ci: Add PR validation flow

Signed-off-by: Bᴇʀɴᴅ Sᴄʜᴏʀɢᴇʀs <me@bjw-s.dev>

.github/workflows/pr-get-metadata.yaml

@@ -0,0 +1,71 @@
+name: "Pull Request: Get metadata"
+
+on:
+  workflow_call:
+    outputs:
+      isRenovatePR:
+        description: "Is the PR coming from Renovate?"
+        value: ${{ jobs.pr-metadata.outputs.isRenovatePR }}
+      isFork:
+        description: "Is the PR coming from a forked repo?"
+        value: ${{ jobs.pr-metadata.outputs.isFork }}
+      addedOrModified:
+        description: "Does the PR contain any changes?"
+        value: ${{ jobs.pr-changes.outputs.addedOrModified }}
+      addedOrModifiedFiles:
+        description: "A list of the files changed in this PR"
+        value: ${{ jobs.pr-changes.outputs.addedOrModifiedFiles }}
+      addedOrModifiedCharts:
+        description: "A list of the charts changed in this PR"
+        value: ${{ jobs.pr-changes.outputs.addedOrModifiedCharts }}
+
+jobs:
+  pr-metadata:
+    name: Collect PR metadata
+    runs-on: ubuntu-latest
+    outputs:
+      isRenovatePR: ${{ startsWith(steps.branch-name.outputs.current_branch, 'renovate/') }}
+      isFork: ${{ github.event.pull_request.head.repo.full_name != github.repository }}
+    steps:
+      - name: Get branch name
+        id: branch-name
+        uses: tj-actions/branch-names@v5.1
+
+  pr-changes:
+    name: Collect PR changes
+    runs-on: ubuntu-latest
+    outputs:
+      addedOrModified: ${{ steps.filter.outputs.addedOrModified }}
+      addedOrModifiedFiles: ${{ steps.filter.outputs.addedOrModified_files }}
+      addedOrModifiedCharts: ${{ steps.filter-charts.outputs.addedOrModified }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Collect changed files
+        uses: dorny/paths-filter@v2
+        id: filter
+        with:
+          list-files: shell
+          filters: |
+            addedOrModified:
+              - added|modified: 'charts/**'
+
+      - name: Collect changed charts
+        if: |
+          steps.filter.outputs.addedOrModified == 'true'
+        id: filter-charts
+        run: |
+          CHARTS=()
+          PATHS=(${{ steps.filter.outputs.addedOrModified_files }})
+          # Get only the chart paths
+          for CHARTPATH in "${PATHS[@]}"
+          do
+            IFS='/' read -r -a path_parts <<< "${CHARTPATH}"
+            CHARTS+=("${path_parts[1]}/${path_parts[2]}")
+          done
+
+          # Remove duplicates
+          CHARTS=( `printf "%s\n" "${CHARTS[@]}" | sort -u` )
+          # Set output to changed charts
+          printf "::set-output name=addedOrModified::%s\n" "${CHARTS[*]}"

.github/workflows/pr-validate.yaml

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+name: "Pull Request: Validate"
+
+on:
+  pull_request:
+    branches:
+      - master
+
+concurrency:
+  group: ${{ github.head_ref }}-pr-validate
+  # cancel-in-progress: true
+
+jobs:
+  pr-get-metadata:
+    uses: k8s-at-home/charts/.github/workflows/pr-get-metadata.yaml@master