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Release Helm Charts - GitHub Action

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Overview​

What it is​

A reusable composite GitHub Action for publishing Helm charts to GitHub Pages. It detects changed charts, updates dependencies, runs helm lint, packages the chart, merges the repository index, and pushes the result to the Pages branch.

Why it exists​

I built it to understand how composite GitHub Actions and Helm chart repositories work under the hood. I also wanted one release step I could reuse across my own projects instead of copying the same Bash workflow into each repo.

The project maps well to DevOps work: release automation, Git branch handling, Helm packaging, and CI jobs that update generated artifacts without causing loops.

Outcome​

Key Results
  • Published on the GitHub Marketplace
  • Reusable composite action built with Bash, Helm, Git, and GitHub Actions
  • Processes only changed charts
  • Preserves older chart versions in index.yaml
  • Publishes packaged charts to GitHub Pages

Tech Stack​

Automation: GitHub Actions composite action
Packaging: Helm
Publishing: GitHub Pages
Scripting: Bash, Git

Implementation Setup​

Action Flow​

The action runs a release workflow inside one GitHub Actions job:

  1. Check out the source branch.
  2. Check out the GitHub Pages branch into a separate directory.
  3. Compare both trees to detect changed charts.
  4. Run helm dependency update for each changed chart.
  5. Run helm lint.
  6. Package the chart with helm package.
  7. Merge new packages into index.yaml.
  8. Commit and push the generated chart repo to the Pages branch.

Composite Action Structure​

  • Bash scripts handle branch paths, chart detection, packaging, and commits
  • Helm commands handle dependency updates, linting, packaging, and index generation
  • Git handles diffing, staged changes, commits, and pushes
  • The action exposes inputs for chart path, source branch, Pages branch, and commit metadata

Key Implementation Details​

  • Dual checkout: The workflow checks out the source branch at the workspace root and the Pages branch in a subdirectory.
  • Change detection: The action compares the source checkout with the Pages checkout so it packages only modified charts.
  • Index merge: helm repo index --merge keeps older chart versions installable.
  • No-op runs: The commit step skips pushing when the action has no generated changes.
  • Marketplace packaging: The repo includes action metadata so other workflows can call it as a reusable action.

Key Challenges & Solutions​

Challenge 1: Preserving Chart Version History​

Problem: A Helm repository index lists every chart version users can install. If the action regenerated index.yaml from only the latest package, older chart versions would disappear from the repo metadata.

Solution: The action keeps the existing index.yaml from the Pages branch and passes it to helm repo index --merge. Helm adds new packages while preserving existing entries.

Result

Older chart versions stay installable after new releases.

Challenge 2: Avoiding Empty Commits​

Problem: A workflow that commits generated artifacts can create noisy history when no chart changed. Empty commits also make it harder to tell which runs produced a real release.

Solution: The script checks for staged changes before committing. If Helm packaging and index generation produce no diff, the action exits without pushing.

Result

Release history only changes when the action publishes chart artifacts.