/
k8s.go
439 lines (378 loc) · 10.5 KB
/
k8s.go
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package host
import (
"context"
"fmt"
"golang.org/x/term"
"io"
"io/ioutil"
"net/http"
"net/url"
"os"
"strings"
"sync"
"time"
v1 "k8s.io/api/core/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/fields"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/cli-runtime/pkg/genericclioptions"
"k8s.io/client-go/kubernetes"
"k8s.io/client-go/kubernetes/scheme"
"k8s.io/client-go/rest"
restclient "k8s.io/client-go/rest"
"k8s.io/client-go/tools/cache"
"k8s.io/client-go/tools/clientcmd"
"k8s.io/client-go/tools/portforward"
"k8s.io/client-go/tools/remotecommand"
"k8s.io/client-go/transport/spdy"
uexec "k8s.io/client-go/util/exec"
"k8s.io/kubectl/pkg/cmd/exec"
"github.com/plumber-cd/runtainer/log"
"github.com/plumber-cd/runtainer/utils"
)
const serviceAccountNamespace = "/var/run/secrets/kubernetes.io/serviceaccount/namespace"
type PodRunMode string
const (
PodRunModeModeAttach PodRunMode = "PodRunModeModeAttach"
PodRunModeModeExec PodRunMode = "PodRunModeModeExec"
PodRunModeModeLogs PodRunMode = "PodRunModeModeLogs"
)
type PodOptions struct {
Config *rest.Config
Clientset *kubernetes.Clientset
Namespace string
PodSpec *v1.Pod
Container string
Mode PodRunMode
ExecCmd []string
Stdin io.Reader
Stdout io.Writer
Stderr io.Writer
Tty bool
Ports map[int]int
}
func GetKubeClient() (
config *rest.Config,
clientset *kubernetes.Clientset,
namespace string,
err error,
) {
namespace = v1.NamespaceDefault
if k8sPort := os.Getenv("KUBERNETES_PORT"); k8sPort != "" {
log.Debug.Printf("Using in-cluster authentication")
config, err = rest.InClusterConfig()
if err != nil {
return
}
// It doesn't seem K8s sdk expose any function for detecting current namespace.
// Best shot I found is here https://github.com/kubernetes/client-go/blob/v0.19.2/tools/clientcmd/client_config.go#L572
// But `type inClusterClientConfig` is not exported and seems accordingly to the comment only used for internal testing.
// So best I guess is to mimic same logic here.
if ns := os.Getenv("POD_NAMESPACE"); ns != "" {
log.Debug.Printf("Detected POD_NAMESPACE=%s", ns)
namespace = ns
} else if data, err := ioutil.ReadFile(serviceAccountNamespace); err == nil {
log.Debug.Printf("Detected %s", serviceAccountNamespace)
if ns := strings.TrimSpace(string(data)); len(ns) > 0 {
log.Debug.Printf("Detected %s=%s", serviceAccountNamespace, ns)
namespace = ns
}
} else {
log.Debug.Printf("Using NamespaceDefault=%s", namespace)
}
} else {
log.Debug.Printf("Using local kubeconfig")
clientConfig := clientcmd.NewNonInteractiveDeferredLoadingClientConfig(
clientcmd.NewDefaultClientConfigLoadingRules(),
&clientcmd.ConfigOverrides{},
)
config, err = clientConfig.ClientConfig()
if err != nil {
return
}
namespace, _, err = clientConfig.Namespace()
if err != nil {
return
}
log.Debug.Printf("Context namespace detected: %s", namespace)
}
clientset, err = kubernetes.NewForConfig(config)
if err != nil {
return
}
return
}
func ExecPod(options *PodOptions) error {
log.Normal.Printf("Running mode: %s", options.Mode)
podsClient := options.Clientset.CoreV1().Pods(options.Namespace)
pod, err := podsClient.Create(context.TODO(), options.PodSpec, metav1.CreateOptions{})
if err != nil {
return err
}
defer func() {
if err := podsClient.Delete(context.TODO(), pod.ObjectMeta.Name, metav1.DeleteOptions{}); err != nil {
if err != nil {
log.Normal.Printf("Failed cleaning up pod %s: %s", pod.ObjectMeta.Name, err)
}
}
}()
stopEventsWatch := watchPodEvents(options.Clientset, pod)
if options.Mode == PodRunModeModeLogs {
waitForPod(options.Clientset, pod, v1.PodRunning, v1.PodSucceeded)
stopEventsWatch.CloseOnce()
podOptions := &v1.PodLogOptions{
Container: options.Container,
Follow: true,
}
req := options.
