Add Hub and Spoke for conversion webhooks

Introduces the required code to add the code implementation for
the interfaces.

docs/book/src/multiversion-tutorial/conversion.md

@@ -1,8 +1,16 @@
 # Implementing conversion
 
 With our model for conversion in place, it's time to actually implement
-the conversion functions.  We'll put them in a file called
-`cronjob_conversion.go` next to our `cronjob_types.go` file, to avoid
+the conversion functions.  We'll create a conversion webhook
+for our CronJob API version `v1` (Hub) to Spoke our CronJob API version
+`v2` see:
+
+```go
+kubebuilder create webhook --group batch --version v1 --kind CronJob --conversion--spoke v2
+```
+
+The above command will generate the `cronjob_conversion.go` next to our
+`cronjob_types.go` file, to avoid
 cluttering up our main types file with extra functions.
 
 ## Hub...

docs/book/src/multiversion-tutorial/testdata/project/PROJECT

@@ -18,7 +18,9 @@ resources:
   path: tutorial.kubebuilder.io/project/api/v1
   version: v1
   webhooks:
+    conversion: true
     defaulting: true
+    spoke: v2
     validation: true
     webhookVersion: v1
 - api:
@@ -30,7 +32,6 @@ resources:
   path: tutorial.kubebuilder.io/project/api/v2
   version: v2
   webhooks:
-    conversion: true
     defaulting: true
     validation: true
     webhookVersion: v1

docs/book/src/multiversion-tutorial/testdata/project/api/v1/cronjob_conversion.go

@@ -1,4 +1,6 @@
 /*
+Copyright 2024 The Kubernetes authors.
+
 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

docs/book/src/multiversion-tutorial/testdata/project/api/v1/cronjob_types.go

@@ -127,6 +127,8 @@ type CronJobStatus struct {
 */
 
 // +kubebuilder:object:root=true
+// +kubebuilder:storageversion
+// +kubebuilder:conversion:hub
 // +kubebuilder:subresource:status
 // +versionName=v1
 // +kubebuilder:storageversion

docs/book/src/multiversion-tutorial/testdata/project/api/v2/cronjob_conversion.go

@@ -1,4 +1,6 @@
 /*
+Copyright 2024 The Kubernetes authors.
+
 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
@@ -21,16 +23,17 @@ For imports, we'll need the controller-runtime
 package, plus the API version for our hub type (v1), and finally some of the
 standard packages.
 */
+
 import (
 	"fmt"
 	"strings"
 
-	"sigs.k8s.io/controller-runtime/pkg/conversion"
+	"log"
 
-	v1 "tutorial.kubebuilder.io/project/api/v1"
-)
+	"sigs.k8s.io/controller-runtime/pkg/conversion"
 
-// +kubebuilder:docs-gen:collapse=Imports
+	batchv1 "tutorial.kubebuilder.io/project/api/v1"
+) // +kubebuilder:docs-gen:collapse=Imports
 
 /*
 Our "spoke" versions need to implement the
@@ -43,9 +46,11 @@ methods to convert to/from the hub version.
 ConvertTo is expected to modify its argument to contain the converted object.
 Most of the conversion is straightforward copying, except for converting our changed field.
 */
+
 // ConvertTo converts this CronJob to the Hub version (v1).
 func (src *CronJob) ConvertTo(dstRaw conversion.Hub) error {
-	dst := dstRaw.(*v1.CronJob)
+	dst := dstRaw.(*batchv1.CronJob)
+	log.Printf("Converting from %T to %T", dst.APIVersion, src.APIVersion)
 
 	sched := src.Spec.Schedule
 	scheduleParts := []string{"*", "*", "*", "*", "*"}
@@ -74,7 +79,7 @@ func (src *CronJob) ConvertTo(dstRaw conversion.Hub) error {
 
