forked from vladimirvivien/ktop
/
client.go
250 lines (216 loc) · 6.4 KB
/
client.go
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package k8s
import (
"context"
"fmt"
"sync"
"time"
appsV1 "k8s.io/api/apps/v1"
authzV1 "k8s.io/api/authorization/v1"
batchV1 "k8s.io/api/batch/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime/schema"
"k8s.io/apimachinery/pkg/version"
"k8s.io/cli-runtime/pkg/genericclioptions"
"k8s.io/client-go/discovery"
"k8s.io/client-go/kubernetes"
_ "k8s.io/client-go/plugin/pkg/client/auth"
_ "k8s.io/client-go/plugin/pkg/client/auth/oidc"
restclient "k8s.io/client-go/rest"
"k8s.io/client-go/tools/clientcmd/api"
metricsapi "k8s.io/metrics/pkg/apis/metrics"
metricsclient "k8s.io/metrics/pkg/client/clientset/versioned"
)
const (
AllNamespaces = metav1.NamespaceAll
)
var (
// GVRs used
GVRs = map[string]schema.GroupVersionResource{
"nodes": {Group: "", Version: "v1", Resource: "nodes"},
"namespaces": {Group: "", Version: "v1", Resource: "namespaces"},
"pods": {Group: "", Version: "v1", Resource: "pods"},
"persistentvolumes": {Group: "", Version: "v1", Resource: "persistentvolumes"},
"persistentvolumeclaims": {Group: "", Version: "v1", Resource: "persistentvolumeclaims"},
"deployments": {Group: appsV1.GroupName, Version: "v1", Resource: "deployments"},
"daemonsets": {Group: appsV1.GroupName, Version: "v1", Resource: "daemonsets"},
"replicasets": {Group: appsV1.GroupName, Version: "v1", Resource: "replicasets"},
"statefulsets": {Group: appsV1.GroupName, Version: "v1", Resource: "statefulsets"},
"jobs": {Group: batchV1.GroupName, Version: "v1", Resource: "jobs"},
"cronjobs": {Group: batchV1.GroupName, Version: "v1", Resource: "cronjobs"},
}
authzdTable = make(map[string]bool)
)
type Client struct {
sync.RWMutex
clusterVersion *version.Info
namespace string
config *restclient.Config
apiConfig api.Config
clusterContext string
username string
kubeClient kubernetes.Interface
discoClient discovery.CachedDiscoveryInterface
metricsClient *metricsclient.Clientset
metricsAvailCount int
refreshTimeout time.Duration
controller *Controller
selectedNode string
}
func New(flags *genericclioptions.ConfigFlags) (*Client, error) {
if flags == nil {
return nil, fmt.Errorf("configuration flagset is nil")
}
config, err := flags.ToRESTConfig()
if err != nil {
return nil, err
}
kubeClient, err := kubernetes.NewForConfig(config)
if err != nil {
return nil, err
}
disco, err := flags.ToDiscoveryClient()
if err != nil {
return nil, err
}
metrics, err := metricsclient.NewForConfig(config)
if err != nil {
return nil, err
}
var namespace = *flags.Namespace
var node = "zz"
apiCfg, err := flags.ToRawKubeConfigLoader().RawConfig()
if err != nil {
return nil, err
}
username := "<empty>"
currCtx, ok := apiCfg.Contexts[apiCfg.CurrentContext]
if ok {
username = currCtx.AuthInfo
}
// get api server version
version, err := disco.ServerVersion()
if err != nil {
return nil, fmt.Errorf("failed to connect to server to get version: %s", err)
}
client := &Client{
clusterVersion: version,
namespace: namespace,
config: config,
apiConfig: apiCfg,
clusterContext: apiCfg.CurrentContext,
username: username,
kubeClient: kubeClient,
discoClient: disco,
metricsClient: metrics,
selectedNode: node,
}
client.controller = newController(client)
return client, nil
}
func (k8s *Client) NewNamespace(name string) string {
k8s.namespace = name
return k8s.namespace
}
func (k8s *Client) Namespace() string {
return k8s.namespace
}
func (k8s *Client) RESTConfig() *restclient.Config {
return k8s.config
}
func (k8s *Client) ClusterContext() string {
return k8s.clusterContext
}
func (k8s *Client) Username() string {
return k8s.username
}
func (k8s *Client) GetServerVersion() string {
return k8s.clusterVersion.String()
}
// AssertMetricsAvailable checks for available metrics server every 10th invocation.
// Otherwise, it returns the last known registration state of metrics server.
func (k8s *Client) AssertMetricsAvailable() error {
if k8s.metricsAvailCount != 0 {
if k8s.metricsAvailCount%10 != 0 {
k8s.metricsAvailCount++
} else {
k8s.metricsAvailCount = 0
}
return nil
}
groups, err := k8s.discoClient.ServerGroups()
if err != nil {
return err
}
avail := false
for _, group := range groups.Groups {
if group.Name == metricsapi.GroupName {
avail = true
break
}
}
if !avail {
return fmt.Errorf("metrics api not available")
}
k8s.metricsAvailCount++
return nil
}
func (k8s *Client) Controller() *Controller {
return k8s.controller
}
// IsAuthz checks access authorization using SelfSubjectAccessReview
func (k8s *Client) IsAuthz(ctx context.Context, resource string, verbs []string) (bool, error) {
k8s.Lock()
defer k8s.Unlock()
gvr, ok := GVRs[resource]
if !ok {
return false, fmt.Errorf("unsupported resource %s", resource)
}
makeAccessReview := func(grv schema.GroupVersionResource, verb string) *authzV1.SelfSubjectAccessReview {
return &authzV1.SelfSubjectAccessReview{
Spec: authzV1.SelfSubjectAccessReviewSpec{
ResourceAttributes: &authzV1.ResourceAttributes{
Namespace: k8s.Namespace(),
Group: grv.Group,
Version: grv.Version,
Resource: grv.Resource,
Verb: verb,
},
},
}
}
arClient := k8s.kubeClient.AuthorizationV1().SelfSubjectAccessReviews()
result := true
for _, verb := range verbs {
key := fmt.Sprintf("%s/%s/%s", gvr.String(), k8s.Namespace(), verb)
if authzd, ok := authzdTable[key]; ok {
result = result && authzd
continue
}
ar := makeAccessReview(gvr, verb)
arResult, err := arClient.Create(ctx, ar, metav1.CreateOptions{})
if err != nil {
delete(authzdTable, key)
return false, err
}
allowed := arResult.Status.Allowed
authzdTable[key] = allowed
result = result && allowed
}
return result, nil
}
// AssertCoreAuthz asserts that user/context can access node and pods
func (k8s *Client) AssertCoreAuthz(ctx context.Context) error {
resources := []string{"namespaces", "nodes", "pods"}
accessible := true
for _, res := range resources {
authzd, err := k8s.IsAuthz(ctx, res, []string{"get", "list"})
if err != nil {
return err
}
accessible = accessible && authzd
}
if !accessible {
return fmt.Errorf("user missing required authorizations")
}
return nil
}