controller.go

package controller

import (
	"context"
	"fmt"
	"os"
	"os/signal"
	"strconv"
	"sync"
	"sync/atomic"
	"syscall"
	"time"

	"github.com/giantswarm/backoff"
	"github.com/giantswarm/k8sclient/v4/pkg/k8sclient"
	"github.com/giantswarm/microerror"
	"github.com/giantswarm/micrologger"
	"github.com/giantswarm/micrologger/loggermeta"
	"github.com/giantswarm/to"
	"github.com/prometheus/client_golang/prometheus"
	"k8s.io/apimachinery/pkg/api/errors"
	"k8s.io/apimachinery/pkg/api/meta"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	pkgruntime "k8s.io/apimachinery/pkg/runtime"
	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
	"sigs.k8s.io/controller-runtime/pkg/builder"
	"sigs.k8s.io/controller-runtime/pkg/controller"
	"sigs.k8s.io/controller-runtime/pkg/event"
	"sigs.k8s.io/controller-runtime/pkg/manager"
	"sigs.k8s.io/controller-runtime/pkg/predicate"
	"sigs.k8s.io/controller-runtime/pkg/reconcile"

	"github.com/giantswarm/operatorkit/v2/pkg/controller/collector"
	"github.com/giantswarm/operatorkit/v2/pkg/controller/context/cachekeycontext"
	"github.com/giantswarm/operatorkit/v2/pkg/controller/context/finalizerskeptcontext"
	"github.com/giantswarm/operatorkit/v2/pkg/controller/context/reconciliationcanceledcontext"
	"github.com/giantswarm/operatorkit/v2/pkg/controller/context/resourcecanceledcontext"
	"github.com/giantswarm/operatorkit/v2/pkg/controller/context/updateallowedcontext"
	"github.com/giantswarm/operatorkit/v2/pkg/controller/internal/recorder"
	"github.com/giantswarm/operatorkit/v2/pkg/controller/internal/sentry"
	"github.com/giantswarm/operatorkit/v2/pkg/resource"
)

const (
	DefaultResyncPeriod = 5 * time.Minute
)

const (
	DisableMetricsServing = "0"
)

const (
	loggerKeyController = "controller"
	loggerKeyEvent      = "event"
	loggerKeyLoop       = "loop"
	loggerKeyObject     = "object"
	loggerKeyResource   = "resource"
	loggerKeyVersion    = "version"
)

var (
	defaultPauseAnnotations = map[string]string{
		"cluster.x-k8s.io/paused":          "true",
		"operatorkit.giantswarm.io/paused": "true",
	}
)

type Config struct {
	// InitCtx is deprecated and should not be used anymore.
	InitCtx func(ctx context.Context, obj interface{}) (context.Context, error)
	// K8sClient is the client collection used to setup and manage certain
	// operatorkit primitives. The Controller Client is used to fetch runtime
	// objects. It therefore must be properly configured using the AddToScheme
	// option. The REST Client is used to patch finalizers on runtime objects.
	K8sClient k8sclient.Interface
	Logger    micrologger.Logger
	// NewRuntimeObjectFunc returns a new initialized pointer of a type
	// implementing the runtime object interface. The object returned is used with
	// the controller-runtime client to fetch the latest version of the object
	// itself. That way we can manage all runtime objects in a somewhat generic
	// way. See the example below.
	//
	//     func() pkgruntime.Object {
	//        return new(corev1.ConfigMap)
	//     }
	//
	NewRuntimeObjectFunc func() pkgruntime.Object
	// Pause is a map of additional pausing annotations, defining their
	// key-value pairs. This can be used to stop reconciliation in case the
	// configured pausing annotations are present in the reconciled runtime
	// object watched by operatorkit.
	Pause map[string]string
	// Resources is the list of controller resources being executed on runtime
	// object reconciliation. Resources are executed in given order.
	Resources []resource.Interface
	// Selector is used to filter objects before passing them to the controller.
	Selector Selector

