Merge pull request #29334 from adellape/imp_golang

Edits to Golang tutorial

Author: adellape

modules/osdk-golang-implement-controller.adoc

@@ -9,7 +9,210 @@ After creating a new API and controller, you can implement the controller logic.
 
 .Procedure
 
-* For this example, replace the generated controller file `controllers/memcached_controller.go` with the `memcached_controller.go` link:https://github.com/operator-framework/operator-sdk/blob/v1.3.0/testdata/go/v2/memcached-operator/controllers/memcached_controller.go[example implementation].
+* For this example, replace the generated controller file `controllers/memcached_controller.go` with following example implementation:
++
+.Example `memcached_controller.go`
+[%collapsible]
+====
+[source,golang]
+----
+/*
+Copyright 2020.
+
+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.
+*/
+
+package controllers
+
+import (
+	appsv1 "k8s.io/api/apps/v1"
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/types"
+	"reflect"
+
+	"context"
+
+	"github.com/go-logr/logr"
+	"k8s.io/apimachinery/pkg/runtime"
+	ctrl "sigs.k8s.io/controller-runtime"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+
+	cachev1alpha1 "github.com/example/memcached-operator/api/v1alpha1"
+)
+
+// MemcachedReconciler reconciles a Memcached object
+type MemcachedReconciler struct {
+	client.Client
+	Log    logr.Logger
+	Scheme *runtime.Scheme
+}
+
+// +kubebuilder:rbac:groups=cache.example.com,resources=memcacheds,verbs=get;list;watch;create;update;patch;delete
+// +kubebuilder:rbac:groups=cache.example.com,resources=memcacheds/status,verbs=get;update;patch
+// +kubebuilder:rbac:groups=cache.example.com,resources=memcacheds/finalizers,verbs=update
+// +kubebuilder:rbac:groups=apps,resources=deployments,verbs=get;list;watch;create;update;patch;delete
+// +kubebuilder:rbac:groups=core,resources=pods,verbs=get;list;
+
+// Reconcile is part of the main kubernetes reconciliation loop which aims to
+// move the current state of the cluster closer to the desired state.
+// TODO(user): Modify the Reconcile function to compare the state specified by
+// the Memcached object against the actual cluster state, and then
+// perform operations to make the cluster state reflect the state specified by
+// the user.
+//
+// For more details, check Reconcile and its Result here:
+// - https://pkg.go.dev/sigs.k8s.io/[email protected]/pkg/reconcile
+func (r *MemcachedReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
+	log := r.Log.WithValues("memcached", req.NamespacedName)
+
+	// Fetch the Memcached instance
+	memcached := &cachev1alpha1.Memcached{}
+	err := r.Get(ctx, req.NamespacedName, memcached)
+	if err != nil {
+		if errors.IsNotFound(err) {
+			// Request object not found, could have been deleted after reconcile request.
+			// Owned objects are automatically garbage collected. For additional cleanup logic use finalizers.
+			// Return and don't requeue
+			log.Info("Memcached resource not found. Ignoring since object must be deleted")
+			return ctrl.Result{}, nil
+		}
+		// Error reading the object - requeue the request.
+		log.Error(err, "Failed to get Memcached")
+		return ctrl.Result{}, err
+	}
+
+	// Check if the deployment already exists, if not create a new one
+	found := &appsv1.Deployment{}
+	err = r.Get(ctx, types.NamespacedName{Name: memcached.Name, Namespace: memcached.Namespace}, found)
+	if err != nil && errors.IsNotFound(err) {
+		// Define a new deployment
+		dep := r.deploymentForMemcached(memcached)
+		log.Info("Creating a new Deployment", "Deployment.Namespace", dep.Namespace, "Deployment.Name", dep.Name)
+		err = r.Create(ctx, dep)
+		if err != nil {
+			log.Error(err, "Failed to create new Deployment", "Deployment.Namespace", dep.Namespace, "Deployment.Name", dep.Name)
+			return ctrl.Result{}, err
+		}
+		// Deployment created successfully - return and requeue