 	// Spec
 	dst.Spec.StartingDeadlineSeconds = src.Spec.StartingDeadlineSeconds
-	dst.Spec.ConcurrencyPolicy = v1.ConcurrencyPolicy(src.Spec.ConcurrencyPolicy)
+	dst.Spec.ConcurrencyPolicy = batchv1.ConcurrencyPolicy(src.Spec.ConcurrencyPolicy)
 	dst.Spec.Suspend = src.Spec.Suspend
 	dst.Spec.JobTemplate = src.Spec.JobTemplate
 	dst.Spec.SuccessfulJobsHistoryLimit = src.Spec.SuccessfulJobsHistoryLimit
@@ -85,6 +90,7 @@ func (src *CronJob) ConvertTo(dstRaw conversion.Hub) error {
 	dst.Status.LastScheduleTime = src.Status.LastScheduleTime
 
 	// +kubebuilder:docs-gen:collapse=rote conversion
+
 	return nil
 }
 
@@ -93,9 +99,10 @@ ConvertFrom is expected to modify its receiver to contain the converted object.
 Most of the conversion is straightforward copying, except for converting our changed field.
 */
 
-// ConvertFrom converts from the Hub version (v1) to this version.
+// ConvertFrom converts the Hub version (v1) to this CronJob (v2).
 func (dst *CronJob) ConvertFrom(srcRaw conversion.Hub) error {
-	src := srcRaw.(*v1.CronJob)
+	src := srcRaw.(*batchv1.CronJob)
+	log.Printf("Converting from %T to %T", src.APIVersion, dst.APIVersion)
 
 	schedParts := strings.Split(src.Spec.Schedule, " ")
 	if len(schedParts) != 5 {
@@ -133,5 +140,6 @@ func (dst *CronJob) ConvertFrom(srcRaw conversion.Hub) error {
 	dst.Status.LastScheduleTime = src.Status.LastScheduleTime
 
 	// +kubebuilder:docs-gen:collapse=rote conversion
+
 	return nil
 }

docs/book/src/multiversion-tutorial/testdata/project/config/crd/kustomization.yaml

@@ -10,6 +10,7 @@ patches:
 # patches here are for enabling the conversion webhook for each CRD
 - path: patches/webhook_in_cronjobs.yaml
 - path: patches/webhook_in_cronjobs.yaml
+- path: patches/webhook_in_cronjobs.yaml
 # +kubebuilder:scaffold:crdkustomizewebhookpatch
 
 # [CERTMANAGER] To enable cert-manager, uncomment all the sections with [CERTMANAGER] prefix.

docs/book/src/multiversion-tutorial/testdata/project/internal/webhook/v1/cronjob_webhook.go

@@ -44,11 +44,7 @@ Next, we'll setup a logger for the webhooks.
 var cronjoblog = logf.Log.WithName("cronjob-resource")
 
 /*
-This setup doubles as setup for our conversion webhooks: as long as our
-types implement the
-[Hub](https://pkg.go.dev/sigs.k8s.io/controller-runtime/pkg/conversion?tab=doc#Hub) and
-[Convertible](https://pkg.go.dev/sigs.k8s.io/controller-runtime/pkg/conversion?tab=doc#Convertible)
-interfaces, a conversion webhook will be registered.
+Then, we set up the webhook with the manager.
 */
 
 // SetupCronJobWebhookWithManager registers the webhook for CronJob in the manager.

docs/book/src/multiversion-tutorial/testdata/project/internal/webhook/v2/cronjob_webhook_test.go

@@ -84,14 +84,4 @@ var _ = Describe("CronJob Webhook", func() {
 		// })
 	})
 
-	Context("When creating CronJob under Conversion Webhook", func() {
-		// TODO (user): Add logic to convert the object to the desired version and verify the conversion
-		// Example:
-		// It("Should convert the object correctly", func() {
-		//     convertedObj := &batchv2.CronJob{}
-		//     Expect(obj.ConvertTo(convertedObj)).To(Succeed())
-		//     Expect(convertedObj).ToNot(BeNil())
-		// })
-	})
-
 })

docs/book/src/multiversion-tutorial/webhooks.md

@@ -3,15 +3,6 @@
 Our conversion is in place, so all that's left is to tell
 controller-runtime about our conversion.
 
-Normally, we'd run
-
-```shell
-kubebuilder create webhook --group batch --version v1 --kind CronJob --conversion
-```
-
-to scaffold out the webhook setup.  However, we've already got webhook
-setup, from when we built our defaulting and validating webhooks!
-
 ## Webhook setup...
 
