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Add simple operator package
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‎pkg/operator/doc.go

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/*
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Copyright 2018 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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// Package operator provides high-level porcelain wrapping the controller and manager libraries. It
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// has a minimalist approach to building simple application focused Controllers.
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//
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// Operator
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//
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// An Operator is a Controller that implements the operational logic for an Application. It is often used
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// to take off-the-shelf OSS applications, and make them Kubernetes native.
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//
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// // Create an Operator
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// op, err := operator.New(config.GetConfigOrDie())
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// if err != nil {
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// log.Fatal(err)
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// }
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//
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//
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// // Implement the Operator logic for a single type - e.g. ReplicaSet
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// rsRecFn := reconcile.Func(func(req reconcile.Request) (reconcile.Result, error) {
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// // Read the ReplicaSet
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// rs := &appsv1.ReplicaSet{}
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// err := op.GetClient().Get(context.TODO(), req.NamespacedName, rs)
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// if err != nil {
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// return reconcile.Result{}, err
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// }
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//
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// // TODO: User writes their implementation here using the op.GetClient() to read, list and write
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// // Kubernetes objects.
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// return reconcile.Result{}, nil
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// })
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//
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// // Handle events (e.g. create, update, delete operations) for a type and owned types - e.g. ReplicaSets and Pods
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// err = op.HandleType(rsRecFn, &appsv1.ReplicaSet{}, &corev1.Pod{})
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// if err != nil {
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// log.Fatal(err)
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// }
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package operator

‎pkg/operator/example_test.go

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/*
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Copyright 2018 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package operator_test
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import (
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"context"
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"log"
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"fmt"
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"github.com/kubernetes-sigs/controller-runtime/pkg/client"
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"github.com/kubernetes-sigs/controller-runtime/pkg/client/config"
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"github.com/kubernetes-sigs/controller-runtime/pkg/operator"
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"github.com/kubernetes-sigs/controller-runtime/pkg/reconcile"
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appsv1 "k8s.io/api/apps/v1"
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corev1 "k8s.io/api/core/v1"
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"k8s.io/apimachinery/pkg/labels"
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)
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// This example creates a simple Operator that is configured for Deployments and ReplicaSets.
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//
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// * Create a new Operator
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//
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// * Setup ReplicaSet handling
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//
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// * Setup Deployment handling
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//
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// * Start the Operator
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func ExampleOperator() {
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// Create a new Operator
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op, err := operator.New(config.GetConfigOrDie())
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if err != nil {
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log.Fatal(err)
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}
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// This function will be called when there is a change to a ReplicaSet or a Pod with an OwnerReference
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// to a ReplicaSet. It will contain the Namespace / Name of the ReplicaSet.
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//
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// Reconcile performs the following actions
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// * Read the ReplicaSet
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// * Read the Pods
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// * Set a Label on the ReplicaSet with the Pod count
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rsRecFn := reconcile.Func(func(req reconcile.Request) (reconcile.Result, error) {
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// Read the ReplicaSet
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rs := &appsv1.ReplicaSet{}
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err := op.GetClient().Get(context.TODO(), req.NamespacedName, rs)
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if err != nil {
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return reconcile.Result{}, err
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}
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// List the Pods matching the PodTemplate Labels
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pods := &corev1.PodList{}
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err = op.GetClient().List(context.TODO(),
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&client.ListOptions{
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Namespace: req.Namespace,
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LabelSelector: labels.SelectorFromSet(rs.Spec.Template.Labels),
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}, pods)
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if err != nil {
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return reconcile.Result{}, err
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}
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// Update the ReplicaSet
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rs.Labels["pod-count"] = fmt.Sprintf("%v", len(pods.Items))
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err = op.GetClient().Update(context.TODO(), rs)
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if err != nil {
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return reconcile.Result{}, err
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}
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return reconcile.Result{}, nil
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})
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// Watch ReplicaSets and Pods owned by ReplicaSets and call recFn with the Namespace / Name of the ReplicaSet
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err = op.HandleType(rsRecFn, &appsv1.ReplicaSet{}, &corev1.Pod{})
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if err != nil {
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log.Fatal(err)
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}
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// This function will be called when there is a change to a Deployment or a ReplicaSet with an OwnerReference
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// to a Deployment. It will contain the Namespace / Name of the Deployment.
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depRecFn := reconcile.Func(func(req reconcile.Request) (reconcile.Result, error) {
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dep := &appsv1.Deployment{}
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err := op.GetClient().Get(context.TODO(), req.NamespacedName, dep)
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if err != nil {
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return reconcile.Result{}, err
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}
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log.Printf("TODO: Implement Deployment Reconcile here.")
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return reconcile.Result{}, nil
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})
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// Watch Deployments and ReplicaSets owned by Deployments and call recFn with the Namespace / Name of the
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// Deployment
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err = op.HandleType(depRecFn, &appsv1.Deployment{}, &appsv1.ReplicaSet{})
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if err != nil {
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log.Fatal(err)
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}
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// Start the Operator
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log.Fatal(op.Start())
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}

