(feat) Lua Scripting for Dynamic Kubernetes Deployments

cmd/main.go

@@ -85,6 +85,7 @@ var (
 	healthAddr              string
 	profilerAddress         string
 	driftDetectionConfigMap string
+	luaConfigMap            string
 	disableCaching          bool
 	disableTelemetry        bool
 )
@@ -169,6 +170,7 @@ func main() {
 	ctx := ctrl.SetupSignalHandler()
 	controllers.SetManagementClusterAccess(mgr.GetClient(), mgr.GetConfig())
 	controllers.SetDriftdetectionConfigMap(driftDetectionConfigMap)
+	controllers.SetLuaConfigMap(luaConfigMap)
 
 	logsettings.RegisterForLogSettings(ctx,
 		libsveltosv1beta1.ComponentAddonManager, ctrl.Log.WithName("log-setter"),
@@ -239,6 +241,10 @@ func initFlags(fs *pflag.FlagSet) {
 	fs.StringVar(&driftDetectionConfigMap, "drift-detection-config", "",
 		"The name of the ConfigMap in the projectsveltos namespace containing the drift-detection-manager configuration")
 
+	fs.StringVar(&luaConfigMap, "lua-methods", "",
+		"The name of the ConfigMap in the projectsveltos namespace containing lua utilities to be loaded."+
+			"Changing the content of the ConfigMap does not cause Sveltos to redeploy.")
+
 	const defautlRestConfigQPS = 20
 	fs.Float32Var(&restConfigQPS, "kube-api-qps", defautlRestConfigQPS,
 		fmt.Sprintf("Maximum queries per second from the controller client to the Kubernetes API server. Defaults to %d",

controllers/handlers_utils.go

@@ -329,6 +329,19 @@ func instantiateTemplate(referencedObject client.Object, logger logr.Logger) boo
 	return false
 }
 
+func instantiateWithLua(referencedObject client.Object, logger logr.Logger) bool {
+	annotations := referencedObject.GetAnnotations()
+	if annotations != nil {
+		if _, ok := annotations[libsveltosv1beta1.PolicyLuaAnnotation]; ok {
+			logger.V(logs.LogInfo).Info(fmt.Sprintf("referencedObject %s %s/%s contains a lua script",
+				referencedObject.GetObjectKind().GroupVersionKind().Kind, referencedObject.GetNamespace(), referencedObject.GetName()))
+			return true
+		}
+	}
+
+	return false
+}
+
 func getSubresources(referencedObject client.Object) []string {
 	annotations := referencedObject.GetAnnotations()
 	if annotations != nil {
@@ -354,7 +367,8 @@ func deployContent(ctx context.Context, deployingToMgmtCluster bool, destConfig
 
 	subresources := getSubresources(referencedObject)
 	instantiateTemplate := instantiateTemplate(referencedObject, logger)
-	resources, err := collectContent(ctx, clusterSummary, mgmtResources, data, instantiateTemplate, logger)
+	instantiateLua := instantiateWithLua(referencedObject, logger)
+	resources, err := collectContent(ctx, clusterSummary, mgmtResources, data, instantiateTemplate, instantiateLua, logger)
 	if err != nil {
 		return nil, err
 	}
@@ -941,7 +955,7 @@ func customSplit(text string) ([]string, error) {
 // Returns an error if one occurred. Otherwise it returns a slice of *unstructured.Unstructured.
 func collectContent(ctx context.Context, clusterSummary *configv1beta1.ClusterSummary,
 	mgmtResources map[string]*unstructured.Unstructured, data map[string]string,
-	instantiateTemplate bool, logger logr.Logger,
+	instantiateTemplate, instantiateLua bool, logger logr.Logger,
 ) ([]*unstructured.Unstructured, error) {
 
 	policies := make([]*unstructured.Unstructured, 0, len(data))
@@ -958,6 +972,16 @@ func collectContent(ctx context.Context, clusterSummary *configv1beta1.ClusterSu
 				return nil, err
 			}
 
+			section = instance
+		} else if instantiateLua {
+			instance, err := instantiateWithLuaScript(ctx, getManagementClusterConfig(), getManagementClusterClient(),
+				clusterSummary.Spec.ClusterType, clusterSummary.Spec.ClusterNamespace, clusterSummary.Spec.ClusterName,
+				section, mgmtResources, logger)
+			if err != nil {
+				logger.Error(err, fmt.Sprintf("failed to instantiate policy from Data %.100s", section))
+				return nil, err
+			}
+			logger.V(logs.LogInfo).Info(fmt.Sprintf("lua output %q", instance))
 			section = instance
 		}
 
