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         "net/http"
  18         "net/url"
  19         "regexp"
  20         "strings"
  21         "sync"
  22
  23         "git.curoverse.com/arvados.git/sdk/go/arvados"
  24         "git.curoverse.com/arvados.git/sdk/go/auth"
  25         "git.curoverse.com/arvados.git/sdk/go/httpserver"
  26         "git.curoverse.com/arvados.git/sdk/go/keepclient"
  27 )
  28
  29 var pathPattern = `^/arvados/v1/%s(/([0-9a-z]{5})-%s-[0-9a-z]{15})?(.*)$`
  30 var wfRe = regexp.MustCompile(fmt.Sprintf(pathPattern, "workflows", "7fd4e"))
  31 var containersRe = regexp.MustCompile(fmt.Sprintf(pathPattern, "containers", "dz642"))
  32 var containerRequestsRe = regexp.MustCompile(fmt.Sprintf(pathPattern, "container_requests", "xvhdp"))
  33 var collectionRe = regexp.MustCompile(fmt.Sprintf(pathPattern, "collections", "4zz18"))
  34 var collectionByPDHRe = regexp.MustCompile(`^/arvados/v1/collections/([0-9a-fA-F]{32}\+[0-9]+)+$`)
  35
  36 type genericFederatedRequestHandler struct {
  37         next    http.Handler
  38         handler *Handler
  39         matcher *regexp.Regexp
  40 }
  41
  42 type collectionFederatedRequestHandler struct {
  43         next    http.Handler
  44         handler *Handler
  45 }
  46
  47 func (h *Handler) remoteClusterRequest(remoteID string, w http.ResponseWriter, req *http.Request, filter ResponseFilter) {
  48         remote, ok := h.Cluster.RemoteClusters[remoteID]
  49         if !ok {
  50                 httpserver.Error(w, "no proxy available for cluster "+remoteID, http.StatusNotFound)
  51                 return
  52         }
  53         scheme := remote.Scheme
  54         if scheme == "" {
  55                 scheme = "https"
  56         }
  57         err := h.saltAuthToken(req, remoteID)
  58         if err != nil {
  59                 httpserver.Error(w, err.Error(), http.StatusBadRequest)
  60                 return
  61         }
  62         urlOut := &url.URL{
  63                 Scheme:   scheme,
  64                 Host:     remote.Host,
  65                 Path:     req.URL.Path,
  66                 RawPath:  req.URL.RawPath,
  67                 RawQuery: req.URL.RawQuery,
  68         }
  69         client := h.secureClient
  70         if remote.Insecure {
  71                 client = h.insecureClient
  72         }
  73         h.proxy.Do(w, req, urlOut, client, filter)
  74 }
  75
  76 // loadParamsFromForm expects a request with
  77 // application/x-www-form-urlencoded body.  It parses the query, adds
  78 // the query parameters to "params", and replaces the request body
  79 // with a buffer holding the original body contents so it can be
  80 // re-read by downstream proxy steps.
  81 func loadParamsFromForm(req *http.Request, params url.Values) error {
  82         body, err := ioutil.ReadAll(req.Body)
  83         if err != nil {
  84                 return err
  85         }
  86         req.Body = ioutil.NopCloser(bytes.NewBuffer(body))
  87         var v2 url.Values
  88         if v2, err = url.ParseQuery(string(body)); err != nil {
  89                 return err
  90         }
  91         for k, v := range v2 {
  92                 params[k] = append(params[k], v...)
  93         }
  94         return nil
  95 }
  96
  97 // loadParamsFromForm expects a request with application/json body.
  98 // It parses the body, populates "loadInto", and replaces the request
  99 // body with a buffer holding the original body contents so it can be
 100 // re-read by downstream proxy steps.
 101 func loadParamsFromJson(req *http.Request, loadInto interface{}) error {
 102         var cl int64
 103         if req.ContentLength > 0 {
 104                 cl = req.ContentLength
 105         }
 106         postBody := bytes.NewBuffer(make([]byte, 0, cl))
 107         defer req.Body.Close()
 108
 109         rdr := io.TeeReader(req.Body, postBody)
 110
 111         err := json.NewDecoder(rdr).Decode(loadInto)
 112         if err != nil {
 113                 return err
 114         }
 115         req.Body = ioutil.NopCloser(postBody)
 116         return nil
 117 }
 118
 119 type multiClusterQueryResponseCollector struct {
 120         mtx       sync.Mutex
 121         responses []interface{}
 122         errors    []error
 123         kind      string
 124 }
 125
 126 func (c *multiClusterQueryResponseCollector) collectResponse(resp *http.Response,
 127         requestError error) (newResponse *http.Response, err error) {
 128         if requestError != nil {
 129                 c.mtx.Lock()
 130                 defer c.mtx.Unlock()
 131                 c.errors = append(c.errors, requestError)
 132                 return nil, nil
 133         }
 134         defer resp.Body.Close()
 135         loadInto := make(map[string]interface{})
 136         err = json.NewDecoder(resp.Body).Decode(&loadInto)
 137
 138         c.mtx.Lock()
 139         defer c.mtx.Unlock()
 140
 141         if err == nil {
 142                 if resp.StatusCode != http.StatusOK {
 143                         c.errors = append(c.errors, fmt.Errorf("error %v", loadInto["errors"]))
 144                 } else {
 145                         c.responses = append(c.responses, loadInto["items"].([]interface{})...)
