test/e2e/testdata/webhook-create-signed-cert.sh

#!/bin/sh
#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License.  You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

# This script is mostly copied from the istio project.
# https://github.com/istio/istio/blob/release-0.7/install/kubernetes/webhook-create-signed-cert.sh

set -e

usage() {
    cat <<EOF
Generate certificate suitable for use with an sidecar-injector webhook service.
This script uses k8s' CertificateSigningRequest API to a generate a
certificate signed by k8s CA suitable for use with sidecar-injector webhook
services. This requires permissions to create and approve CSR. See
https://kubernetes.io/docs/tasks/tls/managing-tls-in-a-cluster for
detailed explanation and additional instructions.
The server key/cert k8s CA cert are stored in a k8s secret.
usage: ${0} [OPTIONS]
The following flags are required.
       --service          Service name of webhook.
       --namespace        Namespace where webhook service and secret reside.
       --secret           Secret name for CA certificate and server certificate/key pair.
EOF
    exit 1
}

while [[ $# -gt 0 ]]; do
    case ${1} in
        --service)
            service="$2"
            shift
            ;;
        --secret)
            secret="$2"
            shift
            ;;
        --namespace)
            namespace="$2"
            shift
            ;;
        *)
            usage
            ;;
    esac
    shift
done

[ -z ${service} ] && service=webhook
[ -z ${secret} ] && secret=webhook-certs
[ -z ${namespace} ] && namespace=ingress-apisix

if [ ! -x "$(command -v openssl)" ]; then
    echo "openssl not found"
    exit 1
fi

csrName=${service}.${namespace}
tmpdir=$(mktemp -d)
echo "creating certs in tmpdir ${tmpdir} "

cat <<EOF >> ${tmpdir}/csr.conf
[req]
req_extensions = v3_req
distinguished_name = req_distinguished_name
[req_distinguished_name]
[ v3_req ]
basicConstraints = CA:FALSE
keyUsage = nonRepudiation, digitalSignature, keyEncipherment
extendedKeyUsage = serverAuth
subjectAltName = @alt_names
[alt_names]
DNS.1 = ${service}
DNS.2 = ${service}.${namespace}
DNS.3 = ${service}.${namespace}.svc
EOF

openssl genrsa -out ${tmpdir}/server-key.pem 2048
openssl req -new -key ${tmpdir}/server-key.pem -subj "/CN=${service}.${namespace}.svc" -out ${tmpdir}/server.csr -config ${tmpdir}/csr.conf

KIND_CTX=`kubectl config get-contexts --output=name | grep "kind-"`

# clean-up any previously created CSR for our service. Ignore errors if not present.
kubectl --context "${KIND_CTX}" delete csr ${csrName} 2>/dev/null || true

# create server cert/key CSR and send to k8s API
cat <<EOF | kubectl --context "${KIND_CTX}" create -f -
apiVersion: certificates.k8s.io/v1beta1
kind: CertificateSigningRequest
metadata:
  name: ${csrName}
spec:
  groups:
  - system:authenticated
  request: $(cat ${tmpdir}/server.csr | base64 | tr -d '\n')
  usages:
  - digital signature
  - key encipherment
  - server auth
EOF

# verify CSR has been created
while true; do
    kubectl --context "${KIND_CTX}" get csr ${csrName}
    if [ "$?" -eq 0 ]; then
        break
    fi
done

# approve and fetch the signed certificate
kubectl --context "${KIND_CTX}" certificate approve ${csrName}

# verify certificate has been signed
for x in $(seq 10); do
    serverCert=$(kubectl get csr ${csrName} -o jsonpath='{.status.certificate}')
    if [[ ${serverCert} != '' ]]; then
        break
    fi
    sleep 1
done
if [[ ${serverCert} == '' ]]; then
    echo "ERROR: After approving csr ${csrName}, the signed certificate did not appear on the resource. Giving up after 10 attempts." >&2
    exit 1
fi

echo ${serverCert} | openssl base64 -d -A -out ${tmpdir}/server-cert.pem

# clean-up any previously created secret for webhook. Ignore errors if not present.
kubectl --context "${KIND_CTX}" -n ${namespace} delete secret ${secret} 2>/dev/null || true

# create the secret with CA cert and server cert/key
kubectl --context "${KIND_CTX}" -n ${namespace} create secret generic ${secret} \
        --from-file=key.pem=${tmpdir}/server-key.pem \
        --from-file=cert.pem=${tmpdir}/server-cert.pem

rm -f "${tmpdir}/*"