✨ Enhance sample external plugin: add Prometheus ServiceMonitor and kustomization, update PROJECT file handling, and improve test script

Author: nerdeveloper

docs/book/src/simple-external-plugin-tutorial/testdata/sampleexternalplugin/v1/go.mod

@@ -3,20 +3,20 @@ module v1
 go 1.24.5
 
 require (
+	github.com/spf13/afero v1.15.0
 	github.com/spf13/pflag v1.0.10
 	sigs.k8s.io/kubebuilder/v4 v4.9.0
-	sigs.k8s.io/yaml v1.6.0
 )
 
 replace sigs.k8s.io/kubebuilder/v4 => ../../../../../../../
 
 require (
 	github.com/gobuffalo/flect v1.0.3 // indirect
 	github.com/kr/text v0.2.0 // indirect
-	github.com/spf13/afero v1.15.0 // indirect
 	go.yaml.in/yaml/v2 v2.4.2 // indirect
 	golang.org/x/mod v0.28.0 // indirect
 	golang.org/x/sync v0.17.0 // indirect
 	golang.org/x/text v0.29.0 // indirect
 	golang.org/x/tools v0.37.0 // indirect
+	sigs.k8s.io/yaml v1.6.0 // indirect
 )

docs/book/src/simple-external-plugin-tutorial/testdata/sampleexternalplugin/v1/scaffolds/internal/templates/prometheus/kustomization.go renamed to docs/book/src/simple-external-plugin-tutorial/testdata/sampleexternalplugin/v1/internal/test/plugins/prometheus/kustomization.go

@@ -16,15 +16,18 @@ limitations under the License.
 package scaffolds
 
 import (
+	"errors"
 	"fmt"
 	"os"
-	"path/filepath"
 
-	"v1/scaffolds/internal/templates/prometheus"
+	"github.com/spf13/afero"
 
+	"v1/internal/test/plugins/prometheus"
+
+	"sigs.k8s.io/kubebuilder/v4/pkg/config/store/yaml"
+	"sigs.k8s.io/kubebuilder/v4/pkg/machinery"
 	"sigs.k8s.io/kubebuilder/v4/pkg/plugin"
 	"sigs.k8s.io/kubebuilder/v4/pkg/plugin/external"
-	yamlv3 "sigs.k8s.io/yaml"
 )
 
 var EditFlags = []external.Flag{}
@@ -77,48 +80,46 @@ func EditCmd(pr *external.PluginRequest) external.PluginResponse {
 
 // ProjectConfig represents the minimal PROJECT file structure we need
 type ProjectConfig struct {
-	Domain      string `yaml:"domain"`
-	ProjectName string `yaml:"projectName"`
-	Repo        string `yaml:"repo"`
+	Domain      string
+	ProjectName string
+	Repo        string
 }
 
-// loadProjectConfig reads the PROJECT file and extracts necessary information
+// loadProjectConfig reads the PROJECT file using the kubebuilder config API.
 func loadProjectConfig() (*ProjectConfig, error) {
-	projectPath := filepath.Join(".", "PROJECT")
-
-	if _, err := os.Stat(projectPath); os.IsNotExist(err) {
-		// Return default values if PROJECT file doesn't exist
-		return &ProjectConfig{
-			Domain:      "example.com",
-			ProjectName: "project",
-			Repo:        "example.com/project",
-		}, nil
-	}
-
-	data, err := os.ReadFile(projectPath)
-	if err != nil {
-		return nil, fmt.Errorf("failed to read PROJECT file: %w", err)
+	store := yaml.New(machinery.Filesystem{FS: afero.NewOsFs()})
+	if err := store.Load(); err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return &ProjectConfig{
+				Domain:      "example.com",
+				ProjectName: "project",
+				Repo:        "example.com/project",
+			}, nil
+		}
+		return nil, fmt.Errorf("failed to load PROJECT file: %w", err)
 	}
 
-	var cfg ProjectConfig
-	if err := yamlv3.Unmarshal(data, &cfg); err != nil {
-		return nil, fmt.Errorf("failed to unmarshal PROJECT file: %w", err)
+	cfg := store.Config()
+	if cfg == nil {
+		return nil, fmt.Errorf("PROJECT file is empty or invalid")
 	}
 
