services/keepstore/proxy_remote.go

   1 // Copyright (C) The Arvados Authors. All rights reserved.
   2 //
   3 // SPDX-License-Identifier: AGPL-3.0
   4
   5 package main
   6
   7 import (
   8         "context"
   9         "errors"
  10         "io"
  11         "net/http"
  12         "regexp"
  13         "strings"
  14         "sync"
  15         "time"
  16
  17         "git.curoverse.com/arvados.git/sdk/go/arvados"
  18         "git.curoverse.com/arvados.git/sdk/go/arvadosclient"
  19         "git.curoverse.com/arvados.git/sdk/go/auth"
  20         "git.curoverse.com/arvados.git/sdk/go/keepclient"
  21 )
  22
  23 type remoteProxy struct {
  24         clients map[string]*keepclient.KeepClient
  25         mtx     sync.Mutex
  26 }
  27
  28 func (rp *remoteProxy) Get(ctx context.Context, w http.ResponseWriter, r *http.Request, cluster *arvados.Cluster) {
  29         // Intervening proxies must not return a cached GET response
  30         // to a prior request if a X-Keep-Signature request header has
  31         // been added or changed.
  32         w.Header().Add("Vary", "X-Keep-Signature")
  33
  34         token := GetAPIToken(r)
  35         if token == "" {
  36                 http.Error(w, "no token provided in Authorization header", http.StatusUnauthorized)
  37                 return
  38         }
  39         if strings.SplitN(r.Header.Get("X-Keep-Signature"), ",", 2)[0] == "local" {
  40                 buf, err := getBufferWithContext(ctx, bufs, BlockSize)
  41                 if err != nil {
  42                         http.Error(w, err.Error(), http.StatusServiceUnavailable)
  43                         return
  44                 }
  45                 defer bufs.Put(buf)
  46                 rrc := &remoteResponseCacher{
  47                         Locator:        r.URL.Path[1:],
  48                         Token:          token,
  49                         Buffer:         buf[:0],
  50                         ResponseWriter: w,
  51                 }
  52                 defer rrc.Flush(ctx)
  53                 w = rrc
  54         }
  55         var remoteClient *keepclient.KeepClient
  56         var parts []string
  57         for i, part := range strings.Split(r.URL.Path[1:], "+") {
  58                 switch {
  59                 case i == 0:
  60                         // don't try to parse hash part as hint
  61                 case strings.HasPrefix(part, "A"):
  62                         // drop local permission hint
  63                         continue
  64                 case len(part) > 7 && part[0] == 'R' && part[6] == '-':
  65                         remoteID := part[1:6]
  66                         remote, ok := cluster.RemoteClusters[remoteID]
  67                         if !ok {
  68                                 http.Error(w, "remote cluster not configured", http.StatusBadGateway)
  69                                 return
  70                         }
  71                         kc, err := rp.remoteClient(remoteID, remote, token)
  72                         if err == auth.ErrObsoleteToken {
  73                                 http.Error(w, err.Error(), http.StatusBadRequest)
  74                                 return
  75                         } else if err != nil {
  76                                 http.Error(w, err.Error(), http.StatusInternalServerError)
  77                                 return
  78                         }
  79                         remoteClient = kc
  80                         part = "A" + part[7:]
  81                 }
  82                 parts = append(parts, part)
  83         }
  84         if remoteClient == nil {
  85                 http.Error(w, "bad request", http.StatusBadRequest)
  86                 return
  87         }
  88         locator := strings.Join(parts, "+")
  89         rdr, _, _, err := remoteClient.Get(locator)
  90         switch err.(type) {
  91         case nil:
  92                 defer rdr.Close()
  93                 io.Copy(w, rdr)
  94         case *keepclient.ErrNotFound:
  95                 http.Error(w, err.Error(), http.StatusNotFound)
