Add PolicyEngine

controller/controller.go

@@ -18,12 +18,12 @@ import (
 	event "github.com/nirmata/kube-policy/pkg/event"
 	eventinterfaces "github.com/nirmata/kube-policy/pkg/event/interfaces"
 	eventutils "github.com/nirmata/kube-policy/pkg/event/utils"
+	"github.com/nirmata/kube-policy/pkg/policyengine"
 	violation "github.com/nirmata/kube-policy/pkg/violation"
 	violationinterfaces "github.com/nirmata/kube-policy/pkg/violation/interfaces"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/labels"
 	mergetypes "k8s.io/apimachinery/pkg/types"
-	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/tools/cache"
 )
@@ -43,6 +43,9 @@ type policyController struct {
 	logger                *log.Logger
 	violationBuilder      violationinterfaces.ViolationGenerator
 	eventBuilder          eventinterfaces.BuilderInternal
+
+	policyEngine policyengine.PolicyEngine
+	kubeClient   *kubeClient.KubeClient
 }
 
 // NewPolicyController from cmd args
@@ -71,6 +74,12 @@ func NewPolicyController(config *rest.Config, logger *log.Logger, kubeClient *ku
 
 	// generate Violation builer
 	violationBuilder, err := violation.NewViolationBuilder(kubeClient, eventBuilder, logger)
+	if err != nil {
+		return nil, err
+	}
+
+	// generate Policy Engine
+	policyEngine := policyengine.NewPolicyEngine(kubeClient, logger)
 
 	controller := &policyController{
 		policyInformerFactory: policyInformerFactory,
@@ -79,15 +88,20 @@ func NewPolicyController(config *rest.Config, logger *log.Logger, kubeClient *ku
 		logger:                logger,
 		violationBuilder:      violationBuilder,
 		eventBuilder:          eventBuilder,
+		policyEngine:          policyEngine,
+		kubeClient:            kubeClient,
 	}
+
 	policyInformer.Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{
 		AddFunc:    controller.CreatePolicyHandler,
 		UpdateFunc: controller.UpdatePolicyHandler,
 		DeleteFunc: controller.DeletePolicyHandler,
 	})
+
 	// Set the controller
 	eventBuilder.SetController(controller)
 	violationBuilder.SetController(controller)
+
 	return controller, nil
 }
 
@@ -165,6 +179,7 @@ func (c *policyController) addPolicyLog(name, text string) {
 func (c *policyController) CreatePolicyHandler(resource interface{}) {
 	key := c.GetResourceKey(resource)
 	c.logger.Printf("Policy created: %s", key)
+	// c.runForPolicy(key)
 }
 
 func (c *policyController) UpdatePolicyHandler(oldResource, newResource interface{}) {
@@ -186,11 +201,11 @@ func (c *policyController) GetResourceKey(resource interface{}) string {
 	}
 	return ""
 }
+
 func (c *policyController) GetPolicy(name string) (*types.Policy, error) {
 	policyNamespace, policyName, err := cache.SplitMetaNamespaceKey(name)
 	if err != nil {
-		utilruntime.HandleError(fmt.Errorf("invalid resource key: %s", name))
-		return nil, err
+		return nil, fmt.Errorf("error when SplitMetaNamespaceKey: %s, err: %v", name, err)
 	}
 	return c.getPolicyInterface(policyNamespace).Get(policyName)
 }

