// Copyright (c) 2020 Gitpod GmbH. All rights reserved.
// Licensed under the GNU Affero General Public License (AGPL).
// See License-AGPL.txt in the project root for license information.

package manager

import (
	"context"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"net/url"
	"os"
	"strconv"
	"strings"
	"sync"
	"time"

	"github.com/opentracing/opentracing-go"
	tracelog "github.com/opentracing/opentracing-go/log"
	"golang.org/x/xerrors"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
	grpc_status "google.golang.org/grpc/status"
	"google.golang.org/protobuf/proto"

	corev1 "k8s.io/api/core/v1"
	k8serr "k8s.io/apimachinery/pkg/api/errors"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/labels"
	"k8s.io/apimachinery/pkg/types"
	"k8s.io/apimachinery/pkg/watch"
	"k8s.io/client-go/tools/record"
	"sigs.k8s.io/controller-runtime/pkg/client"

	"github.com/gitpod-io/gitpod/common-go/kubernetes"
	wsk8s "github.com/gitpod-io/gitpod/common-go/kubernetes"
	"github.com/gitpod-io/gitpod/common-go/log"
	"github.com/gitpod-io/gitpod/common-go/tracing"
	"github.com/gitpod-io/gitpod/common-go/util"
	csapi "github.com/gitpod-io/gitpod/content-service/api"
	wsdaemon "github.com/gitpod-io/gitpod/ws-daemon/api"
	"github.com/gitpod-io/gitpod/ws-manager/api"
	"github.com/gitpod-io/gitpod/ws-manager/pkg/manager/internal/workpool"

	volumesnapshotv1 "github.com/kubernetes-csi/external-snapshotter/client/v4/apis/volumesnapshot/v1"
)

const (
	// eventpoolWorkers is the number of workers in the event workpool. This number limits how many workspace events can be handled
	// in parallel; that is NOT the same as "how many workspaces can start in parallel". The event handling per workspace is written
	// so that it's quick in the "hot path" (i.e. less than 500ms). Thus this number should be around 0.5*expected(events per second).
	eventpoolWorkers = 100
)

var (
	// wsdaemonMaxAttempts is the number of times we'll attempt to work with ws-daemon when a former attempt returned unavailable.
	// We rety for two minutes every 5 seconds (see wsdaemonRetryInterval).
	//
	// Note: this is a variable rather than a constant so that tests can modify this value.
	wsdaemonMaxAttempts = 120 / 5

	// wsdaemonRetryInterval is the time in between attempts to work with ws-daemon.
	//
	// Note: this is a variable rather than a constant so that tests can modify this value.
	wsdaemonRetryInterval = 5 * time.Second
)

// Monitor listens for kubernetes events and periodically checks if everything is still ok.
type Monitor struct {
	startup time.Time

	manager   *Manager
	eventpool *workpool.EventWorkerPool
	ticker    *time.Ticker

	probeMap     map[string]context.CancelFunc
	probeMapLock sync.Mutex

	initializerMap sync.Map
	finalizerMap   sync.Map

	act actingManager

	OnError func(error)

	notifyPod        map[string]chan string
	notifyPodMapLock sync.Mutex

	eventRecorder record.EventRecorder
}

// CreateMonitor creates a new monitor
func (m *Manager) CreateMonitor() (*Monitor, error) {
	monitorInterval := time.Duration(m.Config.HeartbeatInterval)
	// Monitor interval is half the heartbeat interval to catch timed out workspaces in time.
	// See https://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampling_theorem why we need this.
	monitorInterval /= 2

	log.WithField("interval", monitorInterval).Info("starting workspace monitor")
	res := Monitor{
		manager:  m,
		ticker:   time.NewTicker(monitorInterval),
		probeMap: make(map[string]context.CancelFunc),

		OnError: func(err error) {
			log.WithError(err).Error("workspace monitor error")
		},

		notifyPod: make(map[string]chan string),

		eventRecorder: m.eventRecorder,
	}
	res.eventpool = workpool.NewEventWorkerPool(res.handleEvent)
	res.act = struct {
		*Monitor
		*Manager
	}{&res, m}

	return &res, nil
}

// Start starts up the monitor which will check the overall workspace state (on event or periodically).
// Use Stop() to stop the monitor gracefully.
func (m *Monitor) Start() error {
	// mark startup so that we can do proper workspace timeouting
	m.startup = time.Now().UTC()

	m.eventpool.Start(eventpoolWorkers)

	// our activity state is ephemeral and as such we need to mark existing workspaces active after we have
	// restarted (i.e. cleared our state). If we didn't do this, we'd time out all workspaces at ws-manager
	// startup, see: https://github.com/gitpod-io/gitpod/issues/2537 and https://github.com/gitpod-io/gitpod/issues/2619
	err := m.manager.markAllWorkspacesActive()
	if err != nil {
		log.WithError(err).Warn("cannot mark all existing workspaces active - this will wrongly time out user's workspaces")
	}

	go func() {
		for range m.ticker.C {
			m.doHousekeeping(context.Background())
		}
	}()

	return nil
}

// handleEvent dispatches an event to the corresponding event handler based on the event object kind.
// This function is expected to be called from a worker of the event pool.
func (m *Monitor) handleEvent(evt watch.Event) {
	var err error
	switch evt.Object.(type) {
	case *corev1.Pod:
		err = m.onPodEvent(evt)
	case *volumesnapshotv1.VolumeSnapshot:
		err = m.onVolumesnapshotEvent(evt)
	}

	if err != nil {
		m.OnError(err)
	}
}

func (m *Monitor) onVolumesnapshotEvent(evt watch.Event) error {
	vs, ok := evt.Object.(*volumesnapshotv1.VolumeSnapshot)
	if !ok {
		return xerrors.Errorf("received non-volume-snapshot event")
	}

	log := log.WithField("volumesnapshot", vs.Name)

	if vs.Spec.Source.PersistentVolumeClaimName == nil {
		// there is no pvc name within the VolumeSnapshot object
		log.Warn("the spec.source.persistentVolumeClaimName is empty")
		return nil
	}

	// the pod name is 1:1 mapping to pvc name
	podName := *vs.Spec.Source.PersistentVolumeClaimName
	log = log.WithField("pod", podName)

	// get the pod resource
	var pod corev1.Pod
	err := m.manager.Clientset.Get(context.Background(), types.NamespacedName{Namespace: vs.Namespace, Name: podName}, &pod)
	if err != nil && !k8serr.IsNotFound(err) {
		log.WithError(err).Warnf("cannot get pod")
	}

	if vs.Status == nil || vs.Status.ReadyToUse == nil || !*vs.Status.ReadyToUse || vs.Status.BoundVolumeSnapshotContentName == nil {
		if !pod.CreationTimestamp.IsZero() {
			m.eventRecorder.Eventf(&pod, corev1.EventTypeNormal, "VolumeSnapshot", "Volume snapshot %q is in progress", vs.Name)
		}
		return nil
	}

	vsc := *vs.Status.BoundVolumeSnapshotContentName
	log.Infof("the vsc %s is ready to use", vsc)
	if !pod.CreationTimestamp.IsZero() {
		m.eventRecorder.Eventf(&pod, corev1.EventTypeNormal, "VolumeSnapshot", "Volume snapshot %q is ready to use", vs.Name)
	}

	m.notifyPodMapLock.Lock()
	if m.notifyPod[podName] == nil {
		m.notifyPod[podName] = make(chan string)
	}
	m.notifyPodMapLock.Unlock()
	m.notifyPod[podName] <- vsc

	return nil
}

// onPodEvent interpretes Kubernetes events, translates and broadcasts them, and acts based on them
func (m *Monitor) onPodEvent(evt watch.Event) error {
	// Beware: we patch running pods to add annotations. At the moment this is not a problem as do not attach
	//         state to pods from which we did not want events to be created. However, we might have to filter out
	//         some MODIFIED events here if that ever changes. Otherwise the monitor clients will receive multiple
	//		   events with the same status even though nothing changed for them.

