K-EXPLORER: add shell link for local cluster

pkg/resources/cluster/cluster.go

@@ -3,12 +3,14 @@ package cluster
 import (
 	"context"
 	"net/http"
+	"time"
 
 	"github.com/rancher/apiserver/pkg/store/empty"
 	"github.com/rancher/apiserver/pkg/types"
 	detector "github.com/rancher/kubernetes-provider-detector"
 	"github.com/rancher/steve/pkg/accesscontrol"
 	"github.com/rancher/steve/pkg/attributes"
+	"github.com/rancher/steve/pkg/podimpersonation"
 	steveschema "github.com/rancher/steve/pkg/schema"
 	"github.com/rancher/steve/pkg/stores/proxy"
 	"github.com/rancher/wrangler/pkg/genericcondition"
@@ -19,7 +21,19 @@ import (
 	"k8s.io/client-go/discovery"
 )
 
+const (
+	shellPodImage = "rancher/shell:v0.1.6"
+	shellPodNS    = "kube-system"
+)
+
 func Register(ctx context.Context, apiSchemas *types.APISchemas, cg proxy.ClientGetter, schemaFactory steveschema.Factory) {
+	// K-EXPLORER
+	shell := &shell{
+		cg:           cg,
+		namespace:    shellPodNS,
+		impersonator: podimpersonation.New("shell", cg, time.Hour, func() string { return shellPodImage }),
+	}
+
 	apiSchemas.InternalSchemas.TypeName("management.cattle.io.cluster", Cluster{})
 
 	apiSchemas.MustImportAndCustomize(&ApplyInput{}, nil)
@@ -57,6 +71,10 @@ func Register(ctx context.Context, apiSchemas *types.APISchemas, cg proxy.Client
 				Output: "applyOutput",
 			},
 		}
+		// K-EXPLORER
+		schema.LinkHandlers = map[string]http.Handler{
+			"shell": shell,
+		}
 	})
 }
 

pkg/resources/cluster/shell.go

@@ -0,0 +1,148 @@
+package cluster
+
+import (
+	"context"
+	"net/http"
+	"net/http/httputil"
+	"time"
+
+	"github.com/rancher/steve/pkg/podimpersonation"
+	"github.com/rancher/steve/pkg/stores/proxy"
+	"github.com/rancher/wrangler/pkg/schemas/validation"
+	v1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apiserver/pkg/authentication/user"
+	"k8s.io/apiserver/pkg/endpoints/request"
+	"k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/kubernetes/scheme"
+	"k8s.io/client-go/rest"
+)
+
+type shell struct {
+	namespace    string
+	impersonator *podimpersonation.PodImpersonation
+	cg           proxy.ClientGetter
+}
+
+func (s *shell) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
+	ctx, user, client, err := s.contextAndClient(req)
+	if err != nil {
+		http.Error(rw, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	pod, err := s.impersonator.CreatePod(ctx, user, s.createPod(), &podimpersonation.PodOptions{
+		Wait: true,
+	})
+	if err != nil {
+		http.Error(rw, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	defer func() {
+		ctx, cancel := context.WithTimeout(context.Background(), time.Second*30)
+		defer cancel()
+		_ = client.CoreV1().Pods(pod.Namespace).Delete(ctx, pod.Name, metav1.DeleteOptions{})
+	}()
+	s.proxyRequest(rw, req, pod, client)
+}
+
+func (s *shell) proxyRequest(rw http.ResponseWriter, req *http.Request, pod *v1.Pod, client kubernetes.Interface) {
+	attachURL := client.CoreV1().RESTClient().
+		Get().
+		Namespace(pod.Namespace).
+		Resource("pods").
+		Name(pod.Name).
+		SubResource("exec").
+		VersionedParams(&v1.PodExecOptions{
+			Stdin:     true,
+			Stdout:    true,
+			Stderr:    true,
+			TTY:       true,
+			Container: "shell",
+			Command:   []string{"welcome"},
+		}, scheme.ParameterCodec).URL()
+
+	httpClient := client.CoreV1().RESTClient().(*rest.RESTClient).Client
+	p := httputil.ReverseProxy{
+		Director: func(req *http.Request) {
+			req.URL = attachURL
+			req.Host = attachURL.Host
+			delete(req.Header, "Impersonate-Group")
+			delete(req.Header, "Impersonate-User")
+			delete(req.Header, "Authorization")
+			delete(req.Header, "Cookie")
+		},
+		Transport:     httpClient.Transport,
+		FlushInterval: time.Millisecond * 100,
+	}
+
+	p.ServeHTTP(rw, req)
+}
+
+func (s *shell) contextAndClient(req *http.Request) (context.Context, user.Info, kubernetes.Interface, error) {
+	ctx := req.Context()
+	client, err := s.cg.AdminK8sInterface()
+	if err != nil {
+		return ctx, nil, nil, err
+	}
+
+	user, ok := request.UserFrom(ctx)
+	if !ok {
+		return ctx, nil, nil, validation.Unauthorized
+	}
+
+	return ctx, user, client, nil
+}
+
+func (s *shell) createPod() *v1.Pod {
+	return &v1.Pod{
+		ObjectMeta: metav1.ObjectMeta{
+			GenerateName: "dashboard-shell-",
+			Namespace:    s.namespace,
+		},
+		Spec: v1.PodSpec{
+			TerminationGracePeriodSeconds: new(int64),
+			RestartPolicy:                 v1.RestartPolicyNever,
+			NodeSelector: map[string]string{
+				"kubernetes.io/os": "linux",
+			},
+			Tolerations: []v1.Toleration{
+				{
+					Key:      "cattle.io/os",
+					Operator: "Equal",
+					Value:    "linux",
+					Effect:   "NoSchedule",
+				},
+				{
+					Key:      "node-role.kubernetes.io/controlplane",
+					Operator: "Equal",
+					Value:    "true",
+					Effect:   "NoSchedule",
+				},
+				{
+					Key:      "node-role.kubernetes.io/etcd",
+					Operator: "Equal",
+					Value:    "true",
+					Effect:   "NoExecute",
+				},
+			},
+			Containers: []v1.Container{
+				{
+					Name:      "shell",
+					TTY:       true,
+					Stdin:     true,
+					StdinOnce: true,
+					Env: []v1.EnvVar{
+						{
+							Name:  "KUBECONFIG",
+							Value: "/home/shell/.kube/config",
+						},
+					},
+					Image:           shellPodImage,
+					ImagePullPolicy: v1.PullIfNotPresent,
+				},
+			},
+		},
+	}
+}