controller/processPolicy.go

@@ -0,0 +1,120 @@
+package controller
+
+import (
+	"encoding/json"
+	"fmt"
+
+	types "github.com/nirmata/kube-policy/pkg/apis/policy/v1alpha1"
+	eventutils "github.com/nirmata/kube-policy/pkg/event/utils"
+	"github.com/nirmata/kube-policy/pkg/policyengine/mutation"
+	violationutils "github.com/nirmata/kube-policy/pkg/violation/utils"
+	"k8s.io/apimachinery/pkg/labels"
+	"k8s.io/apimachinery/pkg/runtime"
+	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
+)
+
+func (c *policyController) runForPolicy(key string) {
+	//policy, err := c.GetPolicy(key)
+	policy, err := c.getPolicyByKey(key)
+	if err != nil {
+		utilruntime.HandleError(fmt.Errorf("invalid resource key: %s, err: %v", key, err))
+		return
+	}
+
+	if policy == nil {
+		c.logger.Printf("Counld not find policy by key %s", key)
+		return
+	}
+
+	violations, events, err := c.processPolicy(*policy)
+	if err != nil {
+		// add Error processing policy event
+	}
+
+	c.logger.Printf("%v, %v", violations, events)
+	// TODO:
+	// create violations
+	// create events
+
+}
+
+// processPolicy process the policy to all the matched resources
+func (c *policyController) processPolicy(policy types.Policy) (
+	violations []violationutils.ViolationInfo, events []eventutils.EventInfo, err error) {
+
+	for _, rule := range policy.Spec.Rules {
+		resources, err := c.filterResourceByRule(rule)
+		if err != nil {
+			c.logger.Printf("Failed to filter resources by rule %s, err: %v\n", rule.Name, err)
+		}
+
+		for _, resource := range resources {
+			rawResource, err := json.Marshal(resource)
+			if err != nil {
+				c.logger.Printf("Failed to marshal resources map to rule %s, err: %v\n", rule.Name, err)
+				continue
+			}
+
+			violation, eventInfos, err := c.policyEngine.ProcessExisting(policy, rawResource)
+			if err != nil {
+				c.logger.Printf("Failed to process rule %s, err: %v\n", rule.Name, err)
+				continue
+			}
+
+			violations = append(violations, violation...)
+			events = append(events, eventInfos...)
+		}
+	}
+	return violations, events, nil
+}
+
+func (c *policyController) filterResourceByRule(rule types.PolicyRule) ([]runtime.Object, error) {
+	var targetResources []runtime.Object
+	// TODO: make this namespace all
+	var namespace = "default"
+	if err := rule.Validate(); err != nil {
+		return nil, fmt.Errorf("invalid rule detected: %s, err: %v", rule.Name, err)
+	}
+
+	// Get the resource list from kind
+	resources, err := c.kubeClient.ListResource(rule.Resource.Kind, namespace)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, resource := range resources {
+		// TODO:
+		rawResource, err := json.Marshal(resource)
+		// objKind := resource.GetObjectKind()
+		// codecFactory := serializer.NewCodecFactory(runtime.NewScheme())
+		// codecFactory.EncoderForVersion()
+
+		if err != nil {
+			c.logger.Printf("failed to marshal object %v", resource)
+			continue
+		}
+
+		// filter the resource by name and label
+		if ok, _ := mutation.IsRuleApplicableToResource(rawResource, rule.Resource); ok {
+			targetResources = append(targetResources, resource)
+		}
+	}
+	return targetResources, nil
+}
+
+func (c *policyController) getPolicyByKey(key string) (*types.Policy, error) {
+	// Create nil Selector to grab all the policies
+	selector := labels.NewSelector()
+	cachedPolicies, err := c.policyLister.List(selector)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, elem := range cachedPolicies {
+		if elem.Name == key {
+			return elem, nil
+		}
+	}
+
+	return nil, nil
+}

kubeclient/kubeclient.go

@@ -206,7 +206,34 @@ var rMapper = map[string]getter{
 	"StatefulSet":             statefulSetGetter,
 }
 
+var lMapper = map[string]lister{
+	"ConfigMap":               configMapLister,
+	"Pods":                    podLister,
+	"Deployment":              deploymentLister,
+	"CronJob":                 cronJobLister,
+	"Endpoints":               endpointsLister,
+	"HorizontalPodAutoscaler": horizontalPodAutoscalerLister,
+	"Ingress":                 ingressLister,
+	"Job":                     jobLister,
+	"LimitRange":              limitRangeLister,
+	"Namespace":               namespaceLister,
+	"NetworkPolicy":           networkPolicyLister,
+	"PersistentVolumeClaim":   persistentVolumeClaimLister,
+	"PodDisruptionBudget":     podDisruptionBudgetLister,
+	"PodTemplate":             podTemplateLister,
+	"ResourceQuota":           resourceQuotaLister,
+	"Secret":                  secretLister,
+	"Service":                 serviceLister,
+	"StatefulSet":             statefulSetLister,
+}
+
 type getter func(*kubernetes.Clientset, string, string) (runtime.Object, error)
+type lister func(*kubernetes.Clientset, string) ([]runtime.Object, error)
+
+//ListResource to return resource list
+func (kc *KubeClient) ListResource(kind string, namespace string) ([]runtime.Object, error) {
+	return lMapper[kind](kc.client, namespace)
+}
 
 //GetResource get the resource object
 func (kc *KubeClient) GetResource(kind string, resource string) (runtime.Object, error) {
@@ -233,6 +260,19 @@ func configMapGetter(clientSet *kubernetes.Clientset, namespace string, name str
 	}
 	return obj, nil
 }
+
+func configMapLister(clientSet *kubernetes.Clientset, namespace string) ([]runtime.Object, error) {
+	list, err := clientSet.CoreV1().ConfigMaps(namespace).List(metav1.ListOptions{})
+	if err != nil {
+		return nil, err
+	}
+	objList := []runtime.Object{}
+	for _, obj := range list.Items {
+		objList = append(objList, &obj)
+	}
+	return objList, nil
+}
+
 func podsGetter(clientSet *kubernetes.Clientset, namespace string, name string) (runtime.Object, error) {
 	obj, err := clientSet.CoreV1().Pods(namespace).Get(name, metav1.GetOptions{})
 	if err != nil {
@@ -241,6 +281,18 @@ func podsGetter(clientSet *kubernetes.Clientset, namespace string, name string)
 	return obj, nil
 }
 
