cloudfoundry/cf-k8s-controllers

/*
Copyright 2022.

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.
*/

package controllers

import (
    "context"

    korifiv1alpha1 "code.cloudfoundry.org/korifi/controllers/api/v1alpha1"
    "code.cloudfoundry.org/korifi/controllers/controllers/shared"
    "code.cloudfoundry.org/korifi/tools/k8s"

    "github.com/go-logr/logr"
    appsv1 "k8s.io/api/apps/v1"
    "k8s.io/apimachinery/pkg/api/meta"
    metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
    "k8s.io/apimachinery/pkg/runtime"
    "k8s.io/apimachinery/pkg/types"
    ctrl "sigs.k8s.io/controller-runtime"
    "sigs.k8s.io/controller-runtime/pkg/builder"
    "sigs.k8s.io/controller-runtime/pkg/client"
    "sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
    "sigs.k8s.io/controller-runtime/pkg/handler"
    "sigs.k8s.io/controller-runtime/pkg/predicate"
    "sigs.k8s.io/controller-runtime/pkg/reconcile"
)

const (
    // Environment Variable Names
    EnvPodName              = "POD_NAME"
    EnvCFInstanceIP         = "CF_INSTANCE_IP"
    EnvCFInstanceGUID       = "CF_INSTANCE_GUID"
    EnvCFInstanceInternalIP = "CF_INSTANCE_INTERNAL_IP"
    EnvCFInstanceIndex      = "CF_INSTANCE_INDEX"

    // StatefulSet Keys
    AnnotationVersion     = "korifi.cloudfoundry.org/version"
    AnnotationAppID       = "korifi.cloudfoundry.org/application-id"
    AnnotationProcessGUID = "korifi.cloudfoundry.org/process-guid"

    LabelGUID                   = "korifi.cloudfoundry.org/guid"
    LabelVersion                = "korifi.cloudfoundry.org/version"
    LabelAppGUID                = "korifi.cloudfoundry.org/app-guid"
    LabelAppWorkloadGUID        = "korifi.cloudfoundry.org/appworkload-guid"
    LabelProcessType            = "korifi.cloudfoundry.org/process-type"
    LabelStatefulSetRunnerIndex = "korifi.cloudfoundry.org/add-stsr-index"

    ApplicationContainerName  = "application"
    AppWorkloadReconcilerName = "statefulset-runner"
    ServiceAccountName        = "korifi-app"

    LivenessFailureThreshold  = 4
    ReadinessFailureThreshold = 1

    PodAffinityTermWeight = 100
)

//go:generate go run github.com/maxbrunsfeld/counterfeiter/v6 -generate
//counterfeiter:generate -o ../fake -fake-name PDB . PDB
type PDB interface {
    Update(ctx context.Context, statefulSet *appsv1.StatefulSet) error
}

//counterfeiter:generate -o ../fake -fake-name WorkloadToStatefulsetConverter . WorkloadToStatefulsetConverter
type WorkloadToStatefulsetConverter interface {
    Convert(appWorkload *korifiv1alpha1.AppWorkload) (*appsv1.StatefulSet, error)
}

// AppWorkloadReconciler reconciles a AppWorkload object
type AppWorkloadReconciler struct {
    k8sClient        client.Client
    scheme           *runtime.Scheme
    workloadsToStSet WorkloadToStatefulsetConverter
    pdb              PDB
    log              logr.Logger
}

func NewAppWorkloadReconciler(
    c client.Client,
    scheme *runtime.Scheme,
    workloadsToStSet WorkloadToStatefulsetConverter,
    pdb PDB,
    log logr.Logger,
) *k8s.PatchingReconciler[korifiv1alpha1.AppWorkload, *korifiv1alpha1.AppWorkload] {
    appWorkloadReconciler := AppWorkloadReconciler{
        k8sClient:        c,
        scheme:           scheme,
        workloadsToStSet: workloadsToStSet,
        pdb:              pdb,
        log:              log,
    }
    return k8s.NewPatchingReconciler[korifiv1alpha1.AppWorkload, *korifiv1alpha1.AppWorkload](log, c, &appWorkloadReconciler)
}

