main.go

Documentation: k8s.io/kubernetes/test/images/agnhost/no-snat-test-proxy

     1  /*
     2  Copyright 2017 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 nosnatproxy
    18  
    19  import (
    20  	"fmt"
    21  	"io"
    22  	"net/http"
    23  	"os"
    24  
    25  	"github.com/spf13/cobra"
    26  	"k8s.io/component-base/logs"
    27  )
    28  
    29  // CmdNoSnatTestProxy is used by agnhost Cobra.
    30  var CmdNoSnatTestProxy = &cobra.Command{
    31  	Use:   "no-snat-test-proxy",
    32  	Short: "Creates a proxy for the /checknosnat endpoint",
    33  	Long:  `Creates the /checknosnat endpoint which proxies the request to the given target (/checknosnat?target=target_ip&ips=ip1,ip2) and returns its response, or a 500 response on error.`,
    34  	Args:  cobra.MaximumNArgs(0),
    35  	Run:   main,
    36  }
    37  
    38  var port string
    39  
    40  func init() {
    41  	CmdNoSnatTestProxy.Flags().StringVar(&port, "port", "31235", "The port to serve /checknosnat endpoint on.")
    42  }
    43  
    44  // This Pod's /checknosnat takes `target` and `ips` arguments, and queries {target}/checknosnat?ips={ips}
    45  
    46  type masqTestProxy struct {
    47  	Port string
    48  }
    49  
    50  func main(cmd *cobra.Command, args []string) {
    51  	m := &masqTestProxy{
    52  		Port: port,
    53  	}
    54  
    55  	logs.InitLogs()
    56  	defer logs.FlushLogs()
    57  
    58  	if err := m.Run(); err != nil {
    59  		fmt.Fprintf(os.Stderr, "%v\n", err)
    60  		os.Exit(1)
    61  	}
    62  }
    63  
    64  func (m *masqTestProxy) Run() error {
    65  	// register handler
    66  	http.HandleFunc("/checknosnat", checknosnat)
    67  
    68  	// spin up the server
    69  	return http.ListenAndServe(":"+m.Port, nil)
    70  }
    71  
    72  func checknosnatURL(pip, ips string) string {
    73  	return fmt.Sprintf("http://%s/checknosnat?ips=%s", pip, ips)
    74  }
    75  
    76  func checknosnat(w http.ResponseWriter, req *http.Request) {
    77  	url := checknosnatURL(req.URL.Query().Get("target"), req.URL.Query().Get("ips"))
    78  	resp, err := http.Get(url)
    79  	if err != nil {
    80  		w.WriteHeader(500)
    81  		fmt.Fprintf(w, "error querying %q, err: %v", url, err)
    82  		return
    83  	}
    84  	defer resp.Body.Close()
    85  
    86  	body, err := io.ReadAll(resp.Body)
    87  	if err != nil {
    88  		w.WriteHeader(500)
    89  		fmt.Fprintf(w, "error reading body of response from %q, err: %v", url, err)
    90  		return
    91  	}
    92  
    93  	// Respond the same status code and body as /checknosnat on the internal Pod
    94  	w.WriteHeader(resp.StatusCode)
    95  	w.Write(body)
    96  }
    97
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