make the current side available to templates to enable complex logic

On-behalf-of: @SAP christoph.mewes@sap.com

Author: xrstf

internal/sync/syncer_related.go

@@ -516,14 +516,14 @@ func applyTemplateBothSides(relatedOrigin, relatedDest syncSide, origin syncagen
 	_, remoteSide := remapSyncSides(relatedOrigin, relatedDest, origin)
 
 	// evaluate the template for the origin object side
-	ctx := templating.NewRelatedObjectContext(relatedOrigin.object, remoteSide.clusterName, remoteSide.workspacePath)
+	ctx := templating.NewRelatedObjectContext(relatedOrigin.object, origin, remoteSide.clusterName, remoteSide.workspacePath)
 	originValue, err = templating.Render(tpl.Template, ctx)
 	if err != nil {
 		return "", "", fmt.Errorf("failed to evaluate template on origin side: %w", err)
 	}
 
 	// and once more on the other side
-	ctx = templating.NewRelatedObjectContext(relatedDest.object, remoteSide.clusterName, remoteSide.workspacePath)
+	ctx = templating.NewRelatedObjectContext(relatedDest.object, oppositeSide(origin), remoteSide.clusterName, remoteSide.workspacePath)
 	destValue, err = templating.Render(tpl.Template, ctx)
 	if err != nil {
 		return "", "", fmt.Errorf("failed to evaluate template on destination side: %w", err)
@@ -574,3 +574,11 @@ func remapSyncSides(relatedOrigin, relatedDest syncSide, origin syncagentv1alpha
 
 	return relatedDest, relatedOrigin
 }
+
+func oppositeSide(origin syncagentv1alpha1.RelatedResourceOrigin) syncagentv1alpha1.RelatedResourceOrigin {
+	if origin == syncagentv1alpha1.RelatedResourceOriginKcp {
+		return syncagentv1alpha1.RelatedResourceOriginService
+	}
+
+	return syncagentv1alpha1.RelatedResourceOriginKcp
+}

internal/sync/templating/related.go

@@ -19,12 +19,17 @@ package templating
 import (
 	"github.com/kcp-dev/logicalcluster/v3"
 
+	syncagentv1alpha1 "github.com/kcp-dev/api-syncagent/sdk/apis/syncagent/v1alpha1"
+
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 )
 
-// relatedObjectContext is the data available to Go templates when determining
-// the local object name (the `naming` section of a PublishedResource).
+// relatedObjectContext is the data available to Go templates when evaluating
+// the origin of a related object.
 type relatedObjectContext struct {
+	// Side is set to either one of the possible origin values to indicate for
+	// which cluster the template is currently being evaluated for.
+	Side syncagentv1alpha1.RelatedResourceOrigin
 	// Object is the primary object belonging to the related object. Since related
 	// object templates are evaluated twice (once for the origin side and once
 	// for the destination side), object is the primary object on the side the
@@ -39,8 +44,9 @@ type relatedObjectContext struct {
 	ClusterPath logicalcluster.Path
 }
 
-func NewRelatedObjectContext(object *unstructured.Unstructured, clusterName logicalcluster.Name, clusterPath logicalcluster.Path) relatedObjectContext {
+func NewRelatedObjectContext(object *unstructured.Unstructured, side syncagentv1alpha1.RelatedResourceOrigin, clusterName logicalcluster.Name, clusterPath logicalcluster.Path) relatedObjectContext {
 	return relatedObjectContext{
+		Side:        side,
 		Object:      object.Object,
 		ClusterName: clusterName,
 		ClusterPath: clusterPath,