	pod, ok := evt.Object.(*corev1.Pod)
	if !ok {
		return xerrors.Errorf("received non-pod event")
	}

	// We start with the default kubernetes operation timeout to not block everything in case completing
	// the object hangs for some reason. Further down when notifying clients, we move to a context.Background()
	ctx, cancel := context.WithTimeout(context.Background(), kubernetesOperationTimeout)
	defer cancel()

	wso, err := m.manager.getWorkspaceObjects(ctx, pod)
	if err != nil {
		return xerrors.Errorf("cannot handle workspace event: %w", err)
	}

	status, err := m.manager.getWorkspaceStatus(*wso)
	if err != nil {
		log.WithError(err).WithFields(wso.GetOWI()).Error("onPodEvent cannot get status")
		return xerrors.Errorf("cannot handle workspace event: %w", err)
	}

	// There's one bit of the status which we cannot infere from Kubernetes alone, and that's the Git repo status
	// inside the workspace. To get this information, we have to ask ws-daemon. At the moment we only care about this
	// information during shutdown, as we're only showing it for stopped workspaces.

	if evt.Type == watch.Deleted {
		// If we're still probing this workspace (because it was stopped by someone other than the monitor while we
		// were probing), stop doing that.
		m.probeMapLock.Lock()
		if cancelProbe, ok := m.probeMap[pod.Name]; ok {
			cancelProbe()
			delete(m.probeMap, pod.Name)
		}
		m.probeMapLock.Unlock()

		// We're handling a pod event, thus Kubernetes gives us the pod we're handling. However, this is also a deleted
		// event which means the pod doesn't actually exist anymore. We need to reflect that in our status compution, hence
		// we change the deployed condition.
		status.Conditions.Deployed = api.WorkspaceConditionBool_FALSE
	}

	// make sure we tell our clients that things changed - no matter if there's an error in our
	// subsequent handling of the matter or not. However, we want to respond quickly to events,
	// thus we start OnChange as a goroutine.
	// BEWARE beyond this point one must not modify status anymore - we've already sent it out BEWARE
	span := m.traceWorkspaceState(status.Phase.String(), wso)
	ctx = opentracing.ContextWithSpan(context.Background(), span)
	onChangeDone := make(chan bool)
	go func() {
		// We call OnChange in a Go routine to make sure it doesn't block our internal handling of events.
		m.manager.OnChange(ctx, status)
		onChangeDone <- true
	}()

	m.writeEventTraceLog(status, wso)
	err = actOnPodEvent(ctx, m.act, m.manager, status, wso)

	// To make the tracing work though we have to re-sync with OnChange. But we don't want OnChange to block our event
	// handling, thus we wait for it to finish in a Go routine.
	go func() {
		<-onChangeDone
		span.Finish()
	}()

	return err
}

// actOnPodEvent performs actions when a kubernetes event comes in. For example we shut down failed workspaces or start
// polling the ready state of initializing ones.
func actOnPodEvent(ctx context.Context, m actingManager, manager *Manager, status *api.WorkspaceStatus, wso *workspaceObjects) (err error) {
	pod := wso.Pod

	span, ctx := tracing.FromContext(ctx, "actOnPodEvent")
	defer tracing.FinishSpan(span, &err)
	log := log.WithFields(wsk8s.GetOWIFromObject(&pod.ObjectMeta))
	tracing.ApplyOWI(span, wsk8s.GetOWIFromObject(&pod.ObjectMeta))

	workspaceID, ok := pod.Annotations[workspaceIDAnnotation]
	if !ok {
		return xerrors.Errorf("cannot act on pod %s: has no %s annotation", pod.Name, workspaceIDAnnotation)
	}
	span.LogKV("phase", status.Phase.String())

	if status.Phase == api.WorkspacePhase_STOPPING || status.Phase == api.WorkspacePhase_STOPPED {
		// Beware: do not else-if this condition with the other phases as we don't want the stop
		//         login in any other phase, too.
		span.LogKV("event", "stopping or stopped special case")
		m.clearInitializerFromMap(pod.Name)

		// if the secret is already gone, this won't error
		err = m.deleteWorkspaceSecrets(ctx, pod.Name)
		if err != nil {
			return err
		}

		// Special case: workspaces timing out during backup. Normally a timed out workspace would just be stopped
		//               regularly. When a workspace times out during backup though, stopping it won't do any good.
		//               The workspace is already shutting down, it just fails to do so properly. Instead, we need
		//               to update the disposal status to reflect this timeout situation.
		if status.Conditions.Timeout != "" && strings.Contains(status.Conditions.Timeout, string(activityBackup)) {
			span.LogKV("event", "timeout during backup")
			ds := &workspaceDisposalStatus{Status: DisposalFinished, BackupComplete: true, BackupFailure: status.Conditions.Timeout}
			err = manager.markDisposalStatus(ctx, workspaceID, ds)
			if err != nil {
				log.WithError(err).Error("was unable to update pod's disposal state - this will break someone's experience")
			}
		}
	} else if status.Conditions.Failed != "" || status.Conditions.Timeout != "" {
		span.LogKV("event", "failed or timed out")
		// the workspace has failed to run/start - shut it down
		// we should mark the workspace as failedBeforeStopping - this way the failure status will persist
		// while we stop the workspace
		_, hasFailureAnnotation := pod.Annotations[workspaceFailedBeforeStoppingAnnotation]
		if status.Conditions.Failed != "" && !hasFailureAnnotation {
			span.LogKV("event", "failed and no failed before stopping annotation")
			// If this marking operation failes that's ok - we'll still continue to shut down the workspace.
			// The failure message won't persist while stopping the workspace though.
			err := m.markWorkspace(ctx, workspaceID, addMark(workspaceFailedBeforeStoppingAnnotation, util.BooleanTrueString))
			if err != nil {
				log.WithError(err).Debug("cannot mark workspace as workspaceFailedBeforeStoppingAnnotation")
			}
		}

		// At the moment we call stopWorkspace on the same workspace at least twice:
		// First when the workspace originally failed, and
		// second when adding the workspaceFailedBeforeStoppingAnnotation which in turn triggers a new pod event.
		//
		// The alternative is to stop the pod only when the workspaceFailedBeforeStoppingAnnotation is present.
		// However, that's much more brittle than stopping the workspace twice (something that Kubernetes can handle).
		// It is important that we do not fail here if the pod is already gone, i.e. when we lost the race.
		err = m.stopWorkspace(ctx, workspaceID, stopWorkspaceNormallyGracePeriod)
		if err != nil && !isKubernetesObjNotFoundError(err) {
			return xerrors.Errorf("cannot stop workspace: %w", err)
		}

		return nil
	} else if status.Conditions.StoppedByRequest == api.WorkspaceConditionBool_TRUE {
		span.LogKV("event", "stopped by request")
		gracePeriod := stopWorkspaceNormallyGracePeriod
		if gp, ok := pod.Annotations[stoppedByRequestAnnotation]; ok {
			dt, err := time.ParseDuration(gp)
			if err == nil {
				gracePeriod = dt
			} else {
				log.WithError(err).Warn("invalid duration on stoppedByRequestAnnotation")
			}
		}

