kubebuilder example

cluster_controller.go

/*
Copyright 2021.

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 (
	"context"
	"fmt"

	"github.com/go-logr/logr"
	appv1 "k8s.io/api/apps/v1"
	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/runtime"
	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/controller-runtime/pkg/client"

	redisv1 "github.com/mountkin/redis-operator/api/v1"
)

const (
	ownerKey          = ".metadata.controller"
	deploymentNameTpl = "%s-redis-%d"
)

// ClusterReconciler reconciles a Cluster object
type ClusterReconciler struct {
	client.Client
	Log    logr.Logger
	Scheme *runtime.Scheme
}

//+kubebuilder:rbac:groups=redis.example.com,resources=clusters,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=redis.example.com,resources=clusters/status,verbs=get;update;patch
//+kubebuilder:rbac:groups=redis.example.com,resources=clusters/finalizers,verbs=update
//+kubebuilder:rbac:groups=apps,resources=deployments,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=apps,resources=deployments/status,verbs=get
//+kubebuilder:rbac:groups="",resources=pods,verbs=get;list;watch
//+kubebuilder:rbac:groups="",resources=pods/status,verbs=get

// 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 Cluster 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/controller-runtime@v0.7.0/pkg/reconcile
func (r *ClusterReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
	_ = r.Log.WithValues("cluster", req.NamespacedName)

	cluster := &redisv1.Cluster{}
	if err := r.Get(ctx, req.NamespacedName, cluster); err != nil {
		if client.IgnoreNotFound(err) != nil {
			r.Log.Error(err, "failed to get Cluster resource", "cluster", req.NamespacedName)
			return ctrl.Result{}, err
		}
		return ctrl.Result{}, nil
	}

	deployments := &appv1.DeploymentList{}
	if err := r.List(ctx, deployments, client.InNamespace(req.Namespace), client.MatchingFields{ownerKey: req.Name}); err != nil {
		r.Log.Error(err, "failed to list deployments", "cluster", req.NamespacedName)
		return ctrl.Result{Requeue: true}, err
	}

	if len(deployments.Items) < cluster.Spec.Replicas {
		// add missing deployments
		if err := r.createDeployments(ctx, cluster, deployments); err != nil {
			return ctrl.Result{Requeue: true}, err
		}
	} else if len(deployments.Items) > cluster.Spec.Replicas {
		//  delete the extra deployments
	}

	// Update cluster status
	pods := &corev1.PodList{}
	err := r.List(ctx, pods, client.InNamespace(req.Namespace), client.MatchingLabels{
		"redis-cluster-name": cluster.Name,
	})
	if err != nil || len(pods.Items) == 0 {
		return ctrl.Result{}, nil
	}

	var instanceStatus []redisv1.InstanceStatus
	for _, pod := range pods.Items {
		status := redisv1.InstanceStatus{
			Role:           "master",
			DeploymentName: pod.GetOwnerReferences()[0].Name,
			IP:             pod.Status.PodIP,
		}

		instanceStatus = append(instanceStatus, status)
	}
	cluster.Status.Instances = instanceStatus
	if err := r.Status().Update(ctx, cluster); err != nil {
		r.Log.Error(err, "failed to update cluster status", "cluster", req.NamespacedName)
	}

	r.Log.Info("xxxxxxxx Reconcile called", "cluster", cluster)

	return ctrl.Result{}, nil
}

func (r *ClusterReconciler) createDeployments(ctx context.Context, cluster *redisv1.Cluster, deployments *appv1.DeploymentList) error {
	var replicas int32 = 1
	names := r.genDeploymentName(cluster, deployments)
	ns := cluster.GetNamespace()
	if ns == "" {
		ns = metav1.NamespaceDefault
	}
	for _, name := range names {
		deployment := &appv1.Deployment{
			ObjectMeta: metav1.ObjectMeta{
				Name: name,
				Labels: map[string]string{
					"operator-name":      "redis",
					"redis-cluster-name": cluster.Name,
				},
				Annotations: map[string]string{},
				Namespace:   ns,
			},
			Spec: appv1.DeploymentSpec{
				Replicas: &replicas,
				Selector: &metav1.LabelSelector{
					MatchLabels: map[string]string{
						"redis-instance-name": name,
						"redis-cluster-name":  cluster.Name,
					},
				},
				Template: corev1.PodTemplateSpec{
					ObjectMeta: metav1.ObjectMeta{
						Labels: map[string]string{
							"redis-instance-name": name,
							"redis-cluster-name":  cluster.Name,
						},
					},
					Spec: corev1.PodSpec{
						Containers: []corev1.Container{
							{
								Name:  "redis",
								Image: cluster.Spec.Image,
								Ports: []corev1.ContainerPort{
									{
										Name:          "redis",
										Protocol:      corev1.ProtocolTCP,
										ContainerPort: int32(cluster.Spec.Port),
									},
								},
							},
						},
					},
				},
			},
		}
		if err := ctrl.SetControllerReference(cluster, deployment, r.Scheme); err != nil {
			return err
		}
		if err := r.Create(ctx, deployment); err != nil {
			r.Log.Error(err, "failed to create deployment ", "deployment name", name)
			return err
		}
	}

