/
sentry.go
136 lines (124 loc) · 3.54 KB
/
sentry.go
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package sentry
import (
"crypto/tls"
"encoding/json"
"errors"
"flag"
"io/ioutil"
"net/http"
log "github.com/Sirupsen/logrus"
"k8s.io/api/admission/v1beta1"
admissionregistrationv1beta1 "k8s.io/api/admissionregistration/v1beta1"
corev1 "k8s.io/api/core/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/runtime/serializer"
)
func init() {
corev1.AddToScheme(scheme)
admissionregistrationv1beta1.AddToScheme(scheme)
flag.StringVar(&tlscert, "tlscert", "/etc/webhook/certs/cert.pem", "Location of TLS Cert file.")
flag.StringVar(&tlskey, "tlskey", "/etc/webhook/certs/key.pem", "Location of TLS key file.")
}
var (
scheme = runtime.NewScheme()
codecs = serializer.NewCodecFactory(scheme)
tlscert, tlskey string
healthResponse = []byte("200 - Healthy")
wrongContentResponse = []byte("415 - Wrong Content Type")
ErrNoUID = errors.New("No UID from request")
)
type Sentry interface {
Admit(v1beta1.AdmissionReview) *v1beta1.AdmissionResponse
Type() string
}
func admissionResponseError(err error) *v1beta1.AdmissionResponse {
return &v1beta1.AdmissionResponse{
Result: &metav1.Status{
Message: err.Error(),
},
}
}
type SentryHandler struct {
Sentry
}
func (sh SentryHandler) 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
}
}
log.Info("Received request")
if r.URL.Path == "/healthz" {
log.Info("Received health check")
w.WriteHeader(http.StatusOK)
w.Write(healthResponse)
return
}
contentType := r.Header.Get("Content-Type")
if contentType != "application/json" {
log.Errorf("contentType=%s, expect application/json", contentType)
w.WriteHeader(http.StatusUnsupportedMediaType)
w.Write(wrongContentResponse)
return
}
log.Info("Correct ContentType")
var admissionResponse *v1beta1.AdmissionResponse
receivedAdmissionReview := v1beta1.AdmissionReview{}
if err := Decode(body, &receivedAdmissionReview); err != nil {
log.Error(err)
admissionResponse = admissionResponseError(err)
} else {
admissionResponse = sh.Sentry.Admit(receivedAdmissionReview)
log.Infof("Received response of %v from sentry", admissionResponse.Allowed)
}
returnedAdmissionReview := v1beta1.AdmissionReview{}
if admissionResponse != nil {
returnedAdmissionReview.Response = admissionResponse
if receivedAdmissionReview.Request != nil && receivedAdmissionReview.Request.UID != "" {
returnedAdmissionReview.Response.UID = receivedAdmissionReview.Request.UID
} else {
log.Error(ErrNoUID)
returnedAdmissionReview.Response = admissionResponseError(ErrNoUID)
}
}
responseInBytes, err := json.Marshal(returnedAdmissionReview)
if err != nil {
log.Error(err)
return
}
log.Info("Writing response")
if _, err := w.Write(responseInBytes); err != nil {
log.Error(err)
}
}
func NewSentryServer(s Sentry) (*http.Server, error) {
if !flag.Parsed() {
flag.Parse()
}
server := NewSentryServerNoSSL(s)
sCert, err := tls.LoadX509KeyPair(tlscert, tlskey)
if err != nil {
return server, err
}
tlsConfig := &tls.Config{
Certificates: []tls.Certificate{sCert},
}
server.TLSConfig = tlsConfig
server.Addr = ":8080"
return server, nil
}
func NewSentryServerNoSSL(s Sentry) *http.Server {
return &http.Server{
Handler: SentryHandler{
Sentry: s,
},
Addr: ":8080",
}
}
func Decode(b []byte, o runtime.Object) error {
deserializer := codecs.UniversalDeserializer()
_, _, err := deserializer.Decode(b, nil, o)
return err
}