		// we're asked to stop the workspace but aren't doing so yet
		err = m.stopWorkspace(ctx, workspaceID, gracePeriod)
		if err != nil && !isKubernetesObjNotFoundError(err) {
			return xerrors.Errorf("cannot stop workspace: %w", err)
		}
	}

	switch status.Phase {
	case api.WorkspacePhase_CREATING:
		// The workspace has been scheduled on the cluster which means that we can start initializing it
		go func() {
			err := m.initializeWorkspaceContent(ctx, pod)

			if err != nil {
				// workspace initialization failed, which means the workspace as a whole failed
				err = m.markWorkspace(ctx, workspaceID, addMark(workspaceExplicitFailAnnotation, err.Error()))
				if err != nil {
					log.WithError(err).Warn("was unable to mark workspace as failed")
				}
			}
		}()

	case api.WorkspacePhase_INITIALIZING:
		// workspace is initializing (i.e. running but without the ready annotation yet). Start probing and depending on
		// the result add the appropriate annotation or stop the workspace. waitForWorkspaceReady takes care that it does not
		// run for the same workspace multiple times.
		go func() {
			err := m.waitForWorkspaceReady(ctx, pod)

			if err != nil {
				// workspace initialization failed, which means the workspace as a whole failed
				err = m.markWorkspace(ctx, workspaceID, addMark(workspaceExplicitFailAnnotation, err.Error()))
				if err != nil {
					log.WithError(err).Warn("was unable to mark workspace as failed")
				}
			}
		}()

	case api.WorkspacePhase_RUNNING:
		// We need to register the finalizer before the pod is deleted (see https://book.kubebuilder.io/reference/using-finalizers.html).
		// TODO (cw): Figure out if we can replace the "neverReady" flag.
		err = m.modifyFinalizer(ctx, workspaceID, gitpodFinalizerName, true)
		if err != nil {
			return xerrors.Errorf("cannot add gitpod finalizer: %w", err)
		}

		// In case the pod gets evicted we would not know the hostIP that pod ran on anymore.
		// In preparation for those cases, we'll add it as an annotation.
		err = m.markWorkspace(ctx, workspaceID, addMark(nodeNameAnnotation, wso.NodeName()))
		if err != nil {
			log.WithError(err).Warn("was unable to add host IP annotation from/to workspace")
		}

		// workspace is running - we don't need the secret anymore
		err = m.deleteWorkspaceSecrets(ctx, pod.Name)
		if err != nil {
			log.WithError(err).Warn("was unable to remove workspace secret")
		}

	case api.WorkspacePhase_STOPPING:
		span.LogKV("event", "stopping")
		if !isPodBeingDeleted(pod) {
			span.LogKV("event", "pod not being deleted")
			// this might be the case if a headless workspace has just completed but has not been deleted by anyone, yet
			err = m.stopWorkspace(ctx, workspaceID, stopWorkspaceNormallyGracePeriod)
			if err != nil && !isKubernetesObjNotFoundError(err) {
				return xerrors.Errorf("cannot stop workspace: %w", err)
			}
			return nil
		}

		var terminated bool
		for _, c := range wso.Pod.Status.ContainerStatuses {
			if c.Name == "workspace" {
				// Note: sometimes container don't enter `terminated`, but `waiting`. The processes are stopped nonetheless,
				//       and we should be running the backup. The only thing that keeps the pod alive, is our finalizer.
				terminated = c.State.Running == nil
				break
			}
		}
		span.LogKV("terminated", terminated)
		if !terminated {
			// Check the underlying node status
			var node corev1.Node
			err = manager.Clientset.Get(ctx, types.NamespacedName{Namespace: "", Name: wso.NodeName()}, &node)
			if err != nil {
				if k8serr.IsNotFound(err) {
					// The node somehow gone, try to backup the content if possible
					log.Infof("Somehow the node was %s gone, we try to backup the content if possible", wso.NodeName())
					terminated = true
				}
			} else {
				// Check the node taint matches the pod toleration with effect NoExecute.
				// If no, do nothing.
				// If yes, compares if time.Now() - taint.timeAdded > tolerationSeconds, then backup the content
				for _, taint := range node.Spec.Taints {
					if taint.Effect != corev1.TaintEffectNoExecute {
						continue
					}

					var tolerationDuration time.Duration
					var found bool
					for _, toleration := range wso.Pod.Spec.Tolerations {
						if toleration.Effect == corev1.TaintEffectNoExecute && toleration.Key == taint.Key && toleration.TolerationSeconds != nil {
							tolerationDuration = time.Duration(*toleration.TolerationSeconds) * time.Second
							found = true
							break
						}
					}
					if found && !taint.TimeAdded.IsZero() && time.Since(taint.TimeAdded.Time) > tolerationDuration {
						log.Infof("The %s toleration time %v exceeds, going to backup the content", taint.Key, tolerationDuration)
						terminated = true
						break
					}
				}
			}
		}

		ds := &workspaceDisposalStatus{}
		if rawDisposalStatus, ok := pod.Annotations[disposalStatusAnnotation]; ok {
			err := json.Unmarshal([]byte(rawDisposalStatus), ds)
			if err != nil {
				log.WithError(err).Errorf("cannnot parse disposalStatusAnnotation: %s", rawDisposalStatus)
			}
		}

		span.LogKV("disposalStatusAnnotation", ds)
		if terminated && !ds.Status.IsDisposed() {
			if wso.Pod.Annotations[workspaceFailedBeforeStoppingAnnotation] == util.BooleanTrueString && wso.Pod.Annotations[workspaceNeverReadyAnnotation] == util.BooleanTrueString {
				span.LogKV("event", "failed before stopping and never ready")
				// The workspace is never ready, so there is no need for a finalizer.
				if _, ok := pod.Annotations[workspaceExplicitFailAnnotation]; !ok {
					failMessage := status.Conditions.Failed
					if failMessage == "" {
						failMessage = "workspace failed to start."
					}
					err := m.markWorkspace(ctx, workspaceID, addMark(workspaceExplicitFailAnnotation, failMessage))
					if err != nil {
						log.WithError(err).Error("was unable to mark workspace as failed")
					}
				}

				// delete PVC because the workspace pod is never ready
				if err = manager.deleteWorkspacePVC(ctx, pod.Name); err != nil {
					log.Error(err)
					return err
				}
				return m.modifyFinalizer(ctx, workspaceID, gitpodFinalizerName, false)
			} else if wso.Pod.Annotations[abortRequestAnnotation] == util.BooleanTrueString {
				span.LogKV("event", "workspace was aborted")
				// The workspace is aborted, so there is no need to finalize content
				if err = manager.deleteWorkspacePVC(ctx, pod.Name); err != nil {
					log.Error(err)
					return err
				}
				return m.modifyFinalizer(ctx, workspaceID, gitpodFinalizerName, false)
			} else {
				// We start finalizing the workspace content only after the container is gone. This way we ensure there's
				// no process modifying the workspace content as we create the backup.
				go m.finalizeWorkspaceContent(ctx, wso)
			}
		}

	case api.WorkspacePhase_STOPPED:
		// we've disposed already - try to remove the finalizer and call it a day
		return m.modifyFinalizer(ctx, workspaceID, gitpodFinalizerName, false)
	}

	return nil
}

// actingManager contains all functions needed by actOnPodEvent
type actingManager interface {
	waitForWorkspaceReady(ctx context.Context, pod *corev1.Pod) (err error)
	stopWorkspace(ctx context.Context, workspaceID string, gracePeriod time.Duration) (err error)
	markWorkspace(ctx context.Context, workspaceID string, annotations ...*annotation) error
	deleteWorkspaceSecrets(ctx context.Context, podName string) error

	clearInitializerFromMap(podName string)
	initializeWorkspaceContent(ctx context.Context, pod *corev1.Pod) (err error)
	finalizeWorkspaceContent(ctx context.Context, wso *workspaceObjects)
	modifyFinalizer(ctx context.Context, workspaceID string, finalizer string, add bool) error
}

func (m *Monitor) clearInitializerFromMap(podName string) {
	m.initializerMap.Delete(podName)
}

