Add Helm Plugin for Project Distribution

This PR introduces an optional Helm plugin, enabling users to scaffold Helm charts for Kubebuilder projects.

- **Helm Chart Scaffolding**: Allows generation of a Helm chart under the `dist/chart` directory, providing an alternative for distributing and managing projects via Helm.
- **Usage**:
  - **To add when init the project**: `kubebuilder init --plugins=helm/v1-alpha` for new projects.
  - **To Init/Update in a project previously scaffolded**: `kubebuilder edit --plugins=helm/v1-alpha` to add or update Helm charts for existing projects.
- **Sync Helm Chart**: Syncs the Helm chart with project manifests using the `edit` command, with `--force` required for updates after webhook or `DeployImage` plugin changes in order to overwritten the values.yaml and manager.yaml files.

- **Examples**: Usage samples can be found in `testdata/project-v4-with-plugins`.
- **Testing**: Adds GitHub Actions workflows to validate Helm integration, including linting, installation, and e2e checks.

**Note**: For details on the original proposal, see [PR kubernetes-sigs#3632](kubernetes-sigs#3632).

Author: camilamacedo86

.github/workflows/test-helm-samples.yml

@@ -0,0 +1,76 @@
+name: Helm Testdata Sample
+
+on:
+  push:
+    paths:
+      - 'testdata/project-v4-with-plugins/**'
+      - '.github/workflows/test-helm-samples.yml'
+  pull_request:
+    paths:
+      - 'testdata/project-v4-with-plugins/**'
+      - '.github/workflows/test-helm-samples.yml'
+
+jobs:
+  helm-test-project-v4-with-plugins:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: true
+    if: github.event_name == 'push' || github.event.pull_request.head.repo.full_name != github.repository
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Setup Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: '~1.22'
+
+      - name: Install the latest version of kind
+        run: |
+          curl -Lo ./kind https://kind.sigs.k8s.io/dl/latest/kind-linux-amd64
+          chmod +x ./kind
+          sudo mv ./kind /usr/local/bin/kind
+
+      - name: Verify kind installation
+        run: kind version
+
+      - name: Create kind cluster
+        run: kind create cluster
+
+      - name: Install cert-manager via Helm
+        run: |
+          helm repo add jetstack https://charts.jetstack.io
+          helm repo update
+          helm install cert-manager jetstack/cert-manager --namespace cert-manager --create-namespace --set installCRDs=true
+
+      - name: Wait for cert-manager to be ready
+        run: |
+          kubectl wait --namespace cert-manager --for=condition=available --timeout=300s deployment/cert-manager
+          kubectl wait --namespace cert-manager --for=condition=available --timeout=300s deployment/cert-manager-cainjector
+          kubectl wait --namespace cert-manager --for=condition=available --timeout=300s deployment/cert-manager-webhook
+
+      - name: Prepare project-v4-with-plugins
+        run: |
+          cd testdata/project-v4-with-plugins/
+          go mod tidy
+          make docker-build IMG=project-v4-with-plugins:v0.1.0
+          kind load docker-image project-v4-with-plugins:v0.1.0
+
+      - name: Install Helm
+        run: |
+          curl https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 | bash
+
+      - name: Verify Helm installation
+        run: helm version
+
+      - name: Lint Helm chart for project-v4-with-plugins
+        run: |
+          helm lint testdata/project-v4-with-plugins/dist/chart
+
+      - name: Install Helm chart for project-v4-with-plugins
+        run: |
+          helm install my-release testdata/project-v4-with-plugins/dist/chart --create-namespace --namespace project-v4-with-plugins-system
+
+      - name: Check Helm release status
+        run: |
+          helm status my-release --namespace project-v4-with-plugins-system

Makefile

@@ -97,7 +97,7 @@ lint-fix: golangci-lint ## Run golangci-lint linter and perform fixes
 
 .PHONY: yamllint
 yamllint:
-	@files=$$(find testdata -name '*.yaml' ! -path 'testdata/*/dist/install.yaml'); \
+	@files=$$(find testdata -name '*.yaml' ! -path 'testdata/*/dist/*'); \
     	docker run --rm $$(tty -s && echo "-it" || echo) -v $(PWD):/data cytopia/yamllint:latest $$files -d "{extends: relaxed, rules: {line-length: {max: 120}}}" --no-warnings
 
 GOLANGCI_LINT = $(shell pwd)/bin/golangci-lint
@@ -171,3 +171,11 @@ test-spaces:  ## Run the trailing spaces check
 test-legacy:  ## Run the tests to validate legacy path for webhooks
 	rm -rf  ./testdata/**legacy**/
 	./test/testdata/legacy-webhook-path.sh
+
+.PHONY: install-helm
+install-helm: ## Install the latest version of Helm locally
+	@curl https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 | bash
+
+.PHONY: helm-lint
+helm-lint: install-helm ## Lint the Helm chart in testdata
+	helm lint testdata/project-v4-with-plugins/dist/chart