func (r *AppWorkloadReconciler) SetupWithManager(mgr ctrl.Manager) *builder.Builder {
    return ctrl.NewControllerManagedBy(mgr).
        For(&korifiv1alpha1.AppWorkload{}).
        Owns(&appsv1.StatefulSet{}).
        Watches(
            new(appsv1.StatefulSet),
            handler.EnqueueRequestsFromMapFunc(r.enqueueAppWorkloadRequests),
        ).
        WithEventFilter(predicate.NewPredicateFuncs(filterAppWorkloads))
}

func (r *AppWorkloadReconciler) enqueueAppWorkloadRequests(ctx context.Context, o client.Object) []reconcile.Request {
    var requests []reconcile.Request

    if appWorkloadName, ok := o.GetLabels()[LabelAppWorkloadGUID]; ok {
        requests = append(requests, reconcile.Request{
            NamespacedName: types.NamespacedName{
                Name:      appWorkloadName,
                Namespace: o.GetNamespace(),
            },
        })
    }

    return requests
}

func filterAppWorkloads(object client.Object) bool {
    appWorkload, ok := object.(*korifiv1alpha1.AppWorkload)
    if !ok {
        return true
    }

    return appWorkload.Spec.RunnerName == AppWorkloadReconcilerName
}

//+kubebuilder:rbac:groups=korifi.cloudfoundry.org,resources=appworkloads,verbs=get;list;watch;create;patch;delete
//+kubebuilder:rbac:groups=korifi.cloudfoundry.org,resources=appworkloads/status,verbs=get;patch

//+kubebuilder:rbac:groups=apps,resources=statefulsets,verbs=create;patch;get;list;watch
//+kubebuilder:rbac:groups=apps,resources=statefulsets/finalizers,verbs=update

//+kubebuilder:rbac:groups=policy,resources=poddisruptionbudgets,verbs=create;patch;deletecollection

func (r *AppWorkloadReconciler) ReconcileResource(ctx context.Context, appWorkload *korifiv1alpha1.AppWorkload) (ctrl.Result, error) {
    log := logr.FromContextOrDiscard(ctx)

    var err error
    readyConditionBuilder := k8s.NewReadyConditionBuilder(appWorkload)
    defer func() {
        meta.SetStatusCondition(&appWorkload.Status.Conditions, readyConditionBuilder.WithError(err).Build())
    }()

    appWorkload.Status.ObservedGeneration = appWorkload.Generation
    log.V(1).Info("set observed generation", "generation", appWorkload.Status.ObservedGeneration)

    shared.GetConditionOrSetAsUnknown(&appWorkload.Status.Conditions, korifiv1alpha1.StatusConditionReady, appWorkload.Generation)

    statefulSet, err := r.workloadsToStSet.Convert(appWorkload)
    // Not clear what errors this would produce, but we may use it later
    if err != nil {
        log.Info("error when converting AppWorkload", "reason", err)
        return ctrl.Result{}, err
    }

    createdStSet := &appsv1.StatefulSet{
        ObjectMeta: metav1.ObjectMeta{
            Name:      statefulSet.Name,
            Namespace: statefulSet.Namespace,
        },
    }
    _, err = controllerutil.CreateOrPatch(ctx, r.k8sClient, createdStSet, func() error {
        createdStSet.Labels = statefulSet.Labels
        createdStSet.Annotations = statefulSet.Annotations
        createdStSet.OwnerReferences = statefulSet.OwnerReferences
        createdStSet.Spec = statefulSet.Spec

        return nil
    })
    if err != nil {
        log.Info("error when creating or updating StatefulSet", "reason", err)
        return ctrl.Result{}, err
    }

    err = r.pdb.Update(ctx, createdStSet)
    if err != nil {
        log.Info("error when creating or patching pod disruption budget", "reason", err)
        return ctrl.Result{}, err
    }

    appWorkload.Status.ActualInstances = createdStSet.Status.Replicas

    readyConditionBuilder.Ready()
    return ctrl.Result{}, nil
}