Add chart diffing GHA workflow

.github/workflows/diff-changes.yml

@@ -0,0 +1,65 @@
+name: Diff chart changes
+on:
+  pull_request:
+    types: [opened, reopened, synchronize]
+concurrency:
+  group: ${{ github.workflow }}-${{ github.repository }}-${{ github.ref_name }}
+  cancel-in-progress: false
+
+jobs:
+  render-charts-base:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          ref: ${{ github.event.pull_request.base.ref }}
+          show-progress: false
+      - name: Run govuk-app-render
+        run: ./govuk-app-render.sh
+      - name: Archive rendered charts
+        uses: actions/upload-artifact@v4
+        with:
+          name: rendered-charts-base
+          path: output/
+          retention-days: 1
+  render-charts-head:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          ref: ${{ github.event.pull_request.head.ref }}
+          show-progress: false
+      - name: Run govuk-app-render
+        run: ./govuk-app-render.sh
+      - name: Archive rendered charts
+        uses: actions/upload-artifact@v4
+        with:
+          name: rendered-charts-head
+          path: output/
+          retention-days: 1
+  diff-charts:
+    runs-on: ubuntu-latest
+    needs: [render-charts-base, render-charts-head]
+    permissions:
+      pull-requests: write
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          ref: ${{ github.event.pull_request.head.ref }}
+          show-progress: false
+      - uses: actions/download-artifact@v4
+        with:
+          name: rendered-charts-base
+          path: base-r/
+      - uses: actions/download-artifact@v4
+        with:
+          name: rendered-charts-head
+          path: head-r/
+      - name: Diff charts and comment on PR
+        env:
+          GH_TOKEN: ${{ github.token }}
+          PR_URL: ${{ github.event.pull_request.html_url }}
+        run: ./create-diff-pr.sh

charts/app-config/values-staging.yaml

@@ -169,7 +169,7 @@ govukApplications:
           memory: 4Gi
         requests:
           cpu: 10m
-          memory: 2Gi
+          memory: 4Gi
       redis:
         enabled: true
       ingress:

charts/generic-govuk-app/templates/ingress.yaml

@@ -10,6 +10,7 @@ metadata:
     app: {{ $fullName }}
     app.kubernetes.io/name: {{ $fullName }}
     app.kubernetes.io/component: app
+    some-other-label: something
   annotations:
     {{- (tpl (toYaml .Values.ingress.annotations) .) | trim | nindent 4 }}
 spec:

create-diff-pr.sh

@@ -0,0 +1,40 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+echo "directories"
+
+mkdir base head
+
+mv base-r/rendered-charts/* base/
+mv head-r/rendered-charts/* head/
+
+echo "diff"
+
+diff -r base/ head/
+
+DIFF=$(diff -r base/ head/)
+
+echo "before if"
+
+if [ -z "$DIFF" ]; then
+  cat <<'EOF' > pr.md
+No changes detected in rendered charts.
+EOF
+else
+  echo "there are changes"
+  echo "${DIFF}"
+cat <<'EOF' > pr.md
+<details>
+<summary>Rendered charts diff</summary>
+This PR results in the following changes to rendered charts:
+
+```diff
+EOF
+  {
+    echo "$DIFF"
+    echo '```'
+    echo '</details>'
+  } >> pr.md
+fi
+
+gh pr comment "${PR_URL}" --create-if-none --edit-last --body-file pr.md