feat: add kusion config item registry

pkg/config/registry.go

@@ -0,0 +1,72 @@
+package config
+
+import (
+	v1 "kusionstack.io/kusion/pkg/apis/core/v1"
+	"kusionstack.io/kusion/pkg/config/validation"
+)
+
+const (
+	backendCurrent            = v1.ConfigBackends + "." + v1.BackendCurrent
+	backendConfig             = v1.ConfigBackends + "." + "*"
+	backendConfigType         = backendConfig + "." + v1.BackendType
+	backendConfigItems        = backendConfig + "." + v1.BackendConfigItems
+	backendLocalPath          = backendConfigItems + "." + v1.BackendLocalPath
+	backendMysqlDBName        = backendConfigItems + "." + v1.BackendMysqlDBName
+	backendMysqlUser          = backendConfigItems + "." + v1.BackendMysqlUser
+	backendMysqlPassword      = backendConfigItems + "." + v1.BackendMysqlPassword
+	backendMysqlHost          = backendConfigItems + "." + v1.BackendMysqlHost
+	backendMysqlPort          = backendConfigItems + "." + v1.BackendMysqlPort
+	backendGenericOssEndpoint = backendConfigItems + "." + v1.BackendGenericOssEndpoint
+	backendGenericOssAK       = backendConfigItems + "." + v1.BackendGenericOssAK
+	backendGenericOssSK       = backendConfigItems + "." + v1.BackendGenericOssSK
+	backendGenericOssBucket   = backendConfigItems + "." + v1.BackendGenericOssBucket
+	backendGenericOssPrefix   = backendConfigItems + "." + v1.BackendGenericOssPrefix
+	backendS3Region           = backendConfigItems + "." + v1.BackendS3Region
+)
+
+func newRegisteredItems() map[string]*itemInfo {
+	return map[string]*itemInfo{
+		backendCurrent:            {"", validation.ValidateCurrentBackend, nil},
+		backendConfig:             {&v1.BackendConfig{}, validation.ValidateBackendConfig, validation.ValidateUnsetBackendConfig},
+		backendConfigType:         {"", validation.ValidateBackendType, validation.ValidateUnsetBackendType},
+		backendConfigItems:        {map[string]any{}, validation.ValidateBackendConfigItems, nil},
+		backendLocalPath:          {"", validation.ValidateLocalBackendItem, nil},
+		backendMysqlDBName:        {"", validation.ValidateMysqlBackendItem, nil},
+		backendMysqlUser:          {"", validation.ValidateMysqlBackendItem, nil},
+		backendMysqlPassword:      {"", validation.ValidateMysqlBackendItem, nil},
+		backendMysqlHost:          {"", validation.ValidateMysqlBackendItem, nil},
+		backendMysqlPort:          {0, validation.ValidateMysqlBackendPort, nil},
+		backendGenericOssEndpoint: {"", validation.ValidateGenericOssBackendItem, nil},
+		backendGenericOssAK:       {"", validation.ValidateGenericOssBackendItem, nil},
+		backendGenericOssSK:       {"", validation.ValidateGenericOssBackendItem, nil},
+		backendGenericOssBucket:   {"", validation.ValidateGenericOssBackendItem, nil},
+		backendGenericOssPrefix:   {"", validation.ValidateGenericOssBackendItem, nil},
+		backendS3Region:           {"", validation.ValidateS3BackendItem, nil},
+	}
+}
+
+// itemInfo includes necessary information of the config item, which is used when getting, setting and unsetting
+// the config item.
+type itemInfo struct {
+	// zeroValue is the zero value of the type that the config item will be parsed from string to. Support string,
+	// int, bool, map, slice, struct and pointer of struct, the parser rule is shown as below:
+	//	- string: keep the same
+	//	- int: calling strconv.Atoi, e.g. "45" is valid, parsed to 45
+	// 	- bool: calling strconv.ParseBool, e.g. "true" is valid, parsed to true
+	//	- slice, map, struct(pointer of struct): calling json.Unmarshal, zeroValue of these types must be
+	// 	initialized, e.g. map[string]any{}, nil is invalid
+	// For other unsupported types, calling json.Unmarshal to do the parse job, unexpected error or panic may
+	// happen. Please do not use them.
+	zeroValue any
+
+	// validateFunc is used to check the config item is valid or not to set, calling before executing real
+	// config setting. The unregistered config item, empty item value and invalid item value type is forbidden
+	// by config operator by default, which are unnecessary to check in the validateFunc.
+	// Please do not do any real setting job in the validateFunc.
+	validateFunc validation.ValidateFunc
+
+	// validateUnsetFunc is used to check the config item is valid or not to unset, calling before executing
+	// real config unsetting.
+	// Please do not do any real unsetting job in the validateUnsetFunc.
+	validateUnsetFunc validation.ValidateUnsetFunc
+}