> Throughout this document, we will be setting up an application called `podinfo` as a demonstration.
## Project
It is recommended that you create your project in [Big Bang's Sandbox](https://repo1.dso.mil/platform-one/big-bang/apps/sandbox). This allows you to leverage Big Bang's pipelines, collaborate with Big Bang developers, and easily migrate to a fully graduated project.
You will need to request a sandbox project and Developer access from a Big Bang team member.
## Helm Chart
Big Bang requires a Helm chart to deploy your package. This Helm chart must be enhanced to support full integration with Big Bang components.
### Cloning Upstream
To minimize maintenance, it is preferable to reuse existing Helm charts available in the community (upstream). Changes to the upstream Helm chart should be made with new files when possible, and always clearly marked as Big Bang additions.
> Sometimes, it is not possible to find an upstream Helm chart and you must develop your own. This is beyond the scope of this document.
1. Identify the location of an existing Helm chart for the package.
> If selecting between several Helm charts, give preference to a Helm chart that:
>
> - Was created by the company that owns the package
> - Has recent and frequent updates
> - Offers maximum flexibility through values
> - Does not bundle several packages together (unless they can be individually disabled)
> - Provides advanced features like high availability, scaling, affinity, taints/tolerations, and security context
1. Using [Kpt](https://googlecontainertools.github.io/kpt/installation/), create a clone of the package's Helm chart
> Always use an release tag for `GITTAG` so your chart is immutable. Never use a branch or `latest`.
1. Add `-bb.0` suffix on `chart/Chart.yaml`, `version`. For example:
```yaml
version:6.0.0-bb.0
```
> The `bb.#` will increment for each change we merge into our `main` branch. It will also become our release label.
1. Add the following files to the Git repository at the root:
- CHANGELOG.md
The format of the changelog should be based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/) with versions equivalent to the Helm chart version.
Example:
```markdown
# Changelog
Format: [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
## [6.0.0-bb.0] - 2021-09-30
### Added
- Initial creation of the chart
```
- CODEOWNERS
Code owners are required approvals on merge requests in the Big Bang repository. This file should be setup based on [GitLab's Code Owners guidance](https://docs.gitlab.com/ee/user/project/code_owners.html).
Example:
```text
* @gitlabuser
```
- CONTRIBUTING.md
This document should outline the steps required for someone new to contribute to the repository.
1. Open an issue in GitLab describing the scope of your work
1. Assign yourself to the issue
1. Label the issue with `status::doing`
1. Create a branch in the repository using your issue number as a prefix
1. Make changes in code and push to your branch
1. Write tests using [cypress](https://www.cypress.io) and/or shell scripts.
1. Make commits using the [Conventional Commits](https://www.conventionalcommits.org/) format
1. Update `CHANGELOG.md` using the [Keep a Changelog](https://keepachangelog.com) format
1. Open a merge request into the `main` branch
1. Add a reference to the issue in the merge request description
1. Resolve any failures from the pipeline
1. Resolve any merge conflicts
1. Label the Merge Request with `status::review`
1. Contact the code owners to expedite your Merge Request review
1. Address any review comments and merge conflicts during the review process
1. Wait for a code owner to approve and merge your changes
1. Request a repository maintainer to create a release and tag
```
- LICENSE
The license file should contain the license terms and conditions for using the Helm charts. In general, Big Bang uses the [Apache 2.0 License](https://www.apache.org/licenses/LICENSE-2.0).
- README.md
The readme contains high-level information about the package. This document covers the following topics:
- Upstream References: Links to external documentation
- Documents: Links to /docs in repository
- Prerequisites: Tools needed to install and use
- Deployment: How to install / upgrade
- Values: How to configure Helm chart values
- Contributing: Link to contributing guide
There is a standard Big Bang template used for all packages. This can be created by following the [templating instructions](https://repo1.dso.mil/platform-one/big-bang/apps/library-charts/gluon/-/blob/master/docs/bb-package-readme.md)
> This process produces a `README.md`, `README.md.gotpl`, and `.helmdocsignore`. The `gotpl` file is used as values to update the `README.md`.
> To avoid having the `flux` helm chart also added to the `README.md`, run `echo 'flux/*' >> .helmdocsignore`
# After upgrading, identify deltas to upstream chart
kpt pkg diff chart > bb-mods-post.txt
# Look at the differences between the pre and post changes to make sure nothing was missed. Add any missing items back into the chart
diff bb-mods-pre.txt bb-mods-post.txt
# Commit and push changes
rm bb-mods-*.txt
git add -A
git commit -m"chore: update helm chart to $GITTAG"
git push
```
> In Kpt 1.0, `alpha-git-patch` was renamed to `resource-merge`.
## Validation
If you are not already familiar with the package, deploy the package using the upstream helm chart onto a Kubernetes cluster and explore the functionality before continuing. The Helm chart can be deployed according to the upstream package's documentation.
> It is recommended that you follow the instructions in [development environment](../development-environment.md) to get a Kubernetes cluster running.
