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merged 2 commits into from
Mar 16, 2025
Merged

Add unit tests for sharder controller #514

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f350825
Prefactor: extract resync operation
timebertt Mar 16, 2025
e3d9a19
Add unit tests for `sharder` controller
timebertt Mar 16, 2025
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127 changes: 74 additions & 53 deletions pkg/controller/sharder/reconciler.go
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Original file line number Diff line number Diff line change
Expand Up @@ -76,49 +76,45 @@ func (r *Reconciler) Reconcile(ctx context.Context, req reconcile.Request) (reco
return reconcile.Result{}, fmt.Errorf("error retrieving object from store: %w", err)
}

log = log.WithValues("ring", client.ObjectKeyFromObject(controllerRing))
o, err := r.NewOperation(ctx, controllerRing)
if err != nil {
return reconcile.Result{}, err
}

if err := o.ResyncControllerRing(ctx, log); err != nil {
return reconcile.Result{}, err
}

// requeue for periodic resync
return reconcile.Result{RequeueAfter: r.Config.Controller.Sharder.SyncPeriod.Duration}, nil
}

func (r *Reconciler) NewOperation(ctx context.Context, controllerRing *shardingv1alpha1.ControllerRing) (*Operation, error) {
// collect list of shards in the ring
leaseList := &coordinationv1.LeaseList{}
if err := r.Client.List(ctx, leaseList, client.MatchingLabelsSelector{Selector: controllerRing.LeaseSelector()}); err != nil {
return reconcile.Result{}, fmt.Errorf("error listing Leases for ControllerRing: %w", err)
return nil, fmt.Errorf("error listing Leases for ControllerRing: %w", err)
}

// get ring and shards from cache
hashRing, shards := ring.FromLeases(controllerRing, leaseList, r.Clock.Now())

namespaces, err := r.getSelectedNamespaces(ctx, controllerRing)
namespaces, err := r.GetSelectedNamespaces(ctx, controllerRing)
if err != nil {
return reconcile.Result{}, err
}

allErrs := &multierror.Error{
ErrorFormat: utilerrors.FormatErrors,
}

// resync all ring resources
for _, ringResource := range controllerRing.Spec.Resources {
allErrs = multierror.Append(allErrs,
r.resyncResource(ctx, log, ringResource.GroupResource, controllerRing, namespaces, hashRing, shards, false),
)

for _, controlledResource := range ringResource.ControlledResources {
allErrs = multierror.Append(allErrs,
r.resyncResource(ctx, log, controlledResource, controllerRing, namespaces, hashRing, shards, true),
)
}
}

// collect all errors and return a combined error if any occurred
if err := allErrs.ErrorOrNil(); err != nil {
return reconcile.Result{}, err
return nil, err
}

// requeue for periodic resync
return reconcile.Result{RequeueAfter: r.Config.Controller.Sharder.SyncPeriod.Duration}, nil
return &Operation{
Client: r.Client,
Reader: r.Reader,
ControllerRing: controllerRing,
Namespaces: namespaces,
HashRing: hashRing,
Shards: shards,
}, nil
}

func (r *Reconciler) getSelectedNamespaces(ctx context.Context, controllerRing *shardingv1alpha1.ControllerRing) (sets.Set[string], error) {
func (r *Reconciler) GetSelectedNamespaces(ctx context.Context, controllerRing *shardingv1alpha1.ControllerRing) (sets.Set[string], error) {
namespaceSelector := r.Config.Webhook.Config.NamespaceSelector
if controllerRing.Spec.NamespaceSelector != nil {
namespaceSelector = controllerRing.Spec.NamespaceSelector
Expand All @@ -142,19 +138,47 @@ func (r *Reconciler) getSelectedNamespaces(ctx context.Context, controllerRing *
return namespaceSet, err
}

func (r *Reconciler) resyncResource(
type Operation struct {
Client client.Client
Reader client.Reader

ControllerRing *shardingv1alpha1.ControllerRing
Namespaces sets.Set[string]
HashRing *consistenthash.Ring
Shards leases.Shards
}

func (o *Operation) ResyncControllerRing(ctx context.Context, log logr.Logger) error {
allErrs := &multierror.Error{
ErrorFormat: utilerrors.FormatErrors,
}

// resync all ring resources
for _, ringResource := range o.ControllerRing.Spec.Resources {
allErrs = multierror.Append(allErrs,
o.resyncResource(ctx, log, ringResource.GroupResource, false),
)

for _, controlledResource := range ringResource.ControlledResources {
allErrs = multierror.Append(allErrs,
o.resyncResource(ctx, log, controlledResource, true),
)
}
}

