add massif options to suppress nonleaf errors when getting massifs

logverification/massif.go

@@ -21,10 +21,21 @@ var (
 // Massif gets the massif (blob) that contains the given mmrIndex, from azure blob storage
 //
 //	defined by the azblob configuration.
-func Massif(mmrIndex uint64, massifReader massifs.MassifReader, tenantId string, massifHeight uint8) (*massifs.MassifContext, error) {
+func Massif(mmrIndex uint64, massifReader massifs.MassifReader, tenantId string, massifHeight uint8, opts ...MassifOption) (*massifs.MassifContext, error) {
+
+	massifOptions := ParseMassifOptions(opts...)
 
 	massifIndex, err := massifs.MassifIndexFromMMRIndex(massifHeight, mmrIndex)
-	if err != nil {
+
+	// we don't want to suppress NotLeaf error for mmrIndex that are not leaf
+	//  nodes, so just surface any error.
+	if !massifOptions.nonLeafNode && err != nil {
+		return nil, err
+	}
+
+	// we want to suppress NotLeaf error for mmrIndexs that are not leaf
+	//   nodes.
+	if massifOptions.nonLeafNode && !errors.Is(err, massifs.ErrNotleaf) {
 		return nil, err
 	}
 
@@ -42,7 +53,7 @@ func Massif(mmrIndex uint64, massifReader massifs.MassifReader, tenantId string,
 // MassifFromEvent gets the massif (blob) that contains the given event, from azure blob storage
 //
 //	defined by the azblob configuration.
-func MassifFromEvent(eventJson []byte, reader azblob.Reader, options ...VerifyOption) (*massifs.MassifContext, error) {
+func MassifFromEvent(eventJson []byte, reader azblob.Reader, options ...MassifOption) (*massifs.MassifContext, error) {
 
 	verifyOptions := ParseOptions(options...)
 

logverification/massifoptions.go

@@ -0,0 +1,33 @@
+package logverification
+
+type MassifOptions struct {
+
+	// nonLeafNode is an optional suppression
+	//
+	//	of errors that occur due to attempting to get
+	//  a massif based on a non leaf node mmrIndex.
+	nonLeafNode bool
+}
+
+type MassifOption func(*MassifOptions)
+
+// WithNonLeafNode is an optional suppression
+//
+//	of errors that occur due to attempting to get
+//	a massif based on a non leaf node mmrIndex.
+func WithNonLeafNode(nonLeafNode bool) MassifOption {
+	return func(mo *MassifOptions) { mo.nonLeafNode = nonLeafNode }
+}
+
+// ParseMassifOptions parses the given options into a MassifOptions struct
+func ParseMassifOptions(options ...MassifOption) MassifOptions {
+	massifOptions := MassifOptions{
+		nonLeafNode: false, // default to erroring on non leaf nodes
+	}
+
+	for _, option := range options {
+		option(&massifOptions)
+	}
+
+	return massifOptions
+}