generate metadata user id

Signed-off-by: Jörn Friedrich Dreyer <jfd@butonic.de>

ocis-pkg/config/config.go

@@ -67,6 +67,7 @@ type Config struct {
 	TokenManager      *shared.TokenManager `yaml:"token_manager"`
 	MachineAuthAPIKey string               `yaml:"machine_auth_api_key" env:"OCIS_MACHINE_AUTH_API_KEY"`
 	TransferSecret    string               `yaml:"transfer_secret" env:"STORAGE_TRANSFER_SECRET"`
+	MetadataUserID    string               `yaml:"metadata_user_id"`
 	Runtime           Runtime              `yaml:"runtime"`
 
 	Audit             *audit.Config           `yaml:"audit"`

ocis-pkg/config/parser/parse.go

@@ -94,6 +94,10 @@ func EnsureCommons(cfg *config.Config) {
 		cfg.Commons.TransferSecret = cfg.TransferSecret
 	}
 
+	// copy metadata user id to the commons part if set
+	if cfg.MetadataUserID != "" {
+		cfg.Commons.MetadataUserID = cfg.MetadataUserID
+	}
 }
 
 func Validate(cfg *config.Config) error {
@@ -109,5 +113,9 @@ func Validate(cfg *config.Config) error {
 		return shared.MissingMachineAuthApiKeyError("ocis")
 	}
 
+	if cfg.MetadataUserID == "" {
+		return shared.MissingMetadataUserID("ocis")
+	}
+
 	return nil
 }