CPU Usage

Import this State Bar Item to WebSSH

JavaScript Content

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(function() {
  // Check if the SSH connection is active, if not, return empty label and default icon
  if (!$ssh.isConnected()) {
    return { 
      label: '', 
      icon: 'tachometer' 
    };
  }

  /**
  * Parse the first “cpu” line of /proc/stat and compute
  * - total time (sum of all fields)
  * - idle time (idle + iowait)
  *
  * @param {string} statOutput  Full content of /proc/stat
  * @returns {{ total: number, idle: number }}
  */
  function extractCpuTimes(statOutput) {
    // Find the line that starts with “cpu ’ (aggregate over all cores)
    const line = statOutput.split('\n').find(l => l.startsWith('cpu '));
    // Split on whitespace, discard the “cpu” label, take the next 7 fields:
    //   user, nice, system, idle, iowait, irq, softirq
    const parts = line.trim().split(/\s+/).slice(1, 8).map(Number);
    // Sum all fields to get the “total” jiffies since boot
    const total = parts.reduce((sum, val) => sum + val, 0);
    // Idle time is idle + iowait (fields 3 and 4 in our zero-based array)
    const idle = parts[3] + parts[4];
    return { total, idle };
  }

  // Read the current /proc/stat over SSH, typical output:
  // cpu  2255 34 2290 22625563 6290 127 456 0 0 0
  // cpu0 1132 19 1441 11311718 3675 44 240 0 0 0
  // cpu1 1123 15 849 11313845 2615 83 216 0 0 0
  // intr 114930548 113199788 3 0 5 ... 
  // ctxt 1990473
  // btime 1612191234
  // processes 2915
  // procs_running 1
  // procs_blocked 0
  const procStatContent = $ssh.exec('cat /proc/stat');

  // Check if the command was successful
  if (!procStatContent) {
    console.warn('Failed to read /proc/stat');
    // If the command fails, return empty label and default icon
    return { 
      label: '',
      icon: 'tachometer' 
    };
  }

  // Parse the fresh snapshot
  const newStat = extractCpuTimes(procStatContent);
  // Retrieve the previous snapshot from our vars store (or default to newStat on first run)
  const oldStat = $vars.get('CPU_STAT', newStat);
  // Save the new snapshot for next time
  $vars.set('CPU_STAT', newStat);

  // Compute differences in total time and idle time between snapshots
  const totalDiff = newStat.total - oldStat.total;
  const idleDiff = newStat.idle - oldStat.idle;

  // Calculate CPU usage percentage over the interval
  let usagePercent;
  if (totalDiff > 0) {
    // (busy time) / (total time) = (totalDiff – idleDiff) / totalDiff
    usagePercent = Math.round(100 * (totalDiff - idleDiff) / totalDiff);
  } else {
    // If no time has elapsed (unlikely), consider usage 0%
    usagePercent = 0;
  }

  // Choose an icon based on usage tiers
  let icon;
  if (usagePercent < 33) {
    icon = 'gauge.with.dots.needle.0percent';
  } else if (usagePercent < 50) {
    icon = 'gauge.with.dots.needle.33percent';
  } else if (usagePercent < 67) {
    icon = 'gauge.with.dots.needle.50percent';
  } else if (usagePercent < 80) {
    icon = 'gauge.with.dots.needle.67percent';
  } else {
    icon = 'gauge.with.dots.needle.100percent';
  }

  // Return an object that e.g. your dashboard can use
  return { label: usagePercent + '%', icon };
})();