Expose redis quit function

[Joshua-Anderson]

I use socket.io-redis with my node js cluster app. Instead of just exiting on SIGTERM and SIGINT, I gracefully exit and close all connections. However, using the socket.io-redis my child processes never exit, problaby redis connection is persisted, leaving a dead process that has to be forced killed using kill -9. Here is a quick reproduction script:

cluster = require('cluster');

if (cluster.isMaster) {
  cluster.fork();
  process.on('SIGTERM', gracefulMasterExit).on('SIGINT', gracefulMasterExit);

  process.on('exit', function () {
    console.log("Successfully shut down");
  });

  function gracefulMasterExit() {
      console.log("Got SIGINT or SIGTERM, gracefully exiting");
  }

} else {
  var server = require('http').Server();
  var io = require('socket.io')(server);
  io.adapter(require('socket.io-redis')('localhost:6379'));
  server.listen(3000);

  process.on('SIGTERM', gracefulExit).on('SIGINT', gracefulExit);

  function gracefulExit() {
      console.log("Worker " + cluster.worker.process.pid + " exiting gracefully");
      cluster.worker.disconnect();
  }
}

After running this you should see Worker <PID> exiting gracefully, but if you look at your process manager you will still see that worker running with the master process dead. In this particular case sending SIGTERM or SIGINT will trigger a channel closed error but in my actual code the program will just return leaving the worker running in the background. Commenting out the redis adapter line will resolve the problem.

Thanks for taking a look at this!

[rauchg]

For "advanced usecases" like this is that we accept a redis instance that you can control and call methods on:
https://github.com/Automattic/socket.io-redis#adapteropts

Thanks for the thorough explanation though, I really appreciate it.