+func podLister(clientSet *kubernetes.Clientset, namespace string) ([]runtime.Object, error) {
+	list, err := clientSet.CoreV1().Pods(namespace).List(metav1.ListOptions{})
+	if err != nil {
+		return nil, err
+	}
+	objList := []runtime.Object{}
+	for _, obj := range list.Items {
+		objList = append(objList, &obj)
+	}
+	return objList, nil
+}
+
 func deploymentGetter(clientSet *kubernetes.Clientset, namespace string, name string) (runtime.Object, error) {
 	obj, err := clientSet.AppsV1().Deployments(namespace).Get(name, metav1.GetOptions{})
 	if err != nil {
@@ -248,6 +300,17 @@ func deploymentGetter(clientSet *kubernetes.Clientset, namespace string, name st
 	}
 	return obj, nil
 }
+func deploymentLister(clientSet *kubernetes.Clientset, namespace string) ([]runtime.Object, error) {
+	list, err := clientSet.AppsV1().Deployments(namespace).List(metav1.ListOptions{})
+	if err != nil {
+		return nil, err
+	}
+	objList := []runtime.Object{}
+	for _, obj := range list.Items {
+		objList = append(objList, &obj)
+	}
+	return objList, nil
+}
 
 func cronJobGetter(clientSet *kubernetes.Clientset, namespace string, name string) (runtime.Object, error) {
 	obj, err := clientSet.BatchV1beta1().CronJobs(namespace).Get(name, metav1.GetOptions{})
@@ -257,6 +320,18 @@ func cronJobGetter(clientSet *kubernetes.Clientset, namespace string, name strin
 	return obj, nil
 }
 
+func cronJobLister(clientSet *kubernetes.Clientset, namespace string) ([]runtime.Object, error) {
+	list, err := clientSet.BatchV1beta1().CronJobs(namespace).List(metav1.ListOptions{})
+	if err != nil {
+		return nil, err
+	}
+	objList := []runtime.Object{}
+	for _, obj := range list.Items {
+		objList = append(objList, &obj)
+	}
+	return objList, nil
+}
+
 func endpointsbGetter(clientSet *kubernetes.Clientset, namespace string, name string) (runtime.Object, error) {
 	obj, err := clientSet.CoreV1().Endpoints(namespace).Get(name, metav1.GetOptions{})
 	if err != nil {
@@ -265,6 +340,18 @@ func endpointsbGetter(clientSet *kubernetes.Clientset, namespace string, name st
 	return obj, nil
 }
 
+func endpointsLister(clientSet *kubernetes.Clientset, namespace string) ([]runtime.Object, error) {
+	list, err := clientSet.CoreV1().Endpoints(namespace).List(metav1.ListOptions{})
+	if err != nil {
+		return nil, err
+	}
+	objList := []runtime.Object{}
+	for _, obj := range list.Items {
+		objList = append(objList, &obj)
+	}
+	return objList, nil
+}
+
 func horizontalPodAutoscalerGetter(clientSet *kubernetes.Clientset, namespace string, name string) (runtime.Object, error) {
 	obj, err := clientSet.AutoscalingV1().HorizontalPodAutoscalers(namespace).Get(name, metav1.GetOptions{})
 	if err != nil {
@@ -273,6 +360,18 @@ func horizontalPodAutoscalerGetter(clientSet *kubernetes.Clientset, namespace st
 	return obj, nil
 }
 
+func horizontalPodAutoscalerLister(clientSet *kubernetes.Clientset, namespace string) ([]runtime.Object, error) {
+	list, err := clientSet.AutoscalingV1().HorizontalPodAutoscalers(namespace).List(metav1.ListOptions{})
+	if err != nil {
+		return nil, err
+	}
+	objList := []runtime.Object{}
+	for _, obj := range list.Items {
+		objList = append(objList, &obj)
+	}
+	return objList, nil
+}
+
 func ingressGetter(clientSet *kubernetes.Clientset, namespace string, name string) (runtime.Object, error) {
 	obj, err := clientSet.ExtensionsV1beta1().Ingresses(namespace).Get(name, metav1.GetOptions{})
 	if err != nil {
@@ -281,6 +380,18 @@ func ingressGetter(clientSet *kubernetes.Clientset, namespace string, name strin
 	return obj, nil
 }
 