 {{#literatego ./testdata/project/internal/webhook/v1/cronjob_webhook.go}}

docs/book/src/reference/project-config.md

@@ -150,6 +150,7 @@ Now let's check its layout fields definition:
 | `resources.core`                    | It is `true` when  the group used is from Kubernetes API and the API resource is not defined on the project.                                                                                                                                                                    |
 | `resources.external`                | It is `true` when  the flag `--external-api-path` was used to generated the scaffold for an [External Type][external-type].                                                                                                                                                     |
 | `resources.webhooks`                | Store the webhooks data when the sub-command `create webhook` is used.                                                                                                                                                                                                          |
+| `resources.webhooks.spoke`          | Store the API version that will act as the Spoke with the designated Hub version for conversion webhooks.                                                                                                                                                                       |
 | `resources.webhooks.webhookVersion` | The Kubernetes API version (`apiVersion`) used to scaffold the webhook resource.                                                                                                                                                                                                |
 | `resources.webhooks.conversion`     | It is `true` when the webhook was scaffold with the `--conversion` flag which means that is a conversion webhook.                                                                                                                                                               |
 | `resources.webhooks.defaulting`     | It is `true` when the webhook was scaffold with the `--defaulting` flag which means that is a defaulting webhook.                                                                                                                                                               |

hack/docs/internal/multiversion-tutorial/generate_multiversion.go

@@ -17,7 +17,6 @@ limitations under the License.
 package multiversion
 
 import (
-	"os"
 	"os/exec"
 	"path/filepath"
 
@@ -57,14 +56,23 @@ func (sp *Sample) GenerateSampleProject() {
 	)
 	hackutils.CheckError("Creating the v2 API without controller", err)
 
+	log.Infof("Creating conversion webhook for v1")
+	err = sp.ctx.CreateWebhook(
+		"--group", "batch",
+		"--version", "v1",
+		"--kind", "CronJob",
+		"--conversion",
+		"--spoke", "v2",
+	)
+	hackutils.CheckError("Creating conversion webhook for v1", err)
+
 	log.Infof("Creating defaulting and validation webhook for v2")
 	err = sp.ctx.CreateWebhook(
 		"--group", "batch",
 		"--version", "v2",
 		"--kind", "CronJob",
 		"--defaulting",
 		"--programmatic-validation",
-		"--conversion",
 	)
 	hackutils.CheckError("Creating defaulting and validation webhook for v2", err)
 }
@@ -75,25 +83,12 @@ func (sp *Sample) UpdateTutorial() {
 	// Update files according to the multiversion
 	sp.updateApiV1()
 	sp.updateApiV2()
-	sp.updateWebhookV1()
 	sp.updateWebhookV2()
-	sp.createHubFiles()
+	sp.updateConversionFiles()
 	sp.updateSampleV2()
 	sp.updateMain()
 }
 
-func (sp *Sample) updateWebhookV1() {
-	err := pluginutil.ReplaceInFile(
-		filepath.Join(sp.ctx.Dir, "internal/webhook/v1/cronjob_webhook.go"),
-		"Then, we set up the webhook with the manager.",
-		`This setup doubles as setup for our conversion webhooks: as long as our
-types implement the
-[Hub](https://pkg.go.dev/sigs.k8s.io/controller-runtime/pkg/conversion?tab=doc#Hub) and
-[Convertible](https://pkg.go.dev/sigs.k8s.io/controller-runtime/pkg/conversion?tab=doc#Convertible)
-interfaces, a conversion webhook will be registered.`,
-	)
-	hackutils.CheckError("replace webhook setup text", err)
-}
 func (sp *Sample) updateSampleV2() {
 	path := filepath.Join(sp.ctx.Dir, "config/samples/batch_v2_cronjob.yaml")
 	oldText := `# TODO(user): Add fields here`
@@ -106,29 +101,82 @@ func (sp *Sample) updateSampleV2() {
 	hackutils.CheckError("replacing TODO with sampleV2Code in batch_v2_cronjob.yaml", err)
 }
 
-func (sp *Sample) createHubFiles() {
+func (sp *Sample) updateConversionFiles() {
 	path := filepath.Join(sp.ctx.Dir, "api/v1/cronjob_conversion.go")
 
