/
controller.go
215 lines (184 loc) · 5.98 KB
/
controller.go
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package admission
import (
"encoding/json"
"fmt"
"io/ioutil"
"math"
"net/http"
"strconv"
"github.com/wI2L/jsondiff"
v1 "k8s.io/api/admission/v1"
"k8s.io/api/admission/v1beta1"
corev1 "k8s.io/api/core/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/klog/v2"
)
var (
patchTypeJSONPatch = v1.PatchTypeJSONPatch
injectAnnotationKey = "gomaxprocs-injector/inject"
injectDisabledValue = "disabled"
)
type Controller struct {
}
func NewController() *Controller {
return &Controller{}
}
func (c *Controller) ServeHTTP(w http.ResponseWriter, r *http.Request) {
var body []byte
if r.Body != nil {
if data, err := ioutil.ReadAll(r.Body); err == nil {
body = data
}
}
// verify the content type is accurate
contentType := r.Header.Get("Content-Type")
if contentType != "application/json" {
klog.ErrorS(nil, "Got wrong contentType", "got", contentType, "expect", "application/json")
return
}
klog.V(2).Info("Handling", "request", string(body))
deserializer := codecs.UniversalDeserializer()
obj, gvk, err := deserializer.Decode(body, nil, nil)
if err != nil {
msg := fmt.Sprintf("Failed to deserialize request object: %v", err)
klog.ErrorS(err, msg)
http.Error(w, msg, http.StatusBadRequest)
return
}
var responseObj runtime.Object
switch *gvk {
case v1beta1.SchemeGroupVersion.WithKind("AdmissionReview"):
requestedAdmissionReview, ok := obj.(*v1beta1.AdmissionReview)
if !ok {
klog.ErrorS(nil, "Wrong AdmissionReview type", "expect", "v1beta1.AdmissionReview", "got", fmt.Sprintf("%T", obj))
return
}
responseAdmissionReview := &v1beta1.AdmissionReview{}
responseAdmissionReview.SetGroupVersionKind(*gvk)
responseAdmissionReview.Response = c.admitV1beta1(*requestedAdmissionReview)
responseAdmissionReview.Response.UID = requestedAdmissionReview.Request.UID
responseObj = responseAdmissionReview
case v1.SchemeGroupVersion.WithKind("AdmissionReview"):
requestedAdmissionReview, ok := obj.(*v1.AdmissionReview)
if !ok {
klog.ErrorS(nil, "Wrong AdmissionReview type", "expect", "v1.AdmissionReview", "got", fmt.Sprintf("%T", obj))
return
}
responseAdmissionReview := &v1.AdmissionReview{}
responseAdmissionReview.SetGroupVersionKind(*gvk)
responseAdmissionReview.Response = c.admit(*requestedAdmissionReview)
responseAdmissionReview.Response.UID = requestedAdmissionReview.Request.UID
responseObj = responseAdmissionReview
default:
msg := fmt.Sprintf("Unsupported group version kind: %v", gvk)
klog.ErrorS(nil, msg)
http.Error(w, msg, http.StatusBadRequest)
return
}
klog.V(2).Info("Sending", "response", responseObj)
respBytes, err := json.Marshal(responseObj)
if err != nil {
msg := fmt.Sprintf("Failed to serialize response object: %v", err)
klog.ErrorS(err, msg)
http.Error(w, msg, http.StatusInternalServerError)
return
}
w.Header().Set("Content-Type", "application/json")
if _, err := w.Write(respBytes); err != nil {
klog.ErrorS(err, "Failed to write response")
}
}
func (c *Controller) admit(review v1.AdmissionReview) *v1.AdmissionResponse {
podResource := metav1.GroupVersionResource{Group: "", Version: "v1", Resource: "pods"}
if review.Request.Resource != podResource {
err := fmt.Errorf("expected resource to be %s", podResource)
klog.ErrorS(err, "Failed to admit")
return toV1AdmissionResponse(err)
}
var pod corev1.Pod
if err := json.Unmarshal(review.Request.Object.Raw, &pod); err != nil {
klog.ErrorS(err, "Failed to unmarshal pod")
return toV1AdmissionResponse(err)
}
klog.InfoS("Admitting a pod", "pod", klog.KObj(&pod))
if !isInjectionEnabled(&pod) {
klog.InfoS("Skipping pod as injection is disabled", "pod", klog.KObj(&pod))
return &v1.AdmissionResponse{
Allowed: true,
}
}
newPod := pod.DeepCopy()
for i := range newPod.Spec.InitContainers {
if err := mutateContainer(&newPod.Spec.InitContainers[i]); err != nil {
klog.ErrorS(err, "Failed to mutate container")
return toV1AdmissionResponse(err)
}
}
for i := range newPod.Spec.Containers {
if err := mutateContainer(&newPod.Spec.Containers[i]); err != nil {
klog.ErrorS(err, "Failed to mutate container")
return toV1AdmissionResponse(err)
}
}
patch, err := jsondiff.Compare(pod, newPod)
if err != nil {
klog.ErrorS(err, "Failed to create JSONPatch")
return toV1AdmissionResponse(err)
}
if len(patch) == 0 {
klog.InfoS("No changes to pod", "pod", klog.KObj(&pod))
return &v1.AdmissionResponse{
Allowed: true,
}
}
klog.InfoS("Patching pod", "pod", klog.KObj(&pod), "patch", patch)
patchBytes, err := json.Marshal(patch)
if err != nil {
klog.ErrorS(err, "Failed to marshal JSONPatch")
return toV1AdmissionResponse(err)
}
return &v1.AdmissionResponse{
Allowed: true,
Patch: patchBytes,
PatchType: &patchTypeJSONPatch,
}
}
func mutateContainer(container *corev1.Container) error {
for _, env := range container.Env {
if env.Name == "GOMAXPROCS" {
klog.InfoS("Container already has GOMAXPROCS set", "container", container.Name)
return nil
}
}
if container.Resources.Limits == nil || container.Resources.Limits.Cpu().IsZero() {
klog.InfoS("Container has no cpu resource limit", "container", container.Name)
return nil
}
quota := float64(container.Resources.Limits.Cpu().MilliValue()) / 1000.0
gomaxProcs := int64(math.Floor(quota))
if gomaxProcs < 1 {
gomaxProcs = 1
}
klog.InfoS("Setting GOMAXPROCS", "container", container.Name, "value", gomaxProcs)
container.Env = append(container.Env, corev1.EnvVar{
Name: "GOMAXPROCS",
Value: strconv.FormatInt(gomaxProcs, 10),
})
return nil
}
func (c *Controller) admitV1beta1(review v1beta1.AdmissionReview) *v1beta1.AdmissionResponse {
in := v1.AdmissionReview{Request: convertAdmissionRequestToV1(review.Request)}
out := c.admit(in)
return convertAdmissionResponseToV1beta1(out)
}
func isInjectionEnabled(pod *corev1.Pod) bool {
if pod.Annotations == nil {
return true
}
enabled, ok := pod.Annotations[injectAnnotationKey]
if !ok {
return true
}
return enabled != injectDisabledValue
}