lib/controller/federation.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         "database/sql"
  13         "encoding/json"
  14         "fmt"
  15         "io"
  16         "io/ioutil"
  17         "log"
  18         "net/http"
  19         "net/url"
  20         "regexp"
  21         "strings"
  22         "sync"
  23
  24         "git.curoverse.com/arvados.git/sdk/go/arvados"
  25         "git.curoverse.com/arvados.git/sdk/go/auth"
  26         "git.curoverse.com/arvados.git/sdk/go/httpserver"
  27         "git.curoverse.com/arvados.git/sdk/go/keepclient"
  28 )
  29
  30 var pathPattern = `^/arvados/v1/%s(/([0-9a-z]{5})-%s-[0-9a-z]{15})?(.*)$`
  31 var wfRe = regexp.MustCompile(fmt.Sprintf(pathPattern, "workflows", "7fd4e"))
  32 var containersRe = regexp.MustCompile(fmt.Sprintf(pathPattern, "containers", "dz642"))
  33 var containerRequestsRe = regexp.MustCompile(fmt.Sprintf(pathPattern, "container_requests", "xvhdp"))
  34 var collectionRe = regexp.MustCompile(fmt.Sprintf(pathPattern, "collections", "4zz18"))
  35 var collectionByPDHRe = regexp.MustCompile(`^/arvados/v1/collections/([0-9a-fA-F]{32}\+[0-9]+)+$`)
  36
  37 type genericFederatedRequestHandler struct {
  38         next    http.Handler
  39         handler *Handler
  40         matcher *regexp.Regexp
  41 }
  42
  43 type collectionFederatedRequestHandler struct {
  44         next    http.Handler
  45         handler *Handler
  46 }
  47
  48 func (h *Handler) remoteClusterRequest(remoteID string, w http.ResponseWriter, req *http.Request, filter ResponseFilter) {
  49         remote, ok := h.Cluster.RemoteClusters[remoteID]
  50         if !ok {
  51                 httpserver.Error(w, "no proxy available for cluster "+remoteID, http.StatusNotFound)
  52                 return
  53         }
  54         scheme := remote.Scheme
  55         if scheme == "" {
  56                 scheme = "https"
  57         }
  58         err := h.saltAuthToken(req, remoteID)
  59         if err != nil {
  60                 httpserver.Error(w, err.Error(), http.StatusBadRequest)
  61                 return
  62         }
  63         urlOut := &url.URL{
  64                 Scheme:   scheme,
  65                 Host:     remote.Host,
  66                 Path:     req.URL.Path,
  67                 RawPath:  req.URL.RawPath,
  68                 RawQuery: req.URL.RawQuery,
  69         }
  70         client := h.secureClient
  71         if remote.Insecure {
  72                 client = h.insecureClient
  73         }
  74         h.proxy.Do(w, req, urlOut, client, filter)
  75 }
  76
  77 func loadParamsFromForm(req *http.Request, params url.Values) error {
  78         body, err := ioutil.ReadAll(req.Body)
  79         if err != nil {
  80                 return err
  81         }
  82         req.Body = ioutil.NopCloser(bytes.NewBuffer(body))
  83         var v2 url.Values
  84         if v2, err = url.ParseQuery(string(body)); err != nil {
  85                 return err
  86         }
  87         for k, v := range v2 {
  88                 params[k] = append(params[k], v...)
