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

     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 ghmetrics
    18  
    19  import (
    20  	"crypto/sha256"
    21  	"fmt"
    22  	"net/http"
    23  	"sync"
    24  
    25  	"github.com/sirupsen/logrus"
    26  )
    27  
    28  // Hasher knows how to hash an authorization header from a request
    29  type Hasher interface {
    30  	Hash(req *http.Request) string
    31  }
    32  
    33  func NewCachingHasher() Hasher {
    34  	return &cachingHasher{
    35  		lock:   sync.RWMutex{},
    36  		hashes: map[string]string{},
    37  	}
    38  }
    39  
    40  type cachingHasher struct {
    41  	lock   sync.RWMutex
    42  	hashes map[string]string
    43  }
    44  
    45  func (h *cachingHasher) Hash(req *http.Request) string {
    46  	// get authorization header to convert to sha256
    47  	authHeader := req.Header.Get("Authorization")
    48  	if authHeader == "" {
    49  		logrus.Warn("Couldn't retrieve 'Authorization' header, adding to unknown bucket")
    50  		authHeader = "unknown"
    51  	}
    52  	h.lock.RLock()
    53  	hash, cached := h.hashes[authHeader]
    54  	h.lock.RUnlock()
    55  	if cached {
    56  		return hash
    57  	}
    58  
    59  	h.lock.Lock()
    60  	hash = fmt.Sprintf("%x", sha256.Sum256([]byte(authHeader))) // use %x to make this a utf-8 string for use as a label
    61  	h.hashes[authHeader] = hash
    62  	h.lock.Unlock()
    63  	return hash
    64  }