// doHouskeeping is called regularly by the monitor and removes timed out or dangling workspaces/services
func (m *Monitor) doHousekeeping(ctx context.Context) {
	span, ctx := tracing.FromContext(ctx, "doHousekeeping")
	defer tracing.FinishSpan(span, nil)

	err := m.markTimedoutWorkspaces(ctx)
	if err != nil {
		m.OnError(err)
	}
}

// writeEventTraceLog writes an event trace log if one is configured. This function is written in
// such a way that it does not fail - and if it fails it fails silently. This is on purpose.
// The event trace log is for debugging only and has no operational significance.
func (m *Monitor) writeEventTraceLog(status *api.WorkspaceStatus, wso *workspaceObjects) {
	// make sure we recover from a panic in this function - not that we expect this to ever happen
	//nolint:errcheck
	defer recover()

	if m.manager.Config.EventTraceLog == "" {
		return
	}

	// The pod object contains potentially sensitive information, e.g. passwords or tokens.
	// We must do our best to remove that information prior to logging it out.
	twso := *wso
	if twso.Pod != nil {
		twso.Pod = twso.Pod.DeepCopy()

		if _, ok := twso.Pod.Annotations[workspaceInitializerAnnotation]; ok {
			twso.Pod.Annotations[workspaceInitializerAnnotation] = "[redacted]"
		}
		for _, c := range twso.Pod.Spec.Containers {
			for i, env := range c.Env {
				isPersonalIdentifiableVar := strings.HasPrefix(env.Name, "GITPOD_GIT")
				if isPersonalIdentifiableVar {
					c.Env[i].Value = "[redacted]"
					continue
				}
				if isGitpodInternalEnvVar(env.Name) {
					continue
				}

				isKnownVar := env.Name == "PATH"
				if isKnownVar {
					continue
				}

				c.Env[i].Value = "[redacted]"
			}
		}
	}
	type eventTraceEntry struct {
		Time    string               `json:"time"`
		Status  *api.WorkspaceStatus `json:"status"`
		Objects workspaceObjects     `json:"objects"`
	}
	entry := eventTraceEntry{Time: time.Now().UTC().Format(time.RFC3339Nano), Status: status, Objects: twso}

	if m.manager.Config.EventTraceLog == "-" {
		//nolint:errcheck
		log.WithField("evt", entry).Info("event trace log")
		return
	}

	out, err := os.OpenFile(m.manager.Config.EventTraceLog, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
	if err != nil {
		return
	}
	defer out.Close()

	// If writing the event trace log fails that does nothing to harm the function of ws-manager.
	// In fact we don't even want to react to it, hence the nolint.
	//nolint:errcheck
	json.NewEncoder(out).Encode(entry)
}

// traceWorkspaceState creates a new span that records the phase of workspace
func (m *Monitor) traceWorkspaceState(state string, wso *workspaceObjects) opentracing.Span {
	span := opentracing.StartSpan(fmt.Sprintf("/workspace/%s", state))
	if wso.Pod != nil {
		tracing.ApplyOWI(span, wsk8s.GetOWIFromObject(&wso.Pod.ObjectMeta))
		span.LogKV("timeToState", time.Since(wso.Pod.CreationTimestamp.Time))
	}
	span.LogKV("wsState", state)

	// OpenTracing does not support creating a span from a SpanContext https://github.com/opentracing/specification/issues/81.
	// Until that changes we just finish the span immediately after calling on-change.

	return span
}

// waitForWorkspaceReady waits until the workspace's content and Theia to become available.
func (m *Monitor) waitForWorkspaceReady(ctx context.Context, pod *corev1.Pod) (err error) {
	span, ctx := tracing.FromContext(ctx, "waitForWorkspaceReady")
	defer tracing.FinishSpan(span, &err)

	workspaceID, ok := pod.Annotations[workspaceIDAnnotation]
	if !ok {
		m.OnError(xerrors.Errorf("pod %s has no %s annotation", pod.Name, workspaceIDAnnotation))
		return
	}

	r, err := m.probeWorkspaceReady(ctx, pod)
	if err != nil {
		return err
	}
	if r == nil {
		// we're already probing/waiting for this workspace to get ready
		return
	}

	span.LogKV("event", "probeDone")
	probeResult := *r
	if probeResult == WorkspaceProbeStopped {
		// Workspace probe was stopped most likely because the workspace itself was stopped.
		// Should this assumption be wrong we'll clean the dangling workspace when it times out.
		return nil
	}

	// Theia is available - let's wait until the workspace is initialized
	snc, err := m.manager.connectToWorkspaceDaemon(ctx, workspaceObjects{Pod: pod})
	if err != nil {
		return xerrors.Errorf("cannot connect to workspace daemon: %w", err)
	}

	// Note: we don't have to use the same cancelable context that we used for the original Init call.
	//       If the init call gets canceled, WaitForInit will return as well. We're synchronizing through
	//		 wsdaemon here.
	err = retryIfUnavailable(ctx, func(ctx context.Context) error {
		_, err = snc.WaitForInit(ctx, &wsdaemon.WaitForInitRequest{Id: workspaceID})
		return err
	})

	if err != nil {
		// Check if it's a gRPC error.
		// - if not, do nothing.
		// - if yes, check the gRPC status code.
		if grpcErr, ok := grpc_status.FromError(err); ok {
			switch grpcErr.Code() {
			case codes.NotFound:
				// Looks like we have missed the CREATING phase in which we'd otherwise start the workspace content initialization.
				// Let's see if we're initializing already. If so, there's something very wrong because ws-daemon does not know about
				// this workspace yet. In that case we'll run another desperate attempt to initialize the workspace.
				if _, alreadyInitializing := m.initializerMap.Load(pod.Name); alreadyInitializing {
					// we're already initializing but wsdaemon does not know about this workspace. That's very bad.
					log.WithFields(wsk8s.GetOWIFromObject(&pod.ObjectMeta)).Error("we were already initializing but wsdaemon does not know about this workspace (bug in ws-daemon?). Trying again!")
					m.clearInitializerFromMap(pod.Name)
				}

				// It's ok - maybe we were restarting in that time. Instead of waiting for things to finish, we'll just start the
				// initialization now.
				err = m.initializeWorkspaceContent(ctx, pod)
			case codes.Unavailable:
				err = xerrors.Errorf("workspace initialization is currently unavailable - please try again")
			default:
				err = xerrors.Errorf(grpcErr.Message())
			}
		}
	}
	if err != nil {
		return xerrors.Errorf("cannot wait for workspace to initialize: %w", err)
	}
	m.clearInitializerFromMap(pod.Name)
	span.LogKV("event", "contentInitDone")