cmd/main.go

@@ -30,6 +30,7 @@ import (
 	deployimagev1alpha1 "sigs.k8s.io/kubebuilder/v4/pkg/plugins/golang/deploy-image/v1alpha1"
 	golangv4 "sigs.k8s.io/kubebuilder/v4/pkg/plugins/golang/v4"
 	grafanav1alpha1 "sigs.k8s.io/kubebuilder/v4/pkg/plugins/optional/grafana/v1alpha"
+	helmv1alpha1 "sigs.k8s.io/kubebuilder/v4/pkg/plugins/optional/helm/v1alpha"
 )
 
 func init() {
@@ -61,6 +62,7 @@ func main() {
 			&kustomizecommonv2.Plugin{},
 			&deployimagev1alpha1.Plugin{},
 			&grafanav1alpha1.Plugin{},
+			&helmv1alpha1.Plugin{},
 		),
 		cli.WithPlugins(externalPlugins...),
 		cli.WithDefaultPlugins(cfgv3.Version, gov4Bundle),

docs/book/src/cronjob-tutorial/testdata/project/README.md

@@ -68,27 +68,54 @@ make undeploy
 
 ## Project Distribution
 
-Following are the steps to build the installer and distribute this project to users.
+Following the options to release and provide this solution
+to the users.
+
+### By providing a bundle with all YAML files
+
+Following are the steps to build the installer and distribute
+this project to users.
 
 1. Build the installer for the image built and published in the registry:
 
 ```sh
 make build-installer IMG=<some-registry>/project:tag
 ```
 
-NOTE: The makefile target mentioned above generates an 'install.yaml'
+**NOTE:** The makefile target mentioned above generates an 'install.yaml'
 file in the dist directory. This file contains all the resources built
 with Kustomize, which are necessary to install this project without
 its dependencies.
 
 2. Using the installer
 
-Users can just run kubectl apply -f <URL for YAML BUNDLE> to install the project, i.e.:
+Users can just run 'kubectl apply -f <URL for YAML BUNDLE>' to install the project, i.e.:
 
 ```sh
 kubectl apply -f https://raw.githubusercontent.com/<org>/project/<tag or branch>/dist/install.yaml
 ```
 
+### By providing a Helm Chart
+
+Following are the steps to build a Helm Chart to distribute
+this project to users.
+
+1. Build the chart using the optional helm plugin
+
+```sh
+kubebuilder edit --plugins=helm/v1-alpha
+```
+
+2. See that a chart was generated under 'dist/chart', and users
+can obtain this solution from there.
+
+**NOTE:** If you change the project, you need to update the Helm Chart
+using the same command above to sync the latest changes. Furthermore,
+if you create webhooks, you need to use the above command with
+the '--force' flag and manually ensure that any custom configuration
+previously added to 'dist/chart/values.yaml' or 'dist/chart/manager/manager.yaml'
+is manually re-applied afterwards.
+
 ## Contributing
 // TODO(user): Add detailed information on how you would like others to contribute to this project
 

docs/book/src/getting-started/testdata/project/README.md

@@ -68,27 +68,54 @@ make undeploy
 
 ## Project Distribution
 
-Following are the steps to build the installer and distribute this project to users.
+Following the options to release and provide this solution
+to the users.
+
+### By providing a bundle with all YAML files
+
+Following are the steps to build the installer and distribute
+this project to users.
 
 1. Build the installer for the image built and published in the registry:
 
 ```sh
 make build-installer IMG=<some-registry>/project:tag
 ```
 
-NOTE: The makefile target mentioned above generates an 'install.yaml'
+**NOTE:** The makefile target mentioned above generates an 'install.yaml'
 file in the dist directory. This file contains all the resources built
 with Kustomize, which are necessary to install this project without
 its dependencies.
 
 2. Using the installer
 
-Users can just run kubectl apply -f <URL for YAML BUNDLE> to install the project, i.e.:
+Users can just run 'kubectl apply -f <URL for YAML BUNDLE>' to install the project, i.e.:
 
 ```sh
 kubectl apply -f https://raw.githubusercontent.com/<org>/project/<tag or branch>/dist/install.yaml
 ```
 
+### By providing a Helm Chart
+
+Following are the steps to build a Helm Chart to distribute
+this project to users.
+
+1. Build the chart using the optional helm plugin
+
+```sh
+kubebuilder edit --plugins=helm/v1-alpha
+```
+
+2. See that a chart was generated under 'dist/chart', and users
+can obtain this solution from there.
+
+**NOTE:** If you change the project, you need to update the Helm Chart
+using the same command above to sync the latest changes. Furthermore,
+if you create webhooks, you need to use the above command with
+the '--force' flag and manually ensure that any custom configuration
+previously added to 'dist/chart/values.yaml' or 'dist/chart/manager/manager.yaml'
+is manually re-applied afterwards.
+
 ## Contributing
 // TODO(user): Add detailed information on how you would like others to contribute to this project
 

docs/book/src/multiversion-tutorial/testdata/project/README.md

@@ -68,27 +68,54 @@ make undeploy
 
 ## Project Distribution
 
-Following are the steps to build the installer and distribute this project to users.
+Following the options to release and provide this solution
+to the users.
+
+### By providing a bundle with all YAML files
+
+Following are the steps to build the installer and distribute
+this project to users.
 