 146                         c.kind = loadInto["kind"].(string)
 147                 }
 148         } else {
 149                 c.errors = append(c.errors, err)
 150         }
 151
 152         return nil, nil
 153 }
 154
 155 func (h *genericFederatedRequestHandler) handleMultiClusterQuery(w http.ResponseWriter, req *http.Request,
 156         params url.Values, clusterId *string) bool {
 157
 158         var filters [][]interface{}
 159         err := json.Unmarshal([]byte(params["filters"][0]), &filters)
 160         if err != nil {
 161                 httpserver.Error(w, err.Error(), http.StatusBadRequest)
 162                 return true
 163         }
 164
 165         // Split the list of uuids by prefix
 166         queryClusters := make(map[string][]string)
 167         if len(filters) == 1 && len(filters[0]) == 3 {
 168                 f1 := filters[0]
 169                 lhs := f1[0].(string)
 170                 if lhs == "uuid" {
 171                         op, ok := f1[1].(string)
 172                         if !ok {
 173                                 return false
 174                         }
 175
 176                         if op == "in" {
 177                                 rhs, ok := f1[2].([]interface{})
 178                                 if ok {
 179                                         for _, i := range rhs {
 180                                                 u := i.(string)
 181                                                 *clusterId = u[0:5]
 182                                                 queryClusters[u[0:5]] = append(queryClusters[u[0:5]], u)
 183                                         }
 184                                 }
 185                         } else if op == "=" {
 186                                 u, ok := f1[2].(string)
 187                                 if ok {
 188                                         *clusterId = u[0:5]
 189                                         queryClusters[u[0:5]] = append(queryClusters[u[0:5]], u)
 190                                 }
 191                         }
 192                 }
 193
 194         }
 195
 196         if len(queryClusters) <= 1 {
 197                 // Didn't find ["uuid", "in", ...] filters for multiple clusters
 198                 return false
 199         }
 200
 201         if !(len(params["count"]) == 1 && (params["count"][0] == `none` ||
 202                 params["count"][0] == `"none"`)) {
 203                 httpserver.Error(w, "Federated multi-object query must have count=none", http.StatusBadRequest)
 204                 return true
 205         }
 206
 207         wg := sync.WaitGroup{}
 208
 209         // use channel as a semaphore to limit it to 4
 210         // parallel requests at a time
 211         sem := make(chan bool, 4)
 212         defer close(sem)
 213         req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
 214
 215         rc := multiClusterQueryResponseCollector{}
 216         for k, v := range queryClusters {
 217                 // blocks until it can put a value into the
 218                 // channel (which has a max queue capacity)
 219                 sem <- true
 220                 wg.Add(1)
 221                 go func(k string, v []string) {
 222                         defer func() {
 223                                 wg.Done()
 224                                 <-sem
 225                         }()
 226                         var remoteReq http.Request
 227                         remoteReq.Header = req.Header
 228                         remoteReq.Method = "POST"
 229                         remoteReq.URL = &url.URL{Path: req.URL.Path}
 230                         remoteParams := make(url.Values)
 231                         remoteParams["_method"] = []string{"GET"}
 232                         remoteParams["count"] = []string{"none"}
 233                         content, err := json.Marshal(v)
 234                         if err != nil {
 235                                 rc.mtx.Lock()
 236                                 defer rc.mtx.Unlock()
 237                                 rc.errors = append(rc.errors, err)
 238                                 return
 239                         }
 240                         remoteParams["filters"] = []string{fmt.Sprintf(`[["uuid", "in", %s]]`, content)}
 241                         enc := remoteParams.Encode()
 242                         remoteReq.Body = ioutil.NopCloser(bytes.NewBufferString(enc))
 243
 244                         if k == h.handler.Cluster.ClusterID {
 245                                 h.handler.localClusterRequest(w, &remoteReq,
 246                                         rc.collectResponse)
 247                         } else {
 248                                 h.handler.remoteClusterRequest(k, w, &remoteReq,
 249                                         rc.collectResponse)
 250                         }
 251                 }(k, v)
 252         }
 253         wg.Wait()
 254
 255         if len(rc.errors) > 0 {
 256                 // parallel query
 257                 var strerr []string
 258                 for _, e := range rc.errors {
 259                         strerr = append(strerr, e.Error())
 260                 }
 261                 httpserver.Errors(w, strerr, http.StatusBadGateway)
 262         } else {
 263                 w.Header().Set("Content-Type", "application/json")
 264                 w.WriteHeader(http.StatusOK)
 265                 itemList := make(map[string]interface{})
 266                 itemList["items"] = rc.responses
 267                 itemList["kind"] = rc.kind
 268                 json.NewEncoder(w).Encode(itemList)
 269         }
 270
 271         return true
 272 }
 273
 274 func (h *genericFederatedRequestHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 275         m := h.matcher.FindStringSubmatch(req.URL.Path)
 276         clusterId := ""
 277
 278         if len(m) > 0 && m[2] != "" {
 279                 clusterId = m[2]
 280         }
 281
 282         // First, parse the query portion of the URL.