	// workspace is ready - mark it as such
	err = m.manager.markWorkspace(ctx, workspaceID, deleteMark(workspaceNeverReadyAnnotation))
	if err != nil {
		return xerrors.Errorf("cannot workspace: %w", err)
	}

	return nil
}

// probeWorkspaceReady continually HTTP GETs a workspace's ready URL until we've tried a certain number of times
// or the workspace responded with status code 200.
func (m *Monitor) probeWorkspaceReady(ctx context.Context, pod *corev1.Pod) (result *WorkspaceProbeResult, err error) {
	span, ctx := tracing.FromContext(ctx, "probeWorkspaceReady")
	defer tracing.FinishSpan(span, &err)

	workspaceID, ok := pod.Annotations[workspaceIDAnnotation]
	if !ok {
		return nil, xerrors.Errorf("pod %s has no %s annotation", pod.Name, workspaceIDAnnotation)
	}
	wsurl, ok := pod.Annotations[kubernetes.WorkspaceURLAnnotation]
	if !ok {
		return nil, xerrors.Errorf("pod %s has no %s annotation", pod.Name, kubernetes.WorkspaceURLAnnotation)
	}
	workspaceURL, err := url.Parse(wsurl)
	if err != nil {
		return nil, xerrors.Errorf("cannot probe workspace - this will result in a broken experience for a user: %w", err)
	}

	probeTimeout, err := time.ParseDuration(m.manager.Config.InitProbe.Timeout)
	if err != nil {
		probeTimeout = 5 * time.Second
		log.WithFields(wsk8s.GetOWIFromObject(&pod.ObjectMeta)).WithError(err).WithField("defaultProbeTimeout", probeTimeout).Warn("Cannot parse init probe timeout. This is a configuration problem. Using default.")
	}

	// Probe preparation, i.e. checking if a probe exists already and if it doesn't registering a new one has to be atomic with
	// regards to the probeMapLock. Ensure both operations are within the same locked section.
	m.probeMapLock.Lock()
	_, alreadyProbing := m.probeMap[pod.Name]
	if alreadyProbing {
		m.probeMapLock.Unlock()
		return nil, nil
	}

	ctx, cancelProbe := context.WithTimeout(ctx, 30*time.Minute)
	m.probeMap[pod.Name] = cancelProbe
	m.probeMapLock.Unlock()

	// The probe run will block until either the probe finds the pod ready or the probe itself is stopped.
	// Because of that it's best to run probeWorkspaceReady as a go routine.
	probe := NewWorkspaceReadyProbe(workspaceID, *workspaceURL)
	probe.Timeout = probeTimeout
	if m.manager.Config.InitProbe.Disabled {
		// While under test we may not have a publicly exposed workspace, hence use
		// the probe bypass to get over this stage.
		//
		// Note: this code-path should never run in production.
		probe.bypass = func() WorkspaceProbeResult {
			return WorkspaceProbeReady
		}
	}
	probeResult := probe.Run(ctx)
	span.LogFields(tracelog.String("result", string(probeResult)))

	// we're done probing: deregister probe from probe map
	m.probeMapLock.Lock()
	delete(m.probeMap, pod.Name)
	m.probeMapLock.Unlock()

	cancelProbe()

	return &probeResult, nil
}

// initializeWorkspaceContent talks to a ws-daemon daemon on the node of the pod and initializes the workspace content.
// If we're already initializing the workspace, thus function will return immediately. If we were not initializing,
// prior to this call this function returns once initialization is complete.
func (m *Monitor) initializeWorkspaceContent(ctx context.Context, pod *corev1.Pod) (err error) {
	_, fullWorkspaceBackup := pod.Labels[fullWorkspaceBackupLabel]
	_, pvcFeatureEnabled := pod.Labels[pvcWorkspaceFeatureLabel]

	workspaceID, ok := pod.Annotations[workspaceIDAnnotation]
	if !ok {
		return xerrors.Errorf("pod %s has no %s annotation", pod.Name, workspaceIDAnnotation)
	}
	workspaceMeta := getWorkspaceMetadata(pod)
	if workspaceMeta.Owner == "" {
		return xerrors.Errorf("pod %s has no owner", pod.Name)
	}

	class, ok := m.manager.Config.WorkspaceClasses[pod.Labels[workspaceClassLabel]]
	if !ok {
		return xerrors.Errorf("pod %s has unknown workspace class %s", pod.Name, pod.Labels[workspaceClassLabel])
	}
	storage, err := class.Container.Limits.StorageQuantity()
	if !ok {
		return xerrors.Errorf("workspace class %s has invalid storage quantity: %w", pod.Labels[workspaceClassLabel], err)
	}

	var (
		initializer     csapi.WorkspaceInitializer
		snc             wsdaemon.WorkspaceContentServiceClient
		contentManifest []byte
	)
	// The function below deliniates the initializer lock. It's just there so that we can
	// defer the unlock call, thus making sure we actually call it.
	err = func() error {
		_, alreadyInitializing := m.initializerMap.LoadOrStore(pod.Name, struct{}{})
		defer func() {
			if err != nil {
				m.clearInitializerFromMap(pod.Name)
			}
		}()

		if alreadyInitializing {
			return nil
		}

		// There is no need to emit this span if the operation is noop.
		span, ctx := tracing.FromContext(ctx, "initializeWorkspace")
		defer tracing.FinishSpan(span, &err)
		span.SetTag("fullWorkspaceBackup", fullWorkspaceBackup)

		initializerRaw, ok := pod.Annotations[workspaceInitializerAnnotation]
		if !ok {
			return xerrors.Errorf("pod %s has no %s annotation", pod.Name, workspaceInitializerAnnotation)
		}
		initializerPB, err := base64.StdEncoding.DecodeString(initializerRaw)
		if err != nil {
			return xerrors.Errorf("cannot decode init config: %w", err)
		}
		err = proto.Unmarshal(initializerPB, &initializer)
		if err != nil {
			return xerrors.Errorf("cannot unmarshal init config: %w", err)
		}

		var secret corev1.Secret
		err = m.manager.Clientset.Get(ctx, types.NamespacedName{Namespace: pod.Namespace, Name: pod.Name}, &secret)
		if k8serr.IsNotFound(err) {
			// this is ok - do nothing
		} else if err != nil {
			return xerrors.Errorf("cannot get workspace secret: %w", err)
		} else {
			err = csapi.InjectSecretsToInitializer(&initializer, secret.Data)
			if err != nil {
				return xerrors.Errorf("cannot inject initializer secrets: %w", err)
			}
		}

		if fullWorkspaceBackup {
			_, mf, err := m.manager.Content.GetContentLayer(ctx, workspaceMeta.Owner, workspaceMeta.MetaId, &initializer)
			if err != nil {
				return xerrors.Errorf("cannot download workspace content manifest: %w", err)
			}
			if mf != nil {
				contentManifest, err = json.Marshal(mf)
			}
			if err != nil {
				return xerrors.Errorf("cannot remarshal workspace content manifest: %w", err)
			}
		}