  89         }
  90         return nil
  91 }
  92
  93 func loadParamsFromJson(req *http.Request, loadInto interface{}) error {
  94         var cl int64
  95         if req.ContentLength > 0 {
  96                 cl = req.ContentLength
  97         }
  98         postBody := bytes.NewBuffer(make([]byte, 0, cl))
  99         defer req.Body.Close()
 100
 101         rdr := io.TeeReader(req.Body, postBody)
 102
 103         err := json.NewDecoder(rdr).Decode(loadInto)
 104         if err != nil {
 105                 return err
 106         }
 107         req.Body = ioutil.NopCloser(postBody)
 108         return nil
 109 }
 110
 111 type responseCollector struct {
 112         mtx       sync.Mutex
 113         responses []interface{}
 114         errors    []error
 115 }
 116
 117 func (c *responseCollector) collectResponse(resp *http.Response, requestError error) (newResponse *http.Response, err error) {
 118         if requestError != nil {
 119                 c.mtx.Lock()
 120                 defer c.mtx.Unlock()
 121                 c.errors = append(c.errors, requestError)
 122                 return nil, nil
 123         }
 124         defer resp.Body.Close()
 125         loadInto := make(map[string]interface{})
 126         err = json.NewDecoder(resp.Body).Decode(&loadInto)
 127
 128         c.mtx.Lock()
 129         defer c.mtx.Unlock()
 130
 131         if err == nil {
 132                 c.responses = append(c.responses, loadInto["items"].([]interface{})...)
 133         } else {
 134                 c.errors = append(c.errors, err)
 135         }
 136
 137         return nil, nil
 138 }
 139
 140 func (h *genericFederatedRequestHandler) handleMultiClusterQuery(w http.ResponseWriter, req *http.Request,
 141         params url.Values, clusterId *string) bool {
 142
 143         var filters [][]interface{}
 144         err := json.Unmarshal([]byte(params["filters"][0]), &filters)
 145         if err != nil {
 146                 httpserver.Error(w, err.Error(), http.StatusBadRequest)
 147                 return true
 148         }
 149         queryClusters := make(map[string][]string)
 150         if len(filters) == 1 && len(filters[0]) == 3 {
 151                 f1 := filters[0]
 152                 lhs := f1[0].(string)
 153                 op := f1[1].(string)
 154                 rhs := f1[2].([]interface{})
 155                 if lhs == "uuid" && op == "in" {
 156                         for _, i := range rhs {
 157                                 u := i.(string)
 158                                 *clusterId = u[0:5]
 159                                 queryClusters[u[0:5]] = append(queryClusters[u[0:5]], u)
 160                         }
 161                 }
 162         }
 163
 164         if len(queryClusters) <= 1 {
 165                 return false
 166         }
 167
 168         wg := sync.WaitGroup{}
 169         //var errors []string
 170         //var errorCode int = 404
 171
 172         // use channel as a semaphore to limit it to 4
 173         // parallel requests at a time
 174         sem := make(chan bool, 4)
 175         defer close(sem)
 176         req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
 177
 178         rc := responseCollector{}
 179         for k, v := range queryClusters {
 180                 // blocks until it can put a value into the
 181                 // channel (which has a max queue capacity)
 182                 sem <- true
 183                 wg.Add(1)
 184                 go func(k string, v []string) {
 185                         defer func() {
 186                                 wg.Done()
 187                                 <-sem
 188                         }()
 189                         remoteReq := *req
 190                         remoteReq.Method = "POST"
 191                         remoteReq.URL = &url.URL{
 192                                 Path:    req.URL.Path,
 193                                 RawPath: req.URL.RawPath,
 194                         }
 195                         remoteParams := make(url.Values)
 196                         remoteParams["_method"] = []string{"GET"}
 197                         content, err := json.Marshal(v)
 198                         if err != nil {
 199                                 rc.mtx.Lock()
 200                                 rc.errors = append(rc.errors, err)
 201                                 rc.mtx.Unlock()
 202                                 return
 203                         }
 204                         remoteParams["filters"] = []string{fmt.Sprintf(`[["uuid", "in", %s]]`, content)}
 205                         enc := remoteParams.Encode()
 206                         remoteReq.Body = ioutil.NopCloser(bytes.NewBufferString(enc))
 207
 208                         if k == h.handler.Cluster.ClusterID {
 209                                 h.handler.proxy.Do(w, &remoteReq, remoteReq.URL,
 210                                         h.handler.secureClient, rc.collectResponse)
 211                         } else {
 212                                 h.handler.remoteClusterRequest(k, w, &remoteReq,
 213                                         rc.collectResponse)
 214                         }
 215                 }(k, v)
 216         }
 217         wg.Wait()
 218
 219         if len(rc.errors) > 0 {
 220                 // parallel query
 221                 var strerr []string
 222                 for _, e := range rc.errors {
 223                         strerr = append(strerr, e.Error())
 224                 }
 225                 httpserver.Errors(w, strerr, http.StatusBadRequest)
 226         } else {
 227                 log.Printf("Sending status ok %+v", rc)
 228                 w.Header().Set("Content-Type", "application/json")
 229                 w.WriteHeader(http.StatusOK)
 230                 itemList := make(map[string]interface{})
 231                 itemList["items"] = rc.responses
 232                 //x, _ := json.Marshal(itemList)
 233                 //log.Printf("Sending response %v", string(x))
 234                 json.NewEncoder(w).Encode(itemList)
 235                 log.Printf("Sent?")