Clientset.
CoreV1().
Pods(pod.Namespace).
GetLogs(pod.Name, podOptions)
podLogs, err := req.Stream(context.TODO())
if err != nil {
return err
}
go func() {
if _, err := io.Copy(os.Stdout, podLogs); err != nil {
log.Normal.Panic(err)
}
}()
return extractExitCode(options.Clientset, pod)
}
pod = waitForPod(options.Clientset, pod, v1.PodRunning, v1.PodSucceeded)
stopEventsWatch.CloseOnce()
if pod.Status.Phase == v1.PodRunning {
log.Debug.Printf("Pod is still in the running phase - attempt to establish port forwarding....")
stopCh := make(chan struct{})
defer close(stopCh)
readyCh := make(chan struct{})
errChan := make(chan error)
for local, remote := range options.Ports {
log.Debug.Printf("Forwarding %d:%d", local, remote)
tunnelReq := options.Clientset.
CoreV1().
RESTClient().
Post().
Resource("pods").
Namespace(options.Namespace).
Name(pod.ObjectMeta.Name).
SubResource("portforward")
transport, upgrader, err := spdy.RoundTripperFor(options.Config)
if err != nil {
return err
}
dialer := spdy.NewDialer(
upgrader,
&http.Client{Transport: transport},
"POST",
tunnelReq.URL(),
)
ports := []string{fmt.Sprintf("%d:%d", local, remote)}
portforwarder, err := portforward.New(
dialer,
ports,
stopCh,
readyCh,
log.Info.Writer(),
log.Error.Writer(),
)
if err != nil {
return err
}
go func() {
errChan <- portforwarder.ForwardPorts()
}()
select {
case err = <-errChan:
return err
case <-portforwarder.Ready:
log.Debug.Printf("Successfully created port forwarding %d:%d", local, remote)
}
}
}
var podOptions runtime.Object
method := "POST"
req := options.Clientset.CoreV1().RESTClient().Post().
Resource("pods").
Name(pod.Name).
Namespace(pod.Namespace)
switch options.Mode {
case PodRunModeModeAttach:
podOptions = &v1.PodAttachOptions{
Container: options.Container,
Stdin: options.Stdin != nil,
Stdout: options.Stdout != nil,
Stderr: options.Stderr != nil,
TTY: options.Tty,
}
req = req.SubResource("attach")
case PodRunModeModeExec:
podOptions = &v1.PodExecOptions{
Container: options.Container,
Command: options.ExecCmd,
Stdin: options.Stdin != nil,
Stdout: options.Stdout != nil,
Stderr: options.Stderr != nil,
TTY: options.Tty,
}
req = req.SubResource("exec")
default:
return fmt.Errorf("Unknown run mode: %s", options.Mode)
}
req.VersionedParams(
podOptions,
scheme.ParameterCodec,
)
if err := stream(options, req.URL(), method); err != nil {
return err
}
if options.Mode == PodRunModeModeAttach {
return extractExitCode(options.Clientset, pod)
}
return nil
}
func waitForPod(clientset *kubernetes.Clientset, pod *v1.Pod, phases ...v1.PodPhase) (result *v1.Pod) {
stop := utils.NewStopChan()
watchlist := cache.NewListWatchFromClient(clientset.CoreV1().RESTClient(), "pods", pod.Namespace, fields.Everything())
_, controller := cache.NewInformer(watchlist, &v1.Pod{}, time.Second*1, cache.ResourceEventHandlerFuncs{
UpdateFunc: func(o, n interface{}) {
newPod := n.(*v1.Pod)
// not the pod we created
if newPod.Name != pod.Name {
return
}
// if the pod is in expected status - stop watching
for _, phase := range phases {
if newPod.Status.Phase == phase {
