Merge pull request #148 from hasbro17/haseeb/add-example-handler

example: add memcached handler for user-guide

Author: hasbro17

example/memcached-operator/handler.go

@@ -1 +1,154 @@
-// TODO
+package stub
+
+import (
+	"fmt"
+	"reflect"
+
+	v1alpha1 "github.com/example-inc/memcached-operator/pkg/apis/cache/v1alpha1"
+
+	"github.com/coreos/operator-sdk/pkg/sdk/action"
+	"github.com/coreos/operator-sdk/pkg/sdk/handler"
+	"github.com/coreos/operator-sdk/pkg/sdk/query"
+	"github.com/coreos/operator-sdk/pkg/sdk/types"
+	apps_v1 "k8s.io/api/apps/v1"
+	"k8s.io/api/core/v1"
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/labels"
+)
+
+func NewHandler() handler.Handler {
+	return &Handler{}
+}
+
+type Handler struct {
+}
+
+func (h *Handler) Handle(ctx types.Context, event types.Event) error {
+	switch o := event.Object.(type) {
+	case *v1alpha1.Memcached:
+		memcached := o
+
+		// Create the deployment if it doesn't exist
+		dep := deploymentForMemcached(memcached)
+		err := action.Create(dep)
+		if err != nil && !apierrors.IsAlreadyExists(err) {
+			return fmt.Errorf("failed to create deployment: %v", err)
+		}
+
+		// Ensure the deployment size is the same as the spec
+		err = query.Get(dep)
+		if err != nil {
+			return fmt.Errorf("failed to get deployment: %v", err)
+		}
+		size := memcached.Spec.Size
+		if *dep.Spec.Replicas != size {
+			dep.Spec.Replicas = &size
+			err = action.Update(dep)
+			if err != nil {
+				return fmt.Errorf("failed to update deployment: %v", err)
+			}
+		}
+
+		// Update the Memcached status with the pod names
+		podList := podList()
+		labelSelector := labels.SelectorFromSet(labelsForMemcached(memcached.Name)).String()
+		listOps := &metav1.ListOptions{LabelSelector: labelSelector}
+		err = query.List(memcached.Namespace, podList, query.WithListOptions(listOps))
+		if err != nil {
+			return fmt.Errorf("failed to list pods: %v", err)
+		}
+		podNames := getPodNames(podList.Items)
+		if !reflect.DeepEqual(podNames, memcached.Status.Nodes) {
+			memcached.Status.Nodes = podNames
+			err := action.Update(memcached)
+			if err != nil {
+				return fmt.Errorf("failed to update memcached status: %v", err)
+			}
+		}
+	}
+	return nil
+}
+
+// deploymentForMemcached returns a memcached Deployment object
+func deploymentForMemcached(m *v1alpha1.Memcached) *apps_v1.Deployment {
+	ls := labelsForMemcached(m.Name)
+	replicas := m.Spec.Size
+
+	dep := &apps_v1.Deployment{
+		TypeMeta: metav1.TypeMeta{
+			APIVersion: "apps/v1",
+			Kind:       "Deployment",
+		},
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      m.Name,
+			Namespace: m.Namespace,
+		},
+		Spec: apps_v1.DeploymentSpec{
+			Replicas: &replicas,
+			Selector: &metav1.LabelSelector{
+				MatchLabels: ls,
+			},
+			Template: v1.PodTemplateSpec{
+				ObjectMeta: metav1.ObjectMeta{
+					Labels: ls,
+				},
+				Spec: v1.PodSpec{
+					Containers: []v1.Container{{
+						Image:   "memcached:1.4.36-alpine",
+						Name:    "memcached",
+						Command: []string{"memcached", "-m=64", "-o", "modern", "-v"},
+						Ports: []v1.ContainerPort{{
+							ContainerPort: 11211,
+							Name:          "memcached",
+						}},
+					}},
+				},
+			},
+		},
+	}
+	addOwnerRefToObject(dep, asOwner(m))
+	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}
+}
+
+// addOwnerRefToObject appends the desired OwnerReference to the object
+func addOwnerRefToObject(obj metav1.Object, ownerRef metav1.OwnerReference) {
+	obj.SetOwnerReferences(append(obj.GetOwnerReferences(), ownerRef))
+}
+
+// asOwner returns an OwnerReference set as the memcached CR
+func asOwner(m *v1alpha1.Memcached) metav1.OwnerReference {
+	trueVar := true
+	return metav1.OwnerReference{
+		APIVersion: m.APIVersion,
+		Kind:       m.Kind,
+		Name:       m.Name,
+		UID:        m.UID,
+		Controller: &trueVar,
+	}
+}
+
+// podList returns a v1.PodList object
+func podList() *v1.PodList {
+	return &v1.PodList{
+		TypeMeta: metav1.TypeMeta{
+			Kind:       "Pod",
+			APIVersion: "v1",
+		},
+	}
+}
+
+// getPodNames returns the pod names of the array of pods passed in
+func getPodNames(pods []v1.Pod) []string {
+	var podNames []string
+	for _, pod := range pods {
+		podNames = append(podNames, pod.Name)
+	}
+	return podNames
+}