 236         }
 237
 238         return true
 239 }
 240
 241 func (h *genericFederatedRequestHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 242         m := h.matcher.FindStringSubmatch(req.URL.Path)
 243         clusterId := ""
 244
 245         if len(m) > 0 && m[2] != "" {
 246                 clusterId = m[2]
 247         }
 248
 249         var params url.Values
 250         var err error
 251         if params, err = url.ParseQuery(req.URL.RawQuery); err != nil {
 252                 httpserver.Error(w, err.Error(), http.StatusBadRequest)
 253                 return
 254         }
 255
 256         if req.Method == "POST" && req.Header.Get("Content-Type") == "application/x-www-form-urlencoded" {
 257                 if err = loadParamsFromForm(req, params); err != nil {
 258                         httpserver.Error(w, err.Error(), http.StatusBadRequest)
 259                         return
 260                 }
 261         }
 262
 263         if len(params["cluster_id"]) == 1 {
 264                 clusterId = params["cluster_id"][0]
 265         }
 266
 267         if clusterId == "" && req.Method == "POST" && req.Header.Get("Content-Type") == "application/json" {
 268                 var hasClusterId struct {
 269                         ClusterID string `json:"cluster_id"`
 270                 }
 271                 if err = loadParamsFromJson(req, &hasClusterId); err != nil {
 272                         httpserver.Error(w, err.Error(), http.StatusBadRequest)
 273                         return
 274                 }
 275                 clusterId = hasClusterId.ClusterID
 276         }
 277
 278         effectiveMethod := req.Method
 279         if req.Method == "POST" && len(params["_method"]) == 1 {
 280                 effectiveMethod = params["_method"][0]
 281         }
 282
 283         if effectiveMethod == "GET" && clusterId == "" && len(params["filters"]) == 1 {
 284                 if h.handleMultiClusterQuery(w, req, params, &clusterId) {
 285                         return
 286                 }
 287         }
 288         log.Printf("Clusterid is %q", clusterId)
 289
 290         if clusterId == "" || clusterId == h.handler.Cluster.ClusterID {
 291                 h.next.ServeHTTP(w, req)
 292         } else {
 293                 h.handler.remoteClusterRequest(clusterId, w, req, nil)
 294         }
 295 }
 296
 297 type rewriteSignaturesClusterId struct {
 298         clusterID  string
 299         expectHash string
 300 }
 301
 302 func (rw rewriteSignaturesClusterId) rewriteSignatures(resp *http.Response, requestError error) (newResponse *http.Response, err error) {
 303         if requestError != nil {
 304                 return resp, requestError
 305         }
 306
 307         if resp.StatusCode != 200 {
 308                 return resp, nil
 309         }
 310
 311         originalBody := resp.Body
 312         defer originalBody.Close()
 313
 314         var col arvados.Collection
 315         err = json.NewDecoder(resp.Body).Decode(&col)
 316         if err != nil {
 317                 return nil, err
 318         }
 319
 320         // rewriting signatures will make manifest text 5-10% bigger so calculate
 321         // capacity accordingly
 322         updatedManifest := bytes.NewBuffer(make([]byte, 0, int(float64(len(col.ManifestText))*1.1)))
 323
 324         hasher := md5.New()
 325         mw := io.MultiWriter(hasher, updatedManifest)
 326         sz := 0
 327
 328         scanner := bufio.NewScanner(strings.NewReader(col.ManifestText))
 329         scanner.Buffer(make([]byte, 1048576), len(col.ManifestText))
 330         for scanner.Scan() {
 331                 line := scanner.Text()
 332                 tokens := strings.Split(line, " ")
 333                 if len(tokens) < 3 {
 334                         return nil, fmt.Errorf("Invalid stream (<3 tokens): %q", line)
 335                 }
 336
