cronjob.go

/*
Copyright 2022 The Kubernetes authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
// +kubebuilder:docs-gen:collapse=Apache License

/*
We'll start out with some imports.  You'll see below that we'll need a few more imports
than those scaffolded for us.  We'll talk about each one when we use it.
*/
package controllers

import (
	"context"
	"time"

	kbatch "k8s.io/api/batch/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/runtime"
	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/log"

	batchv1 "tutorial.kubebuilder.io/project/api/v1"
)

/*
Next, we'll need a Clock, which will allow us to fake timing in our tests.
*/

// CronJobReconciler reconciles a CronJob object
type CronJobReconciler struct {
	client.Client
	Scheme *runtime.Scheme
	Clock
}

/*
We'll mock out the clock to make it easier to jump around in time while testing,
the "real" clock just calls `time.Now`.
*/
type realClock struct{}

func (_ realClock) Now() time.Time { return time.Now() }

// clock knows how to get the current time.
// It can be used to fake out timing for testing.
type Clock interface {
	Now() time.Time
}

// +kubebuilder:docs-gen:collapse=Clock

/*
Notice that we need a few more RBAC permissions -- since we're creating and
managing jobs now, we'll need permissions for those, which means adding
a couple more [markers](/reference/markers/rbac.md).
*/

//+kubebuilder:rbac:groups=batch.tutorial.kubebuilder.io,resources=cronjobs,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=batch.tutorial.kubebuilder.io,resources=cronjobs/status,verbs=get;update;patch
//+kubebuilder:rbac:groups=batch.tutorial.kubebuilder.io,resources=cronjobs/finalizers,verbs=update
//+kubebuilder:rbac:groups=batch,resources=jobs,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=batch,resources=jobs/status,verbs=get

/*
Now, we get to the heart of the controller -- the reconciler logic.
*/
var (
	scheduledTimeAnnotation = "batch.tutorial.kubebuilder.io/scheduled-at"
)

func (r *CronJobReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
	log := log.FromContext(ctx)

	var cronJob batchv1.CronJob
	if err := r.Get(ctx, req.NamespacedName, &cronJob); err != nil {
		log.Error(err, "unable to fetch CronJob")
		// we'll ignore not-found errors, since they can't be fixed by an immediate
		// requeue (we'll need to wait for a new notification), and we can get them
		// on deleted requests.
		return ctrl.Result{}, client.IgnoreNotFound(err)
	}

	log.V(1).Info("got a job", "active jobs", 0)

	if err := r.Status().Update(ctx, &cronJob); err != nil {
		log.Error(err, "unable to update CronJob status")
		return ctrl.Result{}, err
	}

	return ctrl.Result{}, nil
}

/*
### Setup

Finally, we'll update our setup.  In order to allow our reconciler to quickly
look up Jobs by their owner, we'll need an index.  We declare an index key that
we can later use with the client as a pseudo-field name, and then describe how to
extract the indexed value from the Job object.  The indexer will automatically take
care of namespaces for us, so we just have to extract the owner name if the Job has
a CronJob owner.

Additionally, we'll inform the manager that this controller owns some Jobs, so that it
will automatically call Reconcile on the underlying CronJob when a Job changes, is
deleted, etc.
*/
var (
	jobOwnerKey = ".metadata.controller"
	apiGVStr    = batchv1.GroupVersion.String()
)

func (r *CronJobReconciler) SetupWithManager(mgr ctrl.Manager) error {
	// set up a real clock, since we're not in a test
	if r.Clock == nil {
		r.Clock = realClock{}
	}

	if err := mgr.GetFieldIndexer().IndexField(context.Background(), &kbatch.Job{}, jobOwnerKey, func(rawObj client.Object) []string {
		// grab the job object, extract the owner...
		job := rawObj.(*kbatch.Job)
		owner := metav1.GetControllerOf(job)
		if owner == nil {
			return nil
		}
		// ...make sure it's a CronJob...
		if owner.APIVersion != apiGVStr || owner.Kind != "CronJob" {
			return nil
		}

		// ...and if so, return it
		return []string{owner.Name}
	}); err != nil {
		return err
	}

	return ctrl.NewControllerManagedBy(mgr).
		For(&batchv1.CronJob{}).
		Owns(&kbatch.Job{}).
		Complete(r)
}