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 keepstore
   6
   7 import (
   8         "context"
   9         "errors"
  10         "io"
  11         "net/http"
  12         "regexp"
  13         "strings"
  14         "sync"
  15         "time"
  16
  17         "git.arvados.org/arvados.git/sdk/go/arvados"
  18         "git.arvados.org/arvados.git/sdk/go/arvadosclient"
  19         "git.arvados.org/arvados.git/sdk/go/auth"
  20         "git.arvados.org/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, volmgr *RRVolumeManager) {
  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                         Context:        ctx,
  52                         Cluster:        cluster,
  53                         VolumeManager:  volmgr,
  54                 }
  55                 defer rrc.Close()
  56                 w = rrc
  57         }
  58         var remoteClient *keepclient.KeepClient
  59         var parts []string
  60         for i, part := range strings.Split(r.URL.Path[1:], "+") {
  61                 switch {
  62                 case i == 0:
  63                         // don't try to parse hash part as hint
  64                 case strings.HasPrefix(part, "A"):
  65                         // drop local permission hint
  66                         continue
  67                 case len(part) > 7 && part[0] == 'R' && part[6] == '-':
  68                         remoteID := part[1:6]
  69                         remote, ok := cluster.RemoteClusters[remoteID]
  70                         if !ok {
  71                                 http.Error(w, "remote cluster not configured", http.StatusBadRequest)
  72                                 return
  73                         }
  74                         kc, err := rp.remoteClient(remoteID, remote, token)
  75                         if err == auth.ErrObsoleteToken {
  76                                 http.Error(w, err.Error(), http.StatusBadRequest)
  77                                 return
  78                         } else if err != nil {
  79                                 http.Error(w, err.Error(), http.StatusInternalServerError)
  80                                 return
  81                         }
  82                         remoteClient = kc
  83                         part = "A" + part[7:]
  84                 }
  85                 parts = append(parts, part)
  86         }
  87         if remoteClient == nil {
  88                 http.Error(w, "bad request", http.StatusBadRequest)
  89                 return
  90         }
  91         locator := strings.Join(parts, "+")
  92         rdr, _, _, err := remoteClient.Get(locator)
  93         switch err.(type) {
  94         case nil:
  95                 defer rdr.Close()
  96                 io.Copy(w, rdr)
  97         case *keepclient.ErrNotFound:
  98                 http.Error(w, err.Error(), http.StatusNotFound)
  99         default:
 100                 http.Error(w, err.Error(), http.StatusBadGateway)
 101         }
 102 }
 103
 104 func (rp *remoteProxy) remoteClient(remoteID string, remoteCluster arvados.RemoteCluster, token string) (*keepclient.KeepClient, error) {
 105         rp.mtx.Lock()
 106         kc, ok := rp.clients[remoteID]
 107         rp.mtx.Unlock()
 108         if !ok {
 109                 c := &arvados.Client{
 110                         APIHost:   remoteCluster.Host,
 111                         AuthToken: "xxx",
 112                         Insecure:  remoteCluster.Insecure,
 113                 }
 114                 ac, err := arvadosclient.New(c)
 115                 if err != nil {
 116                         return nil, err
 117                 }
 118                 kc, err = keepclient.MakeKeepClient(ac)
 119                 if err != nil {
 120                         return nil, err
 121                 }
 122
 123                 rp.mtx.Lock()
 124                 if rp.clients == nil {
 125                         rp.clients = map[string]*keepclient.KeepClient{remoteID: kc}
 126                 } else {
 127                         rp.clients[remoteID] = kc
 128                 }
 129                 rp.mtx.Unlock()
 130         }
 131         accopy := *kc.Arvados
 132         accopy.ApiToken = token
 133         kccopy := *kc
 134         kccopy.Arvados = &accopy
 135         token, err := auth.SaltToken(token, remoteID)
 136         if err != nil {
 137                 return nil, err
 138         }
 139         kccopy.Arvados.ApiToken = token
 140         return &kccopy, nil
 141 }
 142
 143 var localOrRemoteSignature = regexp.MustCompile(`\+[AR][^\+]*`)
 144
 145 // remoteResponseCacher wraps http.ResponseWriter. It buffers the
 146 // response data in the provided buffer, writes/touches a copy on a
 147 // local volume, adds a response header with a locally-signed locator,
 148 // and finally writes the data through.
 149 type remoteResponseCacher struct {
 150         Locator       string
 151         Token         string
 152         Buffer        []byte
 153         Context       context.Context
 154         Cluster       *arvados.Cluster
 155         VolumeManager *RRVolumeManager
 156         http.ResponseWriter
 157         statusCode int
 158 }
 159
 160 func (rrc *remoteResponseCacher) Write(p []byte) (int, error) {
 161         if len(rrc.Buffer)+len(p) > cap(rrc.Buffer) {
 162                 return 0, errors.New("buffer full")
 163         }
 164         rrc.Buffer = append(rrc.Buffer, p...)
 165         return len(p), nil
 166 }
 167
 168 func (rrc *remoteResponseCacher) WriteHeader(statusCode int) {
 169         rrc.statusCode = statusCode
 170 }
 171
 172 func (rrc *remoteResponseCacher) Close() error {
 173         if rrc.statusCode == 0 {
 174                 rrc.statusCode = http.StatusOK
 175         } else if rrc.statusCode != http.StatusOK {
 176                 rrc.ResponseWriter.WriteHeader(rrc.statusCode)
 177                 rrc.ResponseWriter.Write(rrc.Buffer)
 178                 return nil
 179         }
 180         _, err := PutBlock(rrc.Context, rrc.VolumeManager, rrc.Buffer, rrc.Locator[:32], nil)
 181         if rrc.Context.Err() != nil {
 182                 // If caller hung up, log that instead of subsequent/misleading errors.
 183                 http.Error(rrc.ResponseWriter, rrc.Context.Err().Error(), http.StatusGatewayTimeout)
 184                 return err
 185         }
 186         if err == RequestHashError {
 187                 http.Error(rrc.ResponseWriter, "checksum mismatch in remote response", http.StatusBadGateway)
 188                 return err
 189         }
 190         if err, ok := err.(*KeepError); ok {
 191                 http.Error(rrc.ResponseWriter, err.Error(), err.HTTPCode)
 192                 return err
 193         }
 194         if err != nil {
 195                 http.Error(rrc.ResponseWriter, err.Error(), http.StatusBadGateway)
 196                 return err
 197         }
 198
 199         unsigned := localOrRemoteSignature.ReplaceAllLiteralString(rrc.Locator, "")
 200         expiry := time.Now().Add(rrc.Cluster.Collections.BlobSigningTTL.Duration())
 201         signed := SignLocator(rrc.Cluster, unsigned, rrc.Token, expiry)
 202         if signed == unsigned {
 203                 err = errors.New("could not sign locator")
 204                 http.Error(rrc.ResponseWriter, err.Error(), http.StatusInternalServerError)
 205                 return err
 206         }
 207         rrc.Header().Set("X-Keep-Locator", signed)
 208         rrc.ResponseWriter.WriteHeader(rrc.statusCode)
 209         _, err = rrc.ResponseWriter.Write(rrc.Buffer)
 210         return err
 211 }