Add cpu usage percentage metric

Author: DivineOmega

src/Metrics.php

@@ -5,6 +5,7 @@
 use DivineOmega\ServerInfo\Interfaces\MetricInterface;
 use DivineOmega\ServerInfo\Metrics\ActiveHttpConnection;
 use DivineOmega\ServerInfo\Metrics\ApacheServerRunning;
+use DivineOmega\ServerInfo\Metrics\CpuUsagePercentage;
 use DivineOmega\ServerInfo\Metrics\DiskUsagePercentage;
 use DivineOmega\ServerInfo\Metrics\LoadAverages;
 use DivineOmega\ServerInfo\Metrics\MemoryUsagePercentage;
@@ -35,6 +36,7 @@ class Metrics
         NginxServerRunning::class,
         ActiveHttpConnection::class,
         LoadAverages::class,
+        CpuUsagePercentage::class,
     ];
 
     public function __construct(Server $server)

src/Metrics/CpuUsagePercentage.php

@@ -0,0 +1,33 @@
+<?php
+
+namespace DivineOmega\ServerInfo\Metrics;
+
+class CpuUsagePercentage extends BaseMetric
+{
+    public function populate()
+    {
+        $output = $this->connection
+            ->run('top -n 1 -b | grep "%Cpu" | cut -d "," -f 4 | cut -d " " -f 2')
+            ->getOutput();
+
+        if (!is_numeric($output)) {
+            $this->value = null;
+            return;
+        }
+
+        $idleCpu = (float) $output;
+
+        if ($idleCpu < 0 || $idleCpu > 100) {
+            $this->value = null;
+            return;
+        }
+
+        $this->value = 100 - $idleCpu;
+    }
+
+    public function getName()
+    {
+        return 'cpu-usage-percentage';
+    }
+
+}