diff-rendered-charts.md

Render and Diff Helm Charts Reusable Workflow

Renders Helm charts from both the base and head refs of a pull request and posts a diff as a PR comment showing what changes will be deployed.

Overview

• Detects changed Helm charts in pull requests
• Renders charts with all values files (supports multi-layer configurations)
• Posts a unified diff as a PR comment

Usage

Call this workflow from your repository's pull request workflow:

name: Review Helm Chart Changes

on:
  pull_request:
    paths:
      - '**/k8s/**'

jobs:
  diff-charts:
    uses: mozilla-it/deploy-actions/.github/workflows/diff-rendered-charts.yml@main

Example Output

When changes are detected, a comment will be posted to the PR:

Changes found in Helm charts.

Changes found in chart: apps/my-service/k8s
--- shared/base-charts/apps/my-service/k8s/values-prod/my-service/templates/deployment.yaml
+++ shared/head-charts/apps/my-service/k8s/values-prod/my-service/templates/deployment.yaml
@@ -15,7 +15,7 @@
       containers:
       - name: my-service
-        image: my-service:v1.0.0
+        image: my-service:v1.1.0