diff options
Diffstat (limited to 'tools/nixery/server/manifest/manifest.go')
| -rw-r--r-- | tools/nixery/server/manifest/manifest.go | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/tools/nixery/server/manifest/manifest.go b/tools/nixery/server/manifest/manifest.go index f777e3f585df..2f236178b65f 100644 --- a/tools/nixery/server/manifest/manifest.go +++ b/tools/nixery/server/manifest/manifest.go @@ -6,6 +6,7 @@ import ( "crypto/sha256" "encoding/json" "fmt" + "sort" ) const ( @@ -27,6 +28,10 @@ type Entry struct { MediaType string `json:"mediaType,omitempty"` Size int64 `json:"size"` Digest string `json:"digest"` + + // This field is internal to Nixery and not part of the + // serialised entry. + MergeRating uint64 `json:"-"` } type manifest struct { @@ -85,6 +90,16 @@ func configLayer(hashes []string) ConfigLayer { // // Callers do not need to set the media type for the layer entries. func Manifest(layers []Entry) (json.RawMessage, ConfigLayer) { + // Sort layers by their merge rating, from highest to lowest. + // This makes it likely for a contiguous chain of shared image + // layers to appear at the beginning of a layer. + // + // Due to moby/moby#38446 Docker considers the order of layers + // when deciding which layers to download again. + sort.Slice(layers, func(i, j int) bool { + return layers[i].MergeRating > layers[j].MergeRating + }) + hashes := make([]string, len(layers)) for i, l := range layers { l.MediaType = "application/vnd.docker.image.rootfs.diff.tar" |