/
dynamicconfig.go
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/
dynamicconfig.go
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package config
import (
"os"
"reflect"
"regexp"
"strings"
"sync"
"github.com/go-logr/logr"
"github.com/minio/minio/pkg/wildcard"
v1 "k8s.io/api/core/v1"
informers "k8s.io/client-go/informers/core/v1"
"k8s.io/client-go/kubernetes"
"k8s.io/client-go/tools/cache"
)
// read the conifgMap with name in env:INIT_CONFIG
// this configmap stores the resources that are to be filtered
const cmNameEnv string = "INIT_CONFIG"
var defaultExcludeGroupRole []string = []string{"system:serviceaccounts:kube-system", "system:nodes", "system:kube-scheduler"}
// ConfigData stores the configuration
type ConfigData struct {
client kubernetes.Interface
cmName string
mux sync.RWMutex
filters []k8Resource
excludeGroupRole []string
excludeUsername []string
restrictDevelopmentUsername []string
cmSycned cache.InformerSynced
reconcilePolicyReport chan<- bool
log logr.Logger
}
// ToFilter checks if the given resource is set to be filtered in the configuration
func (cd *ConfigData) ToFilter(kind, namespace, name string) bool {
cd.mux.RLock()
defer cd.mux.RUnlock()
for _, f := range cd.filters {
if wildcard.Match(f.Kind, kind) && wildcard.Match(f.Namespace, namespace) && wildcard.Match(f.Name, name) {
return true
}
if kind == "Namespace" {
// [Namespace,kube-system,*] || [*,kube-system,*]
if (f.Kind == "Namespace" || f.Kind == "*") && wildcard.Match(f.Namespace, name) {
return true
}
}
}
return false
}
// GetExcludeGroupRole return exclude roles
func (cd *ConfigData) GetExcludeGroupRole() []string {
cd.mux.RLock()
defer cd.mux.RUnlock()
return cd.excludeGroupRole
}
// RestrictDevelopmentUsername return exclude development username
func (cd *ConfigData) RestrictDevelopmentUsername() []string {
cd.mux.RLock()
defer cd.mux.RUnlock()
return cd.restrictDevelopmentUsername
}
// GetExcludeUsername return exclude username
func (cd *ConfigData) GetExcludeUsername() []string {
cd.mux.RLock()
defer cd.mux.RUnlock()
return cd.excludeUsername
}
// FilterNamespaces filters exclude namespace
func (cd *ConfigData) FilterNamespaces(namespaces []string) []string {
var results []string
for _, ns := range namespaces {
if !cd.ToFilter("", ns, "") {
results = append(results, ns)
}
}
return results
}
// Interface to be used by consumer to check filters
type Interface interface {
ToFilter(kind, namespace, name string) bool
GetExcludeGroupRole() []string
GetExcludeUsername() []string
RestrictDevelopmentUsername() []string
FilterNamespaces(namespaces []string) []string
}
// NewConfigData ...
func NewConfigData(rclient kubernetes.Interface, cmInformer informers.ConfigMapInformer, filterK8sResources, excludeGroupRole, excludeUsername string, reconcilePolicyReport chan<- bool, log logr.Logger) *ConfigData {
// environment var is read at start only
if cmNameEnv == "" {
log.Info("ConfigMap name not defined in env:INIT_CONFIG: loading no default configuration")
}
cd := ConfigData{
client: rclient,
cmName: os.Getenv(cmNameEnv),
cmSycned: cmInformer.Informer().HasSynced,
reconcilePolicyReport: reconcilePolicyReport,
log: log,
}
cd.restrictDevelopmentUsername = []string{"minikube-user", "kubernetes-admin"}
//TODO: this has been added to backward support command line arguments
// will be removed in future and the configuration will be set only via configmaps
if filterK8sResources != "" {
cd.log.Info("init configuration from commandline arguments for filterK8sResources")
cd.initFilters(filterK8sResources)
}
if excludeGroupRole != "" {
cd.log.Info("init configuration from commandline arguments for excludeGroupRole")
cd.initRbac("excludeRoles", excludeGroupRole)
} else {
cd.initRbac("excludeRoles", "")
}
if excludeUsername != "" {
cd.log.Info("init configuration from commandline arguments for excludeUsername")
cd.initRbac("excludeUsername", excludeUsername)
}
cmInformer.Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{
AddFunc: cd.addCM,
UpdateFunc: cd.updateCM,
DeleteFunc: cd.deleteCM,
})
return &cd
}
//Run checks syncing
func (cd *ConfigData) Run(stopCh <-chan struct{}) {
logger := cd.log
// wait for cache to populate first time
if !cache.WaitForCacheSync(stopCh, cd.cmSycned) {
logger.Info("configuration: failed to sync informer cache")
}
}
func (cd *ConfigData) addCM(obj interface{}) {
cm := obj.(*v1.ConfigMap)
if cm.Name != cd.cmName {
return
}
cd.load(*cm)
// else load the configuration
}
func (cd *ConfigData) updateCM(old, cur interface{}) {
cm := cur.(*v1.ConfigMap)
if cm.Name != cd.cmName {
return
}
// if data has not changed then dont load configmap
changed := cd.load(*cm)
if changed {
cd.log.Info("resource filters changed, sending reconcile signal to the policy controller")
