From 4262e12921a8e73e642ff8f2cca4188d4b17fc36 Mon Sep 17 00:00:00 2001
From: Tomasz Szuba <tszuba@box.com>
Date: Wed, 11 Oct 2023 16:11:33 +0200
Subject: [PATCH] Handle decimals in k8s resource usage calculation (#20514)

When one of the numerator/denominator is a number and other is bigint this was failing.
decimals cannot be converted to bigints

Signed-off-by: Tomasz Szuba <tszuba@box.com>
---
 .changeset/rare-glasses-play.md               |  5 ++++
 .github/vale/Vocab/Backstage/accept.txt       |  3 ++-
 .../kubernetes-react/src/utils/pod.test.tsx   | 24 +++++++++----------
 plugins/kubernetes-react/src/utils/pod.tsx    |  8 +++++--
 4 files changed, 25 insertions(+), 15 deletions(-)
 create mode 100644 .changeset/rare-glasses-play.md

diff --git a/.changeset/rare-glasses-play.md b/.changeset/rare-glasses-play.md
new file mode 100644
index 0000000000..7613f6f1bc
--- /dev/null
+++ b/.changeset/rare-glasses-play.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-kubernetes-react': patch
+---
+
+Handle mixed decimals and bigint when calculating k8s resource usage
diff --git a/.github/vale/Vocab/Backstage/accept.txt b/.github/vale/Vocab/Backstage/accept.txt
index aadbaa3985..e6c0aa9632 100644
--- a/.github/vale/Vocab/Backstage/accept.txt
+++ b/.github/vale/Vocab/Backstage/accept.txt
@@ -25,6 +25,7 @@ backend's
 backported
 backporting
 BEPs
+bigint
 Bigtable
 Billett
 bitbucket
@@ -453,4 +454,4 @@ zsh
 Pulumi
 Lightsail
 PR
-rebasing
\ No newline at end of file
+rebasing
diff --git a/plugins/kubernetes-react/src/utils/pod.test.tsx b/plugins/kubernetes-react/src/utils/pod.test.tsx
index 06d4e22371..c48e40cd42 100644
--- a/plugins/kubernetes-react/src/utils/pod.test.tsx
+++ b/plugins/kubernetes-react/src/utils/pod.test.tsx
@@ -24,18 +24,18 @@ import { SubvalueCell } from '@backstage/core-components';
 
 describe('pod', () => {
   describe('currentToDeclaredResourceToPerc', () => {
-    it('10%', () => {
-      const tests: (number | string)[][] = [
-        [10, 100],
-        [10, '100'],
-        ['10', 100],
-        ['10', '100'],
-      ];
-      tests.forEach(([a, b]) => {
-        const result = currentToDeclaredResourceToPerc(a, b);
-        expect(result).toBe('10%');
-      });
-    });
+    it.each([
+      [10, 100],
+      [10, '100'],
+      ['10', 100],
+      ['10', '100'],
+      ['10', 100.0],
+      [10.0, '100'],
+      [10.1, '100'],
+      ['10', 100.1],
+    ])('%p out of %p gives 10%%', (current, resource) =>
+      expect(currentToDeclaredResourceToPerc(current, resource)).toBe('10%'),
+    );
   });
   describe('podStatusToCpuUtil', () => {
     it('does use correct units', () => {
diff --git a/plugins/kubernetes-react/src/utils/pod.tsx b/plugins/kubernetes-react/src/utils/pod.tsx
index 9c0ce898a3..1123f11427 100644
--- a/plugins/kubernetes-react/src/utils/pod.tsx
+++ b/plugins/kubernetes-react/src/utils/pod.tsx
@@ -126,8 +126,12 @@ export const currentToDeclaredResourceToPerc = (
     return `${Math.round((current / resource) * 100)}%`;
   }
 
-  const numerator: bigint = BigInt(current);
-  const denominator: bigint = BigInt(resource);
+  const numerator: bigint = BigInt(
+    typeof current === 'number' ? Math.round(current) : current,
+  );
+  const denominator: bigint = BigInt(
+    typeof resource === 'number' ? Math.round(resource) : resource,
+  );
 
   return `${(numerator * BigInt(100)) / denominator}%`;
 };