Add support sub-settings and secrets in sub-settings (#1221)

pipeline/frontend/yaml/compiler/compiler.go

@@ -25,6 +25,7 @@ const (
 	namePipeline = "pipeline"
 )
 
+// Registry represents registry credentials
 type Registry struct {
 	Hostname string
 	Username string
@@ -39,6 +40,16 @@ type Secret struct {
 	Match []string
 }
 
+type secretMap map[string]Secret
+
+func (sm secretMap) toStringMap() map[string]string {
+	m := make(map[string]string, len(sm))
+	for k, v := range sm {
+		m[k] = v.Value
+	}
+	return m
+}
+
 type ResourceLimit struct {
 	MemSwapLimit int64
 	MemLimit     int64
@@ -61,7 +72,7 @@ type Compiler struct {
 	path              string
 	metadata          frontend.Metadata
 	registries        []Registry
-	secrets           map[string]Secret
+	secrets           secretMap
 	cacher            Cacher
 	reslimit          ResourceLimit
 	defaultCloneImage string