Support multiple implementations for IsSameResource

kyaml/kio/filters/merge3.go

@@ -19,17 +19,24 @@ const (
 	mergeSourceDest       = "dest"
 )
 
+// ResourceMatcher interface is used to match two resources based on IsSameResource implementation
+// This is the way to group same logical resources in upstream, local and origin for merge
+// The default way to group them is using GVKNN similar to how kubernetes server identifies resources
+// Users of this library might have their own interpretation of grouping similar resources
+// for e.g. if consumer adds a name-prefix to local resource, it should not be treated as new resource
+// for updates etc.
+// Hence, the callers of this library may pass different implementation for IsSameResource
+type ResourceMatcher interface {
+	IsSameResource(node1, node2 *yaml.RNode) bool
+}
+
 // Merge3 performs a 3-way merge on the original, updated, and destination packages.
 type Merge3 struct {
 	OriginalPath   string
 	UpdatedPath    string
 	DestPath       string
 	MatchFilesGlob []string
-
+	Matcher        ResourceMatcher
-	// MergeOnPath will use the relative filepath as part of the merge key.
-	// This may be necessary if the directory contains multiple copies of
-	// the same resource, or resources patches.
-	MergeOnPath bool
 }
 
 func (m Merge3) Merge() error {
@@ -67,7 +74,11 @@ func (m Merge3) Merge() error {
 // Filter combines Resources with the same GVK + N + NS into tuples, and then merges them
 func (m Merge3) Filter(nodes []*yaml.RNode) ([]*yaml.RNode, error) {
 	// index the nodes by their identity
-	tl := tuples{mergeOnPath: m.MergeOnPath}
+	matcher := m.Matcher
+	if matcher == nil {
+		matcher = &DefaultGVKNNMatcher{MergeOnPath: true}
+	}
+	tl := tuples{matcher: matcher}
 	for i := range nodes {
 		if err := tl.add(nodes[i]); err != nil {
 			return nil, err
@@ -82,7 +93,7 @@ func (m Merge3) Filter(nodes []*yaml.RNode) ([]*yaml.RNode, error) {
 		case t.original == nil && t.updated == nil && t.dest != nil:
 			// added locally -- keep dest
 			output = append(output, t.dest)
-		case t.original == nil && t.updated != nil && t.dest == nil:
+		case t.updated != nil && t.dest == nil:
 			// added in the update -- add update
 			output = append(output, t.updated)
 		case t.original != nil && t.updated == nil:
@@ -109,13 +120,35 @@ func (m Merge3) Filter(nodes []*yaml.RNode) ([]*yaml.RNode, error) {
 type tuples struct {
 	list []*tuple
 
-	// mergeOnPath if set to true will use the resource filepath
+	// matcher matches the resources for merge
-	// as part of the merge key
+	matcher ResourceMatcher
-	mergeOnPath bool
 }
 
-// isSameResource returns true if meta1 and meta2 are for the same logic resource
+// DefaultGVKNNMatcher holds the default matching of resources implementation based on
-func (ts *tuples) isSameResource(meta1, meta2 yaml.ResourceMeta) bool {
+// Group, Version, Kind, Name and Namespace of the resource
+type DefaultGVKNNMatcher struct {
+	// MergeOnPath will use the relative filepath as part of the merge key.
+	// This may be necessary if the directory contains multiple copies of
+	// the same resource, or resources patches.
+	MergeOnPath bool
+}
+
+// IsSameResource returns true if metadata of node1 and metadata of node2 belongs to same logical resource
+func (dm *DefaultGVKNNMatcher) IsSameResource(node1, node2 *yaml.RNode) bool {
+	if node1 == nil || node2 == nil {
+		return false
+	}
+
+	meta1, err := node1.GetMeta()
+	if err != nil {
+		return false
+	}
+
+	meta2, err := node2.GetMeta()
+	if err != nil {
+		return false
+	}
+
 	if meta1.Name != meta2.Name {
 		return false
 	}
@@ -128,7 +161,7 @@ func (ts *tuples) isSameResource(meta1, meta2 yaml.ResourceMeta) bool {
 	if meta1.Kind != meta2.Kind {
 		return false
 	}
-	if ts.mergeOnPath {
+	if dm.MergeOnPath {
 		// directories may contain multiple copies of a resource with the same
 		// name, namespace, apiVersion and kind -- e.g. kustomize patches, or
 		// multiple environments
@@ -143,17 +176,13 @@ func (ts *tuples) isSameResource(meta1, meta2 yaml.ResourceMeta) bool {
 