result = newPod
stop.CloseOnce()
return
}
}
if newPod.Status.Phase == v1.PodFailed || newPod.Status.Phase == v1.PodUnknown {
log.Normal.Printf("Unexpected pod status %s", newPod.Status.Phase)
stop.CloseOnce()
return
}
},
})
controller.Run(stop.Chan)
return
}
func watchPodEvents(clientset *kubernetes.Clientset, pod *v1.Pod) *utils.StopChan {
stop := utils.NewStopChan()
mutex := sync.Mutex{}
watchlist := cache.NewListWatchFromClient(clientset.CoreV1().RESTClient(), "events", pod.Namespace,
fields.Everything())
_, controller := cache.NewInformer(
watchlist,
&v1.Event{},
time.Second*0,
cache.ResourceEventHandlerFuncs{
AddFunc: func(obj interface{}) {
mutex.Lock()
defer mutex.Unlock()
e := obj.(*v1.Event)
if e.InvolvedObject.Kind != "Pod" {
return
}
if e.InvolvedObject.Namespace != pod.Namespace {
return
}
if e.InvolvedObject.Name != pod.Name {
return
}
log.Normal.Printf(
"k8s event [%s] [%s]: %s",
e.Type,
e.Reason,
e.Message,
)
},
},
)
go controller.Run(stop.Chan)
return stop
}
func startStream(
method string,
url *url.URL,
config *restclient.Config,
streamOptions remotecommand.StreamOptions,
) error {
exec, err := remotecommand.NewSPDYExecutor(config, method, url)
if err != nil {
return err
}
return exec.Stream(streamOptions)
}
func stream(options *PodOptions, url *url.URL, method string) error {
streamOptions := remotecommand.StreamOptions{
Stdin: options.Stdin,
Stdout: options.Stdout,
Stderr: options.Stderr,
Tty: options.Tty,
}
if options.Stdin != nil {
switch options.Stdin.(type) {
case *os.File:
in := options.Stdin.(*os.File)
oldState, err := term.MakeRaw(int(in.Fd()))
if err != nil {
log.Normal.Panic(err)
}
defer func() {
if err := term.Restore(int(in.Fd()), oldState); err != nil {
log.Error.Print(err)
}
}()
}
}
if streamOptions.Tty {
s := exec.StreamOptions{
Namespace: options.Namespace,
PodName: options.PodSpec.ObjectMeta.Name,
ContainerName: options.Container,
Stdin: options.Stdin != nil,
TTY: options.Tty,
IOStreams: genericclioptions.IOStreams{
In: options.Stdin,
Out: options.Stdout,
ErrOut: options.Stderr,
},
}
t := s.SetupTTY()
sizeQueue := t.MonitorSize(t.GetSize())
streamOptions.TerminalSizeQueue = sizeQueue
if options.Mode == PodRunModeModeAttach {
log.Normal.Println("If you don't see a command prompt, try pressing enter.")
}
}
return startStream(method, url, options.Config, streamOptions)
}
func extractExitCode(clientset *kubernetes.Clientset, pod *v1.Pod) error {
pod = waitForPod(clientset, pod, v1.PodSucceeded, v1.PodFailed)
unknownRcErr := fmt.Errorf("unknown exit code")
switch pod.Status.Phase {
case v1.PodSucceeded:
return nil
case v1.PodFailed:
if len(pod.Status.ContainerStatuses) < 1 || pod.Status.ContainerStatuses[0].State.Terminated == nil {
return unknownRcErr
}
rc := pod.Status.ContainerStatuses[0].State.Terminated.ExitCode
if rc == 0 {
return unknownRcErr
}
return uexec.CodeExitError{
Err: fmt.Errorf(
"terminated (%s)\n%s",
pod.Status.ContainerStatuses[0].State.Terminated.Reason,
pod.Status.ContainerStatuses[0].State.Terminated.Message,
),
Code: int(rc),
}
}
return unknownRcErr
}