/
kubernetes_version.go
183 lines (156 loc) · 4.58 KB
/
kubernetes_version.go
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package cmd
import (
"crypto/tls"
"encoding/json"
"encoding/pem"
"fmt"
"io"
"net/http"
"os"
"strings"
"time"
"github.com/golang/glog"
)
type KubeVersion struct {
Major string
Minor string
baseVersion string
GitVersion string
}
func (k *KubeVersion) BaseVersion() string {
if k.baseVersion != "" {
return k.baseVersion
}
// Some provides return the minor version like "15+"
minor := strings.Replace(k.Minor, "+", "", -1)
ver := fmt.Sprintf("%s.%s", k.Major, minor)
k.baseVersion = ver
return ver
}
func getKubeVersionFromRESTAPI() (*KubeVersion, error) {
glog.V(2).Info("Try to get version from Rest API")
k8sVersionURL := getKubernetesURL()
serviceaccount := "/var/run/secrets/kubernetes.io/serviceaccount"
cacertfile := fmt.Sprintf("%s/ca.crt", serviceaccount)
tokenfile := fmt.Sprintf("%s/token", serviceaccount)
tlsCert, err := loadCertificate(cacertfile)
if err != nil {
glog.V(2).Infof("Failed loading certificate Error: %s", err)
return nil, err
}
tb, err := os.ReadFile(tokenfile)
if err != nil {
glog.V(2).Infof("Failed reading token file Error: %s", err)
return nil, err
}
token := strings.TrimSpace(string(tb))
data, err := getWebDataWithRetry(k8sVersionURL, token, tlsCert)
if err != nil {
glog.V(2).Infof("Failed to get data Error: %s", err)
return nil, err
}
k8sVersion, err := extractVersion(data)
if err != nil {
return nil, err
}
return k8sVersion, nil
}
// The idea of this function is so if Kubernetes DNS is not completely seetup and the
// Container where kube-bench is running needs time for DNS configure.
// Basically try 10 times, waiting 1 second until either it is successful or it fails.
func getWebDataWithRetry(k8sVersionURL, token string, cacert *tls.Certificate) (data []byte, err error) {
tries := 0
// We retry a few times in case the DNS service has not had time to come up
for tries < 10 {
data, err = getWebData(k8sVersionURL, token, cacert)
if err == nil {
return
}
tries++
time.Sleep(1 * time.Second)
}
return
}
type VersionResponse struct {
Major string
Minor string
GitVersion string
GitCommit string
GitTreeState string
BuildDate string
GoVersion string
Compiler string
Platform string
}
func extractVersion(data []byte) (*KubeVersion, error) {
vrObj := &VersionResponse{}
glog.V(2).Info(fmt.Sprintf("vd: %s\n", string(data)))
err := json.Unmarshal(data, vrObj)
if err != nil {
return nil, err
}
glog.V(2).Info(fmt.Sprintf("vrObj: %#v\n", vrObj))
return &KubeVersion{
Major: vrObj.Major,
Minor: vrObj.Minor,
GitVersion: vrObj.GitVersion,
}, nil
}
func getWebData(srvURL, token string, cacert *tls.Certificate) ([]byte, error) {
glog.V(2).Info(fmt.Sprintf("getWebData srvURL: %s\n", srvURL))
tlsConf := &tls.Config{
Certificates: []tls.Certificate{*cacert},
InsecureSkipVerify: true,
}
tr := &http.Transport{
TLSClientConfig: tlsConf,
}
client := &http.Client{Transport: tr}
req, err := http.NewRequest(http.MethodGet, srvURL, nil)
if err != nil {
return nil, err
}
authToken := fmt.Sprintf("Bearer %s", token)
req.Header.Set("Authorization", authToken)
resp, err := client.Do(req)
if err != nil {
glog.V(2).Info(fmt.Sprintf("HTTP ERROR: %v\n", err))
return nil, err
}
defer resp.Body.Close()
if resp.StatusCode != http.StatusOK {
glog.V(2).Info(fmt.Sprintf("URL:[%s], StatusCode:[%d] \n Headers: %#v\n", srvURL, resp.StatusCode, resp.Header))
err = fmt.Errorf("URL:[%s], StatusCode:[%d]", srvURL, resp.StatusCode)
return nil, err
}
return io.ReadAll(resp.Body)
}
func loadCertificate(certFile string) (*tls.Certificate, error) {
cacert, err := os.ReadFile(certFile)
if err != nil {
return nil, err
}
var tlsCert tls.Certificate
block, _ := pem.Decode(cacert)
if block == nil {
return nil, fmt.Errorf("unable to Decode certificate")
}
glog.V(2).Info("Loading CA certificate")
tlsCert.Certificate = append(tlsCert.Certificate, block.Bytes)
return &tlsCert, nil
}
func getKubernetesURL() string {
k8sVersionURL := "https://kubernetes.default.svc/version"
// The following provides flexibility to use
// K8S provided variables is situations where
// hostNetwork: true
if !isEmpty(os.Getenv("KUBE_BENCH_K8S_ENV")) {
k8sHost := os.Getenv("KUBERNETES_SERVICE_HOST")
k8sPort := os.Getenv("KUBERNETES_SERVICE_PORT_HTTPS")
if !isEmpty(k8sHost) && !isEmpty(k8sPort) {
return fmt.Sprintf("https://%s:%s/version", k8sHost, k8sPort)
}
glog.V(2).Info("KUBE_BENCH_K8S_ENV is set, but environment variables KUBERNETES_SERVICE_HOST or KUBERNETES_SERVICE_PORT_HTTPS are not set")
}
return k8sVersionURL
}