cd.reconcilePolicyReport <- true
}
}
func (cd *ConfigData) deleteCM(obj interface{}) {
logger := cd.log
cm, ok := obj.(*v1.ConfigMap)
if !ok {
tombstone, ok := obj.(cache.DeletedFinalStateUnknown)
if !ok {
logger.Info("failed to get object from tombstone")
return
}
_, ok = tombstone.Obj.(*v1.ConfigMap)
if !ok {
logger.Info("Tombstone contained object that is not a ConfigMap", "object", obj)
return
}
}
if cm.Name != cd.cmName {
return
}
// remove the configuration parameters
cd.unload(*cm)
}
func (cd *ConfigData) load(cm v1.ConfigMap) (changed bool) {
logger := cd.log.WithValues("name", cm.Name, "namespace", cm.Namespace)
if cm.Data == nil {
logger.V(4).Info("configuration: No data defined in ConfigMap")
return
}
cd.mux.Lock()
defer cd.mux.Unlock()
filters, ok := cm.Data["resourceFilters"]
if !ok {
logger.V(4).Info("configuration: No resourceFilters defined in ConfigMap")
} else {
newFilters := parseKinds(filters)
if reflect.DeepEqual(newFilters, cd.filters) {
logger.V(4).Info("resourceFilters did not change")
} else {
logger.V(2).Info("Updated resource filters", "oldFilters", cd.filters, "newFilters", newFilters)
cd.filters = newFilters
changed = true
}
}
excludeGroupRole, ok := cm.Data["excludeGroupRole"]
if !ok {
logger.V(4).Info("configuration: No excludeGroupRole defined in ConfigMap")
}
newExcludeGroupRoles := parseRbac(excludeGroupRole)
newExcludeGroupRoles = append(newExcludeGroupRoles, defaultExcludeGroupRole...)
if reflect.DeepEqual(newExcludeGroupRoles, cd.excludeGroupRole) {
logger.V(4).Info("excludeGroupRole did not change")
} else {
logger.V(2).Info("Updated resource excludeGroupRoles", "oldExcludeGroupRole", cd.excludeGroupRole, "newExcludeGroupRole", newExcludeGroupRoles)
cd.excludeGroupRole = newExcludeGroupRoles
changed = true
}
excludeUsername, ok := cm.Data["excludeUsername"]
if !ok {
logger.V(4).Info("configuration: No excludeUsername defined in ConfigMap")
} else {
excludeUsernames := parseRbac(excludeUsername)
if reflect.DeepEqual(excludeUsernames, cd.excludeUsername) {
logger.V(4).Info("excludeGroupRole did not change")
} else {
logger.V(2).Info("Updated resource excludeUsernames", "oldExcludeUsername", cd.excludeUsername, "newExcludeUsername", excludeUsernames)
cd.excludeUsername = excludeUsernames
changed = true
}
}
return changed
}
//TODO: this has been added to backward support command line arguments
// will be removed in future and the configuration will be set only via configmaps
func (cd *ConfigData) initFilters(filters string) {
logger := cd.log
// parse and load the configuration
cd.mux.Lock()
defer cd.mux.Unlock()
newFilters := parseKinds(filters)
logger.V(2).Info("Init resource filters", "filters", newFilters)
// update filters
cd.filters = newFilters
}
func (cd *ConfigData) initRbac(action, exclude string) {
logger := cd.log
// parse and load the configuration
cd.mux.Lock()
defer cd.mux.Unlock()
rbac := parseRbac(exclude)
logger.V(2).Info("Init resource ", action, exclude)
// update filters
if action == "excludeRoles" {
cd.excludeGroupRole = rbac
cd.excludeGroupRole = append(cd.excludeGroupRole, defaultExcludeGroupRole...)
} else {
cd.excludeUsername = rbac
}
}
func (cd *ConfigData) unload(cm v1.ConfigMap) {
logger := cd.log
logger.Info("ConfigMap deleted, removing configuration filters", "name", cm.Name, "namespace", cm.Namespace)
cd.mux.Lock()
defer cd.mux.Unlock()
cd.filters = []k8Resource{}
cd.excludeGroupRole = []string{}
cd.excludeGroupRole = append(cd.excludeGroupRole, defaultExcludeGroupRole...)
cd.excludeUsername = []string{}
}
type k8Resource struct {
Kind string //TODO: as we currently only support one GVK version, we use the kind only. But if we support multiple GVK, then GV need to be added
Namespace string
Name string
}
//ParseKinds parses the kinds if a single string contains comma separated kinds
// {"1,2,3","4","5"} => {"1","2","3","4","5"}
func parseKinds(list string) []k8Resource {
resources := []k8Resource{}
var resource k8Resource
re := regexp.MustCompile(`\[([^\[\]]*)\]`)
submatchall := re.FindAllString(list, -1)
for _, element := range submatchall {
element = strings.Trim(element, "[")
element = strings.Trim(element, "]")
elements := strings.Split(element, ",")
//TODO: wildcards for namespace and name
if len(elements) == 0 {
continue
}
if len(elements) == 3 {
resource = k8Resource{Kind: elements[0], Namespace: elements[1], Name: elements[2]}
}
if len(elements) == 2 {
resource = k8Resource{Kind: elements[0], Namespace: elements[1]}
}
if len(elements) == 1 {
resource = k8Resource{Kind: elements[0]}
}
resources = append(resources, resource)
}
return resources
}
func parseRbac(list string) []string {
return strings.Split(list, ",")
}