trial_controller.go

/*
Copyright 2022 The Kubeflow 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.
*/

package trial

import (
	"context"
	"errors"
	"fmt"
	"time"

	"github.com/spf13/viper"
	corev1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/api/equality"
	apierrors "k8s.io/apimachinery/pkg/api/errors"
	"k8s.io/apimachinery/pkg/api/meta"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/runtime/schema"
	"k8s.io/apimachinery/pkg/types"
	"k8s.io/client-go/tools/record"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/controller"
	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
	"sigs.k8s.io/controller-runtime/pkg/handler"
	logf "sigs.k8s.io/controller-runtime/pkg/log"
	"sigs.k8s.io/controller-runtime/pkg/manager"
	"sigs.k8s.io/controller-runtime/pkg/metrics"
	"sigs.k8s.io/controller-runtime/pkg/reconcile"
	"sigs.k8s.io/controller-runtime/pkg/source"

	commonapiv1beta1 "github.com/kubeflow/katib/pkg/apis/controller/common/v1beta1"
	trialsv1beta1 "github.com/kubeflow/katib/pkg/apis/controller/trials/v1beta1"
	"github.com/kubeflow/katib/pkg/controller.v1beta1/consts"
	"github.com/kubeflow/katib/pkg/controller.v1beta1/trial/managerclient"
	trialutil "github.com/kubeflow/katib/pkg/controller.v1beta1/trial/util"
)

const (
	// ControllerName is the controller name.
	ControllerName = "trial-controller"
)

var (
	log = logf.Log.WithName(ControllerName)
	// errMetricsNotReported is the error when Trial job is succeeded but metrics are not reported yet
	errMetricsNotReported = fmt.Errorf("metrics are not reported yet")
	// errReportMetricsFailed is the error when `unavailable` metrics value can't be inserted to the Katib DB.
	errReportMetricsFailed = fmt.Errorf("failed to report unavailable metrics")
)

// Add creates a new Trial Controller and adds it to the Manager with default RBAC. The Manager will set fields on the Controller
// and Start it when the Manager is Started.
func Add(mgr manager.Manager) error {
	return add(mgr, newReconciler(mgr))
}

// newReconciler returns a new reconcile.Reconciler
func newReconciler(mgr manager.Manager) reconcile.Reconciler {
	r := &ReconcileTrial{
		Client:        mgr.GetClient(),
		scheme:        mgr.GetScheme(),
		ManagerClient: managerclient.New(),
		recorder:      mgr.GetEventRecorderFor(ControllerName),
		collector:     trialutil.NewTrialsCollector(mgr.GetCache(), metrics.Registry),
	}
	r.updateStatusHandler = r.updateStatus
	return r
}

// add adds a new Controller to mgr with r as the reconcile.Reconciler
func add(mgr manager.Manager, r reconcile.Reconciler) error {
	// Create a new controller
	c, err := controller.New("trial-controller", mgr, controller.Options{Reconciler: r})
	if err != nil {
		log.Error(err, "Create trial controller error")
		return err
	}

	// Watch for changes in Trial
	if err = c.Watch(source.Kind(mgr.GetCache(), &trialsv1beta1.Trial{}), &handler.EnqueueRequestForObject{}); err != nil {
		log.Error(err, "Trial watch error")
		return err
	}

	trialResources := viper.Get(consts.ConfigTrialResources)
	if trialResources != nil {
		// Cast interface to gvk slice object
		gvkList := trialResources.([]schema.GroupVersionKind)

		// Watch for changes in custom resources
		for _, gvk := range gvkList {
			// Check if CRD is installed on the cluster.
			_, err := mgr.GetRESTMapper().RESTMapping(gvk.GroupKind(), gvk.Version)
			if err != nil {
				if meta.IsNoMatchError(err) {
					log.Info("Job watch error. CRD might be missing. Please install CRD and restart katib-controller",
						"CRD Group", gvk.Group, "CRD Version", gvk.Version, "CRD Kind", gvk.Kind)
					continue
				}
				return err
			}
			// Watch for the CRD changes.
			unstructuredJob := &unstructured.Unstructured{}
			unstructuredJob.SetGroupVersionKind(gvk)
			eventHandler := handler.EnqueueRequestForOwner(mgr.GetScheme(), mgr.GetRESTMapper(), &trialsv1beta1.Trial{}, handler.OnlyControllerOwner())
			if err = c.Watch(source.Kind(mgr.GetCache(), unstructuredJob), eventHandler); err != nil {
				return err
			}
			log.Info("Job watch added successfully",
				"CRD Group", gvk.Group, "CRD Version", gvk.Version, "CRD Kind", gvk.Kind)
		}
	}
	log.Info("Trial controller created")
	return nil
}

