = f"RAY_{process_type.upper()}_VALGRIND_PROFILER"
    if os.environ.get(valgrind_profiler_env_var) == "1":
        logger.info("Detected environment variable '%s'.", valgrind_profiler_env_var)