Using the N|Solid Console with Express, Socket.io and the cluster module

This guide explains how to use the N|Solid Console with applications made with express, socket.io and the cluster modules.

Installation

Please refer to our Quick Start Guide for instructions on how to install the latest version of N|Solid.

This example application uses the socket.io-redis module that requires a redis server running, you can run it locally:

Now you can run your own application.

The application is a simple Express + Socket.io application, using the cluster module and running multiple workers. The source code is:

File index.js

const
 http = 
require
(
'http'
)
const
 cluster = 
require
(
'cluster'
)
const
 path = 
require
(
'path'
)
const
 express = 
require
(
'express'
)
const
 sio = 
require
(
'socket.io'
)
const
 RedisStore = 
require
(
'socket.io-redis'
)

const
 port = process.env.PORT || 
3000
const
 numCPUs = 
require
(
'os'
).cpus().length

if
 (cluster.isMaster) {
  
var
 workers = []

   
  
var
 spawn = 
function
 (
i
) {
    workers[i] = cluster.fork()

       
    workers[i].on(
'exit'
, 
function
 (
worker, code, signal
) {
      
console
.log(
'respawning worker'
, i)
      spawn(i)
    })
  }

   
  cluster.on(
'fork'
, 
function
 (
worker
) {
    
return
 
console
.log(
'forked worker '
 + worker.process.pid)
  })

  cluster.on(
'listening'
, 
function
 (
worker, address
) {
    
return
 
console
.log(
'worker '
 + worker.process.pid + 
' is now connected to '
 + address.address + 
':'
 + address.port)
  })

  cluster.on(
'exit'
, 
function
 (
worker, code, signal
) {
    
return
 
console
.log(
'worker '
 + worker.process.pid + 
' died'
)
  })

   
  
for
 (
var
 i = 
0
; i < numCPUs; i++) {
    spawn(i)
  }
} 
else
 {
  
const
 app = express()
  
const
 server = http.createServer(app)
  
const
 io = sio.listen(server)

  io.adapter(RedisStore({ host: 
'localhost'
, port: 
6379
 }))

   
  app.get(
'/'
, 
function
 (
req, res
) {
     
    
return
 res.sendfile(path.join(__dirname, 
'/index.html'
))
  })

  io.sockets.on(
'connection'
, 
function
 (
socket
) {
     
    
console
.log(
'socket call handled by worker with pid '
 + process.pid)

     
    
return
 socket.emit(
'news'
, {
      hello: 
'world'
    })
  })

   
  server.listen(port)
}

File index.html

<
html
>
<
script
 
src
=
"/socket.io/socket.io.js"
>
</
script
>
<
script
>

  
var
 socket = io();
  socket.on(
'news'
, 
function
 (
data
) {
    
console
.log(data);
    socket.emit(
'my other event'
, { my: 
'data'
 });
  });
</
script
>
</
html
>

You can run it using this command:

$ NSOLID_COMMAND=
9001
 NSOLID_APPNAME=
socket
.io-cluster nsolid 
index
.js

You should now see the N|Solid console overview with all the general data of the application.

The cluster view displays a dot in the graph for each worker. Clicking on a dot will provide more detailed information about that worker.