Add missing entries in build artifacts archive metadata

We need full directory structure, but since ZIP does not require it, we
need to calculate missing entries for directories when we generate
archive metadata.

cmd/gitlab-zip-metadata/main.go

@@ -23,7 +23,7 @@ func main() {
 	}
 
 	if len(os.Args) != 2 {
-		fmt.Fprintf(os.Stderr, "Usage: %s FILE.ZIP", progName)
+		fmt.Fprintf(os.Stderr, "Usage: %s FILE.ZIP\n", progName)
 		os.Exit(1)
 	}
 	if err := zipartifacts.GenerateZipMetadataFromFile(os.Args[1], os.Stdout); err != nil {

internal/zipartifacts/metadata.go

@@ -8,6 +8,8 @@ import (
 	"io"
 	"os"
 	"strconv"
+	"strings"
+	"time"
 )
 
 type metadata struct {
@@ -55,22 +57,60 @@ func writeZipEntryMetadata(output io.Writer, entry *zip.File) error {
 	return nil
 }
 
+func handleZipEntryMetadata(output io.Writer, entry *zip.File, entries []*zip.File) error {
+	var dirNodes []string
+
+	var calculateEntryNodes func(string)
+	calculateEntryNodes = func(str string) {
+		idx := strings.LastIndex(str, "/")
+		if idx < 0 {
+			return
+		}
+		dir := str[:idx]
+		dirNodes = append([]string{dir + "/"}, dirNodes...)
+		calculateEntryNodes(dir)
+	}
+	calculateEntryNodes(entry.Name)
+
+	for _, d := range dirNodes {
+		if !hasZipPathEntry(d, entries) {
+			var missingHeader zip.FileHeader
+			missingHeader.Name = d
+			missingHeader.SetModTime(time.Now())
+			missingHeader.SetMode(os.FileMode(uint32(0755)))
+			missingEntry := &zip.File{FileHeader: missingHeader}
+
+			writeZipEntryMetadata(output, missingEntry)
+		}
+	}
+
+	err := writeZipEntryMetadata(output, entry)
+	return err
+}
+
+func hasZipPathEntry(path string, entries []*zip.File) bool {
+	for _, e := range entries {
+		if e.Name == path {
+			return true
+		}
+	}
+
+	return false
+}
+
 func generateZipMetadata(output io.Writer, archive *zip.Reader) error {
-	err := writeString(output, MetadataHeader)
-	if err != nil {
+	if err := writeString(output, MetadataHeader); err != nil {
 		return err
 	}
 
 	// Write empty error string
-	err = writeString(output, "{}")
-	if err != nil {
+	if err := writeString(output, "{}"); err != nil {
 		return err
 	}
 
 	// Write all files
 	for _, entry := range archive.File {
-		err = writeZipEntryMetadata(output, entry)
-		if err != nil {
+		if err := handleZipEntryMetadata(output, entry, archive.File); err != nil {
 			return err
 		}
 	}