lib/controller/fed_collections.go

   1 // Copyright (C) The Arvados Authors. All rights reserved.
   2 //
   3 // SPDX-License-Identifier: AGPL-3.0
   4
   5 package controller
   6
   7 import (
   8         "bufio"
   9         "bytes"
  10         "context"
  11         "crypto/md5"
  12         "encoding/json"
  13         "fmt"
  14         "io"
  15         "io/ioutil"
  16         "net/http"
  17         "strings"
  18         "sync"
  19
  20         "git.arvados.org/arvados.git/sdk/go/arvados"
  21         "git.arvados.org/arvados.git/sdk/go/httpserver"
  22         "git.arvados.org/arvados.git/sdk/go/keepclient"
  23 )
  24
  25 func rewriteSignatures(clusterID string, expectHash string,
  26         resp *http.Response, requestError error) (newResponse *http.Response, err error) {
  27
  28         if requestError != nil {
  29                 return resp, requestError
  30         }
  31
  32         if resp.StatusCode != http.StatusOK {
  33                 return resp, nil
  34         }
  35
  36         originalBody := resp.Body
  37         defer originalBody.Close()
  38
  39         var col arvados.Collection
  40         err = json.NewDecoder(resp.Body).Decode(&col)
  41         if err != nil {
  42                 return nil, err
  43         }
  44
  45         // rewriting signatures will make manifest text 5-10% bigger so calculate
  46         // capacity accordingly
  47         updatedManifest := bytes.NewBuffer(make([]byte, 0, int(float64(len(col.ManifestText))*1.1)))
  48
  49         hasher := md5.New()
  50         mw := io.MultiWriter(hasher, updatedManifest)
  51         sz := 0
  52
  53         scanner := bufio.NewScanner(strings.NewReader(col.ManifestText))
  54         scanner.Buffer(make([]byte, 1048576), len(col.ManifestText))
  55         for scanner.Scan() {
  56                 line := scanner.Text()
  57                 tokens := strings.Split(line, " ")
  58                 if len(tokens) < 3 {
  59                         return nil, fmt.Errorf("Invalid stream (<3 tokens): %q", line)
  60                 }
  61
  62                 n, err := mw.Write([]byte(tokens[0]))
  63                 if err != nil {
  64                         return nil, fmt.Errorf("Error updating manifest: %v", err)
  65                 }
  66                 sz += n
  67                 for _, token := range tokens[1:] {
  68                         n, err = mw.Write([]byte(" "))
  69                         if err != nil {
  70                                 return nil, fmt.Errorf("Error updating manifest: %v", err)
  71                         }
  72                         sz += n
  73
  74                         m := keepclient.SignedLocatorRe.FindStringSubmatch(token)
  75                         if m != nil {
  76                                 // Rewrite the block signature to be a remote signature
  77                                 _, err = fmt.Fprintf(updatedManifest, "%s%s%s+R%s-%s%s", m[1], m[2], m[3], clusterID, m[5][2:], m[8])
  78                                 if err != nil {
  79                                         return nil, fmt.Errorf("Error updating manifest: %v", err)
  80                                 }
  81
  82                                 // for hash checking, ignore signatures
  83                                 n, err = fmt.Fprintf(hasher, "%s%s", m[1], m[2])
  84                                 if err != nil {
  85                                         return nil, fmt.Errorf("Error updating manifest: %v", err)
  86                                 }
  87                                 sz += n
  88                         } else {
  89                                 n, err = mw.Write([]byte(token))
  90                                 if err != nil {
  91                                         return nil, fmt.Errorf("Error updating manifest: %v", err)
  92                                 }
  93                                 sz += n
  94                         }
  95                 }
  96                 n, err = mw.Write([]byte("\n"))
  97                 if err != nil {
  98                         return nil, fmt.Errorf("Error updating manifest: %v", err)
  99                 }
 100                 sz += n
 101         }
 102
 103         // Check that expected hash is consistent with
 104         // portable_data_hash field of the returned record
 105         if expectHash == "" {
 106                 expectHash = col.PortableDataHash
 107         } else if expectHash != col.PortableDataHash {
 108                 return nil, fmt.Errorf("portable_data_hash %q on returned record did not match expected hash %q ", expectHash, col.PortableDataHash)
 109         }
 110
 111         // Certify that the computed hash of the manifest_text matches our expectation
 112         sum := hasher.Sum(nil)
 113         computedHash := fmt.Sprintf("%x+%v", sum, sz)
 114         if computedHash != expectHash {
 115                 return nil, fmt.Errorf("Computed manifest_text hash %q did not match expected hash %q", computedHash, expectHash)
 116         }
 117
 118         col.ManifestText = updatedManifest.String()
 119
 120         newbody, err := json.Marshal(col)
 121         if err != nil {
 122                 return nil, err
 123         }
 124
 125         buf := bytes.NewBuffer(newbody)
 126         resp.Body = ioutil.NopCloser(buf)
 127         resp.ContentLength = int64(buf.Len())
 128         resp.Header.Set("Content-Length", fmt.Sprintf("%v", buf.Len()))
 129
 130         return resp, nil
 131 }
 132
 133 func filterLocalClusterResponse(resp *http.Response, requestError error) (newResponse *http.Response, err error) {
 134         if requestError != nil {
 135                 return resp, requestError
 136         }
 137
 138         if resp.StatusCode == http.StatusNotFound {
 139                 // Suppress returning this result, because we want to
 140                 // search the federation.
