CPU Usage ⚑

Import this State Bar Item to WebSSH

JavaScript Content

(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 };
})();

Icon

tachometer

Compatibility

• WebSSH >=29.3

• iOS >=17.2

• iPadOS >=17.2

• macOS >=14.0

Supported Targets

• Linux

• macOS

• FreeBSD

• Windows

Needed Capabilities

The table below lists the capabilities required for this script to operate. Capabilities marked as “Safe” are generally considered secure. Capabilities with a “Warning” level indicate that, while they are typically acceptable, their safety cannot be fully guaranteed in all scenarios. For your peace of mind, we recommend reviewing the script before running it.

Capability	Safety Level
ssh_exec	🟠 Warning
vars_get	🟢 Safe
vars_set	🟢 Safe

Additional Information

This script retrieves the current CPU usage (percent) of the system by reading the /proc/stat file. It calculates the CPU usage based on the difference between the current and previous CPU times. The script uses a simple algorithm to determine the CPU usage percentage and returns it as a label with an appropriate icon.

Hope to be a cross-platform script in the future. Currently only Linux is supported.