Merge pull request #25 from mozilla-it/add-render-and-diff-helm

feat: add render and diff helm action

render-and-diff-helm/README.md

@@ -0,0 +1,29 @@
+# Render and diff helm charts
+
+This action is used to render helm charts on the base and ref branches of a pull request, create a diff between charts that have been modified and then post the diff as a comment on the pull request. 
+
+## Inputs
+
+### `chart_path`
+
+The path filter for helm charts in the repository. Default `'**/k8s/**/**'`
+
+### Example usage
+```
+name: render-and-diff-charts
+
+on:
+  pull_request:
+    paths:
+      - '**/k8s/**/**'
+
+jobs:
+  run_helm_chart_diff:
+    permissions:
+      contents: read
+      pull-requests: write
+    runs-on: ubuntu-latest
+    steps:
+      - name: Render and diff modified helm charts
+        uses: mozilla-it/deploy-actions/[email protected]
+```

render-and-diff-helm/action.yml

@@ -0,0 +1,179 @@
+# 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/.
+
+name: Matrix render and diff helm charts
+description: Renders BASE and REF helm charts then posts the diff of the rendered charts as a comment on the pull request 
+
+
+on:
+  workflow_call:
+    inputs:
+      chart_path:
+        description: Path filter for helm charts
+        required: false
+        type: string
+        default: '**/k8s/**'
+
+env:
+  CHART_PATH: ${{ inputs.chart_path }}
+
+jobs:
+  get_changed_helm_charts:
+    runs-on: ubuntu-latest
+    outputs:
+      matrix_charts: ${{ steps.find_changed_charts.outputs.matrix_changed_charts }}
+      charts: ${{ steps.find_changed_charts.outputs.changed_charts }}
+    steps:
+      - name: checkout repository
+        uses: actions/checkout@v4
+        with:
+         fetch-depth: '100'
+
+      - name: find changed helm charts
+        id: find_changed_charts
+        run: |
+          git fetch origin ${{ github.base_ref }}:${{ github.base_ref }}
+          echo matrix_changed_charts=$(git diff --name-only ${{ github.base_ref }}...HEAD -- '**/k8s/**/*.yaml' '**/k8s/**/*.yml' '**/k8s/**/*.tpl' '**/k8s/**/*.tmpl' | cut -d'/' -f1,2,3 | uniq | jq -R 'split("\n")' | jq -s 'flatten(1)') >> $GITHUB_OUTPUT
+          echo changed_charts=$(git diff --name-only ${{ github.base_ref }}...HEAD -- '**/k8s/**/*.yaml' '**/k8s/**/*.yml' '**/k8s/**/*.tpl' '**/k8s/**/*.tmpl' | cut -d'/' -f1,2,3 | uniq) >> $GITHUB_OUTPUT
+
+  render_head_ref_charts:
+    runs-on: ubuntu-latest
+    needs: get_changed_helm_charts
+    strategy:
+      matrix:
+        chart: ${{ fromJSON(needs.get_changed_helm_charts.outputs.matrix_charts) }}
+    steps:
+      - name: checkout repository
+        uses: actions/checkout@v4
+
+      - name: setup helm
+        uses: azure/[email protected]
+
+      - name: render ${{ matrix.chart }} from head ref
+        id: render_head
+        run: |
+          mkdir -p shared/head-charts
+          git fetch origin ${{ github.head_ref }}
+          git checkout  ${{ github.head_ref }} --
+          if [ -d "${{ matrix.chart }}" ]; then
+            helm dependency build "${{ matrix.chart }}"
+            values_files="${{ matrix.chart }}"/values-*
+            for values_file in $(basename -a $values_files); do
+              helm template "${{ matrix.chart }}" -f "${{ matrix.chart }}/values.yaml" -f "${{ matrix.chart }}/${values_file}" --output-dir "shared/head-charts/${{ matrix.chart }}/${values_file}"
+            done
+          fi
+          echo sanitized_name=$(echo "${{ matrix.chart }}" | sed 's/\//-/g') >> $GITHUB_OUTPUT
+      - name: upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: "shared-head-${{ steps.render_head.outputs.sanitized_name }}"
+          path: "shared"
+
+  render_base_ref_charts:
+    runs-on: ubuntu-latest
+    needs: get_changed_helm_charts
+    strategy:
+      matrix:
+        chart: ${{ fromJSON(needs.get_changed_helm_charts.outputs.matrix_charts) }}
+    steps:
+      - name: checkout repository
+        uses: actions/checkout@v4
+
+      - name: setup helm
+        uses: azure/[email protected]
+
+      - name: render ${{ matrix.chart }} from base ref
