karmada/pkg/resourceinterpreter/configurableinterpreter/luavm/lua_convert.go

105 lines
2.7 KiB
Go

package luavm
import (
"encoding/json"
"fmt"
"reflect"
lua "github.com/yuin/gopher-lua"
"k8s.io/apimachinery/pkg/conversion"
luajson "layeh.com/gopher-json"
)
// ConvertLuaResultInto convert lua result to obj
func ConvertLuaResultInto(luaResult lua.LValue, obj interface{}) error {
t, err := conversion.EnforcePtr(obj)
if err != nil {
return fmt.Errorf("obj is not pointer")
}
// For example, `GetReplicas` returns requirement with empty:
// {
// nodeClaim: {},
// resourceRequest: {
// cpu: "100m"
// }
// }
// Luajson encodes it to
// {"nodeClaim": [], "resourceRequest": {"cpu": "100m"}}
//
// While go json fails to unmarshal `[]` to ReplicaRequirements.NodeClaim object.
// ReplicaRequirements object.
//
// Here we handle it as follows:
// 1. Walk the object (lua table), delete the key with empty value (`nodeClaim` in this example):
// {
// resourceRequest: {
// cpu: "100m"
// }
// }
// 2. Encode the object with luajson to be:
// {"resourceRequest": {"cpu": "100m"}}
// 4. Finally, unmarshal the new json to object, get
// {
// resourceRequest: {
// cpu: "100m"
// }
// }
isEmptyDic := func(v *lua.LTable) bool {
count := 0
v.ForEach(func(lua.LValue, lua.LValue) {
count++
})
return count == 0
}
var walkValue func(v lua.LValue)
walkValue = func(v lua.LValue) {
if t, ok := v.(*lua.LTable); ok {
t.ForEach(func(key lua.LValue, value lua.LValue) {
if tt, ok := value.(*lua.LTable); ok {
if isEmptyDic(tt) {
// set nil to delete key
t.RawSetH(key, lua.LNil)
} else {
walkValue(value)
}
}
})
}
}
walkValue(luaResult)
jsonBytes, err := luajson.Encode(luaResult)
if err != nil {
return fmt.Errorf("json Encode obj eroor %v", err)
}
// for lua an empty object by json encode be [] not {}
if t.Kind() == reflect.Struct && len(jsonBytes) > 1 && jsonBytes[0] == '[' {
jsonBytes[0], jsonBytes[len(jsonBytes)-1] = '{', '}'
}
err = json.Unmarshal(jsonBytes, obj)
if err != nil {
return fmt.Errorf("can not unmarshal %v to %#v", string(jsonBytes), obj)
}
return nil
}
// ConvertLuaResultToInt convert lua result to int.
func ConvertLuaResultToInt(luaResult lua.LValue) (int32, error) {
if luaResult.Type() != lua.LTNumber {
return 0, fmt.Errorf("result type %#v is not number", luaResult.Type())
}
return int32(luaResult.(lua.LNumber)), nil
}
// ConvertLuaResultToBool convert lua result to bool.
func ConvertLuaResultToBool(luaResult lua.LValue) (bool, error) {
if luaResult.Type() != lua.LTBool {
return false, fmt.Errorf("result type %#v is not bool", luaResult.Type())
}
return bool(luaResult.(lua.LBool)), nil
}