// collect all errors and return a combined error if any occurred
return allErrs.ErrorOrNil()
}

func (o *Operation) resyncResource(
ctx context.Context,
log logr.Logger,
gr metav1.GroupResource,
ring *shardingv1alpha1.ControllerRing,
namespaces sets.Set[string],
hashRing *consistenthash.Ring,
shards leases.Shards,
controlled bool,
) error {
log = log.WithValues("resource", gr)

gvks, err := r.Client.RESTMapper().KindsFor(schema.GroupVersionResource{Group: gr.Group, Resource: gr.Resource})
gvks, err := o.Client.RESTMapper().KindsFor(schema.GroupVersionResource{Group: gr.Group, Resource: gr.Resource})
if err != nil {
return fmt.Errorf("error determining kinds for resource %q: %w", gr.String(), err)
}
Expand All @@ -166,13 +190,13 @@ func (r *Reconciler) resyncResource(

list := &metav1.PartialObjectMetadataList{}
list.SetGroupVersionKind(gvks[0])
err = pager.New(r.Reader).EachListItemWithAlloc(ctx, list,
err = pager.New(o.Reader).EachListItemWithAlloc(ctx, list,
func(obj client.Object) error {
if !namespaces.Has(obj.GetNamespace()) {
if !o.Namespaces.Has(obj.GetNamespace()) {
return nil
}

allErrs = multierror.Append(allErrs, r.resyncObject(ctx, log, gr, obj.(*metav1.PartialObjectMetadata), ring, hashRing, shards, controlled))
allErrs = multierror.Append(allErrs, o.resyncObject(ctx, log, gr, controlled, obj.(*metav1.PartialObjectMetadata)))
return nil
},
// List a recent version from the API server's watch cache by setting resourceVersion=0. This reduces the load on etcd
Expand All @@ -196,15 +220,12 @@ var (
KeyForController = key.ForController
)

func (r *Reconciler) resyncObject(
func (o *Operation) resyncObject(
ctx context.Context,
log logr.Logger,
gr metav1.GroupResource,
obj *metav1.PartialObjectMetadata,
ring *shardingv1alpha1.ControllerRing,
hashRing *consistenthash.Ring,
shards leases.Shards,
controlled bool,
obj *metav1.PartialObjectMetadata,
) error {
log = log.WithValues("object", client.ObjectKeyFromObject(obj))

Expand All @@ -223,8 +244,8 @@ func (r *Reconciler) resyncObject(
}

var (
desiredShard = hashRing.Hash(hashKey)
currentShard = obj.Labels[ring.LabelShard()]
desiredShard = o.HashRing.Hash(hashKey)
currentShard = obj.Labels[o.ControllerRing.LabelShard()]
)

if desiredShard == "" {
Expand All @@ -237,20 +258,20 @@ func (r *Reconciler) resyncObject(
return nil
}

if currentShard != "" && currentShard != desiredShard && shards.ByID(currentShard).State.IsAvailable() && !controlled {
if currentShard != "" && o.Shards.ByID(currentShard).State.IsAvailable() && !controlled {
// If the object should be moved and the current shard is still available, we need to drain it.
// We only drain non-controlled objects, the controller's main object is used as a synchronization point for
// preventing concurrent reconciliations.
log.V(1).Info("Draining object from shard", "currentShard", currentShard)

patch := client.MergeFromWithOptions(obj.DeepCopy(), client.MergeFromWithOptimisticLock{})
metav1.SetMetaDataLabel(&obj.ObjectMeta, ring.LabelDrain(), "true")
if err := r.Client.Patch(ctx, obj, patch); err != nil {
metav1.SetMetaDataLabel(&obj.ObjectMeta, o.ControllerRing.LabelDrain(), "true")
if err := o.Client.Patch(ctx, obj, patch); err != nil {
return fmt.Errorf("error draining %s %q: %w", gr.String(), client.ObjectKeyFromObject(obj), err)
}

shardingmetrics.DrainsTotal.WithLabelValues(
ring.Name, gr.Group, gr.Resource,
o.ControllerRing.Name, gr.Group, gr.Resource,
).Inc()

// object will go through the sharder webhook when shard removes the drain label, which will perform the assignment
Expand All @@ -264,14 +285,14 @@ func (r *Reconciler) resyncObject(
patch := client.MergeFromWithOptions(obj.DeepCopy(), client.MergeFromWithOptimisticLock{})
// remove drain label if it is still present, this might happen when trying to drain an object from a shard that
// just got unavailable
delete(obj.Labels, ring.LabelShard())
delete(obj.Labels, ring.LabelDrain())
if err := r.Client.Patch(ctx, obj, patch); err != nil {
delete(obj.Labels, o.ControllerRing.LabelShard())
delete(obj.Labels, o.ControllerRing.LabelDrain())
if err := o.Client.Patch(ctx, obj, patch); err != nil {
return fmt.Errorf("error triggering assignment for %s %q: %w", gr.String(), client.ObjectKeyFromObject(obj), err)
}

shardingmetrics.MovementsTotal.WithLabelValues(
ring.Name, gr.Group, gr.Resource,
o.ControllerRing.Name, gr.Group, gr.Resource,
).Inc()

return nil
Expand Down
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