Dynamically render units on metrics tab (#1916)

* Dynamically render units on metrics tab; improvements to Count and Bytes charts

---------

Co-authored-by: David Crespo <david.crespo@oxidecomputer.com>

Author: charliepark

app/components/TimeSeriesChart.tsx

@@ -110,6 +110,7 @@ type TimeSeriesChartProps = {
   startTime: Date
   endTime: Date
   unit?: string
+  yAxisTickFormatter?: (val: number) => string
 }
 
 const TICK_COUNT = 6
@@ -129,6 +130,7 @@ export default function TimeSeriesChart({
   startTime,
   endTime,
   unit,
+  yAxisTickFormatter = (val) => val.toLocaleString(),
 }: TimeSeriesChartProps) {
   // We use the largest data point +20% for the graph scale. !rawData doesn't
   // mean it's empty (it will never be empty because we fill in artificial 0s at
@@ -182,7 +184,7 @@ export default function TimeSeriesChart({
           orientation="right"
           tick={textMonoMd}
           tickMargin={8}
-          tickFormatter={(val) => val.toLocaleString()}
+          tickFormatter={yAxisTickFormatter}
           padding={{ top: 32 }}
           {...yTicks}
         />

app/pages/project/instances/instance/tabs/MetricsTab.spec.ts

@@ -0,0 +1,28 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * Copyright Oxide Computer Company
+ */
+import { expect, test } from 'vitest'
+
+import { getCycleCount } from './MetricsTab'
+
+test('getCycleCount', () => {
+  expect(getCycleCount(5, 1000)).toEqual(0)
+  expect(getCycleCount(1000, 1000)).toEqual(0)
+  expect(getCycleCount(1001, 1000)).toEqual(1)
+  expect(getCycleCount(10 ** 6, 1000)).toEqual(1)
+  expect(getCycleCount(10 ** 6 + 1, 1000)).toEqual(2)
+  expect(getCycleCount(10 ** 9, 1000)).toEqual(2)
+  expect(getCycleCount(10 ** 9 + 1, 1000)).toEqual(3)
+
+  expect(getCycleCount(5, 1024)).toEqual(0)
+  expect(getCycleCount(1024, 1024)).toEqual(0)
+  expect(getCycleCount(1025, 1024)).toEqual(1)
+  expect(getCycleCount(2 ** 20, 1024)).toEqual(1)
+  expect(getCycleCount(2 ** 20 + 1, 1024)).toEqual(2)
+  expect(getCycleCount(2 ** 30, 1024)).toEqual(2)
+  expect(getCycleCount(2 ** 30 + 1, 1024)).toEqual(3)
+})

app/pages/project/instances/instance/tabs/MetricsTab.tsx

@@ -22,9 +22,19 @@ import { getInstanceSelector, useInstanceSelector } from 'app/hooks'
 
 const TimeSeriesChart = React.lazy(() => import('app/components/TimeSeriesChart'))
 
+export function getCycleCount(num: number, base: number) {
+  let cycleCount = 0
+  let transformedValue = num
+  while (transformedValue > base) {
+    transformedValue = transformedValue / base
+    cycleCount++
+  }
+  return cycleCount
+}
+
 type DiskMetricParams = {
   title: string
-  unit?: string
+  unit: 'Bytes' | 'Count'
   startTime: Date
   endTime: Date
   metric: DiskMetricName
@@ -54,27 +64,77 @@ function DiskMetric({
     { placeholderData: (x) => x }
   )
 
