prisme-flow/nodes/bridge/cpu/cpu.js

prisme platform flow engine

/**
 * Created by prisme.io on 09/06/2017.
 */

 module.exports = function (RED) {
   var settings = RED.settings
   var os = require('os')

   function CpuNode (n) {
     RED.nodes.createNode(this, n)

     this.name = n.name
     this.previousTotalTick = []
     this.previousTotalIdle = []

     var node = this

     node.on('input', function (msg) {
       var currentTotalTick = []
       var currentTotalIdle = []
       var outputMessages = []

            // Calculate the current CPU usage percentage (for each of the 4 CPU cores)
       for (var i = 0, len = os.cpus().length; i < len; i++) {
         currentTotalTick.push(0)
         currentTotalIdle.push(0)

                // Current total number of CPU ticks (spent in user, nice, sys, idle, and irq)
         for (var type in os.cpus()[i].times) {
           currentTotalTick[i] += os.cpus()[i].times[type]
         }

                // Current total idle time
         currentTotalIdle[i] += os.cpus()[i].times.idle

                // Difference in idle and total time, compared to the previous calculation.
                // I.e. difference since the last time this node has been triggered!
         var totalTickDifference = currentTotalTick[i] - (node.previousTotalTick[i] || 0)
         var totalIdleDifference = currentTotalIdle[i] - (node.previousTotalIdle[i] || 0)

                // Average percentage CPU usage (of the period since the previous trigger of this node)
         var percentageCPU = 100 - ~~(100 * totalIdleDifference / totalTickDifference)

                // Store the CPU usage % in the payload, and the CPU core name in the topic.
         outputMessages.push({ payload: percentageCPU, topic: 'core_' + (i + 1), model: os.cpus()[i].model, speed: os.cpus()[i].speed })
       }

            // Store the current counters for the next calculation
       node.previousTotalTick = currentTotalTick
       node.previousTotalIdle = currentTotalIdle

            // Send all CPU usage percentages to the output port
       node.send([ outputMessages ])
     })
   }

   RED.nodes.registerType('cpu', CpuNode)
 }