+func ingressLister(clientSet *kubernetes.Clientset, namespace string) ([]runtime.Object, error) {
+	list, err := clientSet.ExtensionsV1beta1().Ingresses(namespace).List(metav1.ListOptions{})
+	if err != nil {
+		return nil, err
+	}
+	objList := []runtime.Object{}
+	for _, obj := range list.Items {
+		objList = append(objList, &obj)
+	}
+	return objList, nil
+}
+
 func jobGetter(clientSet *kubernetes.Clientset, namespace string, name string) (runtime.Object, error) {
 	obj, err := clientSet.BatchV1().Jobs(namespace).Get(name, metav1.GetOptions{})
 	if err != nil {
@@ -289,6 +400,18 @@ func jobGetter(clientSet *kubernetes.Clientset, namespace string, name string) (
 	return obj, nil
 }
 
+func jobLister(clientSet *kubernetes.Clientset, namespace string) ([]runtime.Object, error) {
+	list, err := clientSet.BatchV1().Jobs(namespace).List(metav1.ListOptions{})
+	if err != nil {
+		return nil, err
+	}
+	objList := []runtime.Object{}
+	for _, obj := range list.Items {
+		objList = append(objList, &obj)
+	}
+	return objList, nil
+}
+
 func limitRangeGetter(clientSet *kubernetes.Clientset, namespace string, name string) (runtime.Object, error) {
 	obj, err := clientSet.CoreV1().LimitRanges(namespace).Get(name, metav1.GetOptions{})
 	if err != nil {
@@ -296,6 +419,17 @@ func limitRangeGetter(clientSet *kubernetes.Clientset, namespace string, name st
 	}
 	return obj, nil
 }
+func limitRangeLister(clientSet *kubernetes.Clientset, namespace string) ([]runtime.Object, error) {
+	list, err := clientSet.CoreV1().LimitRanges(namespace).List(metav1.ListOptions{})
+	if err != nil {
+		return nil, err
+	}
+	objList := []runtime.Object{}
+	for _, obj := range list.Items {
+		objList = append(objList, &obj)
+	}
+	return objList, nil
+}
 
 func namespaceGetter(clientSet *kubernetes.Clientset, namespace string, name string) (runtime.Object, error) {
 	obj, err := clientSet.CoreV1().Namespaces().Get(name, metav1.GetOptions{})
@@ -305,6 +439,18 @@ func namespaceGetter(clientSet *kubernetes.Clientset, namespace string, name str
 	return obj, nil
 }
 
+func namespaceLister(clientSet *kubernetes.Clientset, namespace string) ([]runtime.Object, error) {
+	list, err := clientSet.CoreV1().Namespaces().List(metav1.ListOptions{})
+	if err != nil {
+		return nil, err
+	}
+	objList := []runtime.Object{}
+	for _, obj := range list.Items {
+		objList = append(objList, &obj)
+	}
+	return objList, nil
+}
+
 func networkPolicyGetter(clientSet *kubernetes.Clientset, namespace string, name string) (runtime.Object, error) {
 	obj, err := clientSet.NetworkingV1().NetworkPolicies(namespace).Get(name, metav1.GetOptions{})
 	if err != nil {
@@ -313,6 +459,18 @@ func networkPolicyGetter(clientSet *kubernetes.Clientset, namespace string, name
 	return obj, nil
 }
 
+func networkPolicyLister(clientSet *kubernetes.Clientset, namespace string) ([]runtime.Object, error) {
+	list, err := clientSet.NetworkingV1().NetworkPolicies(namespace).List(metav1.ListOptions{})
+	if err != nil {
+		return nil, err
+	}
+	objList := []runtime.Object{}
+	for _, obj := range list.Items {
+		objList = append(objList, &obj)
+	}
+	return objList, nil
+}
+
 func persistentVolumeClaimGetter(clientSet *kubernetes.Clientset, namespace string, name string) (runtime.Object, error) {
 	obj, err := clientSet.CoreV1().PersistentVolumeClaims(namespace).Get(name, metav1.GetOptions{})
 	if err != nil {
@@ -321,6 +479,18 @@ func persistentVolumeClaimGetter(clientSet *kubernetes.Clientset, namespace stri
 	return obj, nil
 }
 
+func persistentVolumeClaimLister(clientSet *kubernetes.Clientset, namespace string) ([]runtime.Object, error) {
+	list, err := clientSet.CoreV1().PersistentVolumeClaims(namespace).List(metav1.ListOptions{})
+	if err != nil {
+		return nil, err
+	}
+	objList := []runtime.Object{}
+	for _, obj := range list.Items {
+		objList = append(objList, &obj)
+	}
+	return objList, nil
+}
+
 func podDisruptionBudgetGetter(clientSet *kubernetes.Clientset, namespace string, name string) (runtime.Object, error) {
 	obj, err := clientSet.PolicyV1beta1().PodDisruptionBudgets(namespace).Get(name, metav1.GetOptions{})
 	if err != nil {
@@ -329,6 +499,18 @@ func podDisruptionBudgetGetter(clientSet *kubernetes.Clientset, namespace string
 	return obj, nil
 }
 
