k8s.io/apiserver@v0.31.1/pkg/registry/generic/rest/streamer.go (about)

     1  /*
     2  Copyright 2014 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 rest
    18  
    19  import (
    20  	"context"
    21  	"errors"
    22  	"fmt"
    23  	"io"
    24  	"net/http"
    25  	"net/url"
    26  	"strings"
    27  
    28  	"k8s.io/apimachinery/pkg/runtime"
    29  	"k8s.io/apimachinery/pkg/runtime/schema"
    30  	"k8s.io/apiserver/pkg/registry/rest"
    31  )
    32  
    33  type CounterMetric interface {
    34  	Inc()
    35  }
    36  
    37  // LocationStreamer is a resource that streams the contents of a particular
    38  // location URL.
    39  type LocationStreamer struct {
    40  	Location        *url.URL
    41  	Transport       http.RoundTripper
    42  	ContentType     string
    43  	Flush           bool
    44  	ResponseChecker HttpResponseChecker
    45  	RedirectChecker func(req *http.Request, via []*http.Request) error
    46  	// TLSVerificationErrorCounter is an optional value that will Inc every time a TLS error is encountered.  This can
    47  	// be wired a single prometheus counter instance to get counts overall.
    48  	TLSVerificationErrorCounter CounterMetric
    49  	// DeprecatedTLSVerificationErrorCounter is a temporary field used to rename
    50  	// the kube_apiserver_pod_logs_pods_logs_backend_tls_failure_total metric
    51  	// with a one release deprecation period in 1.27.0.
    52  	DeprecatedTLSVerificationErrorCounter CounterMetric
    53  }
    54  
    55  // a LocationStreamer must implement a rest.ResourceStreamer
    56  var _ rest.ResourceStreamer = &LocationStreamer{}
    57  
    58  func (obj *LocationStreamer) GetObjectKind() schema.ObjectKind {
    59  	return schema.EmptyObjectKind
    60  }
    61  func (obj *LocationStreamer) DeepCopyObject() runtime.Object {
    62  	panic("rest.LocationStreamer does not implement DeepCopyObject")
    63  }
    64  
    65  // InputStream returns a stream with the contents of the URL location. If no location is provided,
    66  // a null stream is returned.
    67  func (s *LocationStreamer) InputStream(ctx context.Context, apiVersion, acceptHeader string) (stream io.ReadCloser, flush bool, contentType string, err error) {
    68  	if s.Location == nil {
    69  		// If no location was provided, return a null stream
    70  		return nil, false, "", nil
    71  	}
    72  	transport := s.Transport
    73  	if transport == nil {
    74  		transport = http.DefaultTransport
    75  	}
    76  
    77  	client := &http.Client{
    78  		Transport:     transport,
    79  		CheckRedirect: s.RedirectChecker,
    80  	}
    81  	req, err := http.NewRequest("GET", s.Location.String(), nil)
    82  	if err != nil {
    83  		return nil, false, "", fmt.Errorf("failed to construct request for %s, got %v", s.Location.String(), err)
    84  	}
    85  	// Pass the parent context down to the request to ensure that the resources
    86  	// will be release properly.
    87  	req = req.WithContext(ctx)
    88  
    89  	resp, err := client.Do(req)
    90  	if err != nil {
    91  		// TODO prefer segregate TLS errors more reliably, but we do want to increment a count
    92  		if strings.Contains(err.Error(), "x509:") && s.TLSVerificationErrorCounter != nil {
    93  			s.TLSVerificationErrorCounter.Inc()
    94  			if s.DeprecatedTLSVerificationErrorCounter != nil {
    95  				s.DeprecatedTLSVerificationErrorCounter.Inc()
    96  			}
    97  		}
    98  		return nil, false, "", err
    99  	}
   100  
   101  	if s.ResponseChecker != nil {
   102  		if err = s.ResponseChecker.Check(resp); err != nil {
   103  			return nil, false, "", err
   104  		}
   105  	}
   106  
   107  	contentType = s.ContentType
   108  	if len(contentType) == 0 {
   109  		contentType = resp.Header.Get("Content-Type")
   110  		if len(contentType) > 0 {
   111  			contentType = strings.TrimSpace(strings.SplitN(contentType, ";", 2)[0])
   112  		}
   113  	}
   114  	flush = s.Flush
   115  	stream = resp.Body
   116  	return
   117  }
   118  
   119  // PreventRedirects is a redirect checker that prevents the client from following a redirect.
   120  func PreventRedirects(_ *http.Request, _ []*http.Request) error {
   121  	return errors.New("redirects forbidden")
   122  }