natsschannel.go

/*
Copyright 2019 The Knative 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 natss

import (
	"context"
	"fmt"
	"strings"

	configmapinformer "knative.dev/pkg/configmap/informer"
	"knative.dev/pkg/tracing"
	tracingconfig "knative.dev/pkg/tracing/config"

	"github.com/google/uuid"
	"github.com/kelseyhightower/envconfig"
	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/types"
	messagingv1 "knative.dev/eventing/pkg/apis/messaging/v1"
	"knative.dev/eventing/pkg/channel"
	"knative.dev/pkg/apis/duck"
	duckv1 "knative.dev/pkg/apis/duck/v1"
	"knative.dev/pkg/kmeta"
	pkgreconciler "knative.dev/pkg/reconciler"

	"go.uber.org/zap"

	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/labels"
	eventingduckv1 "knative.dev/eventing/pkg/apis/duck/v1"
	"knative.dev/eventing/pkg/kncloudevents"
	"knative.dev/pkg/configmap"
	"knative.dev/pkg/controller"
	"knative.dev/pkg/logging"

	"knative.dev/eventing-natss/pkg/apis/messaging/v1beta1"
	clientset "knative.dev/eventing-natss/pkg/client/clientset/versioned"
	"knative.dev/eventing-natss/pkg/client/injection/client"
	"knative.dev/eventing-natss/pkg/client/injection/informers/messaging/v1beta1/natsschannel"
	natsschannelreconciler "knative.dev/eventing-natss/pkg/client/injection/reconciler/messaging/v1beta1/natsschannel"
	listers "knative.dev/eventing-natss/pkg/client/listers/messaging/v1beta1"
	"knative.dev/eventing-natss/pkg/dispatcher"
	"knative.dev/eventing-natss/pkg/util"
)

const (
	// controllerAgentName is the string used by this controller to identify
	// itself when creating events.
	controllerAgentName = "natss-ch-dispatcher"

	finalizerName = controllerAgentName
)

// Reconciler reconciles NATSS Channels.
type Reconciler struct {
	natssDispatcher dispatcher.NatsDispatcher

	natssClientSet clientset.Interface

	natsschannelLister listers.NatssChannelLister
	impl               *controller.Impl
}

// Check that our Reconciler implements controller.Reconciler.
var _ natsschannelreconciler.Interface = (*Reconciler)(nil)
var _ natsschannelreconciler.Finalizer = (*Reconciler)(nil)

type envConfig struct {
	PodName       string `envconfig:"POD_NAME" required:"true"`
	ContainerName string `envconfig:"CONTAINER_NAME" required:"true"`
}

var dNewNatssDispatcher = dispatcher.NewNatssDispatcher
var tSetupPublishingWithDynamicConfig = tracing.SetupPublishingWithDynamicConfig

// NewController initializes the controller and is called by the generated code.
// Registers event handlers to enqueue events.
func NewController(ctx context.Context, watcher configmap.Watcher) *controller.Impl {

	logger := logging.FromContext(ctx)

	// Setup trace publishing.
	iw := watcher.(*configmapinformer.InformedWatcher)
	tracer, err := tSetupPublishingWithDynamicConfig(logger, iw, controllerAgentName, tracingconfig.ConfigName)
	if err != nil {
		logger.Panicw("Error setting up trace publishing", zap.Error(err))
	}

	var env envConfig
	if err := envconfig.Process("", &env); err != nil {
		logger.Fatalw("Failed to process env var", zap.Error(err))
	}

