#1: Split textures processing to 2 separate steps

api/mojang/queue/storage.go

@@ -2,18 +2,29 @@ package queue
 
 import "github.com/elyby/chrly/api/mojang"
 
+type UuidsStorage interface {
+	GetUuid(username string) (string, error)
+	StoreUuid(username string, uuid string)
+}
+
+type TexturesStorage interface {
+	// nil can be returned to indicate that there is no textures for uuid
+	// and we know about it. Return err only in case, when storage completely
+	// don't know anything about uuid
+	GetTextures(uuid string) (*mojang.SignedTexturesResponse, error)
+	StoreTextures(textures *mojang.SignedTexturesResponse)
+}
+
 type Storage interface {
-	Get(username string) *mojang.SignedTexturesResponse
-	Set(textures *mojang.SignedTexturesResponse)
+	UuidsStorage
+	TexturesStorage
 }
 
-// NilStorage used for testing purposes
-type NilStorage struct {
+// This error can be used to indicate, that requested
+// value doesn't exists in the storage
+type ValueNotFound struct {
 }
 
-func (*NilStorage) Get(username string) *mojang.SignedTexturesResponse {
-	return nil
-}
-
-func (*NilStorage) Set(textures *mojang.SignedTexturesResponse) {
+func (*ValueNotFound) Error() string {
+	return "value not found in storage"
 }