+		return ctrl.Result{Requeue: true}, nil
+	} else if err != nil {
+		log.Error(err, "Failed to get Deployment")
+		return ctrl.Result{}, err
+	}
+
+	// Ensure the deployment size is the same as the spec
+	size := memcached.Spec.Size
+	if *found.Spec.Replicas != size {
+		found.Spec.Replicas = &size
+		err = r.Update(ctx, found)
+		if err != nil {
+			log.Error(err, "Failed to update Deployment", "Deployment.Namespace", found.Namespace, "Deployment.Name", found.Name)
+			return ctrl.Result{}, err
+		}
+		// Spec updated - return and requeue
+		return ctrl.Result{Requeue: true}, nil
+	}
+
+	// Update the Memcached status with the pod names
+	// List the pods for this memcached's deployment
+	podList := &corev1.PodList{}
+	listOpts := []client.ListOption{
+		client.InNamespace(memcached.Namespace),
+		client.MatchingLabels(labelsForMemcached(memcached.Name)),
+	}
+	if err = r.List(ctx, podList, listOpts...); err != nil {
+		log.Error(err, "Failed to list pods", "Memcached.Namespace", memcached.Namespace, "Memcached.Name", memcached.Name)
+		return ctrl.Result{}, err
+	}
+	podNames := getPodNames(podList.Items)
+
+	// Update status.Nodes if needed
+	if !reflect.DeepEqual(podNames, memcached.Status.Nodes) {
+		memcached.Status.Nodes = podNames
+		err := r.Status().Update(ctx, memcached)
+		if err != nil {
+			log.Error(err, "Failed to update Memcached status")
+			return ctrl.Result{}, err
+		}
+	}
+
+	return ctrl.Result{}, nil
+}
+
+// deploymentForMemcached returns a memcached Deployment object
+func (r *MemcachedReconciler) deploymentForMemcached(m *cachev1alpha1.Memcached) *appsv1.Deployment {
+	ls := labelsForMemcached(m.Name)
+	replicas := m.Spec.Size
+
+	dep := &appsv1.Deployment{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      m.Name,
+			Namespace: m.Namespace,
+		},
+		Spec: appsv1.DeploymentSpec{
+			Replicas: &replicas,
+			Selector: &metav1.LabelSelector{
+				MatchLabels: ls,
+			},
+			Template: corev1.PodTemplateSpec{
+				ObjectMeta: metav1.ObjectMeta{
+					Labels: ls,
+				},
+				Spec: corev1.PodSpec{
+					Containers: []corev1.Container{{
+						Image:   "memcached:1.4.36-alpine",
+						Name:    "memcached",
+						Command: []string{"memcached", "-m=64", "-o", "modern", "-v"},
+						Ports: []corev1.ContainerPort{{
+							ContainerPort: 11211,
+							Name:          "memcached",
+						}},
+					}},
+				},
+			},
+		},
+	}
+	// Set Memcached instance as the owner and controller
+	ctrl.SetControllerReference(m, dep, r.Scheme)
+	return dep
+}
+
+// labelsForMemcached returns the labels for selecting the resources
+// belonging to the given memcached CR name.
+func labelsForMemcached(name string) map[string]string {
+	return map[string]string{"app": "memcached", "memcached_cr": name}
+}
+
+// getPodNames returns the pod names of the array of pods passed in
+func getPodNames(pods []corev1.Pod) []string {
+	var podNames []string
+	for _, pod := range pods {
+		podNames = append(podNames, pod.Name)
+	}
+	return podNames
+}
+
+// SetupWithManager sets up the controller with the Manager.
+func (r *MemcachedReconciler) SetupWithManager(mgr ctrl.Manager) error {
+	return ctrl.NewControllerManagedBy(mgr).
+		For(&cachev1alpha1.Memcached{}).
+		Owns(&appsv1.Deployment{}).
+		Complete(r)
+}
+----
+====
 +
 The example controller runs the following reconciliation logic for each `Memcached` custom resource (CR):
 +
@@ -18,5 +221,3 @@ The example controller runs the following reconciliation logic for each `Memcach
 * Ensure that the deployment size is the same as specified by the `Memcached` CR spec.
 * Update the `Memcached` CR status with the names of the `memcached` pods.
 --
-
-The next subsections explain how the controller watches resources and how the reconcile loop is triggered. You can skip these subsections to go directly to building and running the Operator.