+func podDisruptionBudgetLister(clientSet *kubernetes.Clientset, namespace string) ([]runtime.Object, error) {
+	list, err := clientSet.PolicyV1beta1().PodDisruptionBudgets(namespace).List(metav1.ListOptions{})
+	if err != nil {
+		return nil, err
+	}
+	objList := []runtime.Object{}
+	for _, obj := range list.Items {
+		objList = append(objList, &obj)
+	}
+	return objList, nil
+}
+
 func podTemplateGetter(clientSet *kubernetes.Clientset, namespace string, name string) (runtime.Object, error) {
 	obj, err := clientSet.CoreV1().PodTemplates(namespace).Get(name, metav1.GetOptions{})
 	if err != nil {
@@ -337,6 +519,18 @@ func podTemplateGetter(clientSet *kubernetes.Clientset, namespace string, name s
 	return obj, nil
 }
 
+func podTemplateLister(clientSet *kubernetes.Clientset, namespace string) ([]runtime.Object, error) {
+	list, err := clientSet.CoreV1().PodTemplates(namespace).List(metav1.ListOptions{})
+	if err != nil {
+		return nil, err
+	}
+	objList := []runtime.Object{}
+	for _, obj := range list.Items {
+		objList = append(objList, &obj)
+	}
+	return objList, nil
+}
+
 func resourceQuotaGetter(clientSet *kubernetes.Clientset, namespace string, name string) (runtime.Object, error) {
 	obj, err := clientSet.CoreV1().ResourceQuotas(namespace).Get(name, metav1.GetOptions{})
 	if err != nil {
@@ -345,6 +539,18 @@ func resourceQuotaGetter(clientSet *kubernetes.Clientset, namespace string, name
 	return obj, nil
 }
 
+func resourceQuotaLister(clientSet *kubernetes.Clientset, namespace string) ([]runtime.Object, error) {
+	list, err := clientSet.CoreV1().ResourceQuotas(namespace).List(metav1.ListOptions{})
+	if err != nil {
+		return nil, err
+	}
+	objList := []runtime.Object{}
+	for _, obj := range list.Items {
+		objList = append(objList, &obj)
+	}
+	return objList, nil
+}
+
 func secretGetter(clientSet *kubernetes.Clientset, namespace string, name string) (runtime.Object, error) {
 	obj, err := clientSet.CoreV1().Secrets(namespace).Get(name, metav1.GetOptions{})
 	if err != nil {
@@ -353,6 +559,18 @@ func secretGetter(clientSet *kubernetes.Clientset, namespace string, name string
 	return obj, nil
 }
 
+func secretLister(clientSet *kubernetes.Clientset, namespace string) ([]runtime.Object, error) {
+	list, err := clientSet.CoreV1().Secrets(namespace).List(metav1.ListOptions{})
+	if err != nil {
+		return nil, err
+	}
+	objList := []runtime.Object{}
+	for _, obj := range list.Items {
+		objList = append(objList, &obj)
+	}
+	return objList, nil
+}
+
 func serviceGetter(clientSet *kubernetes.Clientset, namespace string, name string) (runtime.Object, error) {
 	obj, err := clientSet.CoreV1().Services(namespace).Get(name, metav1.GetOptions{})
 	if err != nil {
@@ -361,6 +579,18 @@ func serviceGetter(clientSet *kubernetes.Clientset, namespace string, name strin
 	return obj, nil
 }
 
+func serviceLister(clientSet *kubernetes.Clientset, namespace string) ([]runtime.Object, error) {
+	list, err := clientSet.CoreV1().Services(namespace).List(metav1.ListOptions{})
+	if err != nil {
+		return nil, err
+	}
+	objList := []runtime.Object{}
+	for _, obj := range list.Items {
+		objList = append(objList, &obj)
+	}
+	return objList, nil
+}
+
 func statefulSetGetter(clientSet *kubernetes.Clientset, namespace string, name string) (runtime.Object, error) {
 	obj, err := clientSet.AppsV1().StatefulSets(namespace).Get(name, metav1.GetOptions{})
 	if err != nil {
@@ -368,3 +598,15 @@ func statefulSetGetter(clientSet *kubernetes.Clientset, namespace string, name s
 	}
 	return obj, nil
 }
+
+func statefulSetLister(clientSet *kubernetes.Clientset, namespace string) ([]runtime.Object, error) {
+	list, err := clientSet.AppsV1().StatefulSets(namespace).List(metav1.ListOptions{})
+	if err != nil {
+		return nil, err
+	}
+	objList := []runtime.Object{}
+	for _, obj := range list.Items {
+		objList = append(objList, &obj)
+	}
+	return objList, nil
+}