	natssConfig := util.GetNatssConfig()
	reporter := channel.NewStatsReporter(env.ContainerName, kmeta.ChildName(env.PodName, uuid.New().String()))
	dispatcherArgs := dispatcher.Args{
		NatssURL:       util.GetDefaultNatssURL(),
		ClusterID:      util.GetDefaultClusterID(),
		ClientID:       natssConfig.ClientID,
		AckWaitMinutes: util.GetAckWaitMinutes(),
		MaxInflight:    util.GetMaxInflight(),
		Cargs: kncloudevents.ConnectionArgs{
			MaxIdleConns:        natssConfig.MaxIdleConns,
			MaxIdleConnsPerHost: natssConfig.MaxIdleConnsPerHost,
		},
		Logger:   logger.Desugar(),
		Reporter: reporter,
	}
	natssDispatcher, err := dNewNatssDispatcher(dispatcherArgs)
	if err != nil {
		logger.Fatal("Unable to create natss dispatcher", zap.Error(err))
	}

	logger = logger.With(zap.String("controller/impl", "pkg"))
	logger.Info("Starting the NATSS dispatcher")

	channelInformer := natsschannel.Get(ctx)

	r := &Reconciler{
		natssDispatcher:    natssDispatcher,
		natsschannelLister: channelInformer.Lister(),
		natssClientSet:     client.Get(ctx),
	}
	r.impl = natsschannelreconciler.NewImpl(ctx, r)

	logger.Info("Setting up event handlers")

	channelInformer.Informer().AddEventHandler(controller.HandleAll(r.impl.Enqueue))

	logger.Info("Starting dispatcher.")
	go func() {
		if err := natssDispatcher.Start(ctx); err != nil {
			logger.Errorw("Cannot start dispatcher", zap.Error(err))
		}
		tracer.Shutdown(context.Background())
	}()
	return r.impl
}

// reconcile performs the following steps
// - update natss subscriptions
// - set NatssChannel SubscribableStatus
// - update host2channel map
func (r *Reconciler) ReconcileKind(ctx context.Context, natssChannel *v1beta1.NatssChannel) pkgreconciler.Event {
	// Try to subscribe.
	failedSubscriptions, err := r.natssDispatcher.UpdateSubscriptions(ctx, natssChannel.Name, natssChannel.Namespace, natssChannel.Spec.Subscribers, false)
	if err != nil {
		logging.FromContext(ctx).Errorw("Error updating subscriptions", zap.Any("channel", natssChannel), zap.Error(err))
		return err
	}

	if err := r.patchSubscriberStatus(ctx, natssChannel, failedSubscriptions); err != nil {
		logging.FromContext(ctx).Errorw("Error patching subscription statuses", zap.Any("channel", natssChannel), zap.Error(err))
		return err
	}

	natssChannels, err := r.natsschannelLister.List(labels.Everything())
	if err != nil {
		logging.FromContext(ctx).Error("Error listing natss channels")
		return err
	}

	channels := make([]messagingv1.Channel, 0)
	for _, nc := range natssChannels {
		if nc.Status.IsReady() {
			channels = append(channels, *toChannel(nc))
		}
	}

	if err := r.natssDispatcher.ProcessChannels(ctx, channels); err != nil {
		logging.FromContext(ctx).Errorw("Error updating host to channel map", zap.Error(err))
		return err
	}
	if len(failedSubscriptions) > 0 {
		var b strings.Builder
		for _, subError := range failedSubscriptions {
			b.WriteString("\n")
			b.WriteString(subError.Error())
		}
		errMsg := b.String()
		logging.FromContext(ctx).Error(errMsg)
		return fmt.Errorf(errMsg)
	}
	return nil
}

func (r *Reconciler) FinalizeKind(ctx context.Context, c *v1beta1.NatssChannel) pkgreconciler.Event {
	if _, err := r.natssDispatcher.UpdateSubscriptions(ctx, c.Name, c.Namespace, c.Spec.Subscribers, true); err != nil {
		logging.FromContext(ctx).Errorw("Error updating subscriptions", zap.Any("channel", c), zap.Error(err))
		return err
	}
	return nil
}