@@ -1993,7 +2017,7 @@ func getClusterProfileSpecHash(ctx context.Context, clusterSummary *configv1beta
 	// If drift-detectionmanager configuration is in a ConfigMap. fetch ConfigMap and use its Data
 	// section in the hash evaluation.
 	if driftDetectionConfigMap := getDriftDetectionConfigMap(); driftDetectionConfigMap != "" {
-		configMap, err := collectDriftDetectionConfigMap(ctx, driftDetectionConfigMap)
+		configMap, err := collectDriftDetectionConfigMap(ctx)
 		if err != nil {
 			return nil, err
 		}

controllers/handlers_utils_test.go

@@ -1419,7 +1419,7 @@ subjects:
 `
 		data := map[string]string{"policy.yaml": content}
 		u, err := controllers.CollectContent(context.TODO(), clusterSummary, nil, data, false,
-			textlogger.NewLogger(textlogger.NewConfig()))
+			false, textlogger.NewLogger(textlogger.NewConfig()))
 		Expect(err).To(BeNil())
 		Expect(len(u)).To(Equal(1))
 		Expect(u[0].GetName()).To(Equal("contour-gateway-provisioner"))
@@ -1480,7 +1480,7 @@ stringData:
 		policies := []string{service, deployment, secret}
 		configMap := createConfigMapWithPolicy(randomString(), randomString(), policies...)
 		u, err := controllers.CollectContent(context.TODO(), clusterSummary, nil, configMap.Data, false,
-			textlogger.NewLogger(textlogger.NewConfig()))
+			false, textlogger.NewLogger(textlogger.NewConfig()))
 		Expect(err).To(BeNil())
 		Expect(len(u)).To(Equal(3))
 	})

controllers/lua_instantiation.go

@@ -0,0 +1,126 @@
+/*
+Copyright 2024. projectsveltos.io. All rights reserved.
+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 controllers
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+
+	"github.com/go-logr/logr"
+	lua "github.com/yuin/gopher-lua"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/client-go/rest"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+
+	libsveltosv1beta1 "github.com/projectsveltos/libsveltos/api/v1beta1"
+	logs "github.com/projectsveltos/libsveltos/lib/logsettings"
+	sveltoslua "github.com/projectsveltos/libsveltos/lib/lua"
+)
+
+type luaResult struct {
+	// Resources is a list of Kubernetes resources
+	Resources string `json:"resources"`
+}
+
+func instantiateWithLuaScript(ctx context.Context, config *rest.Config, c client.Client,
+	clusterType libsveltosv1beta1.ClusterType, clusterNamespace, clusterName, script string,
+	mgmtResources map[string]*unstructured.Unstructured, logger logr.Logger) (string, error) {
+
+	if script == "" {
+		return "", nil
+	}
+
+	luaCode := ""
+
+	if luaConfigMap := getLuaConfigMap(); luaConfigMap != "" {
+		configMap, err := collectLuaConfigMap(ctx)
+		if err != nil {
+			return "", err
+		}
+
+		for k := range configMap.Data {
+			luaCode += configMap.Data[k]
+			luaCode += "\n"
+		}
+	}
+
+	luaCode += script
+
+	objects, err := fecthClusterObjects(ctx, config, c, clusterNamespace, clusterName, clusterType, logger)
+	if err != nil {
+		return "", err
+	}
+
+	if mgmtResources != nil {
+		objects.MgmtResources = make(map[string]map[string]interface{})
+		for k := range mgmtResources {
+			logger.V(logs.LogDebug).Info(fmt.Sprintf("using mgmt resource %s %s/%s with identifier %s",
+				mgmtResources[k].GetKind(), mgmtResources[k].GetNamespace(), mgmtResources[k].GetName(), k))
+			objects.MgmtResources[k] = mgmtResources[k].UnstructuredContent()
+		}
+	}
+
+	// Create a new Lua state
+	l := lua.NewState()
+	defer l.Close()
+
+	sveltoslua.LoadModulesAndRegisterMethods(l)
+
+	// Load the Lua code
+	if err := l.DoString(luaCode); err != nil {
+		logger.V(logs.LogInfo).Info(fmt.Sprintf("doString failed: %v", err))
+		return "", err
+	}
+
+	argTable := l.NewTable()
+	for key, resource := range objects.MgmtResources {
+		lValue := sveltoslua.MapToTable(resource)
+		argTable.RawSetString(key, lValue)
+	}
+
+	l.SetGlobal("resources", argTable)
+
+	if err := l.CallByParam(lua.P{
+		Fn:      l.GetGlobal("evaluate"), // name of Lua function
+		NRet:    1,                       // number of returned values
+		Protect: true,                    // return err or panic
+	}, argTable); err != nil {
+		logger.V(logs.LogInfo).Info(fmt.Sprintf("failed to call evaluate function: %s", err.Error()))
+		return "", err
+	}
+
+	lv := l.Get(-1)
+	tbl, ok := lv.(*lua.LTable)
+	if !ok {
+		logger.V(logs.LogInfo).Info(sveltoslua.LuaTableError)
+		return "", fmt.Errorf("%s", sveltoslua.LuaTableError)
+	}
+
+	goResult := sveltoslua.ToGoValue(tbl)
+	resultJson, err := json.Marshal(goResult)
+	if err != nil {
+		logger.V(logs.LogInfo).Info(fmt.Sprintf("failed to marshal result: %v", err))
+		return "", err
+	}
+
+	var result luaResult
+	err = json.Unmarshal(resultJson, &result)
+	if err != nil {
+		logger.V(logs.LogInfo).Info(fmt.Sprintf("failed to marshal result: %v", err))
+		return "", err
+	}
+
+	return result.Resources, nil
+}