-	_, err := os.Create(path)
-	hackutils.CheckError("creating conversion file v1", err)
+	err := pluginutil.InsertCodeIfNotExist(path,
+		"limitations under the License.\n*/",
+		"\n// +kubebuilder:docs-gen:collapse=Apache License")
+	hackutils.CheckError("appending into hub v1 collapse docs", err)
 
-	err = pluginutil.AppendCodeAtTheEnd(path, "")
-	hackutils.CheckError("creating empty conversion file v1", err)
-
-	err = pluginutil.AppendCodeAtTheEnd(path, hubV1Code)
-	hackutils.CheckError("appending hubV1Code to cronjob_conversion.go", err)
+	err = pluginutil.ReplaceInFile(path,
+		"// EDIT THIS FILE!  THIS IS SCAFFOLDING FOR YOU TO OWN!",
+		hubV1CodeComment)
+	hackutils.CheckError("adding comment to hub v1", err)
 
 	path = filepath.Join(sp.ctx.Dir, "api/v2/cronjob_conversion.go")
 
-	_, err = os.Create(path)
-	hackutils.CheckError("creating conversion file v2", err)
+	err = pluginutil.InsertCodeIfNotExist(path,
+		"limitations under the License.\n*/",
+		"\n// +kubebuilder:docs-gen:collapse=Apache License")
+	hackutils.CheckError("appending into hub v2 collapse docs", err)
 
-	err = pluginutil.AppendCodeAtTheEnd(path, "")
-	hackutils.CheckError("creating empty conversion file v2", err)
+	err = pluginutil.InsertCode(path,
+		"import (",
+		`
+	"fmt"
+	"strings"
 
-	err = pluginutil.AppendCodeAtTheEnd(path, hubV2Code)
-	hackutils.CheckError("appending hubV2Code to cronjob_conversion.go", err)
+`)
+	hackutils.CheckError("adding imports to hub v2", err)
+
+	err = pluginutil.InsertCodeIfNotExist(path,
+		"batchv1 \"tutorial.kubebuilder.io/project/api/v1\"\n)",
+		`// +kubebuilder:docs-gen:collapse=Imports
+
+/*
+Our "spoke" versions need to implement the
+[`+"`"+`Convertible`+"`"+`](https://pkg.go.dev/sigs.k8s.io/controller-runtime/pkg/conversion?tab=doc#Convertible)
+interface. Namely, they'll need `+"`"+`ConvertTo()`+"`"+` and `+"`"+`ConvertFrom()`+"`"+`
+methods to convert to/from the hub version.
+*/
+`)
+	hackutils.CheckError("appending into hub v2 collapse docs", err)
+
+	err = pluginutil.ReplaceInFile(path,
+		"package v2",
+		hubV2CodeComment)
+	hackutils.CheckError("adding comment to hub v2", err)
+
+	err = pluginutil.ReplaceInFile(path,
+		"// TODO: Implement conversion logic from v2 to v1",
+		hubV2CovertTo)
+	hackutils.CheckError("replace covertTo at hub v2", err)
+
+	err = pluginutil.ReplaceInFile(path,
+		"// TODO: Implement conversion logic from v1 to v2",
+		hubV2ConvertFromCode)
+	hackutils.CheckError("replace covert from at hub v2", err)
+
+	err = pluginutil.ReplaceInFile(path,
+		"// ConvertFrom converts the Hub version (v1) to this CronJob (v2).",
+		`/*
+ConvertFrom is expected to modify its receiver to contain the converted object.
+Most of the conversion is straightforward copying, except for converting our changed field.
+*/
+
+// ConvertFrom converts the Hub version (v1) to this CronJob (v2).`)
+	hackutils.CheckError("replace covert from info at hub v2", err)
+
+	err = pluginutil.ReplaceInFile(path,
+		"// ConvertTo converts this CronJob to the Hub version (v1).",
+		`/*
+ConvertTo is expected to modify its argument to contain the converted object.
+Most of the conversion is straightforward copying, except for converting our changed field.
+*/
 
+// ConvertTo converts this CronJob to the Hub version (v1).`)
+	hackutils.CheckError("replace covert info at hub v2", err)
 }
 
 func (sp *Sample) updateApiV1() {