github.com/zppinho/prow@v0.0.0-20240510014325-1738badeb017/pkg/ghcache/partitioner.go (about)

     1  /*
     2  Copyright 2020 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 ghcache
    18  
    19  import (
    20  	"crypto/sha256"
    21  	"fmt"
    22  	"net/http"
    23  	"sync"
    24  	"time"
    25  
    26  	"github.com/sirupsen/logrus"
    27  )
    28  
    29  type roundTripperCreator func(partitionKey string, expiresAt *time.Time) http.RoundTripper
    30  
    31  // partitioningRoundTripper is a http.RoundTripper
    32  var _ http.RoundTripper = &partitioningRoundTripper{}
    33  
    34  func newPartitioningRoundTripper(rtc roundTripperCreator) *partitioningRoundTripper {
    35  	return &partitioningRoundTripper{
    36  		roundTripperCreator: rtc,
    37  		lock:                &sync.Mutex{},
    38  		roundTrippers:       map[string]http.RoundTripper{},
    39  	}
    40  }
    41  
    42  type partitioningRoundTripper struct {
    43  	roundTripperCreator roundTripperCreator
    44  	lock                *sync.Mutex
    45  	roundTrippers       map[string]http.RoundTripper
    46  }
    47  
    48  func getCachePartition(r *http.Request) string {
    49  	// Hash the key to make sure we dont leak it into the directory layout
    50  	return fmt.Sprintf("%x", sha256.Sum256([]byte(r.Header.Get("Authorization"))))
    51  }
    52  
    53  func getExpiry(r *http.Request) *time.Time {
    54  	raw := r.Header.Get(TokenExpiryAtHeader)
    55  	if raw == "" {
    56  		return nil
    57  	}
    58  	parsed, err := time.Parse(time.RFC3339, raw)
    59  	if err != nil {
    60  		logrus.WithError(err).WithFields(logrus.Fields{
    61  			"path":       r.URL.Path,
    62  			"raw_value":  raw,
    63  			"user-agent": r.Header.Get("User-Agent"),
    64  		}).Errorf("failed to parse value of %s header as RFC3339 time", TokenExpiryAtHeader)
    65  		return nil
    66  	}
    67  	return &parsed
    68  }
    69  
    70  func (prt *partitioningRoundTripper) RoundTrip(r *http.Request) (*http.Response, error) {
    71  	cachePartition := getCachePartition(r)
    72  	expiresAt := getExpiry(r)
    73  
    74  	prt.lock.Lock()
    75  	roundTripper, found := prt.roundTrippers[cachePartition]
    76  	if !found {
    77  		logrus.WithField("cache-parition-key", cachePartition).Info("Creating a new cache for partition")
    78  		cachePartitionsCounter.WithLabelValues(cachePartition).Add(1)
    79  		prt.roundTrippers[cachePartition] = prt.roundTripperCreator(cachePartition, expiresAt)
    80  		roundTripper = prt.roundTrippers[cachePartition]
    81  	}
    82  	prt.lock.Unlock()
    83  
    84  	return roundTripper.RoundTrip(r)
    85  }