 337                 n, err := mw.Write([]byte(tokens[0]))
 338                 if err != nil {
 339                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 340                 }
 341                 sz += n
 342                 for _, token := range tokens[1:] {
 343                         n, err = mw.Write([]byte(" "))
 344                         if err != nil {
 345                                 return nil, fmt.Errorf("Error updating manifest: %v", err)
 346                         }
 347                         sz += n
 348
 349                         m := keepclient.SignedLocatorRe.FindStringSubmatch(token)
 350                         if m != nil {
 351                                 // Rewrite the block signature to be a remote signature
 352                                 _, err = fmt.Fprintf(updatedManifest, "%s%s%s+R%s-%s%s", m[1], m[2], m[3], rw.clusterID, m[5][2:], m[8])
 353                                 if err != nil {
 354                                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 355                                 }
 356
 357                                 // for hash checking, ignore signatures
 358                                 n, err = fmt.Fprintf(hasher, "%s%s", m[1], m[2])
 359                                 if err != nil {
 360                                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 361                                 }
 362                                 sz += n
 363                         } else {
 364                                 n, err = mw.Write([]byte(token))
 365                                 if err != nil {
 366                                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 367                                 }
 368                                 sz += n
 369                         }
 370                 }
 371                 n, err = mw.Write([]byte("\n"))
 372                 if err != nil {
 373                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 374                 }
 375                 sz += n
 376         }
 377
 378         // Check that expected hash is consistent with
 379         // portable_data_hash field of the returned record
 380         if rw.expectHash == "" {
 381                 rw.expectHash = col.PortableDataHash
 382         } else if rw.expectHash != col.PortableDataHash {
 383                 return nil, fmt.Errorf("portable_data_hash %q on returned record did not match expected hash %q ", rw.expectHash, col.PortableDataHash)
 384         }
 385
 386         // Certify that the computed hash of the manifest_text matches our expectation
 387         sum := hasher.Sum(nil)
 388         computedHash := fmt.Sprintf("%x+%v", sum, sz)
 389         if computedHash != rw.expectHash {
 390                 return nil, fmt.Errorf("Computed manifest_text hash %q did not match expected hash %q", computedHash, rw.expectHash)
 391         }
 392
 393         col.ManifestText = updatedManifest.String()
 394
 395         newbody, err := json.Marshal(col)
 396         if err != nil {
 397                 return nil, err
 398         }
 399
 400         buf := bytes.NewBuffer(newbody)
 401         resp.Body = ioutil.NopCloser(buf)
 402         resp.ContentLength = int64(buf.Len())
 403         resp.Header.Set("Content-Length", fmt.Sprintf("%v", buf.Len()))
 404
 405         return resp, nil
 406 }
 407
 408 type searchLocalClusterForPDH struct {
 409         sentResponse bool
 410 }
 411
 412 func (s *searchLocalClusterForPDH) filterLocalClusterResponse(resp *http.Response, requestError error) (newResponse *http.Response, err error) {
 413         if requestError != nil {
 414                 return resp, requestError
 415         }
 416
 417         if resp.StatusCode == 404 {
 418                 // Suppress returning this result, because we want to
 419                 // search the federation.