-  const data = (metrics?.items || []).map(({ datum, timestamp }) => ({
-    timestamp: timestamp.getTime(),
-    // all of these metrics are cumulative ints
-    value: (datum.datum as Cumulativeint64).value,
-  }))
+  const isBytesChart = unit === 'Bytes'
+
+  const largestValue = useMemo(() => {
+    if (!metrics || metrics.items.length === 0) return 0
+    return Math.max(...metrics.items.map((m) => (m.datum.datum as Cumulativeint64).value))
+  }, [metrics])
+
+  // We'll need to divide each number in the set by a consistent exponent
+  // of 1024 (for Bytes) or 1000 (for Counts)
+  const base = isBytesChart ? 1024 : 1000
+  // Figure out what that exponent is:
+  const cycleCount = getCycleCount(largestValue, base)
+
+  // Now that we know how many cycles of "divide by 1024 || 1000" to run through
+  // (via cycleCount), we can determine the proper unit for the set
+  let unitForSet = ''
+  let label = '(COUNT)'
+  if (isBytesChart) {
+    const byteUnits = ['Bytes', 'KiB', 'MiB', 'GiB', 'TiB']
+    unitForSet = byteUnits[cycleCount]
+    label = `(${unitForSet})`
+  }
+
+  const divisor = base ** cycleCount
+
+  const data = useMemo(
+    () =>
+      (metrics?.items || []).map(({ datum, timestamp }) => ({
+        timestamp: timestamp.getTime(),
+        // All of these metrics are cumulative ints.
+        // The value passed in is what will render in the tooltip.
+        value: isBytesChart
+          ? // We pass a pre-divided value to the chart if the unit is Bytes
+            (datum.datum as Cumulativeint64).value / divisor
+          : // If the unit is Count, we pass the raw value
+            (datum.datum as Cumulativeint64).value,
+      })),
+    [metrics, isBytesChart, divisor]
+  )
+
+  // Create a label for the y-axis ticks. "Count" charts will be
+  // abbreviated and will have a suffix (e.g. "k") appended. Because
+  // "Bytes" charts will have already been divided by the divisor
+  // before the yAxis is created, we can use their given value.
+  const yAxisTickFormatter = (val: number) => {
+    if (isBytesChart) {
+      return val.toLocaleString()
+    }
+    const tickValue = (val / divisor).toFixed(2)
+    const countUnits = ['', 'k', 'M', 'B', 'T']
+    const unitForTick = countUnits[cycleCount]
+    return `${tickValue}${unitForTick}`
+  }
 
   return (
     <div className="flex w-1/2 flex-grow flex-col">
-      <h2 className="ml-3 flex items-center text-mono-xs text-secondary">
-        {title} {unit && <div className="ml-1 text-quaternary">{unit}</div>}
+      <h2 className="ml-3 flex items-center text-mono-xs text-secondary ">
+        {title} <div className="ml-1 normal-case text-quaternary">{label}</div>
         {isLoading && <Spinner className="ml-2" />}
       </h2>
       <Suspense fallback={<div className="mt-3 h-[300px]" />}>
         <TimeSeriesChart
           className="mt-3"
           data={data}
           title={title}
+          unit={unitForSet}
           width={480}
           height={240}
           startTime={startTime}
           endTime={endTime}
+          yAxisTickFormatter={yAxisTickFormatter}
         />
       </Suspense>
     </div>
@@ -151,17 +211,17 @@ export function MetricsTab() {
         {/* see the following link for the source of truth on what these mean
             https://github.com/oxidecomputer/crucible/blob/258f162b/upstairs/src/stats.rs#L9-L50 */}
         <div className="flex w-full space-x-4">
-          <DiskMetric {...commonProps} title="Reads" unit="(Count)" metric="read" />
-          <DiskMetric {...commonProps} title="Read" unit="(Bytes)" metric="read_bytes" />
+          <DiskMetric {...commonProps} title="Reads" unit="Count" metric="read" />
+          <DiskMetric {...commonProps} title="Read" unit="Bytes" metric="read_bytes" />
         </div>
 
         <div className="flex w-full space-x-4">
-          <DiskMetric {...commonProps} title="Writes" unit="(Count)" metric="write" />
-          <DiskMetric {...commonProps} title="Write" unit="(Bytes)" metric="write_bytes" />
+          <DiskMetric {...commonProps} title="Writes" unit="Count" metric="write" />
+          <DiskMetric {...commonProps} title="Write" unit="Bytes" metric="write_bytes" />
         </div>
 
         <div className="flex w-full space-x-4">
-          <DiskMetric {...commonProps} title="Flushes" unit="(Count)" metric="flush" />
+          <DiskMetric {...commonProps} title="Flushes" unit="Count" metric="flush" />
         </div>
       </div>
     </>