example_test.go

Documentation: sigs.k8s.io/controller-runtime/pkg/builder

     1  /*
     2  Copyright 2018 The Kubernetes Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package builder_test
    18  
    19  import (
    20  	"context"
    21  	"fmt"
    22  	"os"
    23  
    24  	appsv1 "k8s.io/api/apps/v1"
    25  	corev1 "k8s.io/api/core/v1"
    26  	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
    27  
    28  	"sigs.k8s.io/controller-runtime/pkg/builder"
    29  	"sigs.k8s.io/controller-runtime/pkg/client"
    30  	"sigs.k8s.io/controller-runtime/pkg/client/config"
    31  	logf "sigs.k8s.io/controller-runtime/pkg/log"
    32  	"sigs.k8s.io/controller-runtime/pkg/log/zap"
    33  	"sigs.k8s.io/controller-runtime/pkg/manager"
    34  	"sigs.k8s.io/controller-runtime/pkg/manager/signals"
    35  	"sigs.k8s.io/controller-runtime/pkg/reconcile"
    36  )
    37  
    38  func ExampleBuilder_metadata_only() {
    39  	logf.SetLogger(zap.New())
    40  
    41  	log := logf.Log.WithName("builder-examples")
    42  
    43  	mgr, err := manager.New(config.GetConfigOrDie(), manager.Options{})
    44  	if err != nil {
    45  		log.Error(err, "could not create manager")
    46  		os.Exit(1)
    47  	}
    48  
    49  	cl := mgr.GetClient()
    50  	err = builder.
    51  		ControllerManagedBy(mgr).                  // Create the ControllerManagedBy
    52  		For(&appsv1.ReplicaSet{}).                 // ReplicaSet is the Application API
    53  		Owns(&corev1.Pod{}, builder.OnlyMetadata). // ReplicaSet owns Pods created by it, and caches them as metadata only
    54  		Complete(reconcile.Func(func(ctx context.Context, req reconcile.Request) (reconcile.Result, error) {
    55  			// Read the ReplicaSet
    56  			rs := &appsv1.ReplicaSet{}
    57  			err := cl.Get(ctx, req.NamespacedName, rs)
    58  			if err != nil {
    59  				return reconcile.Result{}, client.IgnoreNotFound(err)
    60  			}
    61  
    62  			// List the Pods matching the PodTemplate Labels, but only their metadata
    63  			var podsMeta metav1.PartialObjectMetadataList
    64  			err = cl.List(ctx, &podsMeta, client.InNamespace(req.Namespace), client.MatchingLabels(rs.Spec.Template.Labels))
    65  			if err != nil {
    66  				return reconcile.Result{}, client.IgnoreNotFound(err)
    67  			}
    68  
    69  			// Update the ReplicaSet
    70  			rs.Labels["pod-count"] = fmt.Sprintf("%v", len(podsMeta.Items))
    71  			err = cl.Update(ctx, rs)
    72  			if err != nil {
    73  				return reconcile.Result{}, err
    74  			}
    75  
    76  			return reconcile.Result{}, nil
    77  		}))
    78  	if err != nil {
    79  		log.Error(err, "could not create controller")
    80  		os.Exit(1)
    81  	}
    82  
    83  	if err := mgr.Start(signals.SetupSignalHandler()); err != nil {
    84  		log.Error(err, "could not start manager")
    85  		os.Exit(1)
    86  	}
    87  }
    88  
    89  // This example creates a simple application ControllerManagedBy that is configured for ReplicaSets and Pods.
    90  //
    91  // * Create a new application for ReplicaSets that manages Pods owned by the ReplicaSet and calls into
    92  // ReplicaSetReconciler.
    93  //
    94  // * Start the application.
    95  func ExampleBuilder() {
    96  	logf.SetLogger(zap.New())
    97  
    98  	log := logf.Log.WithName("builder-examples")
    99  
   100  	mgr, err := manager.New(config.GetConfigOrDie(), manager.Options{})
   101  	if err != nil {
   102  		log.Error(err, "could not create manager")
   103  		os.Exit(1)
   104  	}
   105  
   106  	err = builder.
   107  		ControllerManagedBy(mgr).  // Create the ControllerManagedBy
   108  		For(&appsv1.ReplicaSet{}). // ReplicaSet is the Application API
   109  		Owns(&corev1.Pod{}).       // ReplicaSet owns Pods created by it
   110  		Complete(&ReplicaSetReconciler{
   111  			Client: mgr.GetClient(),
   112  		})
   113  	if err != nil {
   114  		log.Error(err, "could not create controller")
   115  		os.Exit(1)
   116  	}
   117  
   118  	if err := mgr.Start(signals.SetupSignalHandler()); err != nil {
   119  		log.Error(err, "could not start manager")
   120  		os.Exit(1)
   121  	}
   122  }
   123  
   124  // ReplicaSetReconciler is a simple ControllerManagedBy example implementation.
   125  type ReplicaSetReconciler struct {
   126  	client.Client
   127  }
   128  
   129  // Implement the business logic:
   130  // This function will be called when there is a change to a ReplicaSet or a Pod with an OwnerReference
   131  // to a ReplicaSet.
   132  //
   133  // * Read the ReplicaSet
   134  // * Read the Pods
   135  // * Set a Label on the ReplicaSet with the Pod count.
   136  func (a *ReplicaSetReconciler) Reconcile(ctx context.Context, req reconcile.Request) (reconcile.Result, error) {
   137  	// Read the ReplicaSet
   138  	rs := &appsv1.ReplicaSet{}
   139  	err := a.Get(ctx, req.NamespacedName, rs)
   140  	if err != nil {
   141  		return reconcile.Result{}, err
   142  	}
   143  
   144  	// List the Pods matching the PodTemplate Labels
   145  	pods := &corev1.PodList{}
   146  	err = a.List(ctx, pods, client.InNamespace(req.Namespace), client.MatchingLabels(rs.Spec.Template.Labels))
   147  	if err != nil {
   148  		return reconcile.Result{}, err
   149  	}
   150  
   151  	// Update the ReplicaSet
   152  	rs.Labels["pod-count"] = fmt.Sprintf("%v", len(pods.Items))
   153  	err = a.Update(ctx, rs)
   154  	if err != nil {
   155  		return reconcile.Result{}, err
   156  	}
   157  
   158  	return reconcile.Result{}, nil
   159  }
   160
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