openclaw - 💡(How to fix) Fix MCP child process leak: disposeSession() doesn't kill process groups [1 comments, 2 participants]

TL;DR

To fix the issue of openclaw-gateway leaking MCP child processes, modify the createBundleLspToolRuntime() function to spawn child processes with detached: true and update the disposeSession() function to kill the entire process group.

Guidance

• Verify that the issue is caused by the wrapper process chain created by npx or uvx commands by checking the process tree of the orphaned processes.
• Apply the suggested fix by updating the createBundleLspToolRuntime() and disposeSession() functions as described.
• As a temporary workaround, replace npx/uvx with direct binary paths in openclaw.json to avoid creating wrapper processes.
• Test the fix by running the application for an extended period and checking for orphaned processes.

Example

const child = spawn(launchConfig.command, launchConfig.args ?? [], {
  stdio: ["pipe", "pipe", "pipe"],
  detached: true,  
  env: { ...process.env, ...launchConfig.env },
  cwd: launchConfig.cwd
});

try {
  process.kill(-session.process.pid, 'SIGTERM');  
} catch {
  session.process.kill();  
}

Notes

The suggested fix assumes that the createBundleLspToolRuntime() and disposeSession() functions are correctly implemented and that the issue is solely caused by the wrapper process chain. Additional testing and verification may be necessary to ensure the fix works as expected.

Recommendation

Apply the workaround by replacing npx/uvx with direct binary paths in openclaw.json until the suggested fix can be properly implemented and tested, as this provides a more immediate solution to the issue.