	// Name is the name which the controller uses on finalizers for resources.
	// The name used should be unique in the kubernetes cluster, to ensure that
	// two operators which handle the same resource add two distinct finalizers.
	Name string
	// ResyncPeriod is the duration after which a complete sync with all known
	// runtime objects the controller watches is performed. Defaults to
	// DefaultResyncPeriod.
	ResyncPeriod time.Duration
	// SentryDSN is the optional URL used to forward runtime errors to the sentry.io service.
	// If this field is empty, logs will not be forwarded.
	SentryDSN string
}

type Controller struct {
	event                recorder.Interface
	initCtx              func(ctx context.Context, obj interface{}) (context.Context, error)
	k8sClient            k8sclient.Interface
	logger               micrologger.Logger
	newRuntimeObjectFunc func() pkgruntime.Object
	pause                map[string]string
	resources            []resource.Interface
	selector             Selector

	backOffFactory         func() backoff.Interface
	bootOnce               sync.Once
	booted                 chan struct{}
	collector              *collector.Set
	loop                   int64
	removedFinalizersCache *stringCache
	sentry                 sentry.Interface

	name         string
	resyncPeriod time.Duration
}

// New creates a new configured operator controller.
func New(config Config) (*Controller, error) {
	if config.InitCtx == nil {
		config.InitCtx = func(ctx context.Context, obj interface{}) (context.Context, error) {
			return ctx, nil
		}
	}
	if config.K8sClient == nil {
		return nil, microerror.Maskf(invalidConfigError, "%T.K8sClient must not be empty", config)
	}
	if config.Logger == nil {
		return nil, microerror.Maskf(invalidConfigError, "%T.Logger must not be empty", config)
	}
	if config.NewRuntimeObjectFunc == nil {
		return nil, microerror.Maskf(invalidConfigError, "%T.NewRuntimeObjectFunc must not be empty", config)
	}
	{
		if config.Pause == nil {
			config.Pause = map[string]string{}
		}
		for k, v := range defaultPauseAnnotations {
			config.Pause[k] = v
		}
	}
	if len(config.Resources) == 0 {
		return nil, microerror.Maskf(invalidConfigError, "%T.Resources must not be empty", config)
	}
	if config.Selector == nil {
		config.Selector = NewSelectorEverything()
	}

	if config.Name == "" {
		return nil, microerror.Maskf(invalidConfigError, "%T.Name must not be empty", config)
	}
	if config.ResyncPeriod == 0 {
		config.ResyncPeriod = DefaultResyncPeriod
	}

	var err error

	var collectorSet *collector.Set
	{
		c := collector.SetConfig{
			Logger:               config.Logger,
			K8sClient:            config.K8sClient,
			NewRuntimeObjectFunc: config.NewRuntimeObjectFunc,

			Controller: config.Name,
		}

		collectorSet, err = collector.NewSet(c)
		if err != nil {
			return nil, microerror.Mask(err)
		}
	}

	var eventRecorder recorder.Interface
	{
		c := recorder.Config{
			K8sClient: config.K8sClient,

			Component: config.Name,
		}

		eventRecorder = recorder.New(c)
	}

	var sentryClient sentry.Interface
	{
		c := sentry.Config{
			DSN: config.SentryDSN,
		}

		sentryClient, err = sentry.New(c)
		if err != nil {
			// Error during sentry initialization.
			return nil, microerror.Mask(err)
		}
	}

	c := &Controller{
		event:                eventRecorder,
		initCtx:              config.InitCtx,
		k8sClient:            config.K8sClient,
		logger:               config.Logger,
		newRuntimeObjectFunc: config.NewRuntimeObjectFunc,
		pause:                config.Pause,
		resources:            config.Resources,
		selector:             config.Selector,

		backOffFactory:         func() backoff.Interface { return backoff.NewMaxRetries(7, 1*time.Second) },
		bootOnce:               sync.Once{},
		booted:                 make(chan struct{}),
		collector:              collectorSet,
		loop:                   -1,
		removedFinalizersCache: newStringCache(config.ResyncPeriod * 3),
		sentry:                 sentryClient,

		name:         config.Name,
		resyncPeriod: config.ResyncPeriod,
	}

	return c, nil
}

func (c *Controller) Boot(ctx context.Context) {
	ctx = setLoggerCtxValue(ctx, loggerKeyController, c.name)

	c.bootOnce.Do(func() {
		operation := func() error {
			err := c.bootWithError(ctx)
			if err != nil {
				return microerror.Mask(err)
			}

