func()

in pkg/controllers/clusterresourceplacement/controller.go [428:536]
86 lines of code
23 McCabe index (conditional complexity)

func (r *Reconciler) getOrCreateClusterResourceSnapshot(ctx context.Context, crp *fleetv1beta1.ClusterResourcePlacement, envelopeObjCount int, resourceSnapshotSpec *fleetv1beta1.ResourceSnapshotSpec, revisionHistoryLimit int) (*fleetv1beta1.ClusterResourceSnapshot, error) {
	resourceHash, err := resource.HashOf(resourceSnapshotSpec)
	crpKObj := klog.KObj(crp)
	if err != nil {
		klog.ErrorS(err, "Failed to generate resource hash of crp", "clusterResourcePlacement", crpKObj)
		return nil, controller.NewUnexpectedBehaviorError(err)
	}

	// latestResourceSnapshotIndex should be -1 when there is no snapshot.
	latestResourceSnapshot, latestResourceSnapshotIndex, err := r.lookupLatestResourceSnapshot(ctx, crp)
	if err != nil {
		return nil, err
	}

	latestResourceSnapshotHash := ""
	numberOfSnapshots := -1
	if latestResourceSnapshot != nil {
		latestResourceSnapshotHash, err = parseResourceGroupHashFromAnnotation(latestResourceSnapshot)
		if err != nil {
			klog.ErrorS(err, "Failed to get the ResourceGroupHashAnnotation", "clusterResourceSnapshot", klog.KObj(latestResourceSnapshot))
			return nil, controller.NewUnexpectedBehaviorError(err)
		}
		numberOfSnapshots, err = annotations.ExtractNumberOfResourceSnapshotsFromResourceSnapshot(latestResourceSnapshot)
		if err != nil {
			klog.ErrorS(err, "Failed to get the NumberOfResourceSnapshotsAnnotation", "clusterResourceSnapshot", klog.KObj(latestResourceSnapshot))
			return nil, controller.NewUnexpectedBehaviorError(err)
		}
	}

	shouldCreateNewMasterClusterSnapshot := true
	// This index indicates the selected resource in the split selectedResourceList, if this index is zero we start
	// from creating the master clusterResourceSnapshot if it's greater than zero it means that the master clusterResourceSnapshot
	// got created but not all sub-indexed clusterResourceSnapshots have been created yet. It covers the corner case where the
	// controller crashes in the middle.
	resourceSnapshotStartIndex := 0
	if latestResourceSnapshot != nil && latestResourceSnapshotHash == resourceHash {
		if err := r.ensureLatestResourceSnapshot(ctx, latestResourceSnapshot); err != nil {
			return nil, err
		}
		// check to see all that the master cluster resource snapshot and sub-indexed snapshots belonging to the same group index exists.
		latestGroupResourceLabelMatcher := client.MatchingLabels{
			fleetv1beta1.ResourceIndexLabel: latestResourceSnapshot.Labels[fleetv1beta1.ResourceIndexLabel],
			fleetv1beta1.CRPTrackingLabel:   crp.Name,
		}
		resourceSnapshotList := &fleetv1beta1.ClusterResourceSnapshotList{}
		if err := r.Client.List(ctx, resourceSnapshotList, latestGroupResourceLabelMatcher); err != nil {
			klog.ErrorS(err, "Failed to list the latest group clusterResourceSnapshots associated with the clusterResourcePlacement",
				"clusterResourcePlacement", crp.Name)
			return nil, controller.NewAPIServerError(true, err)
		}
		if len(resourceSnapshotList.Items) == numberOfSnapshots {
			klog.V(2).InfoS("ClusterResourceSnapshots have not changed", "clusterResourcePlacement", crpKObj, "clusterResourceSnapshot", klog.KObj(latestResourceSnapshot))
			return latestResourceSnapshot, nil
		}
		// we should not create a new master cluster resource snapshot.
		shouldCreateNewMasterClusterSnapshot = false
		// set resourceSnapshotStartIndex to start from this index, so we don't try to recreate existing sub-indexed cluster resource snapshots.
		resourceSnapshotStartIndex = len(resourceSnapshotList.Items)
	}

	// Need to create new snapshot when 1) there is no snapshots or 2) the latest snapshot hash != current one.
	// mark the last resource snapshot as inactive if it is different from what we have now or 3) when some
	// sub-indexed cluster resource snapshots belonging to the same group have not been created, the master
	// cluster resource snapshot should exist and be latest.
	if latestResourceSnapshot != nil &&
		latestResourceSnapshotHash != resourceHash &&
		latestResourceSnapshot.Labels[fleetv1beta1.IsLatestSnapshotLabel] == strconv.FormatBool(true) {
		// set the latest label to false first to make sure there is only one or none active resource snapshot
		latestResourceSnapshot.Labels[fleetv1beta1.IsLatestSnapshotLabel] = strconv.FormatBool(false)
		if err := r.Client.Update(ctx, latestResourceSnapshot); err != nil {
			klog.ErrorS(err, "Failed to set the isLatestSnapshot label to false", "clusterResourceSnapshot", klog.KObj(latestResourceSnapshot))
			return nil, controller.NewUpdateIgnoreConflictError(err)
		}
		klog.V(2).InfoS("Marked the existing clusterResourceSnapshot as inactive", "clusterResourcePlacement", crpKObj, "clusterResourceSnapshot", klog.KObj(latestResourceSnapshot))
	}

	// only delete redundant resource snapshots and increment the latest resource snapshot index if new master cluster resource snapshot is to be created.
	if shouldCreateNewMasterClusterSnapshot {
		// delete redundant snapshot revisions before creating a new master cluster resource snapshot to guarantee that the number of snapshots
		// won't exceed the limit.
		if err := r.deleteRedundantResourceSnapshots(ctx, crp, revisionHistoryLimit); err != nil {
			return nil, err
		}
		latestResourceSnapshotIndex++
	}
	// split selected resources as list of lists.
	selectedResourcesList := splitSelectedResources(resourceSnapshotSpec.SelectedResources)
	var resourceSnapshot *fleetv1beta1.ClusterResourceSnapshot
	for i := resourceSnapshotStartIndex; i < len(selectedResourcesList); i++ {
		if i == 0 {
			resourceSnapshot = buildMasterClusterResourceSnapshot(latestResourceSnapshotIndex, len(selectedResourcesList), envelopeObjCount, crp.Name, resourceHash, selectedResourcesList[i])
			latestResourceSnapshot = resourceSnapshot
		} else {
			resourceSnapshot = buildSubIndexResourceSnapshot(latestResourceSnapshotIndex, i-1, crp.Name, selectedResourcesList[i])
		}
		if err = r.createResourceSnapshot(ctx, crp, resourceSnapshot); err != nil {
			return nil, err
		}
	}
	// shouldCreateNewMasterClusterSnapshot is used here to be defensive in case of the regression.
	if shouldCreateNewMasterClusterSnapshot && len(selectedResourcesList) == 0 {
		resourceSnapshot = buildMasterClusterResourceSnapshot(latestResourceSnapshotIndex, 1, envelopeObjCount, crp.Name, resourceHash, []fleetv1beta1.ResourceContent{})
		latestResourceSnapshot = resourceSnapshot
		if err = r.createResourceSnapshot(ctx, crp, resourceSnapshot); err != nil {
			return nil, err
		}
	}
	return latestResourceSnapshot, nil
}