		// connect to the appropriate ws-daemon
		snc, err = m.manager.connectToWorkspaceDaemon(ctx, workspaceObjects{Pod: pod})
		if err != nil {
			return err
		}

		return nil
	}()
	if err != nil {
		return xerrors.Errorf("cannot initialize workspace: %w", err)
	}
	if err == nil && snc == nil {
		// we are already initialising
		return nil
	}
	t := time.Now()
	err = retryIfUnavailable(ctx, func(ctx context.Context) error {
		_, err = snc.InitWorkspace(ctx, &wsdaemon.InitWorkspaceRequest{
			Id: workspaceID,
			Metadata: &wsdaemon.WorkspaceMetadata{
				Owner:  workspaceMeta.Owner,
				MetaId: workspaceMeta.MetaId,
			},
			Initializer:           &initializer,
			FullWorkspaceBackup:   fullWorkspaceBackup,
			PersistentVolumeClaim: pvcFeatureEnabled,
			ContentManifest:       contentManifest,
			RemoteStorageDisabled: shouldDisableRemoteStorage(pod),
			StorageQuotaBytes:     storage.Value(),
		})
		return err
	})

	if err != nil {
		// Check if it's a gRPC error.
		// - if not, do nothing.
		// - if yes, check the gRPC status code.
		if grpcErr, ok := grpc_status.FromError(err); ok {
			switch grpcErr.Code() {
			case codes.AlreadyExists:
				// we're already initializing, things are good - we'll wait for it later
				err = nil
			case codes.Unavailable:
				err = xerrors.Errorf("workspace initialization is currently unavailable - please try again")
			default:
				err = xerrors.Errorf(grpcErr.Message())
			}
		}
	}

	wsType := strings.ToUpper(pod.Labels[wsk8s.TypeLabel])
	wsClass := pod.Labels[workspaceClassLabel]
	hist, errHist := m.manager.metrics.initializeTimeHistVec.GetMetricWithLabelValues(wsType, wsClass)
	if errHist != nil {
		log.WithError(errHist).WithField("type", wsType).Warn("cannot get initialize time histogram metric")
	} else {
		hist.Observe(time.Since(t).Seconds())
	}

	_, isBackup := initializer.Spec.(*csapi.WorkspaceInitializer_Backup)

	if isBackup {
		m.manager.metrics.totalRestoreCounterVec.WithLabelValues(wsType, strconv.FormatBool(pvcFeatureEnabled), wsClass).Inc()
		if err != nil {
			m.manager.metrics.totalRestoreFailureCounterVec.WithLabelValues(wsType, strconv.FormatBool(pvcFeatureEnabled), wsClass).Inc()
		}
	}

	if err != nil {
		return xerrors.Errorf("cannot initialize workspace: %w", err)
	}
	return nil
}

// retryIfUnavailable makes multiple attempts to execute op if op returns an UNAVAILABLE gRPC status code
func retryIfUnavailable(ctx context.Context, op func(ctx context.Context) error) (err error) {
	span, ctx := tracing.FromContext(ctx, "retryIfUnavailable")
	defer tracing.FinishSpan(span, &err)

	for i := 0; i < wsdaemonMaxAttempts; i++ {
		err := op(ctx)
		span.LogKV("attempt", i)

		if st, ok := grpc_status.FromError(err); ok && st.Code() == codes.Unavailable {
			// service is unavailable - try again after some time
			time.Sleep(wsdaemonRetryInterval)
		} else if err != nil {
			// some other error happened, we'done done here
			return err
		} else {
			// err is nil, we're done here
			return nil
		}
	}

	// we've maxed out our retry attempts
	return grpc_status.Error(codes.Unavailable, "workspace content initialization is currently unavailable")
}

func shouldDisableRemoteStorage(pod *corev1.Pod) bool {
	wso := &workspaceObjects{Pod: pod}
	tpe, err := wso.WorkspaceType()
	if err != nil {
		log.WithFields(wso.GetOWI()).WithError(err).Warn("cannot determine workspace type - assuming this is a regular")
		tpe = api.WorkspaceType_REGULAR
	}
	switch tpe {
	case api.WorkspaceType_IMAGEBUILD:
		return true
	default:
		return false
	}
}

// finalizeWorkspaceContent talks to a ws-daemon daemon on the node of the pod and creates a backup of the workspace content.
func (m *Monitor) finalizeWorkspaceContent(ctx context.Context, wso *workspaceObjects) {
	span, ctx := tracing.FromContext(ctx, "finalizeWorkspaceContent")
	defer tracing.FinishSpan(span, nil)
	tracing.ApplyOWI(span, wso.GetOWI())
	log := log.WithFields(wso.GetOWI())

	workspaceID, ok := wso.WorkspaceID()
	if !ok {
		tracing.LogError(span, xerrors.Errorf("cannot find %s annotation", workspaceIDAnnotation))
		log.Errorf("cannot find %s annotation", workspaceIDAnnotation)
		return
	}

	disposalStatus := &workspaceDisposalStatus{}
	defer func() {
		if disposalStatus.Status == DisposalEmpty {
			span.LogKV("disposalStatus", "empty")
			return
		}

		err := m.manager.markDisposalStatus(ctx, workspaceID, disposalStatus)
		if err != nil {
			tracing.LogError(span, err)
			log.WithError(err).Error("was unable to update pod's disposal status - this will break someone's experience")
		}
	}()

	tpe, err := wso.WorkspaceType()
	if err != nil {
		tracing.LogError(span, err)
		log.WithError(err).Warn("cannot determine workspace type - assuming this is a regular")
		tpe = api.WorkspaceType_REGULAR
	}
	wsType := api.WorkspaceType_name[int32(tpe)]

	var (
		createdVolumeSnapshot        bool
		readyVolumeSnapshot          bool
		deletedPVC                   bool
		pvcFeatureEnabled            bool
		markVolumeSnapshotAnnotation bool
		// volume snapshot name is 1:1 mapped to workspace id
		pvcVolumeSnapshotName        string = workspaceID
		pvcVolumeSnapshotContentName string
		pvcVolumeSnapshotClassName   string

		volumeSnapshotTime time.Time
	)
	if wso.Pod != nil {
		_, pvcFeatureEnabled = wso.Pod.Labels[pvcWorkspaceFeatureLabel]

		if _, ok := wso.Pod.Labels[workspaceClassLabel]; ok {
			wsClassName := wso.Pod.Labels[workspaceClassLabel]

			workspaceClass := m.manager.Config.WorkspaceClasses[wsClassName]
			if workspaceClass != nil {
				pvcVolumeSnapshotClassName = workspaceClass.PVC.SnapshotClass
			}
		}
	}

	doBackup := wso.WasEverReady() && !wso.IsWorkspaceHeadless()
	doBackupLogs := tpe == api.WorkspaceType_PREBUILD
	doSnapshot := tpe == api.WorkspaceType_PREBUILD
	doFinalize := func() (worked bool, gitStatus *csapi.GitStatus, err error) {
		_, alreadyFinalizing := m.finalizerMap.Load(workspaceID)
		if alreadyFinalizing {
			span.LogKV("alreadyFinalizing", true)
			return false, nil, nil
		}

		// Maybe the workspace never made it to a phase where we actually initialized a workspace.
		// Assuming that once we've had a nodeName we've spoken to ws-daemon it's safe to assume that if
		// we don't have a nodeName we don't need to dipose the workspace.
		// Obviously that only holds if we do not require a backup. If we do require one, we want to
		// fail as loud as we can in this case.
		if !doBackup && !doSnapshot && wso.NodeName() == "" {
			// we don't need a backup and have never spoken to ws-daemon: we're good here.
			span.LogKV("noBackupNeededAndNoNode", true)
			return true, &csapi.GitStatus{}, nil
		}

		// we're not yet finalizing - start the process
		snc, err := m.manager.connectToWorkspaceDaemon(ctx, *wso)
		if err != nil {
			tracing.LogError(span, err)
			return true, nil, status.Errorf(codes.Unavailable, "cannot connect to workspace daemon: %q", err)
		}

		defer func() {
			// we're done disposing - remove from the finalizerMap
			val, ok := m.finalizerMap.LoadAndDelete(workspaceID)
			if !ok {
				return
			}

			cancelReq := val.(context.CancelFunc)
			cancelReq()
		}()