			return nil
		}

		notifier := backoff.NewNotifier(c.logger, ctx)

		err := backoff.RetryNotify(operation, c.backOffFactory(), notifier)
		if err != nil {
			c.sentry.Capture(ctx, err)
			c.logger.LogCtx(ctx, "level", "error", "message", "stop controller boot retries due to too many errors", "stack", microerror.JSON(err))
			os.Exit(1)
		}
	})
}

func (c *Controller) Booted() chan struct{} {
	return c.booted
}

// Reconcile implements the reconciler given to the controller-runtime
// controller. Reconcile never returns any error as we deal with them in
// operatorkit internally.
func (c *Controller) Reconcile(req reconcile.Request) (reconcile.Result, error) {
	ctx := context.Background()

	// Add common keys to the logger context.
	{
		loop := strconv.FormatInt(atomic.AddInt64(&c.loop, 1), 10)

		ctx = cachekeycontext.NewContext(ctx, fmt.Sprintf("%s-%s", c.name, loop))
		ctx = finalizerskeptcontext.NewContext(ctx, make(chan struct{}))
		ctx = updateallowedcontext.NewContext(ctx, make(chan struct{}))

		ctx = setLoggerCtxValue(ctx, loggerKeyLoop, loop)
		ctx = setLoggerCtxValue(ctx, loggerKeyController, c.name)
	}

	obj := c.newRuntimeObjectFunc()
	err := c.k8sClient.CtrlClient().Get(ctx, req.NamespacedName, obj)
	if errors.IsNotFound(err) {
		// At this point the controller-runtime cache dispatches a runtime object
		// which is already being deleted, which is why it cannot be found here
		// anymore. We then likely perceive the last delete event of that runtime
		// object and it got purged from the controller-runtime cache. We do not
		// need to log these errors and just stop processing here in a more graceful
		// way.
		return reconcile.Result{}, nil
	} else if err != nil {
		return reconcile.Result{}, microerror.Mask(err)
	}

	res, err := c.reconcile(ctx, req, obj)
	if err != nil {
		// Microerror creates an error event on the object when kind and description is set.
		c.event.Emit(ctx, obj, err)
		errorGauge.Inc()
		c.sentry.Capture(ctx, err)
		c.logger.LogCtx(ctx, "level", "error", "message", "failed to reconcile", "stack", microerror.JSON(err))
		return reconcile.Result{}, nil
	}

	return res, nil
}

func (c *Controller) bootWithError(ctx context.Context) error {
	var err error

	// Boot the collector.
	err = c.collector.Boot(ctx)
	if err != nil {
		return microerror.Mask(err)
	}

	go func() {
		for {
			resetWait := c.resyncPeriod * 4
			time.Sleep(resetWait)
			errorGauge.Set(0)
		}
	}()

	// We overwrite the k8s error handlers so they do not intercept our log
	// streams. The format is way easier to parse for us that way. Here we also
	// emit metrics for the occured errors to ensure we create more awareness of
	// anything going wrong in our operators.
	{
		utilruntime.ErrorHandlers = []func(err error){
			func(err error) {
				// When we see a port forwarding error we ignore it because we cannot do
				// anything about it. Errors like we check here would have to be dealt
				// with in the third party tools we use. The port forwarding in general
				// is broken by design which will go away with Helm 3, soon TM.
				if IsPortforward(err) {
					return
				}

				errorGauge.Inc()
				c.logger.LogCtx(ctx, "level", "error", "message", "caught third party runtime error", "stack", microerror.JSON(err))
			},
		}
	}

	var mgr manager.Manager
	{
		o := manager.Options{
			// MetricsBindAddress is set to 0 in order to disable it. We do this
			// ourselves.
			MetricsBindAddress: DisableMetricsServing,
			SyncPeriod:         to.DurationP(c.resyncPeriod),
		}

		mgr, err = manager.New(c.k8sClient.RESTConfig(), o)
		if err != nil {
			return microerror.Mask(err)
		}
	}