-	// Set defaults if fields are empty
-	if cfg.Domain == "" {
-		cfg.Domain = "example.com"
+	domain := cfg.GetDomain()
+	if domain == "" {
+		domain = "example.com"
 	}
-	if cfg.ProjectName == "" {
-		cfg.ProjectName = "project"
-		if cfg.Repo != "" {
-			// Extract project name from repo path
-			cfg.ProjectName = filepath.Base(cfg.Repo)
-		}
+	projectName := cfg.GetProjectName()
+	if projectName == "" {
+		projectName = "project"
 	}
-	if cfg.Repo == "" {
-		cfg.Repo = cfg.Domain + "/" + cfg.ProjectName
+	repo := cfg.GetRepository()
+	if repo == "" {
+		repo = fmt.Sprintf("%s/%s", domain, projectName)
 	}
 
-	return &cfg, nil
+	return &ProjectConfig{
+		Domain:      domain,
+		ProjectName: projectName,
+		Repo:        repo,
+	}, nil
 }

docs/book/src/simple-external-plugin-tutorial/testdata/sampleexternalplugin/v1/scaffolds/internal/templates/prometheus/servicemonitor.go renamed to docs/book/src/simple-external-plugin-tutorial/testdata/sampleexternalplugin/v1/internal/test/plugins/prometheus/servicemonitor.go

@@ -22,5 +22,10 @@ cd testdata/testplugin
 rm -rf *
 
 # Run Kubebuilder commands inside the testplugin directory
-kubebuilder init --plugins sampleexternalplugin/v1 --domain sample.domain.com
-kubebuilder create api --plugins sampleexternalplugin/v1 --number 2 --group samplegroup --version v1 --kind SampleKind
+kubebuilder init --plugins go/v4 --domain sample.domain.com --repo sample.domain.com/test-operator
+kubebuilder edit --plugins sampleexternalplugin/v1
+
+# Ensure Prometheus assets were scaffolded
+test -f config/prometheus/monitor.yaml
+test -f config/prometheus/kustomization.yaml
+test -f config/default/kustomization_prometheus_patch.yaml

docs/book/src/simple-external-plugin-tutorial/testdata/sampleexternalplugin/v1/scaffolds/edit.go

@@ -0,0 +1,135 @@
+# testplugin
+// TODO(user): Add simple overview of use/purpose
+
+## Description
+// TODO(user): An in-depth paragraph about your project and overview of use
+
+## Getting Started
+
+### Prerequisites
+- go version v1.24.0+
+- docker version 17.03+.
+- kubectl version v1.11.3+.
+- Access to a Kubernetes v1.11.3+ cluster.
+
+### To Deploy on the cluster
+**Build and push your image to the location specified by `IMG`:**
+
+```sh
+make docker-build docker-push IMG=<some-registry>/testplugin:tag
+```
+
+**NOTE:** This image ought to be published in the personal registry you specified.
+And it is required to have access to pull the image from the working environment.
+Make sure you have the proper permission to the registry if the above commands don’t work.
+
+**Install the CRDs into the cluster:**
+
+```sh
+make install
+```
+
+**Deploy the Manager to the cluster with the image specified by `IMG`:**
+
+```sh
+make deploy IMG=<some-registry>/testplugin:tag
+```
+
+> **NOTE**: If you encounter RBAC errors, you may need to grant yourself cluster-admin
+privileges or be logged in as admin.
+
+**Create instances of your solution**
+You can apply the samples (examples) from the config/sample:
+
+```sh
+kubectl apply -k config/samples/
+```
+
+>**NOTE**: Ensure that the samples has default values to test it out.
+
+### To Uninstall
+**Delete the instances (CRs) from the cluster:**
+
+```sh
+kubectl delete -k config/samples/
+```
+
+**Delete the APIs(CRDs) from the cluster:**
+
+```sh
+make uninstall
+```
+
+**UnDeploy the controller from the cluster:**
+
+```sh
+make undeploy
+```
+
+## Project Distribution
+
+Following the options to release and provide this solution to the users.
+
+### By providing a bundle with all YAML files
+
+1. Build the installer for the image built and published in the registry:
+
+```sh
+make build-installer IMG=<some-registry>/testplugin:tag
+```
+
+**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.:
+
+```sh
+kubectl apply -f https://raw.githubusercontent.com/<org>/testplugin/<tag or branch>/dist/install.yaml
+```
+
+### By providing a Helm Chart
+
+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
+
+**NOTE:** Run `make help` for more information on all potential `make` targets
+
+More information can be found via the [Kubebuilder Documentation](https://book.kubebuilder.io/introduction.html)
+
+## License
+
+Copyright 2025.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+