 // add adds a node to the list, combining it with an existing matching Resource if found
 func (ts *tuples) add(node *yaml.RNode) error {
-	nodeMeta, err := node.GetMeta()
-	if err != nil {
-		return err
-	}
 	for i := range ts.list {
 		t := ts.list[i]
-		if ts.isSameResource(t.meta, nodeMeta) {
+		if ts.matcher.IsSameResource(addedNode(t), node) {
 			return t.add(node)
 		}
 	}
-	t := &tuple{meta: nodeMeta}
+	t := &tuple{}
 	if err := t.add(node); err != nil {
 		return err
 	}
@@ -161,9 +190,19 @@ func (ts *tuples) add(node *yaml.RNode) error {
 	return nil
 }
 
+// addedNode returns one on the existing added nodes in the tuple
+func addedNode(t *tuple) *yaml.RNode {
+	if t.updated != nil {
+		return t.updated
+	}
+	if t.original != nil {
+		return t.original
+	}
+	return t.dest
+}
+
 // tuple wraps an original, updated, and dest tuple for a given Resource
 type tuple struct {
-	meta     yaml.ResourceMeta
 	original *yaml.RNode
 	updated  *yaml.RNode
 	dest     *yaml.RNode
@@ -178,17 +217,17 @@ func (t *tuple) add(node *yaml.RNode) error {
 	switch meta.Annotations[mergeSourceAnnotation] {
 	case mergeSourceDest:
 		if t.dest != nil {
-			return fmt.Errorf("dest source already specified")
+			return duplicateError("local", meta.Annotations[kioutil.PathAnnotation])
 		}
 		t.dest = node
 	case mergeSourceOriginal:
 		if t.original != nil {
-			return fmt.Errorf("original source already specified")
+			return duplicateError("original upstream", meta.Annotations[kioutil.PathAnnotation])
 		}
 		t.original = node
 	case mergeSourceUpdated:
 		if t.updated != nil {
-			return fmt.Errorf("updated source already specified")
+			return duplicateError("updated upstream", meta.Annotations[kioutil.PathAnnotation])
 		}
 		t.updated = node
 	default:
@@ -201,3 +240,8 @@ func (t *tuple) add(node *yaml.RNode) error {
 func (t *tuple) merge() (*yaml.RNode, error) {
 	return merge3.Merge(t.dest, t.original, t.updated)
 }
+
+// duplicateError returns duplicate resources error
+func duplicateError(source, filePath string) error {
+	return fmt.Errorf(`found duplicate %q resources in file %q, please refer to "update" documentation for the fix`, source, filePath)
+}

kyaml/kio/filters/merge3_test.go

@@ -44,6 +44,7 @@ func TestMerge3_Merge(t *testing.T) {
 		OriginalPath: filepath.Join(datadir, "dataset1"),
 		UpdatedPath:  filepath.Join(datadir, "dataset1-remoteupdates"),
 		DestPath:     filepath.Join(dir, "dataset1"),
+		Matcher:      &filters.DefaultGVKNNMatcher{MergeOnPath: false},
 	}.Merge()
 	if !assert.NoError(t, err) {
 		t.FailNow()
@@ -89,7 +90,6 @@ func TestMerge3_Merge_path(t *testing.T) {
 		OriginalPath: filepath.Join(datadir, "dataset1"),
 		UpdatedPath:  filepath.Join(datadir, "dataset1-remoteupdates"),
 		DestPath:     filepath.Join(dir, "dataset1"),
-		MergeOnPath:  true,
 	}.Merge()
 	if !assert.NoError(t, err) {
 		t.FailNow()
@@ -135,6 +135,7 @@ func TestMerge3_Merge_fail(t *testing.T) {
 		OriginalPath: filepath.Join(datadir, "dataset1"),
 		UpdatedPath:  filepath.Join(datadir, "dataset1-remoteupdates"),
 		DestPath:     filepath.Join(dir, "dataset1"),
+		Matcher:      &filters.DefaultGVKNNMatcher{MergeOnPath: false},
 	}.Merge()
 	if !assert.Error(t, err) {
 		t.FailNow()