		// only build prebuild snapshots of initialized/ready workspaces.
		if doSnapshot {
			_, err = snc.WaitForInit(ctx, &wsdaemon.WaitForInitRequest{Id: workspaceID})
			if st, ok := grpc_status.FromError(err); ok {
				if st.Code() == codes.FailedPrecondition &&
					(st.Message() == "workspace is not initializing or ready" || st.Message() == "workspace is not ready") {
					log.Warn("skipping snapshot creation because content-initializer never finished or the workspace reached a ready state")
					doSnapshot = false
				} else if st.Code() == codes.NotFound {
					// the workspace has gone some reason
					// e.g. since it was a retry, it already succeeded the first time.
					log.WithError(err).Warnf("skipping snapshot and disposing because the workspace has already gone")
					return false, &csapi.GitStatus{}, nil
				}
			}
		}

		ctx, cancelReq := context.WithTimeout(ctx, time.Duration(m.manager.Config.Timeouts.ContentFinalization))
		m.finalizerMap.Store(workspaceID, cancelReq)

		if pvcFeatureEnabled {
			// pvc was created with the name of the pod. see createDefiniteWorkspacePod()
			pvcName := wso.Pod.Name
			if !createdVolumeSnapshot {
				// create snapshot object out of PVC
				volumeSnapshot := &volumesnapshotv1.VolumeSnapshot{
					ObjectMeta: metav1.ObjectMeta{
						Name:      pvcVolumeSnapshotName,
						Namespace: m.manager.Config.Namespace,
					},
					Spec: volumesnapshotv1.VolumeSnapshotSpec{
						Source: volumesnapshotv1.VolumeSnapshotSource{
							PersistentVolumeClaimName: &pvcName,
						},
						VolumeSnapshotClassName: &pvcVolumeSnapshotClassName,
					},
				}

				err = m.manager.Clientset.Create(ctx, volumeSnapshot)
				if err != nil && !k8serr.IsAlreadyExists(err) {
					err = xerrors.Errorf("cannot create volumesnapshot: %v", err)
					return true, nil, err
				}
				createdVolumeSnapshot = true
				volumeSnapshotTime = time.Now()
			}
			if createdVolumeSnapshot {
				m.notifyPodMapLock.Lock()
				if m.notifyPod[wso.Pod.Name] == nil {
					m.notifyPod[wso.Pod.Name] = make(chan string)
				}
				m.notifyPodMapLock.Unlock()

				select {
				case pvcVolumeSnapshotContentName = <-m.notifyPod[wso.Pod.Name]:
					readyVolumeSnapshot = true
				case <-ctx.Done():
					// There might be a chance that the VolumeSnapshot is ready but somehow
					// we did not receive the notification.
					// For example, the ws-manager restarts before the VolumeSnapshot becomes ready.
					// Let's give it the last chance to check the VolumeSnapshot is ready.
					var vs volumesnapshotv1.VolumeSnapshot
					err := m.manager.Clientset.Get(ctx, types.NamespacedName{Namespace: m.manager.Config.Namespace, Name: pvcVolumeSnapshotName}, &vs)
					if err == nil && vs.Status != nil && vs.Status.ReadyToUse != nil && *vs.Status.ReadyToUse && vs.Status.BoundVolumeSnapshotContentName != nil {
						pvcVolumeSnapshotContentName = *vs.Status.BoundVolumeSnapshotContentName
						readyVolumeSnapshot = true
						break
					}

					err = xerrors.Errorf("%s timed out while waiting for volume snapshot to get ready", m.manager.Config.Timeouts.ContentFinalization.String())
					log.Error(err.Error())
					return true, nil, err
				}

				hist, err := m.manager.metrics.volumeSnapshotTimeHistVec.GetMetricWithLabelValues(wsType, wso.Pod.Labels[workspaceClassLabel])
				if err != nil {
					log.WithError(err).WithField("type", wsType).Warn("cannot get volume snapshot time histogram metric")
				} else {
					hist.Observe(time.Since(volumeSnapshotTime).Seconds())
				}
			}
			if readyVolumeSnapshot && !markVolumeSnapshotAnnotation {
				log = log.WithField("VolumeSnapshotContent.Name", pvcVolumeSnapshotContentName)
				var volumeSnapshotContent volumesnapshotv1.VolumeSnapshotContent
				err := m.manager.Clientset.Get(ctx, types.NamespacedName{Namespace: "", Name: pvcVolumeSnapshotContentName}, &volumeSnapshotContent)
				if err != nil {
					log.WithError(err).Error("was unable to get volume snapshot content")
					return true, nil, err
				}

				if volumeSnapshotContent.Status == nil {
					return true, nil, xerrors.Errorf("volume snapshot content status is nil")
				}
				if volumeSnapshotContent.Status.SnapshotHandle == nil {
					return true, nil, xerrors.Errorf("volume snapshot content's snapshot handle is nil")
				}
				snapshotHandle := *volumeSnapshotContent.Status.SnapshotHandle

				b, err := json.Marshal(workspaceVolumeSnapshotStatus{VolumeSnapshotName: pvcVolumeSnapshotName, VolumeSnapshotHandle: snapshotHandle})
				if err != nil {
					return true, nil, err
				}

				err = m.manager.markWorkspace(context.Background(), workspaceID, addMark(pvcWorkspaceVolumeSnapshotAnnotation, string(b)))
				if err != nil {
					log.WithError(err).Error("cannot mark workspace with volume snapshot name - snapshot will be orphaned and backup lost")
					errMark := m.manager.markWorkspace(ctx, workspaceID, addMark(workspaceExplicitFailAnnotation, xerrors.Errorf("cannot add mark to save snapshot info: %v", err).Error()))
					if errMark != nil {
						log.WithError(errMark).Warn("was unable to mark workspace as failed")
					}
					return true, nil, err
				}

				if doSnapshot {
					err = m.manager.markWorkspace(context.Background(), workspaceID, addMark(workspaceSnapshotAnnotation, pvcVolumeSnapshotName))
					if err != nil {
						tracing.LogError(span, err)
						log.WithError(err).Warn("cannot mark headless workspace with snapshot - that's one prebuild lost")
						errMark := m.manager.markWorkspace(ctx, workspaceID, addMark(workspaceExplicitFailAnnotation, xerrors.Errorf("cannot add mark for prebuild snapshot info: %v", err).Error()))
						if errMark != nil {
							log.WithError(errMark).Warn("was unable to mark workspace as failed")
						}
						return true, nil, err
					}
				}

				markVolumeSnapshotAnnotation = true
			}

			// backup is done and we are ready to kill the pod, mark PVC for deletion
			if readyVolumeSnapshot && !deletedPVC {
				// todo: once we add snapshot objects, this will be changed to create snapshot object first
				err = m.manager.deleteWorkspacePVC(ctx, pvcName)
				if err != nil {
					log.Error(err)
					return true, nil, err
				}
				deletedPVC = true
			}
		} else if doSnapshot {
			// if this is a prebuild take a snapshot and mark the workspace
			var res *wsdaemon.TakeSnapshotResponse
			res, err = snc.TakeSnapshot(ctx, &wsdaemon.TakeSnapshotRequest{Id: workspaceID})
			if err != nil {
				tracing.LogError(span, err)
				log.WithError(err).Error("cannot take snapshot")
				err = xerrors.Errorf("cannot take snapshot: %v", err)
				err = m.manager.markWorkspace(ctx, workspaceID, addMark(workspaceExplicitFailAnnotation, err.Error()))
				if err != nil {
					log.WithError(err).Error("was unable to mark workspace as failed")
				}
			}

			if res != nil {
				err = m.manager.markWorkspace(context.Background(), workspaceID, addMark(workspaceSnapshotAnnotation, res.Url))
				if err != nil {
					tracing.LogError(span, err)
					log.WithError(err).Error("cannot mark headless workspace with snapshot - that's one prebuild lost")
					err = xerrors.Errorf("cannot remember snapshot: %v", err)
					err = m.manager.markWorkspace(ctx, workspaceID, addMark(workspaceExplicitFailAnnotation, err.Error()))
					if err != nil {
						log.WithError(err).Error("was unable to mark workspace as failed")
					}
				}
			}
		}