// createSubscribableStatus creates the SubscribableStatus based on the failedSubscriptions
// checks for each subscriber on the natss channel if there is a failed subscription on natss side
// if there is no failed subscription => set ready status
func (r *Reconciler) createSubscribableStatus(subscribers []eventingduckv1.SubscriberSpec, failedSubscriptions map[eventingduckv1.SubscriberSpec]error) eventingduckv1.SubscribableStatus {
	subscriberStatus := make([]eventingduckv1.SubscriberStatus, 0)
	for _, sub := range subscribers {
		status := eventingduckv1.SubscriberStatus{
			UID:                sub.UID,
			ObservedGeneration: sub.Generation,
			Ready:              corev1.ConditionTrue,
		}

		if err := getFailedSub(sub, failedSubscriptions); err != nil {
			status.Ready = corev1.ConditionFalse
			status.Message = err.Error()
		}
		subscriberStatus = append(subscriberStatus, status)
	}
	return eventingduckv1.SubscribableStatus{
		Subscribers: subscriberStatus,
	}
}

// TODO: We should really look at not using the sub as the key since it has
// pointers in it. This is inefficient, but at least it's correct.
func getFailedSub(sub eventingduckv1.SubscriberSpec, failedSubscriptions map[eventingduckv1.SubscriberSpec]error) error {
	for f, e := range failedSubscriptions {
		if f.UID == sub.UID && f.Generation == sub.Generation {
			return e
		}
	}
	return nil
}

func (r *Reconciler) patchSubscriberStatus(ctx context.Context, nc *v1beta1.NatssChannel, failedSubscriptions map[eventingduckv1.SubscriberSpec]error) error {
	after := nc.DeepCopy()

	after.Status.SubscribableStatus = r.createSubscribableStatus(after.Spec.Subscribers, failedSubscriptions)
	jsonPatch, err := duck.CreatePatch(nc, after)
	if err != nil {
		return fmt.Errorf("creating JSON patch: %w", err)
	}
	// If there is nothing to patch, we are good, just return.
	// Empty patch is [], hence we check for that.
	if len(jsonPatch) == 0 {
		return nil
	}

	patch, err := jsonPatch.MarshalJSON()
	if err != nil {
		return fmt.Errorf("marshaling JSON patch: %w", err)
	}
	patched, err := r.natssClientSet.MessagingV1beta1().NatssChannels(nc.Namespace).Patch(ctx, nc.Name, types.JSONPatchType, patch, metav1.PatchOptions{}, "status")
	if err != nil {
		return fmt.Errorf("Failed patching: %w", err)
	}
	logging.FromContext(ctx).Debugw("Patched resource", zap.Any("patch", patch), zap.Any("patched", patched))
	return nil
}

func toChannel(natssChannel *v1beta1.NatssChannel) *messagingv1.Channel {
	channel := &messagingv1.Channel{
		ObjectMeta: v1.ObjectMeta{
			Name:      natssChannel.Name,
			Namespace: natssChannel.Namespace,
		},
		Spec: messagingv1.ChannelSpec{
			ChannelTemplate: nil,
			ChannelableSpec: eventingduckv1.ChannelableSpec{
				SubscribableSpec: eventingduckv1.SubscribableSpec{},
			},
		},
	}

	if natssChannel.Status.Address != nil {
		channel.Status = messagingv1.ChannelStatus{
			ChannelableStatus: eventingduckv1.ChannelableStatus{
				AddressStatus: duckv1.AddressStatus{
					Address: &duckv1.Addressable{
						URL: natssChannel.Status.Address.URL,
					}},
				SubscribableStatus: eventingduckv1.SubscribableStatus{},
			},
			Channel: nil,
		}
	}

	for _, s := range natssChannel.Spec.Subscribers {
		sbeta1 := eventingduckv1.SubscriberSpec{
			UID:           s.UID,
			Generation:    s.Generation,
			SubscriberURI: s.SubscriberURI,
			ReplyURI:      s.ReplyURI,
			Delivery:      s.Delivery,
		}
		channel.Spec.Subscribers = append(channel.Spec.Subscribers, sbeta1)
	}

	return channel
}