How to make child process die after parent exits?

Question

Suppose I have a process which spawns exactly one child process. Now when the parent process exits for whatever reason (normally or abnormally, by kill, ^C, assert failure o

Answer 1

I found 2 solutions, both not perfect.

1.Kill all children by kill(-pid) when received SIGTERM signal.
Obviously, this solution can not handle "kill -9", but it do work for most case and very simple because it need not to remember all child processes.

    var childProc = require('child_process').spawn('tail', ['-f', '/dev/null'], {stdio:'ignore'});

    var counter=0;
    setInterval(function(){
      console.log('c  '+(++counter));
    },1000);

    if (process.platform.slice(0,3) != 'win') {
      function killMeAndChildren() {
        /*
        * On Linux/Unix(Include Mac OS X), kill (-pid) will kill process group, usually
        * the process itself and children.
        * On Windows, an JOB object has been applied to current process and children,
        * so all children will be terminated if current process dies by anyway.
        */
        console.log('kill process group');
        process.kill(-process.pid, 'SIGKILL');
      }

      /*
      * When you use "kill pid_of_this_process", this callback will be called
      */
      process.on('SIGTERM', function(err){
        console.log('SIGTERM');
        killMeAndChildren();
      });
    }

By same way, you can install 'exit' handler like above way if you call process.exit somewhere. Note: Ctrl+C and sudden crash have automatically been processed by OS to kill process group, so no more here.

2.Use chjj/pty.js to spawn your process with controlling terminal attached.
When you kill current process by anyway even kill -9, all child processes will be automatically killed too (by OS?). I guess that because current process hold another side of the terminal, so if current process dies, the child process will get SIGPIPE so dies.

    var pty = require('pty.js');

    //var term =
    pty.spawn('any_child_process', [/*any arguments*/], {
      name: 'xterm-color',
      cols: 80,
      rows: 30,
      cwd: process.cwd(),
      env: process.env
    });
    /*optionally you can install data handler
    term.on('data', function(data) {
      process.stdout.write(data);
    });
    term.write(.....);
    */