pkg/policyengine/mutation.go

@@ -0,0 +1,96 @@
+package policyengine
+
+import (
+	"errors"
+	"fmt"
+
+	types "github.com/nirmata/kube-policy/pkg/apis/policy/v1alpha1"
+	"github.com/nirmata/kube-policy/pkg/policyengine/mutation"
+)
+
+func (p *policyEngine) ProcessMutation(policy types.Policy, rawResource []byte) ([]mutation.PatchBytes, error) {
+	patchingSets := mutation.GetPolicyPatchingSets(policy)
+	var policyPatches []mutation.PatchBytes
+
+	for ruleIdx, rule := range policy.Spec.Rules {
+		err := rule.Validate()
+		if err != nil {
+			p.logger.Printf("Invalid rule detected: #%s in policy %s, err: %v\n", rule.Name, policy.ObjectMeta.Name, err)
+			continue
+		}
+
+		if ok, err := mutation.IsRuleApplicableToResource(rawResource, rule.Resource); !ok {
+			p.logger.Printf("Rule %d of policy %s is not applicable to the request", ruleIdx, policy.Name)
+			return nil, err
+		}
+
+		err = p.applyRuleGenerators(rawResource, rule)
+		if err != nil && patchingSets == mutation.PatchingSetsStopOnError {
+			return nil, fmt.Errorf("Failed to apply generators from rule #%s: %v", rule.Name, err)
+		}
+
+		rulePatchesProcessed, err := mutation.ProcessPatches(rule.Patches, rawResource, patchingSets)
+		if err != nil {
+			return nil, fmt.Errorf("Failed to process patches from rule #%s: %v", rule.Name, err)
+		}
+
+		if rulePatchesProcessed != nil {
+			policyPatches = append(policyPatches, rulePatchesProcessed...)
+			p.logger.Printf("Rule %d: prepared %d patches", ruleIdx, len(rulePatchesProcessed))
+			// TODO: add PolicyApplied events per rule for policy and resource
+		} else {
+			p.logger.Printf("Rule %d: no patches prepared", ruleIdx)
+		}
+	}
+
+	// empty patch, return error to deny resource creation
+	if policyPatches == nil {
+		return nil, fmt.Errorf("no patches prepared")
+	}
+
+	return policyPatches, nil
+}
+
+// Applies "configMapGenerator" and "secretGenerator" described in PolicyRule
+func (p *policyEngine) applyRuleGenerators(rawResource []byte, rule types.PolicyRule) error {
+	kind := mutation.ParseKindFromObject(rawResource)
+
+	// configMapGenerator and secretGenerator can be applied only to namespaces
+	if kind == "Namespace" {
+		namespaceName := mutation.ParseNameFromObject(rawResource)
+
+		err := p.applyConfigGenerator(rule.ConfigMapGenerator, namespaceName, "ConfigMap")
+		if err == nil {
+			err = p.applyConfigGenerator(rule.SecretGenerator, namespaceName, "Secret")
+		}
+		return err
+	}
+	return nil
+}
+
+// Creates resourceKind (ConfigMap or Secret) with parameters specified in generator in cluster specified in request.
+func (p *policyEngine) applyConfigGenerator(generator *types.PolicyConfigGenerator, namespace string, configKind string) error {
+	if generator == nil {
+		return nil
+	}
+
+	err := generator.Validate()
+	if err != nil {
+		return errors.New(fmt.Sprintf("Generator for '%s' is invalid: %s", configKind, err))
+	}
+
+	switch configKind {
+	case "ConfigMap":
+		err = p.kubeClient.GenerateConfigMap(*generator, namespace)
+	case "Secret":
+		err = p.kubeClient.GenerateSecret(*generator, namespace)
+	default:
+		err = errors.New(fmt.Sprintf("Unsupported config Kind '%s'", configKind))
+	}
+
+	if err != nil {
+		return errors.New(fmt.Sprintf("Unable to apply generator for %s '%s/%s' : %s", configKind, namespace, generator.Name, err))
+	}
+
+	return nil
+}

pkg/policyengine/mutation/checkRules.go

@@ -8,10 +8,11 @@ import (
 
 // kind is the type of object being manipulated
 // Checks requests kind, name and labels to fit the policy
-func IsRuleApplicableToResource(kind string, resourceRaw []byte, policyResource types.PolicyResource) (bool, error) {
-	if policyResource.Kind != kind {
-		return false, nil
-	}
+func IsRuleApplicableToResource(resourceRaw []byte, policyResource types.PolicyResource) (bool, error) {
+	// kind := ParseKindFromObject(resourceRaw)
+	// if policyResource.Kind != kind {
+	// 	return false, nil
+	// }
 
 	if resourceRaw != nil {
 		meta := ParseMetadataFromObject(resourceRaw)

