Function _run_with_sync

Lib/profiling/sampling/cli.py:250–302

Run a command with socket-based synchronization and return the process.

(original_cmd, suppress_output=False)

def _run_with_sync(original_cmd, suppress_output=False):
    """Run a command with socket-based synchronization and return the process."""
    # Create a TCP socket for synchronization with better socket options
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sync_sock:
        # Set SO_REUSEADDR to avoid "Address already in use" errors
        sync_sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        sync_sock.bind(("127.0.0.1", 0))  # Let OS choose a free port
        sync_port = sync_sock.getsockname()[1]
        sync_sock.listen(1)
        sync_sock.settimeout(_SYNC_TIMEOUT_SEC)

        # Get current working directory to preserve it
        cwd = os.getcwd()

        # Build command using the sync coordinator
        target_args = original_cmd[1:]  # Remove python executable
        cmd = (
            sys.executable,
            "-m",
            "profiling.sampling._sync_coordinator",
            str(sync_port),
            cwd,
        ) + tuple(target_args)

        # Start the process with coordinator
        # When suppress_output=True (live mode), capture stderr so we can
        # report errors if the process dies before signaling ready.
        # When suppress_output=False (normal mode), let stderr inherit so
        # script errors print to the terminal.
        popen_kwargs = {}
        if suppress_output:
            popen_kwargs["stdin"] = subprocess.DEVNULL
            popen_kwargs["stdout"] = subprocess.DEVNULL
            popen_kwargs["stderr"] = subprocess.PIPE

        process = subprocess.Popen(cmd, **popen_kwargs)

        try:
            _wait_for_ready_signal(sync_sock, process, _SYNC_TIMEOUT_SEC)
        except socket.timeout:
            # If we timeout, kill the process and raise an error
            if process.poll() is None:
                process.terminate()
                try:
                    process.wait(timeout=_PROCESS_KILL_TIMEOUT_SEC)
                except subprocess.TimeoutExpired:
                    process.kill()
                    process.wait()
            raise RuntimeError(
                "Process failed to signal readiness within timeout"
            )

        return process


_RATE_PATTERN = re.compile(r'''