var _ reconcile.Reconciler = &ReconcileTrial{}

// ReconcileTrial reconciles a Trial object
type ReconcileTrial struct {
	client.Client
	scheme   *runtime.Scheme
	recorder record.EventRecorder

	managerclient.ManagerClient
	// updateStatusHandler is defined for test purpose.
	updateStatusHandler updateStatusFunc
	// collector is a wrapper for experiment metrics.
	collector *trialutil.TrialsCollector
}

// Reconcile reads that state of the cluster for a Trial object and makes changes based on the state read
// and what is in the Trial.Spec
// +kubebuilder:rbac:groups=trials.kubeflow.org,resources=trials,verbs=get;list;watch;create;update;patch;delete
// +kubebuilder:rbac:groups=trials.kubeflow.org,resources=trials/status,verbs=get;update;patch
func (r *ReconcileTrial) Reconcile(ctx context.Context, request reconcile.Request) (reconcile.Result, error) {
	// Fetch the Trial instance
	logger := log.WithValues("Trial", request.NamespacedName)
	original := &trialsv1beta1.Trial{}
	err := r.Get(ctx, request.NamespacedName, original)
	if err != nil {
		if apierrors.IsNotFound(err) {
			// Object not found, return.  Created objects are automatically garbage collected.
			// For additional cleanup logic use finalizers.
			return reconcile.Result{}, nil
		}
		// Error reading the object - requeue the request.
		logger.Error(err, "Trial Get error")
		return reconcile.Result{}, err
	}

	instance := original.DeepCopy()

	if needUpdate, finalizers := needUpdateFinalizers(instance); needUpdate {
		return r.updateFinalizers(instance, finalizers)
	}

	if !instance.IsCreated() {
		if instance.Status.StartTime == nil {
			now := metav1.Now()
			instance.Status.StartTime = &now
		}
		if instance.Status.CompletionTime == nil {
			instance.Status.CompletionTime = &metav1.Time{}
		}
		msg := "Trial is created"
		instance.MarkTrialStatusCreated(TrialCreatedReason, msg)
	} else {
		err := r.reconcileTrial(instance)
		if err != nil {
			if errors.Is(err, errMetricsNotReported) || errors.Is(err, errReportMetricsFailed) {
				return reconcile.Result{
					RequeueAfter: time.Second * 1,
				}, nil
			}
			logger.Error(err, "Reconcile trial error")
			r.recorder.Eventf(instance,
				corev1.EventTypeWarning, consts.ReconcileErrorReason,
				"Failed to reconcile: %v", err)
			return reconcile.Result{}, err
		}
	}

	if !equality.Semantic.DeepEqual(original.Status, instance.Status) {
		//assuming that only status change
		err = r.updateStatusHandler(instance)
		if err != nil {
			logger.Info("Update trial instance status failed, reconcile requeued", "err", err)
			return reconcile.Result{
				Requeue: true,
			}, nil
		}
	}

	return reconcile.Result{}, nil
}

func (r *ReconcileTrial) reconcileTrial(instance *trialsv1beta1.Trial) error {

	var err error
	logger := log.WithValues("Trial", types.NamespacedName{Name: instance.GetName(), Namespace: instance.GetNamespace()})
	desiredJob, err := r.getDesiredJobSpec(instance)
	if err != nil {
		logger.Error(err, "Job Spec Get error")
		return err
	}

	deployedJob, err := r.reconcileJob(instance, desiredJob)
	if err != nil {
		logger.Error(err, "Reconcile job error")
		return err
	}