pkg/policyengine/policyengine.go

@@ -0,0 +1,129 @@
+package policyengine
+
+import (
+	"fmt"
+	"log"
+
+	kubeClient "github.com/nirmata/kube-policy/kubeclient"
+	policytype "github.com/nirmata/kube-policy/pkg/apis/policy/v1alpha1"
+	types "github.com/nirmata/kube-policy/pkg/apis/policy/v1alpha1"
+	eventutils "github.com/nirmata/kube-policy/pkg/event/utils"
+	"github.com/nirmata/kube-policy/pkg/policyengine/mutation"
+	violationutils "github.com/nirmata/kube-policy/pkg/violation/utils"
+)
+
+type PolicyEngine interface {
+	// ProcessMutation should be called from admission contoller
+	// when there is an creation / update of the resource
+	// ProcessMutation(policy types.Policy, rawResource []byte) (patchBytes []byte, events []Events, err error)
+	ProcessMutation(policy types.Policy, rawResource []byte) ([]mutation.PatchBytes, error)
+
+	// ProcessValidation should be called from admission contoller
+	// when there is an creation / update of the resource
+	ProcessValidation(policy types.Policy, rawResource []byte)
+
+	// ProcessExisting should be called from policy controller
+	// when there is an create / update of the policy
+	// we should process the policy on matched resources, generate violations accordingly
+	ProcessExisting(policy types.Policy, rawResource []byte) ([]violationutils.ViolationInfo, []eventutils.EventInfo, error)
+}
+
+type policyEngine struct {
+	kubeClient *kubeClient.KubeClient
+	// controller controllerinterfaces.PolicyGetter
+	logger *log.Logger
+}
+
+func NewPolicyEngine(kubeClient *kubeClient.KubeClient, logger *log.Logger) PolicyEngine {
+	return &policyEngine{
+		kubeClient: kubeClient,
+		logger:     logger,
+	}
+}
+
+func (p *policyEngine) ProcessExisting(policy types.Policy, rawResource []byte) ([]violationutils.ViolationInfo, []eventutils.EventInfo, error) {
+	var violations []violationutils.ViolationInfo
+	var events []eventutils.EventInfo
+
+	patchingSets := mutation.GetPolicyPatchingSets(policy)
+
+	for _, rule := range policy.Spec.Rules {
+		err := rule.Validate()
+		if err != nil {
+			p.logger.Printf("Invalid rule detected: #%s in policy %s, err: %v\n", rule.Name, policy.ObjectMeta.Name, err)
+			continue
+		}
+
+		if ok, err := mutation.IsRuleApplicableToResource(rawResource, rule.Resource); !ok {
+			p.logger.Printf("Rule %s of policy %s is not applicable to the request", rule.Name, policy.Name)
+			return nil, nil, err
+		}
+
+		violation, eventInfos, err := p.processRuleOnResource(policy.Name, rule, rawResource, patchingSets)
+		if err != nil {
+			p.logger.Printf("Failed to process rule %s, err: %v\n", rule.Name, err)
+			continue
+		}
+		// } else {
+		// 	policyPatches = append(policyPatches, processedPatches...)
+		// }
+		violations = append(violations, violation)
+		events = append(events, eventInfos...)
+	}
+	return violations, events, nil
+}
+
+func (p *policyEngine) processRuleOnResource(policyName string, rule types.PolicyRule, rawResource []byte, patchingSets mutation.PatchingSets) (
+	violationutils.ViolationInfo, []eventutils.EventInfo, error) {
+
+	var violationInfo violationutils.ViolationInfo
+	var eventInfos []eventutils.EventInfo
+
+	resourceKind := mutation.ParseKindFromObject(rawResource)
+	resourceName := mutation.ParseNameFromObject(rawResource)
+	resourceNamespace := mutation.ParseNamespaceFromObject(rawResource)
+
+	rulePatchesProcessed, err := mutation.ProcessPatches(rule.Patches, nil, patchingSets)
+	if err != nil {
+		return violationInfo, eventInfos, fmt.Errorf("Failed to process patches from rule %s: %v", rule.Name, err)
+	}
+
+	if rulePatchesProcessed != nil {
+		log.Printf("Rule %s: prepared %d patches", rule.Name, len(rulePatchesProcessed))
+
+		// add a violation to queue
+		violationInfo = violationutils.ViolationInfo{
+			Policy: policyName,
+			Violation: policytype.Violation{
+				Kind:     resourceKind,
+				Resource: resourceNamespace + "/" + resourceName,
+				Rule:     rule.Name,
+				// TODO:
+				Reason:  "testing violation reason",
+				Message: "testing violation message",
+			},
+		}
+
+		// add an event to policy
+		eventInfos = append(eventInfos, eventutils.EventInfo{
+			Kind:     "Policy",
+			Resource: policyName,
+			Rule:     rule.Name,
+			// TODO:
+			Reason:  "PolicyViolation",
+			Message: "testing event message for policy",
+		})
+
+		// add an event to resource
+		eventInfos = append(eventInfos, eventutils.EventInfo{
+			Kind:     resourceKind,
+			Resource: resourceNamespace + "/" + resourceName,
+			Rule:     rule.Name,
+			// TODO:
+			Reason:  "PolicyViolation",
+			Message: "testing event message for policy",
+		})
+	}
+
+	return violationInfo, eventInfos, nil
+}

