CODEWITHSUNDEEP
linuxnode.jssocket.iorestart
Axil
Axil

Reputation: 3311

Auto restart or Proper Handling socket.io server on exception in linux

I'ved got my socket.io server running in the background. However, there are several situation where it died. What can I do to make my socket.io server auto restart whenever it dies or terminated.

This is how I started my node server

> node server &

however the server thrown an exception and died.

events.js:141
      throw er; // Unhandled 'error' event
      ^

Error: Redis connection to pub-redis-us-east1-garantiabata.com:12087 failed - connect ETIMEDOUT 54.179.28.165:12087
    at RedisClient.on_error (/home/org-chatserver/node_modules/redis/index.js:185:24)
    at Socket.<anonymous> (/home/org-chatserver/node_modules/redis/index.js:95:14)
    at emitOne (events.js:77:13)
    at Socket.emit (events.js:169:7)
    at emitErrorNT (net.js:1253:8)
    at doNTCallback2 (node.js:450:9)
    at process._tickCallback (node.js:364:17)
^C

This is my environment

Linux version 2.6.32-042stab090.5 (root@kbuild-rh6-x64) (gcc version 4.4.6 20120305 (Red Hat 4.4.6-4) (GCC) ) #1 SMP Sat Jun 21 00:15:09 MSK 2014

and I believe my team is using this:

https://github.com/jbavari/ionic-socket.io-redis-chat

Upvotes: 4

Views: 2178

Answers (3)

UndeadKernel
UndeadKernel

Reputation: 533

For the server to connect back, you might need to use some program (like forever) that checks the status of the server and restarts it when it dies. This, however, does not solve the problem for the clients. The clients also need to reinitialize the connection to the server when the server dies. Let me show you a minimal example of how you can make your clients connect back to the server.

The main idea is that you will listen for the "close" event from the client socket and will restart a connection if needed. Let us use OOP to better illustrate this.

function Connector(host, port)
{
  // Connection parameters
  this.host = host;
  this.port = port;

  this.socket = null;

  // Attempt to establish a connection with the server.
  this._connect();
}

Connector.prototype._connect = function()
{
  this.socket = net.connect(this.port, this.host);

  this.socket.on('connect', this._onConnect);
  this.socket.on('error', this._onError);
  this.socket.on('close', this._onClose);
  this.socket.on('data', this._onData);
}


Connector.prototype._onConnect = function()
{
  console.log('Incoming connection');
}

Connector.prototype._onError = function(err)
{
  console.error('Connection error: ' + err);
}

Connector.prototype._onClose = function(had_error)
{
  console.log('Reconnecting to server.');
  self._scheduleReconnection();
}


Connector.prototype._scheduleReconnection = function()
{
  self.socket.removeAllListeners();
  self.socket = null;

  // Try to connect to the server again after 2 seconds.
  setTimeout(self._connect.bind(self), 2000);
}

Connector.prototype._onData = function(data)
{
  console.log('Incoming data.')
}

With the Connector object you can now start a connection with:

connection = new Connector(127.0.0.1, 8080)

and you know this connection will constantly try to stay connected with the server.

Upvotes: -1

Tan Hong Tat
Tan Hong Tat

Reputation: 6864

You can use Supervisor - http://supervisord.org

Supervisor is a client/server system that allows its users to monitor and control a number of processes on UNIX-like operating systems.

After installation, create a supervisor config file for your app.

For example, under /etc/supervisor/conf.d/myserver.conf -

[program:my-server]
    command=node /path/to/server.js
    numprocs=1
    autostart=true  
    autorestart=true
    startretries=99999
    environment=NODE_ENV=production  
    stderr_logfile=/var/log/my-server.err.log  
    stdout_logfile=/var/log/my-server.log  
    user=myuser

Edit the supervisor main config file - /etc/supervisor/supervisord.conf

[unix_http_server]
file=/var/run/supervisor.sock    ; (the path to the socket file)
chmod=0700                       ; socket file mode (default 0700)

[supervisord]
logfile=/var/log/supervisor/supervisord.log ; (main log file;default    ] $CWD/supervisord.log)
pidfile=/var/run/supervisord.pid            ; (supervisord pidfile;default supervisord.pid)
childlogdir=/var/log/supervisor             ; ('AUTO' child log dir, default $TEMP)

; the below section must remain in the config file for RPC
; (supervisorctl/web interface) to work, additional interfaces may be
; added by defining them in separate rpcinterface: sections
 [rpcinterface:supervisor]
supervisor.rpcinterface_factory =  supervisor.rpcinterface:make_main_rpcinterface

[supervisorctl]
serverurl=unix:///var/run//supervisor.sock ; use a unix:// URL  for a unix socket

; The [include] section can just contain the "files" setting.  This
; setting can list multiple files (separated by whitespace or
; newlines).  It can also contain wildcards.  The filenames are
; interpreted as relative to this file.  Included files *cannot*
; include files themselves.

[include]
files = /etc/supervisor/conf.d/*.conf

Usage: /etc/init.d/supervisord {start|stop|restart|force-reload|status|force-stop}

For more information/documentation - please read http://supervisord.org/

Upvotes: 2

hankchiutw
hankchiutw

Reputation: 1662

You can use pm2 to monitor logs, auto restart... etc. For example:

sudo npm install -g pm2
pm2 start app.js --watch

More about watch & restart.

Upvotes: 0

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