pm2

var io = require('@pm2/io')

// Here the value function will be called each second to get the value
var metric = io.metric({
name : 'Realtime user',
value : function() {
return Object.keys(users).length
}
})

// Here we are going to call valvar.set() to set the new value
var valvar = io.metric({
name : 'Realtime Value'
})

valvar.set(23)

var io = require('@pm2/io')
var http = require('http')

var counter = io.counter({
name : 'Active requests'
})

http.createServer(function (req, res) {
counter.inc()

req.on('end', function() {
// Decrement the counter, counter will eq 0
counter.dec()
})
res.writeHead(200, {'Content-Type': 'text/plain'})
res.write('Hello World!')
res.end()
}).listen(6001)

var io = require('@pm2/io')
var http = require('http')

var meter = io.meter({
name : 'req/min',
samples : 1,
timeframe : 60
})

http.createServer(function (req, res) {
meter.mark()
res.writeHead(200, {'Content-Type': 'text/plain'})
res.write('Hello World!')
res.end()
}).listen(6001)

var io = require('@pm2/io')

var histogram = io.histogram({
name : 'latency',
measurement : 'mean'
})

var latency = 0

setInterval(function() {
latency = Math.round(Math.random() * 100)
histogram.update(latency)
}, 100)