	{
		// We build our controller and set up its reconciliation.
		// We use the Complete() method instead of Build() because we don't
		// need the controller instance.
		err = builder.
			ControllerManagedBy(mgr).
			For(c.newRuntimeObjectFunc()).
			WithOptions(controller.Options{
				MaxConcurrentReconciles: 1,
				Reconciler:              c,
			}).
			WithEventFilter(predicate.Funcs{
				CreateFunc:  func(e event.CreateEvent) bool { return c.selector.Matches(internalLabels(e.Meta.GetLabels())) },
				DeleteFunc:  func(e event.DeleteEvent) bool { return c.selector.Matches(internalLabels(e.Meta.GetLabels())) },
				UpdateFunc:  func(e event.UpdateEvent) bool { return c.selector.Matches(internalLabels(e.MetaNew.GetLabels())) },
				GenericFunc: func(e event.GenericEvent) bool { return c.selector.Matches(internalLabels(e.Meta.GetLabels())) },
			}).
			Complete(c)
		if err != nil {
			return microerror.Mask(err)
		}

		// We put the controller into a booted state by closing its booted
		// channel once so users know when to go ahead.
		select {
		case <-c.booted:
		default:
			close(c.booted)
		}

		// mgr.Start() blocks the boot process until it ends gracefully or fails.
		err = mgr.Start(setupSignalHandler())
		if err != nil {
			return microerror.Mask(err)
		}
	}

	return nil
}

func (c *Controller) deleteFunc(ctx context.Context, obj interface{}) error {
	var err error

	hasFinalizer, err := c.hasFinalizer(ctx, obj)
	if err != nil {
		return microerror.Mask(err)
	}
	if !hasFinalizer {
		return nil
	}

	err = ProcessDelete(ctx, obj, c.resources)
	if err != nil {
		return microerror.Mask(err)
	}

	err = c.removeFinalizer(ctx, obj)
	if err != nil {
		return microerror.Mask(err)
	}

	return nil
}

func (c *Controller) hasPauseAnnotation(m map[string]string) bool {
	for k, v := range m {
		if hasAnnotation(c.pause, k, v) {
			return true
		}
	}

	return false
}

func (c *Controller) reconcile(ctx context.Context, req reconcile.Request, obj interface{}) (reconcile.Result, error) {
	ctx, err := c.initCtx(ctx, obj)
	if err != nil {
		return reconcile.Result{}, microerror.Mask(err)
	}

	var m metav1.Object
	{
		m, err = meta.Accessor(obj)
		if err != nil {
			return reconcile.Result{}, microerror.Mask(err)
		}
	}

	{
		if c.hasPauseAnnotation(m.GetAnnotations()) {
			c.logger.LogCtx(ctx, "level", "debug", "message", "found pause annotation")
			c.logger.LogCtx(ctx, "level", "debug", "message", "cancelling reconciliation")
			return reconcile.Result{}, nil
		}
	}

	if m.GetDeletionTimestamp() != nil {
		event := "delete"

		t := prometheus.NewTimer(eventHistogram.WithLabelValues(event))
		ctx = setLoggerCtxValue(ctx, loggerKeyEvent, event)
		ctx = setLoggerCtxValue(ctx, loggerKeyObject, m.GetSelfLink())
		ctx = setLoggerCtxValue(ctx, loggerKeyVersion, m.GetResourceVersion())

		err = c.deleteFunc(ctx, obj)
		if err != nil {
			return reconcile.Result{}, microerror.Mask(err)
		}

		t.ObserveDuration()
	} else {
		event := "update"

		t := prometheus.NewTimer(eventHistogram.WithLabelValues(event))
		ctx = setLoggerCtxValue(ctx, loggerKeyEvent, event)
		ctx = setLoggerCtxValue(ctx, loggerKeyObject, m.GetSelfLink())
		ctx = setLoggerCtxValue(ctx, loggerKeyVersion, m.GetResourceVersion())

		err = c.updateFunc(ctx, obj)
		if err != nil {
			return reconcile.Result{}, microerror.Mask(err)
		}

		t.ObserveDuration()
	}

	return reconcile.Result{}, nil
}

func (c *Controller) updateFunc(ctx context.Context, obj interface{}) error {
	var err error

	ok, err := c.addFinalizer(ctx, obj)
	if err != nil {
		return microerror.Mask(err)
	}
	if ok {
		// A finalizer was added, this causes a new update event, so we stop
		// reconciling here and will pick up the new event.
		return nil
	}