 420                 s.sentResponse = false
 421                 return nil, nil
 422         }
 423         s.sentResponse = true
 424         return resp, nil
 425 }
 426
 427 type searchRemoteClusterForPDH struct {
 428         pdh           string
 429         remoteID      string
 430         mtx           *sync.Mutex
 431         sentResponse  *bool
 432         sharedContext *context.Context
 433         cancelFunc    func()
 434         errors        *[]string
 435         statusCode    *int
 436 }
 437
 438 func (s *searchRemoteClusterForPDH) filterRemoteClusterResponse(resp *http.Response, requestError error) (newResponse *http.Response, err error) {
 439         s.mtx.Lock()
 440         defer s.mtx.Unlock()
 441
 442         if *s.sentResponse {
 443                 // Another request already returned a response
 444                 return nil, nil
 445         }
 446
 447         if requestError != nil {
 448                 *s.errors = append(*s.errors, fmt.Sprintf("Request error contacting %q: %v", s.remoteID, requestError))
 449                 // Record the error and suppress response
 450                 return nil, nil
 451         }
 452
 453         if resp.StatusCode != 200 {
 454                 // Suppress returning unsuccessful result.  Maybe
 455                 // another request will find it.
 456                 // TODO collect and return error responses.
 457                 *s.errors = append(*s.errors, fmt.Sprintf("Response from %q: %v", s.remoteID, resp.Status))
 458                 if resp.StatusCode != 404 {
 459                         // Got a non-404 error response, convert into BadGateway
 460                         *s.statusCode = http.StatusBadGateway
 461                 }
 462                 return nil, nil
 463         }
 464
 465         s.mtx.Unlock()
 466
 467         // This reads the response body.  We don't want to hold the
 468         // lock while doing this because other remote requests could
 469         // also have made it to this point, and we don't want a
 470         // slow response holding the lock to block a faster response
 471         // that is waiting on the lock.
 472         newResponse, err = rewriteSignaturesClusterId{s.remoteID, s.pdh}.rewriteSignatures(resp, nil)
 473
 474         s.mtx.Lock()
 475
 476         if *s.sentResponse {
 477                 // Another request already returned a response
 478                 return nil, nil
 479         }
 480
 481         if err != nil {
 482                 // Suppress returning unsuccessful result.  Maybe
 483                 // another request will be successful.
 484                 *s.errors = append(*s.errors, fmt.Sprintf("Error parsing response from %q: %v", s.remoteID, err))
 485                 return nil, nil
 486         }
 487
 488         // We have a successful response.  Suppress/cancel all the
 489         // other requests/responses.
 490         *s.sentResponse = true
 491         s.cancelFunc()
 492
 493         return newResponse, nil
 494 }
 495
 496 func (h *collectionFederatedRequestHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 497         if req.Method != "GET" {
 498                 // Only handle GET requests right now
 499                 h.next.ServeHTTP(w, req)
 500                 return
 501         }
 502
 503         m := collectionByPDHRe.FindStringSubmatch(req.URL.Path)
 504         if len(m) != 2 {
 505                 // Not a collection PDH GET request
 506                 m = collectionRe.FindStringSubmatch(req.URL.Path)
 507                 clusterId := ""
 508
 509                 if len(m) > 0 {
 510                         clusterId = m[2]
 511                 }
 512
 513                 if clusterId != "" && clusterId != h.handler.Cluster.ClusterID {
 514                         // request for remote collection by uuid
 515                         h.handler.remoteClusterRequest(clusterId, w, req,
 516                                 rewriteSignaturesClusterId{clusterId, ""}.rewriteSignatures)
 517                         return
 518                 }
 519                 // not a collection UUID request, or it is a request
 520                 // for a local UUID, either way, continue down the
 521                 // handler stack.
 522                 h.next.ServeHTTP(w, req)
 523                 return
 524         }
 525
 526         // Request for collection by PDH.  Search the federation.
