kube.go

/*
Copyright 2022 The Karmada Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package luavm

import (
	lua "github.com/yuin/gopher-lua"
	corev1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/api/resource"

	"github.com/karmada-io/karmada/pkg/util/helper"
)

const (
	// KubeLibName is the name of the kube library.
	KubeLibName = "kube"
)

// KubeLoader loads the kube library. Import this library before your script by:
//
//	local kube = require("kube")
//
// Then you can call functions in this library by:
//
//	kube.xxx()
//
// This library Contains:
//   - function resourceAdd(r1, r2, ...)
//     accruing the quantity of resources. Example:
//     cpu = kube.resourceAdd(r1.cpu, r2.cpu, r3.cpu)
//   - function accuratePodRequirements(pod) requirements
//     accurate total resource requirements for pod. Example:
//     requirements = kube.accuratePodRequirements(pod)
//   - function getPodDependencies(podTemplate, namespace) dependencies
//     get total dependencies from podTemplate and namespace. Example:
//     dependencies = kube.getPodDependencies(podTemplate, namespace)
func KubeLoader(ls *lua.LState) int {
	mod := ls.SetFuncs(ls.NewTable(), kubeFuncs)
	ls.Push(mod)
	return 1
}

var kubeFuncs = map[string]lua.LGFunction{
	"resourceAdd":             resourceAdd,
	"accuratePodRequirements": accuratePodRequirements,
	"getPodDependencies":      getPodDependencies,
}

func resourceAdd(ls *lua.LState) int {
	res := resource.Quantity{}
	n := ls.GetTop()
	for i := 1; i <= n; i++ {
		q := checkResourceQuantity(ls, i)
		res.Add(q)
	}

	s := res.String()
	ls.Push(lua.LString(s))
	return 1
}

func accuratePodRequirements(ls *lua.LState) int {
	n := ls.GetTop()
	if n != 1 {
		ls.RaiseError("getPodRequirements only accepts one argument")
		return 0
	}

	v := ls.CheckTable(1)
	pod := &corev1.PodTemplateSpec{}
	err := ConvertLuaResultInto(v, pod)
	if err != nil {
		ls.RaiseError("fail to convert lua value %#v to PodTemplateSpec: %v", v, err)
		return 0
	}

	requirements := helper.GenerateReplicaRequirements(pod)
	retValue, err := decodeValue(ls, requirements)
	if err != nil {
		ls.RaiseError("fail to convert %#v to Lua value: %v", requirements, err)
		return 0
	}

	ls.Push(retValue)
	return 1
}

func getPodDependencies(ls *lua.LState) int {
	n := ls.GetTop()
	if n != 2 {
		ls.RaiseError("getPodDependencies only accepts two argument")
		return 0
	}

	podTemplate := ls.CheckTable(1)
	namespace := checkNamespace(ls, 2)

	template := &corev1.PodTemplateSpec{}
	err := ConvertLuaResultInto(podTemplate, template)
	if err != nil {
		ls.RaiseError("fail to convert lua value %#v to corev1.PodTemplateSpec: %v", podTemplate, err)
		return 0
	}

	pod := helper.GeneratePodFromTemplateAndNamespace(template, namespace)
	dependencies, _ := helper.GetDependenciesFromPodTemplate(pod)
	retValue, err := decodeValue(ls, dependencies)
	if err != nil {
		ls.RaiseError("fail to convert %#v to Lua value: %v", dependencies, err)
		return 0
	}

	ls.Push(retValue)
	return 1
}

func checkResourceQuantity(ls *lua.LState, n int) resource.Quantity {
	v := ls.Get(n)
	switch typ := v.Type(); typ {
	case lua.LTNil:
		return resource.Quantity{}
	case lua.LTString:
		s := string(v.(lua.LString))
		return resource.MustParse(s)
	default:
		ls.TypeError(n, lua.LTString)
		return resource.Quantity{}
	}
}

func checkNamespace(ls *lua.LState, n int) string {
	v := ls.Get(n)
	switch typ := v.Type(); typ {
	case lua.LTNil:
		return "default"
	case lua.LTString, lua.LTNumber:
		return ls.CheckString(n)
	default:
		ls.TypeError(n, lua.LTString)
		return ""
	}
}