Normalize backend config validation

internal/config/backend_view.go

@@ -0,0 +1,50 @@
+package config
+
+type backendView struct {
+	Backend   string
+	Host      string
+	User      string
+	Port      int
+	Path      string
+	Endpoint  string
+	Bucket    string
+	Prefix    string
+	Region    string
+	ForcePath *bool
+	Creds     Credentials
+	SSH       SSH
+}
+
+func backendViewFromSource(source Backend) backendView {
+	return backendView{
+		Backend:   source.Backend,
+		Host:      source.Host,
+		User:      source.User,
+		Port:      source.Port,
+		Path:      source.Path,
+		Endpoint:  source.Endpoint,
+		Bucket:    source.Bucket,
+		Prefix:    source.Prefix,
+		Region:    source.Region,
+		ForcePath: source.ForcePath,
+		Creds:     source.Creds,
+		SSH:       source.SSH,
+	}
+}
+
+func backendViewFromDestination(destination Destination) backendView {
+	return backendView{
+		Backend:   destination.Backend,
+		Host:      destination.Host,
+		User:      destination.User,
+		Port:      destination.Port,
+		Path:      destination.Path,
+		Endpoint:  destination.Endpoint,
+		Bucket:    destination.Bucket,
+		Prefix:    destination.Prefix,
+		Region:    destination.Region,
+		ForcePath: destination.ForcePath,
+		Creds:     destination.Creds,
+		SSH:       destination.SSH,
+	}
+}