	// Job already exists.
	// If Trial is EarlyStopped we need to verify/update observation logs.
	// In that case, Trial's job will be deleted even if metrics are not available.
	if deployedJob != nil && (!instance.IsCompleted() || instance.IsEarlyStopped()) {
		jobStatus, err := trialutil.GetDeployedJobStatus(instance, deployedJob)
		if err != nil {
			logger.Error(err, "GetDeployedJobStatus error")
		}

		// Not needed to update status if jobStatus is nil.
		if jobStatus == nil {
			return nil
		}

		// If Job status is succeeded or Trial is early stopped, update Trial observation.
		if jobStatus.Condition == trialutil.JobSucceeded || instance.IsEarlyStopped() {
			if err = r.UpdateTrialStatusObservation(instance); err != nil {
				logger.Error(err, "Update trial status observation error")
				return err
			}
		}

		// If observation is empty, metrics collector doesn't finish.
		// For early stopping scenario, metrics collector will report logs before Trial status is changed to EarlyStopped.
		// We need to requeue reconcile when the Trial is succeeded, metrics collector's type is not `Push`, and metrics are not reported.
		if jobStatus.Condition == trialutil.JobSucceeded &&
			instance.Status.Observation == nil &&
			instance.Spec.MetricsCollector.Collector.Kind != commonapiv1beta1.PushCollector {
			logger.Info("Trial job is succeeded but metrics are not reported, reconcile requeued")
			return errMetricsNotReported
		}

		// Update Trial job status only
		//    if job has succeeded and if observation field is available.
		//    if job has failed
		// This will ensure that trial is set to be complete only if metric is collected at least once
		return r.UpdateTrialStatusCondition(instance, deployedJob.GetName(), jobStatus)
	}
	return nil
}

func (r *ReconcileTrial) reconcileJob(instance *trialsv1beta1.Trial, desiredJob *unstructured.Unstructured) (*unstructured.Unstructured, error) {
	var err error
	logger := log.WithValues("Trial", types.NamespacedName{Name: instance.GetName(), Namespace: instance.GetNamespace()})
	apiVersion := desiredJob.GetAPIVersion()
	kind := desiredJob.GetKind()
	gvk := schema.FromAPIVersionAndKind(apiVersion, kind)

	deployedJob := &unstructured.Unstructured{}
	deployedJob.SetGroupVersionKind(gvk)
	err = r.Get(context.TODO(), types.NamespacedName{Name: desiredJob.GetName(), Namespace: desiredJob.GetNamespace()}, deployedJob)
	if err != nil {
		if apierrors.IsNotFound(err) {
			if instance.IsCompleted() {
				return nil, nil
			}

			logger.Info("Creating Job", "kind", kind,
				"name", desiredJob.GetName())
			err = r.Create(context.TODO(), desiredJob)
			if err != nil {
				logger.Error(err, "Create job error")
				return nil, err
			}
			// We should assign desiredJob to deployedJob to update Trial status
			// properly on the first reconcile run.
			deployedJob = desiredJob

			eventMsg := fmt.Sprintf("Job %s has been created", desiredJob.GetName())
			r.recorder.Eventf(instance, corev1.EventTypeNormal, JobCreatedReason, eventMsg)
		} else {
			logger.Error(err, "Trial Get error")
			return nil, err
		}
	} else {
		if instance.IsCompleted() && !instance.Spec.RetainRun {
			if err = r.Delete(context.TODO(), desiredJob, client.PropagationPolicy(metav1.DeletePropagationForeground)); err != nil {
				logger.Error(err, "Delete job error")
				return nil, err
			} else {
				eventMsg := fmt.Sprintf("Job %s has been deleted", desiredJob.GetName())
				r.recorder.Eventf(instance, corev1.EventTypeNormal, JobDeletedReason, eventMsg)
				return nil, nil
			}
		}
	}

	return deployedJob, nil
}

func (r *ReconcileTrial) getDesiredJobSpec(instance *trialsv1beta1.Trial) (*unstructured.Unstructured, error) {

	logger := log.WithValues("Trial", types.NamespacedName{Name: instance.GetName(), Namespace: instance.GetNamespace()})

	desiredJobSpec := instance.Spec.RunSpec

	if err := controllerutil.SetControllerReference(instance, desiredJobSpec, r.scheme); err != nil {
		logger.Error(err, "Set controller reference error")
		return nil, err
	}

	return desiredJobSpec, nil
}