"""Utility functions for FlexSim MCP Server."""
import os
import sys
import psutil
def suppress_stderr():
"""Suppress stderr to hide CEF subprocess error messages.
CEF (Chromium Embedded Framework) tries to launch helper processes
by relaunching the parent executable with flags like --type=gpu-process.
When FlexSim is launched from Python, CEF incorrectly tries to launch
python.exe as helper processes, causing "unknown option" errors.
This function redirects stderr to devnull to keep the console clean
while FlexSim GUI is running.
Returns:
int: File descriptor for the saved stderr (to restore later if needed)
Note:
Only works on Windows. Returns -1 on other platforms.
"""
if os.name != "nt":
return -1
# Save original stderr
original_stderr = sys.stderr.fileno()
saved_stderr = os.dup(original_stderr)
# Redirect stderr to NUL
devnull = os.open(os.devnull, os.O_WRONLY)
os.dup2(devnull, original_stderr)
os.close(devnull)
return saved_stderr
def restore_stderr(saved_stderr: int):
"""Restore stderr to its original file descriptor.
Args:
saved_stderr: File descriptor returned by suppress_stderr()
"""
if saved_stderr < 0:
return
original_stderr = sys.stderr.fileno()
os.dup2(saved_stderr, original_stderr)
os.close(saved_stderr)
def kill_flexsim_processes() -> list[int]:
"""Kill all FlexSim.exe processes.
Returns:
List of process IDs that were killed
"""
killed = []
for proc in psutil.process_iter(["pid", "name"]):
try:
if proc.info["name"] and "flexsim" in proc.info["name"].lower():
proc.kill()
killed.append(proc.info["pid"])
except (psutil.NoSuchProcess, psutil.AccessDenied):
pass
return killed
def force_exit() -> None:
"""Force exit to avoid segfault during Python cleanup.
FlexSimPy module has issues with proper shutdown that cause
segmentation faults during normal Python cleanup.
"""
os._exit(0)