 141                 return nil, nil
 142         }
 143         return resp, nil
 144 }
 145
 146 type searchRemoteClusterForPDH struct {
 147         pdh           string
 148         remoteID      string
 149         mtx           *sync.Mutex
 150         sentResponse  *bool
 151         sharedContext *context.Context
 152         cancelFunc    func()
 153         errors        *[]string
 154         statusCode    *int
 155 }
 156
 157 func fetchRemoteCollectionByUUID(
 158         h *genericFederatedRequestHandler,
 159         effectiveMethod string,
 160         clusterID *string,
 161         uuid string,
 162         remainder string,
 163         w http.ResponseWriter,
 164         req *http.Request) bool {
 165
 166         if effectiveMethod != "GET" {
 167                 // Only handle GET requests right now
 168                 return false
 169         }
 170
 171         if uuid != "" {
 172                 // Collection UUID GET request
 173                 *clusterID = uuid[0:5]
 174                 if *clusterID != "" && *clusterID != h.handler.Cluster.ClusterID {
 175                         // request for remote collection by uuid
 176                         resp, err := h.handler.remoteClusterRequest(*clusterID, req)
 177                         newResponse, err := rewriteSignatures(*clusterID, "", resp, err)
 178                         h.handler.proxy.ForwardResponse(w, newResponse, err)
 179                         return true
 180                 }
 181         }
 182
 183         return false
 184 }
 185
 186 func fetchRemoteCollectionByPDH(
 187         h *genericFederatedRequestHandler,
 188         effectiveMethod string,
 189         clusterID *string,
 190         uuid string,
 191         remainder string,
 192         w http.ResponseWriter,
 193         req *http.Request) bool {
 194
 195         if effectiveMethod != "GET" {
 196                 // Only handle GET requests right now
 197                 return false
 198         }
 199
 200         m := collectionsByPDHRe.FindStringSubmatch(req.URL.Path)
 201         if len(m) != 2 {
 202                 return false
 203         }
 204
 205         // Request for collection by PDH.  Search the federation.
 206
 207         // First, query the local cluster.
 208         resp, err := h.handler.localClusterRequest(req)
 209         newResp, err := filterLocalClusterResponse(resp, err)
 210         if newResp != nil || err != nil {
 211                 h.handler.proxy.ForwardResponse(w, newResp, err)
 212                 return true
 213         }
 214
 215         // Create a goroutine for each cluster in the
 216         // RemoteClusters map.  The first valid result gets
 217         // returned to the client.  When that happens, all
 218         // other outstanding requests are cancelled
 219         sharedContext, cancelFunc := context.WithCancel(req.Context())
 220         defer cancelFunc()
 221
 222         req = req.WithContext(sharedContext)
 223         wg := sync.WaitGroup{}
 224         pdh := m[1]
 225         success := make(chan *http.Response)
 226         errorChan := make(chan error, len(h.handler.Cluster.RemoteClusters))
 227
 228         acquire, release := semaphore(h.handler.Cluster.API.MaxRequestAmplification)
 229
 230         for remoteID := range h.handler.Cluster.RemoteClusters {
 231                 if remoteID == h.handler.Cluster.ClusterID {
 232                         // No need to query local cluster again
 233                         continue
 234                 }
 235                 if remoteID == "*" {
 236                         // This isn't a real remote cluster: it just sets defaults for unlisted remotes.
 237                         continue
 238                 }
 239
 240                 wg.Add(1)
 241                 go func(remote string) {
 242                         defer wg.Done()
 243                         acquire()
 244                         defer release()
 245                         select {
 246                         case <-sharedContext.Done():
 247                                 return
 248                         default:
 249                         }
 250
 251                         resp, err := h.handler.remoteClusterRequest(remote, req)
 252                         wasSuccess := false
 253                         defer func() {
 254                                 if resp != nil && !wasSuccess {
 255                                         resp.Body.Close()
 256                                 }
 257                         }()
 258                         if err != nil {
 259                                 errorChan <- err
 260                                 return
 261                         }
 262                         if resp.StatusCode != http.StatusOK {
 263                                 errorChan <- HTTPError{resp.Status, resp.StatusCode}
 264                                 return
 265                         }
 266                         select {
 267                         case <-sharedContext.Done():
 268                                 return
 269                         default:
 270                         }
 271
 272                         newResponse, err := rewriteSignatures(remote, pdh, resp, nil)
 273                         if err != nil {
 274                                 errorChan <- err
 275                                 return
 276                         }
 277                         select {
 278                         case <-sharedContext.Done():
 279                         case success <- newResponse:
 280                                 wasSuccess = true
 281                         }
 282                 }(remoteID)
 283         }
 284         go func() {
 285                 wg.Wait()
 286                 cancelFunc()
 287         }()
 288
 289         errorCode := http.StatusNotFound
 290
 291         for {
 292                 select {
 293                 case newResp = <-success:
 294                         h.handler.proxy.ForwardResponse(w, newResp, nil)
 295                         return true
 296                 case <-sharedContext.Done():
 297                         var errors []string
 298                         for len(errorChan) > 0 {
 299                                 err := <-errorChan
 300                                 if httperr, ok := err.(HTTPError); !ok || httperr.Code != http.StatusNotFound {
 301                                         errorCode = http.StatusBadGateway
 302                                 }
 303                                 errors = append(errors, err.Error())
 304                         }
 305                         httpserver.Errors(w, errors, errorCode)
 306                         return true
 307                 }
 308         }
 309
 310         // shouldn't ever get here
 311         return true
 312 }