 1. Build the installer for the image built and published in the registry:
 
 ```sh
 make build-installer IMG=<some-registry>/project:tag
 ```
 
-NOTE: The makefile target mentioned above generates an 'install.yaml'
+**NOTE:** The makefile target mentioned above generates an 'install.yaml'
 file in the dist directory. This file contains all the resources built
 with Kustomize, which are necessary to install this project without
 its dependencies.
 
 2. Using the installer
 
-Users can just run kubectl apply -f <URL for YAML BUNDLE> to install the project, i.e.:
+Users can just run 'kubectl apply -f <URL for YAML BUNDLE>' to install the project, i.e.:
 
 ```sh
 kubectl apply -f https://raw.githubusercontent.com/<org>/project/<tag or branch>/dist/install.yaml
 ```
 
+### By providing a Helm Chart
+
+Following are the steps to build a Helm Chart to distribute
+this project to users.
+
+1. Build the chart using the optional helm plugin
+
+```sh
+kubebuilder edit --plugins=helm/v1-alpha
+```
+
+2. See that a chart was generated under 'dist/chart', and users
+can obtain this solution from there.
+
+**NOTE:** If you change the project, you need to update the Helm Chart
+using the same command above to sync the latest changes. Furthermore,
+if you create webhooks, you need to use the above command with
+the '--force' flag and manually ensure that any custom configuration
+previously added to 'dist/chart/values.yaml' or 'dist/chart/manager/manager.yaml'
+is manually re-applied afterwards.
+
 ## Contributing
 // TODO(user): Add detailed information on how you would like others to contribute to this project
 

docs/book/src/plugins/available/helm-v1-alpha.md

@@ -0,0 +1,92 @@
+# Helm Plugin (`helm/v1-alpha`)
+
+The Helm plugin is an optional plugin that can be used to scaffold a Helm chart, allowing you to distribute the project using Helm.
+
+By default, users can generate a bundle with all the manifests by running the following command:
+
+```bash
+make build-installer IMG=<some-registry>/<project-name:tag>
+```
+
+This allows the project consumer to install the solution by applying the bundle with:
+
+```bash
+kubectl apply -f https://raw.githubusercontent.com/<org>/project-v4/<tag or branch>/dist/install.yaml
+```
+
+However, in many scenarios, you might prefer to provide a Helm chart to package your solution.
+If so, you can use this plugin to generate the Helm chart under the `dist` directory.
+
+<aside class="note">
+<h1>Examples</h1>
+
+You can check the plugin usage by looking at `project-v4-with-plugins` samples
+under the [testdata][testdata] directory on the root directory of the Kubebuilder project.
+
+</aside>
+
+## When to use it
+
+- If you want to provide a Helm chart for users to install and manage your project.
+- If you need to update the Helm chart generated under `dist/chart/` with the latest project changes:
+  - After generating new manifests, use the `edit` option to sync the Helm chart.
+  - **IMPORTANT:** If you have created a webhook or an API using the [DeployImage][deployImage-plugin] plugin,
+  you must run the `edit` command with the `--force` flag to regenerate the Helm chart values based
+  on the latest manifests (_after running `make manifests`_) to ensure that the HelmChart values are
+  updated accordingly. In this case, if you have customized the files
+  under `dist/chart/values.yaml`, and the `templates/manager/manager.yaml`, you will need to manually reapply your customizations on top
+  of the latest changes after regenerating the Helm chart.
+
+## How to use it ?
+
+### Basic Usage
+
+The Helm plugin is attached to the `init` subcommand and the `edit` subcommand:
+
+```sh
+
+# Initialize a new project with helm chart
+kubebuilder init --plugins=helm/v1-alpha
+
+# Enable or Update the helm chart via the helm plugin to an existing project
+# Before run the edit command, run `make manifests` to generate the manifest under `config/`
+make manifests
+kubebuilder edit --plugins=helm/v1-alpha
+```
+<aside class="note">
+  <h1>Use the edit command to update the Helm Chart with the latest changes</h1>
+
+  After making changes to your project, ensure that you run `make manifests` and then
+  use the command `kubebuilder edit --plugins=helm/v1-alpha` to update the Helm Chart.
+
+  Note that the following files will **not** be updated unless you use the `--force` flag:
+
+  <pre>
+  dist/chart/
+  ├── values.yaml
+  └── templates/
+      └── manager/
+          └── manager.yaml
+  </pre>
+
+  The files `chart/Chart.yaml`, `chart/templates/_helpers.tpl`, and `chart/.helmignore` are never updated
+  after their initial creation unless you remove them.
+
+</aside>
+
+## Subcommands
+
+The Helm plugin implements the following subcommands:
+
+- edit (`$ kubebuilder edit [OPTIONS]`)
+
+- init (`$ kubebuilder init [OPTIONS]`)
+
+## Affected files
+
+The following scaffolds will be created or updated by this plugin:
+
+- `dist/chart/*`
+
+[testdata]: https://github.com/kubernetes-sigs/kubebuilder/tree/master/testdata/project-v4-with-plugins
+[deployImage-plugin]: ./deploy-image-plugin-v1-alpha.md