 527
 528         // First, query the local cluster.
 529         urlOut, insecure, err := findRailsAPI(h.handler.Cluster, h.handler.NodeProfile)
 530         if err != nil {
 531                 httpserver.Error(w, err.Error(), http.StatusInternalServerError)
 532                 return
 533         }
 534
 535         urlOut = &url.URL{
 536                 Scheme:   urlOut.Scheme,
 537                 Host:     urlOut.Host,
 538                 Path:     req.URL.Path,
 539                 RawPath:  req.URL.RawPath,
 540                 RawQuery: req.URL.RawQuery,
 541         }
 542         client := h.handler.secureClient
 543         if insecure {
 544                 client = h.handler.insecureClient
 545         }
 546         sf := &searchLocalClusterForPDH{}
 547         h.handler.proxy.Do(w, req, urlOut, client, sf.filterLocalClusterResponse)
 548         if sf.sentResponse {
 549                 return
 550         }
 551
 552         sharedContext, cancelFunc := context.WithCancel(req.Context())
 553         defer cancelFunc()
 554         req = req.WithContext(sharedContext)
 555
 556         // Create a goroutine for each cluster in the
 557         // RemoteClusters map.  The first valid result gets
 558         // returned to the client.  When that happens, all
 559         // other outstanding requests are cancelled or
 560         // suppressed.
 561         sentResponse := false
 562         mtx := sync.Mutex{}
 563         wg := sync.WaitGroup{}
 564         var errors []string
 565         var errorCode int = 404
 566
 567         // use channel as a semaphore to limit it to 4
 568         // parallel requests at a time
 569         sem := make(chan bool, 4)
 570         defer close(sem)
 571         for remoteID := range h.handler.Cluster.RemoteClusters {
 572                 // blocks until it can put a value into the
 573                 // channel (which has a max queue capacity)
 574                 sem <- true
 575                 if sentResponse {
 576                         break
 577                 }
 578                 search := &searchRemoteClusterForPDH{m[1], remoteID, &mtx, &sentResponse,
 579                         &sharedContext, cancelFunc, &errors, &errorCode}
 580                 wg.Add(1)
 581                 go func() {
 582                         h.handler.remoteClusterRequest(search.remoteID, w, req, search.filterRemoteClusterResponse)
 583                         wg.Done()
 584                         <-sem
 585                 }()
 586         }
 587         wg.Wait()
 588
 589         if sentResponse {
 590                 return
 591         }
 592
 593         // No successful responses, so return the error
 594         httpserver.Errors(w, errors, errorCode)
 595 }
 596
 597 func (h *Handler) setupProxyRemoteCluster(next http.Handler) http.Handler {
 598         mux := http.NewServeMux()
 599         mux.Handle("/arvados/v1/workflows", &genericFederatedRequestHandler{next, h, wfRe})
 600         mux.Handle("/arvados/v1/workflows/", &genericFederatedRequestHandler{next, h, wfRe})
 601         mux.Handle("/arvados/v1/containers", &genericFederatedRequestHandler{next, h, containersRe})
 602         mux.Handle("/arvados/v1/containers/", &genericFederatedRequestHandler{next, h, containersRe})
 603         mux.Handle("/arvados/v1/container_requests", &genericFederatedRequestHandler{next, h, containerRequestsRe})
 604         mux.Handle("/arvados/v1/container_requests/", &genericFederatedRequestHandler{next, h, containerRequestsRe})
 605         mux.Handle("/arvados/v1/collections", next)
 606         mux.Handle("/arvados/v1/collections/", &collectionFederatedRequestHandler{next, h})
 607         mux.Handle("/", next)
 608
 609         return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
 610                 parts := strings.Split(req.Header.Get("Authorization"), "/")
 611                 alreadySalted := (len(parts) == 3 && parts[0] == "Bearer v2" && len(parts[2]) == 40)
 612
 613                 if alreadySalted ||
 614                         strings.Index(req.Header.Get("Via"), "arvados-controller") != -1 {
 615                         // The token is already salted, or this is a
 616                         // request from another instance of
 617                         // arvados-controller.  In either case, we
 618                         // don't want to proxy this query, so just
 619                         // continue down the instance handler stack.
