Improve error handling when creating fdb directories

directories.go

@@ -0,0 +1,24 @@
+package blobs
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/apple/foundationdb/bindings/go/src/fdb"
+	"github.com/apple/foundationdb/bindings/go/src/fdb/directory"
+)
+
+type pathSegments []string
+
+func (p pathSegments) String() string {
+	return strings.Join(p, "/")
+}
+
+func createDirectory(db fdb.Database, parentDir directory.Directory, path ...string) (directory.DirectorySubspace, error) {
+	dir, err := parentDir.CreateOrOpen(db, path, nil)
+	if err != nil {
+		var newDirectoryPath pathSegments = append(parentDir.GetPath(), path...)
+		return nil, fmt.Errorf("%w: could not create directory %s", err, newDirectoryPath)
+	}
+	return dir, err
+}

store.go

@@ -29,19 +29,19 @@ type Store struct {
 // NewStore constructs a new blob store with the given FoundationDB instance, a
 // namespace ns the blobs are stored under and a list of options.
 func NewStore(db fdb.Database, ns string, opts ...Option) (*Store, error) {
-	dir, err := directory.CreateOrOpen(db, []string{"fdb-blobs", ns}, nil)
+	dir, err := createDirectory(db, directory.Root(), "fdb-blobs", ns)
 	if err != nil {
 		return nil, err
 	}
-	blobsDir, err := dir.CreateOrOpen(db, []string{"blobs"}, nil)
+	blobsDir, err := createDirectory(db, dir, "blobs")
 	if err != nil {
 		return nil, err
 	}
-	uploadsDir, err := dir.CreateOrOpen(db, []string{"uploads"}, nil)
+	uploadsDir, err := createDirectory(db, dir, "uploads")
 	if err != nil {
 		return nil, err
 	}
-	removedDir, err := dir.CreateOrOpen(db, []string{"removed"}, nil)
+	removedDir, err := createDirectory(db, dir, "removed")
 	if err != nil {
 		return nil, err
 	}