INNER CODE UNIT · Python

_exit_when_parent_closes

pasteurlabs/tesseract-core · tesseract_core/runtime/cli.py:525

def _exit_when_parent_closes(fd: int) -> None:
    """Shut down orphaned Tesseract once the far end of `fd` is closed.

    Parent processes are not guaranteed to clean up if ended prematurely.
    However, reading a pipe the parent is meant to hold open is guaranteed to
    return EOF if the parent is no longer live.
    """

    def watch() -> None:
        try:
            while os.read(fd, 1):
                # Nothing is expected to be written; a stray byte is not EOF.
                pass
        except OSError:
            pass
        # Ask uvicorn to stop rather than dying where we stand, so workers are
        # shut down and the port is released.
        os.kill(os.getpid(), signal.SIGTERM)

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