main.go

Documentation: k8s.io/kubernetes/test/images/agnhost/inclusterclient

     1  /*
     2  Copyright 2019 The Kubernetes Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package inclusterclient
    18  
    19  import (
    20  	"context"
    21  	"crypto/sha256"
    22  	"encoding/base64"
    23  	"flag"
    24  	"fmt"
    25  	"log"
    26  	"net/http"
    27  	"time"
    28  
    29  	"github.com/spf13/cobra"
    30  
    31  	"k8s.io/client-go/kubernetes"
    32  	"k8s.io/client-go/rest"
    33  	"k8s.io/component-base/logs"
    34  	"k8s.io/klog/v2"
    35  )
    36  
    37  var pollInterval int
    38  
    39  // CmdInClusterClient is used by agnhost Cobra.
    40  var CmdInClusterClient = &cobra.Command{
    41  	Use:   "inclusterclient",
    42  	Short: "Periodically poll the Kubernetes \"/healthz\" endpoint",
    43  	Long: `Periodically polls the Kubernetes "/healthz" endpoint using the in-cluster config. Because of this, this subcommand is meant to be run inside of a Kubernetes pod.
    44  
    45  This subcommand can also be used to validate token rotation.`,
    46  	Args: cobra.MaximumNArgs(0),
    47  	Run:  main,
    48  }
    49  
    50  func init() {
    51  	CmdInClusterClient.Flags().IntVar(&pollInterval, "poll-interval", 30,
    52  		"poll interval of call to /healthz in seconds")
    53  }
    54  
    55  func main(cmd *cobra.Command, args []string) {
    56  	logs.InitLogs()
    57  	defer logs.FlushLogs()
    58  
    59  	flag.Set("logtostderr", "true")
    60  
    61  	klog.Infof("started")
    62  
    63  	cfg, err := rest.InClusterConfig()
    64  	if err != nil {
    65  		log.Fatalf("err: %v", err)
    66  	}
    67  
    68  	cfg.Wrap(func(rt http.RoundTripper) http.RoundTripper {
    69  		return &debugRt{
    70  			rt: rt,
    71  		}
    72  	})
    73  
    74  	c := kubernetes.NewForConfigOrDie(cfg).RESTClient()
    75  
    76  	t := time.Tick(time.Duration(pollInterval) * time.Second)
    77  	for {
    78  		<-t
    79  		klog.Infof("calling /healthz")
    80  		b, err := c.Get().AbsPath("/healthz").Do(context.TODO()).Raw()
    81  		if err != nil {
    82  			klog.Errorf("status=failed")
    83  			klog.Errorf("error checking /healthz: %v\n%s\n", err, string(b))
    84  		}
    85  	}
    86  }
    87  
    88  type debugRt struct {
    89  	rt http.RoundTripper
    90  }
    91  
    92  func (rt *debugRt) RoundTrip(req *http.Request) (*http.Response, error) {
    93  	authHeader := req.Header.Get("Authorization")
    94  	if len(authHeader) != 0 {
    95  		authHash := sha256.Sum256([]byte(fmt.Sprintf("%s|%s", "salt", authHeader)))
    96  		klog.Infof("authz_header=%s", base64.RawURLEncoding.EncodeToString(authHash[:]))
    97  	} else {
    98  		klog.Errorf("authz_header=<empty>")
    99  	}
   100  	return rt.rt.RoundTrip(req)
   101  }
   102  
   103  func (rt *debugRt) WrappedRoundTripper() http.RoundTripper { return rt.rt }
   104
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