controllerutil

Documentation

Overview

Package controllerutil contains utility functions for working with and implementing Controllers.

Index

• func SetControllerReference(owner, object metav1.Object, scheme *runtime.Scheme) error
• type AlreadyOwnedError
  • func (e *AlreadyOwnedError) Error() string
• type MutateFn
• type OperationResult
  • func CreateOrUpdate(ctx context.Context, c client.Client, obj runtime.Object, f MutateFn) (OperationResult, error)

Examples

• CreateOrUpdate

Functions

func SetControllerReference

func SetControllerReference(owner, object metav1.Object, scheme *runtime.Scheme) error

SetControllerReference sets owner as a Controller OwnerReference on owned. This is used for garbage collection of the owned object and for reconciling the owner object on changes to owned (with a Watch + EnqueueRequestForOwner). Since only one OwnerReference can be a controller, it returns an error if there is another OwnerReference with Controller flag set.

Types

type AlreadyOwnedError

type AlreadyOwnedError struct {
	Object metav1.Object
	Owner  metav1.OwnerReference
}

AlreadyOwnedError is an error returned if the object you are trying to assign a controller reference is already owned by another controller Object is the subject and Owner is the reference for the current owner

func (*AlreadyOwnedError) Error

func (e *AlreadyOwnedError) Error() string

type MutateFn

type MutateFn func() error

MutateFn is a function which mutates the existing object into it's desired state.

type OperationResult

type OperationResult string

OperationResult is the action result of a CreateOrUpdate call

const (
	// OperationResultNone means that the resource has not been changed
	OperationResultNone OperationResult = "unchanged"
	// OperationResultCreated means that a new resource is created
	OperationResultCreated OperationResult = "created"
	// OperationResultUpdated means that an existing resource is updated
	OperationResultUpdated OperationResult = "updated"
)

func CreateOrUpdate

func CreateOrUpdate(ctx context.Context, c client.Client, obj runtime.Object, f MutateFn) (OperationResult, error)

CreateOrUpdate creates or updates the given object in the Kubernetes cluster. The object's desired state must be reconciled with the existing state inside the passed in callback MutateFn.

The MutateFn is called regardless of creating or updating an object.

It returns the executed operation and an error.

Example

This example creates or updates an existing deployment

package main

import (
	"context"

	appsv1 "k8s.io/api/apps/v1"
	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"

	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
	logf "sigs.k8s.io/controller-runtime/pkg/log"
)

var (
	log = logf.Log.WithName("controllerutil-examples")
)

// This example creates or updates an existing deployment
func main() {
	// c is client.Client

	// Create or Update the deployment default/foo
	deploy := &appsv1.Deployment{ObjectMeta: metav1.ObjectMeta{Name: "foo", Namespace: "default"}}

	op, err := controllerutil.CreateOrUpdate(context.TODO(), c, deploy, func() error {

		// Deployment selector is immutable so we set this value only if
		// a new object is going to be created
		if deploy.ObjectMeta.CreationTimestamp.IsZero() {
			deploy.Spec.Selector = &metav1.LabelSelector{
				MatchLabels: map[string]string{"foo": "bar"},
			}
		}

		// update the Deployment pod template
		deploy.Spec.Template = corev1.PodTemplateSpec{
			ObjectMeta: metav1.ObjectMeta{
				Labels: map[string]string{
					"foo": "bar",
				},
			},
			Spec: corev1.PodSpec{
				Containers: []corev1.Container{
					{
						Name:  "busybox",
						Image: "busybox",
					},
				},
			},
		}

		return nil
	})

	if err != nil {
		log.Error(err, "Deployment reconcile failed")
	} else {
		log.Info("Deployment successfully reconciled", "operation", op)
	}
}