pkg/policyengine/validation.go

@@ -0,0 +1,5 @@
+package policyengine
+
+import types "github.com/nirmata/kube-policy/pkg/apis/policy/v1alpha1"
+
+func (p *policyEngine) ProcessValidation(policy types.Policy, rawResource []byte) {}

webhooks/admission.go

@@ -3,7 +3,7 @@ package webhooks
 import (
 	kubeclient "github.com/nirmata/kube-policy/kubeclient"
 	types "github.com/nirmata/kube-policy/pkg/apis/policy/v1alpha1"
-	mutation "github.com/nirmata/kube-policy/pkg/mutation"
+	mutation "github.com/nirmata/kube-policy/pkg/policyengine/mutation"
 	"k8s.io/api/admission/v1beta1"
 )
 
@@ -24,5 +24,5 @@ func AdmissionIsRequired(request *v1beta1.AdmissionRequest) bool {
 
 // Checks requests kind, name and labels to fit the policy
 func IsRuleApplicableToRequest(policyResource types.PolicyResource, request *v1beta1.AdmissionRequest) (bool, error) {
-	return mutation.IsRuleApplicableToResource(request.Kind.Kind, request.Object.Raw, policyResource)
+	return mutation.IsRuleApplicableToResource(request.Object.Raw, policyResource)
 }

webhooks/mutation.go

@@ -9,7 +9,8 @@ import (
 	controllerinterfaces "github.com/nirmata/kube-policy/controller/interfaces"
 	kubeclient "github.com/nirmata/kube-policy/kubeclient"
 	types "github.com/nirmata/kube-policy/pkg/apis/policy/v1alpha1"
-	mutation "github.com/nirmata/kube-policy/pkg/mutation"
+	policyengine "github.com/nirmata/kube-policy/pkg/policyengine"
+	mutation "github.com/nirmata/kube-policy/pkg/policyengine/mutation"
 	v1beta1 "k8s.io/api/admission/v1beta1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
@@ -20,6 +21,7 @@ import (
 // business logic for resource mutation
 type MutationWebhook struct {
 	kubeclient   *kubeclient.KubeClient
+	policyEngine policyengine.PolicyEngine
 	controller   controllerinterfaces.PolicyGetter
 	registration *MutationWebhookRegistration
 	logger       *log.Logger
@@ -44,8 +46,11 @@ func CreateMutationWebhook(clientConfig *rest.Config, kubeclient *kubeclient.Kub
 	if logger == nil {
 		logger = log.New(os.Stdout, "Mutation WebHook: ", log.LstdFlags|log.Lshortfile)
 	}
+	policyengine := policyengine.NewPolicyEngine(kubeclient, logger)
+
 	return &MutationWebhook{
 		kubeclient:   kubeclient,
+		policyEngine: policyengine,
 		controller:   controller,
 		registration: registration,
 		logger:       logger,
@@ -101,10 +106,10 @@ func (mw *MutationWebhook) Mutate(request *v1beta1.AdmissionRequest) *v1beta1.Ad
 // May return nil patches if it is not necessary to create patches for requested object.
 // Returns error ONLY in case when creation of resource should be denied.
 func (mw *MutationWebhook) applyPolicyRules(request *v1beta1.AdmissionRequest, policy types.Policy) ([]mutation.PatchBytes, error) {
-	return mw.applyPolicyRulesOnResource(request.Kind.Kind, request.Object.Raw, policy)
+	return mw.policyEngine.ProcessMutation(policy, request.Object.Raw)
 }
 
-// kind is the type of object being manipulated
+// kind is the type of object being manipulated, e.g. request.Kind.kind
 func (mw *MutationWebhook) applyPolicyRulesOnResource(kind string, rawResource []byte, policy types.Policy) ([]mutation.PatchBytes, error) {
 	patchingSets := mutation.GetPolicyPatchingSets(policy)
 	var policyPatches []mutation.PatchBytes
@@ -116,7 +121,7 @@ func (mw *MutationWebhook) applyPolicyRulesOnResource(kind string, rawResource [
 			continue
 		}
 
-		if ok, err := mutation.IsRuleApplicableToResource(kind, rawResource, rule.Resource); !ok {
+		if ok, err := mutation.IsRuleApplicableToResource(rawResource, rule.Resource); !ok {
 			mw.logger.Printf("Rule %d of policy %s is not applicable to the request", ruleIdx, policy.Name)
 			return nil, err
 		}