From 460abc97f18fe527205461e53687fa2e65e9961f Mon Sep 17 00:00:00 2001
From: Roman Dmytrenko <rdmytrenko@gmail.com>
Date: Fri, 19 Jul 2024 00:09:28 +0300
Subject: [PATCH] address PR feedback

Signed-off-by: Roman Dmytrenko <rdmytrenko@gmail.com>
---
 internal/storage/fs/git/store.go |  2 +-
 internal/storage/fs/oci/store.go |  2 +-
 internal/storage/fs/snapshot.go  | 25 +++++++++++++++++++++++--
 3 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/internal/storage/fs/git/store.go b/internal/storage/fs/git/store.go
index a00901c3cf..890038e4d4 100644
--- a/internal/storage/fs/git/store.go
+++ b/internal/storage/fs/git/store.go
@@ -355,5 +355,5 @@ func (s *SnapshotStore) buildSnapshot(ctx context.Context, hash plumbing.Hash) (
 		}
 	}
 
-	return storagefs.SnapshotFromFS(s.logger, gfs)
+	return storagefs.SnapshotFromFS(s.logger, gfs, storagefs.WithEtag(hash.String()))
 }
diff --git a/internal/storage/fs/oci/store.go b/internal/storage/fs/oci/store.go
index 7c797fd7fe..12f1c56377 100644
--- a/internal/storage/fs/oci/store.go
+++ b/internal/storage/fs/oci/store.go
@@ -89,7 +89,7 @@ func (s *SnapshotStore) update(ctx context.Context) (bool, error) {
 		return false, nil
 	}
 
-	snap, err := storagefs.SnapshotFromFiles(s.logger, resp.Files)
+	snap, err := storagefs.SnapshotFromFiles(s.logger, resp.Files, storagefs.WithEtag(resp.Digest.Hex()))
 	if err != nil {
 		return false, err
 	}
diff --git a/internal/storage/fs/snapshot.go b/internal/storage/fs/snapshot.go
index c2acc6319c..a73e5819f5 100644
--- a/internal/storage/fs/snapshot.go
+++ b/internal/storage/fs/snapshot.go
@@ -68,14 +68,31 @@ func newNamespace(key, name string, created *timestamppb.Timestamp) *namespace {
 
 type SnapshotOption struct {
 	validatorOption []validation.FeaturesValidatorOption
+	etagFn          EtagFn
 }
 
+type EtagFn func(stat fs.FileInfo) string
+
 func WithValidatorOption(opts ...validation.FeaturesValidatorOption) containers.Option[SnapshotOption] {
 	return func(so *SnapshotOption) {
 		so.validatorOption = opts
 	}
 }
 
+func WithEtag(etag string) containers.Option[SnapshotOption] {
+	return func(so *SnapshotOption) {
+		so.etagFn = func(stat fs.FileInfo) string { return etag }
+	}
+}
+
+func WithFileInfoEtag() containers.Option[SnapshotOption] {
+	return func(so *SnapshotOption) {
+		so.etagFn = func(stat fs.FileInfo) string {
+			return fmt.Sprintf("%x-%x", stat.ModTime().Unix(), stat.Size())
+		}
+	}
+}
+
 // SnapshotFromFS is a convenience function for building a snapshot
 // directly from an implementation of fs.FS using the list state files
 // function to source the relevant Flipt configuration files.
@@ -119,6 +136,7 @@ func SnapshotFromFiles(logger *zap.Logger, files []fs.File, opts ...containers.O
 	}
 
 	var so SnapshotOption
+	containers.ApplyAll(&so, WithFileInfoEtag())
 	containers.ApplyAll(&so, opts...)
 
 	for _, fi := range files {
@@ -162,7 +180,9 @@ func WalkDocuments(logger *zap.Logger, src fs.FS, fn func(*ext.Document) error)
 		}
 		defer fi.Close()
 
-		docs, err := documentsFromFile(fi, SnapshotOption{})
+		var so SnapshotOption
+		containers.ApplyAll(&so, WithFileInfoEtag())
+		docs, err := documentsFromFile(fi, so)
 		if err != nil {
 			return err
 		}
@@ -227,7 +247,8 @@ func documentsFromFile(fi fs.File, opts SnapshotOption) ([]*ext.Document, error)
 		if doc.Namespace == "" {
 			doc.Namespace = "default"
 		}
-		doc.Etag = fmt.Sprintf("%x-%x", stat.ModTime().Unix(), stat.Size())
+
+		doc.Etag = opts.etagFn(stat)
 		docs = append(docs, doc)
 	}