+        id: render_base
+        run: |
+          mkdir -p shared/base-charts
+          git fetch origin ${{ github.base_ref }}
+          git checkout  ${{ github.base_ref }} --
+          if [ -d "${{ matrix.chart }}" ]; then
+            helm dependency build "${{ matrix.chart }}"
+            values_files="${{ matrix.chart }}"/values-*
+            for values_file in $(basename -a $values_files); do
+              helm template "${{ matrix.chart }}" -f "${{ matrix.chart }}/values.yaml" -f "${{ matrix.chart }}/${values_file}" --output-dir "shared/base-charts/${{ matrix.chart }}/${values_file}"
+            done
+          fi
+          echo sanitized_name=$(echo "${{ matrix.chart }}" | sed 's/\//-/g') >> $GITHUB_OUTPUT
+      - name: upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: "shared-base-${{ steps.render_base.outputs.sanitized_name }}"
+          path: "shared"
+
+  diff_helm_charts:
+    runs-on: ubuntu-latest
+    needs:
+      - get_changed_helm_charts
+      - render_base_ref_charts
+      - render_head_ref_charts
+    steps:
+      - name: setup helm
+        uses: azure/[email protected]
+
+      - name: download artifacts
+        uses: actions/download-artifact@v4
+        with:
+          pattern: shared-*
+          merge-multiple: true
+          path: "shared"
+
+      - name: diff helm charts
+        id: diff_helm_charts
+        run: |
+          for chart in ${{ needs.get_changed_helm_charts.outputs.charts }}; do
+            chart_diff_output=$(diff -r "shared/base-charts/${chart}" "shared/head-charts/${chart}" || true)
+            if [ -n "$chart_diff_output" ]; then
+              echo -e "Changes found in chart: ${chart}\n$(diff -ru shared/base-charts/${chart} shared/head-charts/${chart})\n" >> diff.log
+            fi
+          done
+      - name: post diff as comment on pull request
+        if: needs.get_changed_helm_charts.outputs.charts != ''
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const fs = require('fs');
+            const comment_char_limit = 65536; // GitHub comment character limit
+            const diff = fs.readFileSync('diff.log', 'utf8');
+
+            function splitComment(comment, maxSize, sepEnd, sepStart, comStart) {
+              // Adapted from Atlantis SplitComment function
+              // https://github.com/runatlantis/atlantis/blob/main/server/events/vcs/common/common.go#L18
+              if (comment.length <= (comment_char_limit - comStart.length)) {
+                return [comStart + diff]
+              }
+              maxWithSep = comment_char_limit - sepEnd.length - sepStart.length;
+              var comments = [];
+              var numComments = Math.ceil(comment.length / maxWithSep);
+              for (var i = 0; i < numComments; i++) {
+                var upTo = Math.min(comment.length, (i + 1) * maxWithSep);
+                var portion = comment.slice(i * maxWithSep, upTo);
+                if (i < numComments - 1) {
+                  portion += sepEnd;
+                }
+                if (i > 0) {
+                  portion = sepStart + portion
+                } else {
+                  portion = comStart + portion
+                }
+                comments.push(portion);
+              }
+              return comments;
+            }
+
+            var sepEnd = "\n```\n</details>" + "\n<br>\n\n**Warning**: Output length greater than max comment size. Continued in next comment.";
+            var sepStart = "Continued from previous comment.\n<details><summary>Show Output</summary>\n\n" + "```diff\n";
+            var comStart = "Changes found in Helm charts.\n<details><summary>Show Output</summary>\n\n" + "```diff\n";
+
+            comments = splitComment(diff, comment_char_limit, sepEnd, sepStart, comStart);
+
+            for (const comment of comments) {
+              await github.rest.issues.createComment({
+                issue_number: context.issue.number,
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                body: comment
+              })
+            }