roundtripper.go

Documentation: helm.sh/helm/v3/pkg/cli

     1  /*
     2  Copyright The Helm 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 cli
    18  
    19  import (
    20  	"bytes"
    21  	"encoding/json"
    22  	"io"
    23  	"net/http"
    24  	"strings"
    25  )
    26  
    27  type retryingRoundTripper struct {
    28  	wrapped http.RoundTripper
    29  }
    30  
    31  func (rt *retryingRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
    32  	return rt.roundTrip(req, 1, nil)
    33  }
    34  
    35  func (rt *retryingRoundTripper) roundTrip(req *http.Request, retry int, prevResp *http.Response) (*http.Response, error) {
    36  	if retry < 0 {
    37  		return prevResp, nil
    38  	}
    39  	resp, rtErr := rt.wrapped.RoundTrip(req)
    40  	if rtErr != nil {
    41  		return resp, rtErr
    42  	}
    43  	if resp.StatusCode < 500 {
    44  		return resp, rtErr
    45  	}
    46  	if resp.Header.Get("content-type") != "application/json" {
    47  		return resp, rtErr
    48  	}
    49  	b, err := io.ReadAll(resp.Body)
    50  	resp.Body.Close()
    51  	if err != nil {
    52  		return resp, rtErr
    53  	}
    54  
    55  	var ke kubernetesError
    56  	r := bytes.NewReader(b)
    57  	err = json.NewDecoder(r).Decode(&ke)
    58  	r.Seek(0, io.SeekStart)
    59  	resp.Body = io.NopCloser(r)
    60  	if err != nil {
    61  		return resp, rtErr
    62  	}
    63  	if ke.Code < 500 {
    64  		return resp, rtErr
    65  	}
    66  	// Matches messages like "etcdserver: leader changed"
    67  	if strings.HasSuffix(ke.Message, "etcdserver: leader changed") {
    68  		return rt.roundTrip(req, retry-1, resp)
    69  	}
    70  	// Matches messages like "rpc error: code = Unknown desc = raft proposal dropped"
    71  	if strings.HasSuffix(ke.Message, "raft proposal dropped") {
    72  		return rt.roundTrip(req, retry-1, resp)
    73  	}
    74  	return resp, rtErr
    75  }
    76  
    77  type kubernetesError struct {
    78  	Message string `json:"message"`
    79  	Code    int    `json:"code"`
    80  }
    81
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