mathew_controller.go

package mathew

import (
	"context"
	"reflect"

	mathewv1 "github.com/operator-mathew/pkg/apis/mathew/v1"
	corev1 "k8s.io/api/core/v1"
	appsv1 "k8s.io/api/apps/v1"
	"k8s.io/apimachinery/pkg/api/errors"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/types"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/controller"
	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
	"sigs.k8s.io/controller-runtime/pkg/handler"
	logf "sigs.k8s.io/controller-runtime/pkg/log"
	"sigs.k8s.io/controller-runtime/pkg/manager"
	"sigs.k8s.io/controller-runtime/pkg/reconcile"
	"sigs.k8s.io/controller-runtime/pkg/source"
)

var log = logf.Log.WithName("controller_mathew")

/**
* USER ACTION REQUIRED: This is a scaffold file intended for the user to modify with their own Controller
* business logic.  Delete these comments after modifying this file.*
 */

// Add creates a new Mathew Controller and adds it to the Manager. The Manager will set fields on the Controller
// and Start it when the Manager is Started.
func Add(mgr manager.Manager) error {
	return add(mgr, newReconciler(mgr))
}

// newReconciler returns a new reconcile.Reconciler
func newReconciler(mgr manager.Manager) reconcile.Reconciler {
	return &ReconcileMathew{client: mgr.GetClient(), scheme: mgr.GetScheme()}
}

// add adds a new Controller to mgr with r as the reconcile.Reconciler
func add(mgr manager.Manager, r reconcile.Reconciler) error {
	// Create a new controller
	c, err := controller.New("mathew-controller", mgr, controller.Options{Reconciler: r})
	if err != nil {
		return err
	}

	// Watch for changes to primary resource Mathew
	err = c.Watch(&source.Kind{Type: &mathewv1.Mathew{}}, &handler.EnqueueRequestForObject{})
	if err != nil {
		return err
	}

	// TODO(user): Modify this to be the types you create that are owned by the primary resource
	// Watch for changes to secondary resource Pods and requeue the owner Mathew
	err = c.Watch(&source.Kind{Type: &corev1.Pod{}}, &handler.EnqueueRequestForOwner{
		IsController: true,
		OwnerType:    &mathewv1.Mathew{},
	})
	if err != nil {
		return err
	}

	return nil
}

// blank assignment to verify that ReconcileMathew implements reconcile.Reconciler
var _ reconcile.Reconciler = &ReconcileMathew{}

// ReconcileMathew reconciles a Mathew object
type ReconcileMathew struct {
	// This client, initialized using mgr.Client() above, is a split client
	// that reads objects from the cache and writes to the apiserver
	client client.Client
	scheme *runtime.Scheme
}

// Reconcile reads that state of the cluster for a Mathew object and makes changes based on the state read
// and what is in the Mathew.Spec
// TODO(user): Modify this Reconcile function to implement your Controller logic.  This example creates
// a Pod as an example
// Note:
// The Controller will requeue the Request to be processed again if the returned error is non-nil or
// Result.Requeue is true, otherwise upon completion it will remove the work from the queue.
func (r *ReconcileMathew) Reconcile(request reconcile.Request) (reconcile.Result, error) {
	reqLogger := log.WithValues("Request.Namespace", request.Namespace, "Request.Name", request.Name)
	reqLogger.Info("Reconciling Mathew")

	// Fetch the Mathew instance
	mathew := &mathewv1.Mathew{}
	err := r.client.Get(context.TODO(), request.NamespacedName, mathew)
	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
			return reconcile.Result{}, nil
		}
		// Error reading the object - requeue the request.
		return reconcile.Result{}, err
	}


	// Check if this Deployment already exists, if not create a new one
	found := &appsv1.Deployment{}
	err = r.client.Get(context.TODO(), types.NamespacedName{Name: mathew.Name, Namespace: mathew.Namespace}, found)
	if err != nil && errors.IsNotFound(err) {
		// Define a new deployment
		dep := r.deploymentforMathew(mathew)
		reqLogger.Info("Creating a new Deployment", "Deployment.Namespace", dep.Namespace, "Deployment.Name", dep.Name)
		err = r.client.Create(context.TODO(), dep)
		if err != nil {
			reqLogger.Error(err, "Failed to create new Deployment", "Deployment.Namespace", dep.Namespace, "Deployment.Name", dep.Name)
			return reconcile.Result{}, err
		}

		// Deployment created successfully - don't requeue
		return reconcile.Result{}, nil
	} else if err != nil {
		reqLogger.Error(err, "Failed to get Deployment")
		return reconcile.Result{}, err
	}

	// Ensure the deployment size is the same as the spec
	size := mathew.Spec.Size
	if *found.Spec.Replicas != size {
		found.Spec.Replicas = &size
		err = r.client.Update(context.TODO(), found)
		if err != nil {
			reqLogger.Error(err, "Failed to update deployment", "Deployment.Namespaces", found.Namespace, "Deployment.Name", found.Name)
			return reconcile.Result{}, err
		}
		// Spec updated - return and requeue
		return reconcile.Result{Requeue: true}, nil
	}


	// Update the Mathew status with pod names
	// List the pods for this mathew's deployment
	podList := &corev1.PodList{}
	listOpts := []client.ListOption{
		client.InNamespace(mathew.Namespace),
		client.MatchingLabels(labelsForMathew(mathew.Name)),
	}
	if err = r.client.List(context.TODO(), podList, listOpts...); err != nil {
		reqLogger.Error(err, "Failed to list pods", "Mathew.Namespaces", mathew.Namespace, "Mathew.Name", mathew.Name)
		return reconcile.Result{}, err
	}
	podNames := getPodNames(podList.Items)

	// Update status.PodNames if needed
	if !reflect.DeepEqual(podNames, mathew.Status.PodNames) {
		mathew.Status.PodNames = podNames
		err := r.client.Status().Update(context.TODO(), mathew)
		if err != nil {
			reqLogger.Error(err, "Failed to update Mathew status")
			return reconcile.Result{}, err
		}
	}
	return reconcile.Result{}, nil
}

// deploymentForMathew returns a mathew deployment object

func (r *ReconcileMathew) deploymentforMathew(m *mathewv1.Mathew) *appsv1.Deployment {
	ls := labelsForMathew(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:	"busybox",
						Name:	"mathew",
						Command: []string{"sleep", "3600"},
						Ports: []corev1.ContainerPort{{
							ContainerPort: 10211,
							Name:		   "mathew",
						}},
					}},
				},
			},
		},
	}
	// Set Mathew instance as the owner and controller
	controllerutil.SetControllerReference(m, dep, r.scheme)
	return dep
}

// labelsForMathew returns the labels for selecting the resources
// belonging to the given learn CR name

func labelsForMathew(name string) map[string]string  {
	return map[string]string{"app": "mathew", "mathew_cr": name}
}

func getPodNames(pods []corev1.Pod) []string  {
	var podNames []string
	for _, pod := range pods {
		podNames = append(podNames, pod.Name)
	}
	return podNames
}


// newPodForCR returns a busybox pod with the same name/namespace as the cr
func newPodForCR(cr *mathewv1.Mathew) *corev1.Pod {
	labels := map[string]string{
		"app": cr.Name,
	}
	return &corev1.Pod{
		ObjectMeta: metav1.ObjectMeta{
			Name:      cr.Name + "-pod",
			Namespace: cr.Namespace,
			Labels:    labels,
		},
		Spec: corev1.PodSpec{
			Containers: []corev1.Container{
				{
					Name:    "busybox",
					Image:   "busybox",
					Command: []string{"sleep", "3600"},
				},
			},
		},
	}
}