 620                         next.ServeHTTP(w, req)
 621                         return
 622                 }
 623
 624                 mux.ServeHTTP(w, req)
 625         })
 626
 627         return mux
 628 }
 629
 630 type CurrentUser struct {
 631         Authorization arvados.APIClientAuthorization
 632         UUID          string
 633 }
 634
 635 func (h *Handler) validateAPItoken(req *http.Request, user *CurrentUser) error {
 636         db, err := h.db(req)
 637         if err != nil {
 638                 return err
 639         }
 640         return db.QueryRowContext(req.Context(), `SELECT api_client_authorizations.uuid, users.uuid FROM api_client_authorizations JOIN users on api_client_authorizations.user_id=users.id WHERE api_token=$1 AND (expires_at IS NULL OR expires_at > current_timestamp) LIMIT 1`, user.Authorization.APIToken).Scan(&user.Authorization.UUID, &user.UUID)
 641 }
 642
 643 // Extract the auth token supplied in req, and replace it with a
 644 // salted token for the remote cluster.
 645 func (h *Handler) saltAuthToken(req *http.Request, remote string) error {
 646         creds := auth.NewCredentials()
 647         creds.LoadTokensFromHTTPRequest(req)
 648         if len(creds.Tokens) == 0 && req.Header.Get("Content-Type") == "application/x-www-form-encoded" {
 649                 // Override ParseForm's 10MiB limit by ensuring
 650                 // req.Body is a *http.maxBytesReader.
 651                 req.Body = http.MaxBytesReader(nil, req.Body, 1<<28) // 256MiB. TODO: use MaxRequestSize from discovery doc or config.
 652                 if err := creds.LoadTokensFromHTTPRequestBody(req); err != nil {
 653                         return err
 654                 }
 655                 // Replace req.Body with a buffer that re-encodes the
 656                 // form without api_token, in case we end up
 657                 // forwarding the request.
 658                 if req.PostForm != nil {
 659                         req.PostForm.Del("api_token")
 660                 }
 661                 req.Body = ioutil.NopCloser(bytes.NewBufferString(req.PostForm.Encode()))
 662         }
 663         if len(creds.Tokens) == 0 {
 664                 return nil
 665         }
 666         token, err := auth.SaltToken(creds.Tokens[0], remote)
 667         if err == auth.ErrObsoleteToken {
 668                 // If the token exists in our own database, salt it
 669                 // for the remote. Otherwise, assume it was issued by
 670                 // the remote, and pass it through unmodified.
 671                 currentUser := CurrentUser{Authorization: arvados.APIClientAuthorization{APIToken: creds.Tokens[0]}}
 672                 err = h.validateAPItoken(req, &currentUser)
 673                 if err == sql.ErrNoRows {
 674                         // Not ours; pass through unmodified.
 675                         token = currentUser.Authorization.APIToken
 676                 } else if err != nil {
 677                         return err
 678                 } else {
 679                         // Found; make V2 version and salt it.
 680                         token, err = auth.SaltToken(currentUser.Authorization.TokenV2(), remote)
 681                         if err != nil {
 682                                 return err
 683                         }
 684                 }
 685         } else if err != nil {
 686                 return err
 687         }
 688         req.Header.Set("Authorization", "Bearer "+token)
 689
 690         // Remove api_token=... from the the query string, in case we
 691         // end up forwarding the request.
 692         if values, err := url.ParseQuery(req.URL.RawQuery); err != nil {
 693                 return err
 694         } else if _, ok := values["api_token"]; ok {
 695                 delete(values, "api_token")
 696                 req.URL.RawQuery = values.Encode()
 697         }
 698         return nil
 699 }