	return nil
}

func (r *ClusterReconciler) genDeploymentName(cluster *redisv1.Cluster, deployments *appv1.DeploymentList) []string {
	existedNames := make(map[string]bool)
	newNames := []string{}
	diff := cluster.Spec.Replicas - len(deployments.Items)
	for _, d := range deployments.Items {
		existedNames[d.Name] = true
	}
	for i := 1; i <= cluster.Spec.Replicas; i++ {
		name := fmt.Sprintf(deploymentNameTpl, cluster.Name, i)
		if !existedNames[name] {
			newNames = append(newNames, name)
			if len(newNames) == diff {
				return newNames
			}
		}
	}
	return newNames
}

// SetupWithManager sets up the controller with the Manager.
func (r *ClusterReconciler) SetupWithManager(mgr ctrl.Manager) error {
	err := mgr.GetFieldIndexer().IndexField(context.Background(), &appv1.Deployment{}, ownerKey, func(o client.Object) []string {
		deploy := o.(*appv1.Deployment)
		owner := metav1.GetControllerOf(deploy)
		if owner == nil {
			return nil
		}
		if owner.APIVersion != redisv1.GroupVersion.String() || owner.Kind != "Cluster" {
			return nil
		}
		return []string{owner.Name}
	})
	if err != nil {
		return err
	}

	return ctrl.NewControllerManagedBy(mgr).
		For(&redisv1.Cluster{}).
		Owns(&appv1.Deployment{}).
		Complete(r)
}

cluster_types.go

/*
Copyright 2021.

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 v1

import (
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
)

// EDIT THIS FILE!  THIS IS SCAFFOLDING FOR YOU TO OWN!
// NOTE: json tags are required.  Any new fields you add must have json tags for the fields to be serialized.

// ClusterSpec defines the desired state of Cluster
type ClusterSpec struct {
	// INSERT ADDITIONAL SPEC FIELDS - desired state of cluster
	// Important: Run "make" to regenerate code after modifying this file

	// Foo is an example field of Cluster. Edit cluster_types.go to remove/update
	Image    string `json:"image"`
	Replicas int    `json:"replicas"`
	Port     int    `json:"port"`
}

// InstanceStatus holds the status of the redis instance.
type InstanceStatus struct {
	Role           string `json:"role,omitempty"`
	IP             string `json:"ip,omitempty"`
	DeploymentName string `json:"deployment_name,omitempty"`
}

// ClusterStatus defines the observed state of Cluster
type ClusterStatus struct {
	// INSERT ADDITIONAL STATUS FIELD - define observed state of cluster
	// Important: Run "make" to regenerate code after modifying this file
	Instances []InstanceStatus `json:"instances,omitempty"`
	Phase     string           `json:"phase,omitempty"`
}

//+kubebuilder:object:root=true
//+kubebuilder:subresource:status
// +kubebuilder:resource:scope=Cluster

// Cluster is the Schema for the clusters API
type Cluster struct {
	metav1.TypeMeta   `json:",inline"`
	metav1.ObjectMeta `json:"metadata,omitempty"`

	Spec   ClusterSpec   `json:"spec,omitempty"`
	Status ClusterStatus `json:"status,omitempty"`
}

//+kubebuilder:object:root=true

// ClusterList contains a list of Cluster
type ClusterList struct {
	metav1.TypeMeta `json:",inline"`
	metav1.ListMeta `json:"metadata,omitempty"`
	Items           []Cluster `json:"items"`
}

func init() {
	SchemeBuilder.Register(&Cluster{}, &ClusterList{})
}