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| #!/bin/bash
name=mywebhook
namespace=mynamespace
go mod init ${name}
cat <<EOF > ./main.go
package main
import (
"context"
"encoding/json"
"log"
"net/http"
"os"
"os/signal"
"syscall"
admissionv1 "k8s.io/api/admission/v1"
corev1 "k8s.io/api/core/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
)
type jsonPatch struct {
OP string \`json:"op"\`
Path string \`json:"path"\`
Value interface{} \`json:"value"\`
}
s
func podsMutate(w http.ResponseWriter, r *http.Request) {
admissionReviewReq := &admissionv1.AdmissionReview{}
if err := json.NewDecoder(r.Body).Decode(admissionReviewReq); err != nil {
return
}
pod := &corev1.Pod{}
if err := json.Unmarshal(admissionReviewReq.Request.Object.Raw, pod); err != nil {
return
}
labels := pod.Labels
if pod.Labels == nil {
labels = make(map[string]string)
}
labels["a"] = "1"
var patchs []jsonPatch
patchs = append(patchs, jsonPatch{
OP: "add",
Path: "/metadata/labels",
Value: labels,
})
jsonPatchata, err := json.Marshal(patchs)
if err != nil {
return
}
patchType := admissionv1.PatchTypeJSONPatch
resp := &admissionv1.AdmissionResponse{
UID: admissionReviewReq.Request.UID,
Allowed: true,
Patch: jsonPatchata,
PatchType: &patchType,
}
admissionReviewResp := &admissionv1.AdmissionReview{
TypeMeta: metav1.TypeMeta{
Kind: "AdmissionReview",
APIVersion: "admission.k8s.io/v1",
},
Response: resp,
}
if err := json.NewEncoder(w).Encode(admissionReviewResp); err != nil {
return
}
}
func main() {
mux := http.NewServeMux()
server := &http.Server{
Handler: mux,
}
mux.HandleFunc("/pods/mutate", podsMutate)
ch := make(chan os.Signal, 1)
signal.Notify(ch, syscall.SIGINT, syscall.SIGTERM)
go func() {
<-ch
server.Shutdown(context.TODO())
}()
if err := server.ListenAndServeTLS("/etc/${name}/tls.crt", "/etc/${name}/tls.key"); err != nil &&
err != http.ErrServerClosed {
log.Fatalf("Failed to ListenAndServeTLS, err:%#v", err)
}
}
EOF
go mod tidy
cat <<EOF > ./Dockerfile
FROM golang:alpine as builder
ENV GO111MODULE=on \
GOPROXY=https://goproxy.cn,direct
ARG CONF=dev
WORKDIR /go/app
COPY go.mod .
COPY go.sum .
RUN go mod download
COPY main.go main.go
RUN CGO_ENABLED=0 GOARCH=amd64 GOOS=linux go build -o app .
FROM alpine:latest as prod
ARG CONF=dev
RUN sed -i 's/dl-cdn.alpinelinux.org/mirrors.aliyun.com/g' /etc/apk/repositories && apk --no-cache add ca-certificates && apk add tzdata && cp /usr/share/zoneinfo/Asia/Shanghai /etc/localtime && echo "Asia/Shanghai" > /etc/timezone
WORKDIR /app/
COPY --from=0 /go/app/app .
CMD ["./app"]
EOF
docker build -t mywebhook:0.1 .
kubectl create ns ${namespace}
openssl genrsa -out ca.key 2048
openssl req -new -x509 -days 365 -key ca.key \
-subj "/C=AU/CN=${name}"\
-out ca.crt
openssl req -newkey rsa:2048 -nodes -keyout server.key \
-subj "/C=AU/CN=${name}" \
-out server.csr
openssl x509 -req \
-extfile <(printf "subjectAltName=DNS:${name}.${namespace}.svc") \
-days 365 \
-in server.csr \
-CA ca.crt -CAkey ca.key -CAcreateserial \
-out server.crt
kubectl create secret tls -n ${namespace} ${name} \
--cert=server.crt \
--key=server.key \
--dry-run=client -o yaml \
> ./secret.yaml
caBundle=`cat ca.crt | base64 | fold |awk BEGIN{RS=EOF}'{gsub(/\n/,"");print}'`
cat <<EOF > ./webhook.yaml
apiVersion: admissionregistration.k8s.io/v1
kind: MutatingWebhookConfiguration
metadata:
name: ${name}
namespace: ${namespace}
webhooks:
- name: ${name}.${namespace}.com
failurePolicy: "Fail"
matchPolicy: "Equivalent"
rules:
- apiGroups: [""]
apiVersions: ["v1"]
operations: ["CREATE","UPDATE"]
resources: ["pods"]
scope: "*"
clientConfig:
service:
namespace: ${namespace}
name: ${name}
path: /pods/mutate
port: 443
caBundle: ${caBundle}
admissionReviewVersions: ["v1", "v1beta1"]
sideEffects: None
timeoutSeconds: 10
reinvocationPolicy: "Never"
EOF
cat <<EOF > ./deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: ${name}
namespace: ${namespace}
spec:
replicas: 1
selector:
matchLabels:
app: ${name}
template:
metadata:
labels:
app: ${name}
spec:
containers:
- image: ${name}:0.1
imagePullPolicy: Never
name: app
volumeMounts:
- name: tls
mountPath: "/etc/${name}"
readOnly: true
volumes:
- name: tls
secret:
secretName: ${name}
EOF
cat <<EOF > ./service.yaml
apiVersion: v1
kind: Service
metadata:
name: ${name}
namespace: ${namespace}
spec:
type: ClusterIP
ports:
- port: 443
protocol: TCP
targetPort: 443
selector:
app: ${name}
EOF
cat <<EOF > ./demo.yaml
apiVersion: v1
kind: Pod
metadata:
name: demo
namespace: ${namespace}
spec:
containers:
- command:
- sh
- -c
- 'sleep 10'
image: busybox
name: busybox
EOF
|