KPI Autro Scale

app.js

@@ -31,6 +31,7 @@ import {
   renderFleetCards,
 } from './ui/fleet.js'
 import { createLogsView } from './ui/logs.js'
+import { formatMib, formatKilobitsPerSec } from './shared/format.js'
 
 const $ = (id) => document.getElementById(id)
 
@@ -711,11 +712,11 @@ function syncOverviewKpis() {
   const cpu = lastSeriesValue('cpu')
   if (els.statCpu) els.statCpu.textContent = cpu == null ? '—' : `${cpu.toFixed(1)}%`
   const ram = lastSeriesValue('ram')
-  if (els.statRam) els.statRam.textContent = ram == null ? '—' : `${ram.toFixed(0)} MiB`
+  if (els.statRam) els.statRam.textContent = formatMib(ram)
   const load = lastSeriesValue('load')
   if (els.statLoad) els.statLoad.textContent = load == null ? '—' : load.toFixed(2)
   const net = lastSeriesValue('net')
-  if (els.statNet) els.statNet.textContent = net == null ? '—' : `${net.toFixed(1)} kb/s`
+  if (els.statNet) els.statNet.textContent = formatKilobitsPerSec(net)
 }
 
 /** Map a queryData row to a values object keyed by dimension id. */

shared/format.js

@@ -0,0 +1,67 @@
+/**
+ * Human-readable metric formatting with automatic unit scaling.
+ */
+
+/**
+ * @param {number} n
+ * @param {number} digits
+ */
+function trimFixed(n, digits) {
+  const s = n.toFixed(digits)
+  if (!s.includes('.')) return s
+  return s.replace(/0+$/, '').replace(/\.$/, '')
+}
+
+/**
+ * Pick decimal places from magnitude after scaling.
+ * @param {number} n
+ */
+function autoDigits(n) {
+  const a = Math.abs(n)
+  if (a >= 100) return 0
+  if (a >= 10) return 1
+  return 2
+}
+
+/**
+ * Scale a magnitude through a unit ladder.
+ * @param {number} value absolute magnitude in base units
+ * @param {string[]} units
+ * @param {number} base
+ * @returns {{ n: number, unit: string }}
+ */
+function scaleUnit(value, units, base) {
+  let n = Math.abs(value)
+  let i = 0
+  while (n >= base && i < units.length - 1) {
+    n /= base
+    i++
+  }
+  return { n: value < 0 ? -n : n, unit: units[i] }
+}
+
+/**
+ * Format memory stored as MiB → B / KiB / MiB / GiB / TiB / PiB.
+ * @param {number|null|undefined} mib
+ * @returns {string}
+ */
+export function formatMib(mib) {
+  if (mib == null || !Number.isFinite(Number(mib))) return '—'
+  const bytes = Number(mib) * 1024 * 1024
+  if (bytes === 0) return '0 B'
+  const { n, unit } = scaleUnit(bytes, ['B', 'KiB', 'MiB', 'GiB', 'TiB', 'PiB'], 1024)
+  return `${trimFixed(n, autoDigits(n))} ${unit}`
+}
+
+/**
+ * Format network rate stored as kilobits/s → b/s / kb/s / Mb/s / Gb/s / Tb/s.
+ * @param {number|null|undefined} kbps
+ * @returns {string}
+ */
+export function formatKilobitsPerSec(kbps) {
+  if (kbps == null || !Number.isFinite(Number(kbps))) return '—'
+  const bps = Number(kbps) * 1000
+  if (bps === 0) return '0 b/s'
+  const { n, unit } = scaleUnit(bps, ['b/s', 'kb/s', 'Mb/s', 'Gb/s', 'Tb/s'], 1000)
+  return `${trimFixed(n, autoDigits(n))} ${unit}`
+}

test/format.test.js

@@ -0,0 +1,23 @@
+import test from 'brittle'
+import { formatMib, formatKilobitsPerSec } from '../shared/format.js'
+
+test('formatMib scales through binary units', async (t) => {
+  t.is(formatMib(null), '—')
+  t.is(formatMib(NaN), '—')
+  t.is(formatMib(0), '0 B')
+  t.is(formatMib(0.5), '512 KiB')
+  t.is(formatMib(256), '256 MiB')
+  t.is(formatMib(1024), '1 GiB')
+  t.is(formatMib(1536), '1.5 GiB')
+  t.is(formatMib(1024 * 1024), '1 TiB')
+})
+
+test('formatKilobitsPerSec scales through SI bit rates', async (t) => {
+  t.is(formatKilobitsPerSec(null), '—')
+  t.is(formatKilobitsPerSec(0), '0 b/s')
+  t.is(formatKilobitsPerSec(0.5), '500 b/s')
+  t.is(formatKilobitsPerSec(12.5), '12.5 kb/s')
+  t.is(formatKilobitsPerSec(1500), '1.5 Mb/s')
+  t.is(formatKilobitsPerSec(2_500_000), '2.5 Gb/s')
+  t.is(formatKilobitsPerSec(3_000_000_000), '3 Tb/s')
+})