		// DiposeWorkspace will "degenerate" to a simple wait if the finalization/disposal process is already running.
		// This is unlike the initialization process where we wait for things to finish in a later phase.
		resp, err := snc.DisposeWorkspace(ctx, &wsdaemon.DisposeWorkspaceRequest{
			Id:         workspaceID,
			Backup:     doBackup && !pvcFeatureEnabled,
			BackupLogs: doBackupLogs,
		})
		if resp != nil {
			gitStatus = resp.GitStatus
		}
		return true, gitStatus, err
	}

	var (
		dataloss    bool
		backupError error
		gitStatus   *csapi.GitStatus
	)
	t := time.Now()

	disposalStatus = &workspaceDisposalStatus{
		Status: DisposalStarted,
	}
	err = m.manager.markDisposalStatus(ctx, workspaceID, disposalStatus)
	if err != nil {
		tracing.LogError(span, err)
		log.WithError(err).Error("was unable to update pod's start disposal status - this might cause an incorrect disposal status")
	}
	for i := 0; i < wsdaemonMaxAttempts; i++ {
		span.LogKV("attempt", i)
		didSometing, gs, err := doFinalize()
		if !didSometing {
			// someone else is managing finalization process ... we don't have to bother
			span.LogKV("did-nothing", true)
			return
		}

		// by default we assume the worst case scenario. If things aren't just as bad, we'll tune it down below.
		dataloss = true
		backupError = handleGRPCError(ctx, err)
		gitStatus = gs

		// At this point one of three things may have happened:
		//   1. the context deadline was exceeded, e.g. due to misconfiguration (not enough time to upload) or network issues. We'll try again.
		//   2. the service was unavailable, in which case we'll try again.
		//   3. none of the above, in which case we'll give up
		st, isGRPCError := grpc_status.FromError(err)
		if !isGRPCError {
			break
		}

		if (err != nil && strings.Contains(err.Error(), context.DeadlineExceeded.Error())) ||
			st.Code() == codes.Unavailable ||
			st.Code() == codes.Canceled {
			if disposalStatus.Status != DisposalRetrying {
				disposalStatus.Status = DisposalRetrying
				err = m.manager.markDisposalStatus(ctx, workspaceID, disposalStatus)
				if err != nil {
					tracing.LogError(span, err)
					log.WithError(err).Error("was unable to update pod's retrying disposal status - this might cause an incorrect disposal status")
				}
			}
			// service is currently unavailable or we did not finish in time - let's wait some time and try again
			span.LogKV("retrying-after-sleep", true)
			time.Sleep(wsdaemonRetryInterval)
			continue
		}

		// service was available, we've tried to do the work and failed. Tell the world about it.
		if (doBackup || doSnapshot) && isGRPCError {
			switch st.Code() {
			case codes.DataLoss:
				// ws-daemon told us that it's lost data
				dataloss = true
			case codes.FailedPrecondition:
				// the workspace content was not in the state we thought it was
				dataloss = true
			}
		}
		break
	}

	hist, err := m.manager.metrics.finalizeTimeHistVec.GetMetricWithLabelValues(wsType, wso.Pod.Labels[workspaceClassLabel])
	if err != nil {
		log.WithError(err).WithField("type", wsType).Warn("cannot get finalize time histogram metric")
	} else {
		hist.Observe(time.Since(t).Seconds())
	}

	disposalStatus = &workspaceDisposalStatus{
		Status:         DisposalFinished,
		BackupComplete: true,
		GitStatus:      gitStatus,
	}

	if doBackup || doSnapshot {
		m.manager.metrics.totalBackupCounterVec.WithLabelValues(wsType, strconv.FormatBool(pvcFeatureEnabled), wso.Pod.Labels[workspaceClassLabel]).Inc()
	}

	if backupError != nil {
		tracing.LogError(span, backupError)
		log.WithError(backupError).Warn("internal error while disposing workspace content")

		m.manager.metrics.totalBackupFailureCounterVec.WithLabelValues(wsType, strconv.FormatBool(pvcFeatureEnabled), wso.Pod.Labels[workspaceClassLabel]).Inc()

		if dataloss {
			disposalStatus.BackupFailure = backupError.Error()
		}
	}
}

// markTimedoutWorkspaces finds workspaces which can be timeout due to inactivity or max lifetime allowed
func (m *Monitor) markTimedoutWorkspaces(ctx context.Context) (err error) {
	span, ctx := tracing.FromContext(ctx, "markTimedoutWorkspaces")
	defer tracing.FinishSpan(span, &err)

	var pods corev1.PodList
	err = m.manager.Clientset.List(ctx, &pods, workspaceObjectListOptions(m.manager.Config.Namespace))
	if err != nil {
		return xerrors.Errorf("stopTimedoutWorkspaces: %w", err)
	}

	errs := make([]string, 0)
	idx := make(map[string]struct{})
	for _, pod := range pods.Items {
		workspaceID, ok := pod.Annotations[workspaceIDAnnotation]
		if !ok {
			log.WithFields(wsk8s.GetOWIFromObject(&pod.ObjectMeta)).WithError(err).Errorf("while checking if timed out: found workspace without %s annotation", workspaceIDAnnotation)
			errs = append(errs, fmt.Sprintf("cannot check if pod %s is timed out: has no %s annotation", pod.Name, workspaceIDAnnotation))
			continue
		}
		idx[workspaceID] = struct{}{}

		if _, timedout := pod.Annotations[workspaceTimedOutAnnotation]; timedout {
			// workspace is already marked as timedout
			continue
		}

		timedout, err := m.manager.isWorkspaceTimedOut(workspaceObjects{Pod: &pod})
		if err != nil {
			errs = append(errs, fmt.Sprintf("workspaceId=%s: %q", workspaceID, err))
			continue
		}
		if timedout == "" {
			continue
		}
		err = m.manager.markWorkspace(ctx, workspaceID, addMark(workspaceTimedOutAnnotation, timedout))
		if err != nil {
			errs = append(errs, fmt.Sprintf("workspaceId=%s: %q", workspaceID, err))
			// don't skip the next step - even if we did not mark the workspace as timed out, we still want to stop it
		}
	}

	if len(errs) > 0 {
		return xerrors.Errorf("error during periodic run:\n%s", strings.Join(errs, "\n\t"))
	}

	return nil
}

// Stop ends the monitor's involvement. A stopped monitor cannot be started again.
func (m *Monitor) Stop() {
	if m.ticker != nil {
		m.ticker.Stop()
	}
}

func workspaceObjectListOptions(namespace string) *client.ListOptions {
	return &client.ListOptions{
		Namespace: namespace,
		LabelSelector: labels.SelectorFromSet(labels.Set{
			markerLabel: "true",
		}),
	}
}

func handleGRPCError(ctx context.Context, err error) error {
	if err == nil {
		return err
	}

	grpcErr, ok := grpc_status.FromError(err)
	if !ok {
		return err
	}

	return xerrors.Errorf(grpcErr.Message())
}