  96         default:
  97                 http.Error(w, err.Error(), http.StatusBadGateway)
  98         }
  99 }
 100
 101 func (rp *remoteProxy) remoteClient(remoteID string, remoteCluster arvados.RemoteCluster, token string) (*keepclient.KeepClient, error) {
 102         rp.mtx.Lock()
 103         kc, ok := rp.clients[remoteID]
 104         rp.mtx.Unlock()
 105         if !ok {
 106                 c := &arvados.Client{
 107                         APIHost:   remoteCluster.Host,
 108                         AuthToken: "xxx",
 109                         Insecure:  remoteCluster.Insecure,
 110                 }
 111                 ac, err := arvadosclient.New(c)
 112                 if err != nil {
 113                         return nil, err
 114                 }
 115                 kc, err = keepclient.MakeKeepClient(ac)
 116                 if err != nil {
 117                         return nil, err
 118                 }
 119
 120                 rp.mtx.Lock()
 121                 if rp.clients == nil {
 122                         rp.clients = map[string]*keepclient.KeepClient{remoteID: kc}
 123                 } else {
 124                         rp.clients[remoteID] = kc
 125                 }
 126                 rp.mtx.Unlock()
 127         }
 128         accopy := *kc.Arvados
 129         accopy.ApiToken = token
 130         kccopy := *kc
 131         kccopy.Arvados = &accopy
 132         token, err := auth.SaltToken(token, remoteID)
 133         if err != nil {
 134                 return nil, err
 135         }
 136         kccopy.Arvados.ApiToken = token
 137         return &kccopy, nil
 138 }
 139
 140 var localOrRemoteSignature = regexp.MustCompile(`\+[AR][^\+]*`)
 141
 142 // remoteResponseCacher wraps http.ResponseWriter. It buffers the
 143 // response data in the provided buffer, writes/touches a copy on a
 144 // local volume, adds a response header with a locally-signed locator,
 145 // and finally writes the data through.
 146 type remoteResponseCacher struct {
 147         Locator string
 148         Token   string
 149         Buffer  []byte
 150         http.ResponseWriter
 151         statusCode int
 152 }
 153
 154 func (rrc *remoteResponseCacher) Write(p []byte) (int, error) {
 155         if len(rrc.Buffer)+len(p) > cap(rrc.Buffer) {
 156                 return 0, errors.New("buffer full")
 157         }
 158         rrc.Buffer = append(rrc.Buffer, p...)
 159         return len(p), nil
 160 }
 161
 162 func (rrc *remoteResponseCacher) WriteHeader(statusCode int) {
 163         rrc.statusCode = statusCode
 164 }
 165
 166 func (rrc *remoteResponseCacher) Flush(ctx context.Context) {
 167         if rrc.statusCode == 0 {
 168                 rrc.statusCode = http.StatusOK
 169         } else if rrc.statusCode != http.StatusOK {
 170                 rrc.ResponseWriter.WriteHeader(rrc.statusCode)
 171                 rrc.ResponseWriter.Write(rrc.Buffer)
 172                 return
 173         }
 174         _, err := PutBlock(ctx, rrc.Buffer, rrc.Locator[:32])
 175         if err == RequestHashError {
 176                 http.Error(rrc.ResponseWriter, "checksum mismatch in remote response", http.StatusBadGateway)
 177                 return
 178         }
 179         if err, ok := err.(*KeepError); ok {
 180                 http.Error(rrc.ResponseWriter, err.Error(), err.HTTPCode)
 181                 return
 182         }
 183         if err != nil {
 184                 http.Error(rrc.ResponseWriter, err.Error(), http.StatusBadGateway)
 185                 return
 186         }
 187
 188         unsigned := localOrRemoteSignature.ReplaceAllLiteralString(rrc.Locator, "")
 189         signed := SignLocator(unsigned, rrc.Token, time.Now().Add(theConfig.BlobSignatureTTL.Duration()))
 190         if signed == unsigned {
 191                 http.Error(rrc.ResponseWriter, "could not sign locator", http.StatusInternalServerError)
 192                 return
 193         }
 194         rrc.Header().Set("X-Keep-Locator", signed)
 195         rrc.ResponseWriter.WriteHeader(rrc.statusCode)
 196         rrc.ResponseWriter.Write(rrc.Buffer)
 197 }