modules/osdk-run-deployment.adoc

@@ -58,11 +58,6 @@ $ make deploy IMG=<registry>/<user>/<image_name>:<tag>
 ----
 +
 By default, this command creates a namespace with the name of your Operator project in the form `<project_name>-system` and is used for the deployment. This command also installs the RBAC manifests from `config/rbac`.
-+
-[NOTE]
-====
-If you enabled webhooks in your deployments, you must have `cert-manager` already installed in the cluster or the `make deploy` command will fail when it attempts to create the `cert-manager` resources.
-====
 
 . Verify that the Operator is running:
 +

operators/operator_sdk/ansible/osdk-ansible-tutorial.adoc

@@ -40,4 +40,4 @@ include::modules/osdk-create-cr.adoc[leveloffset=+1]
 [id="osdk-ansible-tutorial-addtl-resources"]
 == Additional resources
 
-- See xref:../../../operators/operator_sdk/ansible/osdk-ansible-project-layout.adoc#osdk-ansible-project-layout_osdk-ansible-project-layout[Appendices] to learn about the project directory structures created by the Operator SDK.
+- See xref:../../../operators/operator_sdk/ansible/osdk-ansible-project-layout.adoc#osdk-ansible-project-layout[Project layout for Ansible-based Operators] to learn about the directory structures created by the Operator SDK.

operators/operator_sdk/golang/osdk-golang-tutorial.adoc

@@ -31,6 +31,9 @@ include::modules/osdk-golang-generate-crd.adoc[leveloffset=+2]
 include::modules/osdk-about-openapi-validation.adoc[leveloffset=+3]
 
 include::modules/osdk-golang-implement-controller.adoc[leveloffset=+1]
+
+The next subsections explain how the controller in the example implementation watches resources and how the reconcile loop is triggered. You can skip these subsections to go directly to xref:../../../operators/operator_sdk/golang/osdk-golang-tutorial.adoc#osdk-run-operator_osdk-golang-tutorial[Running the Operator].
+
 include::modules/osdk-golang-controller-resources.adoc[leveloffset=+2]
 include::modules/osdk-golang-controller-configs.adoc[leveloffset=+2]
 include::modules/osdk-golang-controller-reconcile-loop.adoc[leveloffset=+2]
@@ -47,4 +50,4 @@ include::modules/osdk-create-cr.adoc[leveloffset=+1]
 [id="osdk-golang-tutorial-addtl-resources"]
 == Additional resources
 
-- See xref:../../../operators/operator_sdk/golang/osdk-golang-project-layout.adoc#osdk-golang-project-layout_osdk-golang-project-layout[Appendices] to learn about the project directory structures created by the Operator SDK.
+- See xref:../../../operators/operator_sdk/golang/osdk-golang-project-layout.adoc#osdk-golang-project-layout[Project layout for Go-based Operators] to learn about the directory structures created by the Operator SDK.

operators/operator_sdk/helm/osdk-helm-tutorial.adoc

@@ -42,4 +42,4 @@ include::modules/osdk-create-cr.adoc[leveloffset=+1]
 [id="osdk-helm-tutorial-addtl-resources"]
 == Additional resources
 
-- See xref:../../../operators/operator_sdk/helm/osdk-helm-project-layout.adoc#osdk-helm-project-layout_osdk-helm-project-layout[Appendices] to learn about the project directory structures created by the Operator SDK.
+- See xref:../../../operators/operator_sdk/helm/osdk-helm-project-layout.adoc#osdk-helm-project-layout[Project layout for Helm-based Operators] to learn about the directory structures created by the Operator SDK.