	err = ProcessUpdate(ctx, obj, c.resources)
	if err != nil {
		return microerror.Mask(err)
	}

	return nil
}

// ProcessDelete is a drop-in for an informer's DeleteFunc. It receives the
// custom object observed during custom resource watches and anything that
// implements Resource. ProcessDelete takes care about all necessary
// reconciliation logic for delete events.
//
//     func deleteFunc(obj interface{}) {
//         err := c.ProcessDelete(obj, resources)
//         if err != nil {
//             // error handling here
//         }
//     }
//
//     newResourceEventHandler := &cache.ResourceEventHandlerFuncs{
//         DeleteFunc:    deleteFunc,
//     }
//
func ProcessDelete(ctx context.Context, obj interface{}, resources []resource.Interface) error {
	if len(resources) == 0 {
		return microerror.Maskf(executionFailedError, "resources must not be empty")
	}

	ctx = reconciliationcanceledcontext.NewContext(ctx, make(chan struct{}))

	defer func() {
		ctx = unsetLoggerCtxValue(ctx, loggerKeyResource)
	}()
	for _, r := range resources {
		ctx = setLoggerCtxValue(ctx, loggerKeyResource, r.Name())
		ctx = resourcecanceledcontext.NewContext(ctx, make(chan struct{}))

		err := r.EnsureDeleted(ctx, obj)
		if err != nil {
			return microerror.Mask(err)
		}

		if reconciliationcanceledcontext.IsCanceled(ctx) {
			return nil
		}
	}

	return nil
}

// ProcessUpdate is a drop-in for an informer's UpdateFunc. It receives the new
// custom object observed during custom resource watches and anything that
// implements Resource. ProcessUpdate takes care about all necessary
// reconciliation logic for update events. For complex resources this means
// state has to be created, deleted and updated eventually, in this order.
//
//     func updateFunc(oldObj, newObj interface{}) {
//         err := c.ProcessUpdate(newObj, resources)
//         if err != nil {
//             // error handling here
//         }
//     }
//
//     newResourceEventHandler := &cache.ResourceEventHandlerFuncs{
//         UpdateFunc:    updateFunc,
//     }
//
func ProcessUpdate(ctx context.Context, obj interface{}, resources []resource.Interface) error {
	if len(resources) == 0 {
		return microerror.Maskf(executionFailedError, "resources must not be empty")
	}

	ctx = reconciliationcanceledcontext.NewContext(ctx, make(chan struct{}))

	defer func() {
		ctx = unsetLoggerCtxValue(ctx, loggerKeyResource)
	}()
	for _, r := range resources {
		ctx = setLoggerCtxValue(ctx, loggerKeyResource, r.Name())
		ctx = resourcecanceledcontext.NewContext(ctx, make(chan struct{}))

		err := r.EnsureCreated(ctx, obj)
		if err != nil {
			return microerror.Mask(err)
		}

		if reconciliationcanceledcontext.IsCanceled(ctx) {
			return nil
		}
	}

	return nil
}

func hasAnnotation(annotations map[string]string, targetKey string, targetValue string) bool {
	if annotations == nil {
		return false
	}

	actualValue, ok := annotations[targetKey]
	if !ok {
		return false
	}

	return actualValue == targetValue
}

func setLoggerCtxValue(ctx context.Context, key, value string) context.Context {
	m, ok := loggermeta.FromContext(ctx)
	if !ok {
		m = loggermeta.New()
		ctx = loggermeta.NewContext(ctx, m)
	}

	m.KeyVals[key] = value

	return ctx
}

func setupSignalHandler() (stopCh <-chan struct{}) {
	stop := make(chan struct{})
	c := make(chan os.Signal, 2)
	signal.Notify(c, os.Interrupt, syscall.SIGTERM)
	go func() {
		<-c
		close(stop)
		<-c
		os.Exit(1) // second signal. Exit directly.
	}()

	return stop
}

func unsetLoggerCtxValue(ctx context.Context, key string) context.Context {
	m, ok := loggermeta.FromContext(ctx)
	if !ok {
		m = loggermeta.New()
		ctx = loggermeta.NewContext(ctx, m)
		return ctx
	}

	delete(m.KeyVals, key)

	return ctx
}