‎pkg/operator/operator.go

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/*
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Copyright 2018 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package operator
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import (
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"fmt"
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"strings"
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"github.com/kubernetes-sigs/controller-runtime/pkg/client"
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"github.com/kubernetes-sigs/controller-runtime/pkg/client/apiutil"
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"github.com/kubernetes-sigs/controller-runtime/pkg/controller"
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"github.com/kubernetes-sigs/controller-runtime/pkg/handler"
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"github.com/kubernetes-sigs/controller-runtime/pkg/manager"
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"github.com/kubernetes-sigs/controller-runtime/pkg/reconcile"
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"github.com/kubernetes-sigs/controller-runtime/pkg/runtime/signals"
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"github.com/kubernetes-sigs/controller-runtime/pkg/source"
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"k8s.io/apimachinery/pkg/runtime"
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"k8s.io/apimachinery/pkg/runtime/schema"
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"k8s.io/client-go/rest"
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)
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// Operator is a very simple Controller that embeds a Manager.
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type Operator struct {
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mrg manager.Manager
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stopFn func() <-chan struct{}
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// Allow deps to be mocked out for testing
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newController func(name string, mrg manager.Manager, options controller.Options) (controller.Controller, error)
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getGvk func(obj runtime.Object, scheme *runtime.Scheme) (schema.GroupVersionKind, error)
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}
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// New returns a new Operator
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func New(config *rest.Config) (*Operator, error) {
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mrg, err := manager.New(config, manager.Options{})
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if err != nil {
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return nil, err
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}
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o := &Operator{
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mrg: mrg,
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stopFn: signals.SetupSignalHandler,
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newController: controller.New,
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getGvk: apiutil.GVKForObject,
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}
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return o, nil
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}
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// HandleType configures the Operator for a Kubernetes Resource type.
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//
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// * Watch for changes (e.g. create,update,delete operations) to objects of the Resource type
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//
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// * Watch for changes to objects created or managed by the Resource type.
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//
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// * Reconcile the object that was changed or that owns the changed objects.
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//
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// impl: the Reconcile implementation. reconcile.Reconcile is a function that may be called at anytime with the
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// name / Namespace of an object. When called, it will ensure that the state of the system matches what is
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// specified in the object at the time reconcile is called.
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//
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// reconcileObject: the type of the Kubernetes object that will be Watched and Reconciled - e.g. &v1.ReplicaSet{}
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//
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// ownedTypes: list of types of objects that may be created or managed by the reconcileObject. These
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// objects must have the OwnersReference set to the owning object in the ObjectMeta - e.g. &v1.Pod{}
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func (o *Operator) HandleType(impl reconcile.Reconcile,
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reconcileObject runtime.Object, ownedTypes ...runtime.Object) error {
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gvk, err := o.getGvk(reconcileObject, o.mrg.GetScheme())
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if err != nil {
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return err
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}
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// Create the controller
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name := fmt.Sprintf("%s-operator", strings.ToLower(gvk.Kind))
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c, err := o.newController(name, o.mrg, controller.Options{Reconcile: impl})
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if err != nil {
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return err
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}
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// Reconcile type
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err = c.Watch(&source.Kind{Type: reconcileObject}, &handler.Enqueue{})
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if err != nil {
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return err
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}
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// Watch the managed types
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for _, t := range ownedTypes {
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err = c.Watch(&source.Kind{Type: t}, &handler.EnqueueOwner{OwnerType: reconcileObject, IsController: true})
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if err != nil {
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return err
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}
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}
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return err
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}
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// Start starts the Operator and blocks until the program is shutdown.
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func (o *Operator) Start() error {
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return o.mrg.Start(o.stopFn())
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}
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// GetClient returns a client configured with the Config
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func (o *Operator) GetClient() client.Client {
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return o.mrg.GetClient()
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}

‎pkg/operator/operator_suite_test.go

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package operator
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import (
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"testing"
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. "github.com/onsi/ginkgo"
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. "github.com/onsi/gomega"
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)
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import (
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"time"
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logf "github.com/kubernetes-sigs/controller-runtime/pkg/runtime/log"
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"github.com/kubernetes-sigs/controller-runtime/pkg/test"
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"k8s.io/client-go/rest"
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)
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func TestSource(t *testing.T) {
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RegisterFailHandler(Fail)
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RunSpecsWithDefaultAndCustomReporters(t, "Operator Suite", []Reporter{test.NewlineReporter{}})
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}
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var testenv *test.Environment
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var cfg *rest.Config
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var _ = BeforeSuite(func(done Done) {
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logf.SetLogger(logf.ZapLogger(false))
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testenv = &test.Environment{}
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var err error
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cfg, err = testenv.Start()
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Expect(err).NotTo(HaveOccurred())
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time.Sleep(1 * time.Second)
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close(done)
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}, 60)
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var _ = AfterSuite(func() {
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testenv.Stop()
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})

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