servermon

This is a simple server helper. It responds to SIGHUP to reload it's children. This is particularly useful in a docker workflow where you need to monitor file changes and send a SIGHUP signal to a docker container to dynamically reload child processes.

• Uses cluster to create child processes specified by "children"
• Restart child process if it exits with an error
• Responds to SIGHUP sent to master process to gracefully shut down children
• Specify the number of miliseconds to wait before retrying a failed process
• Custom start/shutdown code supported
• Set custom log function to log when child processes are started/stopped
• Set custom error log function to log when a child process dies

example

var servermon = require('servermon');

servermon({
  children: 1,
  log: function (msg) { console.log(msg); },
  error: function (msg) { console.error(msg); },
  delay: 1000,
  onMaster: function (callback) {
    console.log('onMaster called');
    callback();
  },
  onStart: function () {
    var http = require('http');
    this.server = http.createServer(function (req, res) {
      res.writeHead(200, {'Content-Type': 'text/plain'});
      res.end('Hello World 2\n');
    }).listen(3000);
    console.log('listening on port 3000')
  },
  onShutdown: function (callback) {
    // initiate graceful close of any connections to server
    console.log('closing gracefully...');
    this.server.close(callback);
  }
});

Usage

var servermon = require('servermon'); servermon(options)

options

children

The number of child processes that will be forked.

If 0, then no child processes will be created. This is useful for debugging in an IDE such as webstorm.

log

This is a function that will be called any time a child process is created or destroyed. Should conform to the following signature:

function (msg)

error

This is a function that will be called when a child process dies unexpectedly. Should conform to the following signature:

function (msg)

delay

The number of milliseconds to delay restarting a child process that dies unexpectedly.

onStart

The end result of this function should be a listening server.

onShutdown

This is the graceful exit of a server. Should conform to the following signature:

function (callback)