 283         var params url.Values
 284         var err error
 285         if params, err = url.ParseQuery(req.URL.RawQuery); err != nil {
 286                 httpserver.Error(w, err.Error(), http.StatusBadRequest)
 287                 return
 288         }
 289
 290         // Next, if appropriate, merge in parameters from the form POST body.
 291         if req.Method == "POST" && req.Header.Get("Content-Type") == "application/x-www-form-urlencoded" {
 292                 if err = loadParamsFromForm(req, params); err != nil {
 293                         httpserver.Error(w, err.Error(), http.StatusBadRequest)
 294                         return
 295                 }
 296         }
 297
 298         // Check if the parameters have an explicit cluster_id
 299         if len(params["cluster_id"]) == 1 {
 300                 clusterId = params["cluster_id"][0]
 301         }
 302
 303         // Handle the POST-as-GET special case (workaround for large
 304         // GET requests that potentially exceed maximum URL length,
 305         // like multi-object queries where the filter has 100s of
 306         // items)
 307         effectiveMethod := req.Method
 308         if req.Method == "POST" && len(params["_method"]) == 1 {
 309                 effectiveMethod = params["_method"][0]
 310         }
 311
 312         if effectiveMethod == "GET" && clusterId == "" && len(params["filters"]) == 1 {
 313                 if h.handleMultiClusterQuery(w, req, params, &clusterId) {
 314                         return
 315                 }
 316         }
 317
 318         if clusterId == "" || clusterId == h.handler.Cluster.ClusterID {
 319                 h.next.ServeHTTP(w, req)
 320         } else {
 321                 h.handler.remoteClusterRequest(clusterId, w, req, nil)
 322         }
 323 }
 324
 325 type rewriteSignaturesClusterId struct {
 326         clusterID  string
 327         expectHash string
 328 }
 329
 330 func (rw rewriteSignaturesClusterId) rewriteSignatures(resp *http.Response, requestError error) (newResponse *http.Response, err error) {
 331         if requestError != nil {
 332                 return resp, requestError
 333         }
 334
 335         if resp.StatusCode != 200 {
 336                 return resp, nil
 337         }
 338
 339         originalBody := resp.Body
 340         defer originalBody.Close()
 341
 342         var col arvados.Collection
 343         err = json.NewDecoder(resp.Body).Decode(&col)
 344         if err != nil {
 345                 return nil, err
 346         }
 347
 348         // rewriting signatures will make manifest text 5-10% bigger so calculate
 349         // capacity accordingly
 350         updatedManifest := bytes.NewBuffer(make([]byte, 0, int(float64(len(col.ManifestText))*1.1)))
 351
 352         hasher := md5.New()
 353         mw := io.MultiWriter(hasher, updatedManifest)
 354         sz := 0
 355
 356         scanner := bufio.NewScanner(strings.NewReader(col.ManifestText))
 357         scanner.Buffer(make([]byte, 1048576), len(col.ManifestText))
 358         for scanner.Scan() {
 359                 line := scanner.Text()
 360                 tokens := strings.Split(line, " ")
 361                 if len(tokens) < 3 {
 362                         return nil, fmt.Errorf("Invalid stream (<3 tokens): %q", line)
 363                 }
 364
 365                 n, err := mw.Write([]byte(tokens[0]))
 366                 if err != nil {
 367                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 368                 }
 369                 sz += n
 370                 for _, token := range tokens[1:] {
 371                         n, err = mw.Write([]byte(" "))
 372                         if err != nil {
 373                                 return nil, fmt.Errorf("Error updating manifest: %v", err)
 374                         }
 375                         sz += n
 376
 377                         m := keepclient.SignedLocatorRe.FindStringSubmatch(token)
 378                         if m != nil {
 379                                 // Rewrite the block signature to be a remote signature
 380                                 _, err = fmt.Fprintf(updatedManifest, "%s%s%s+R%s-%s%s", m[1], m[2], m[3], rw.clusterID, m[5][2:], m[8])
 381                                 if err != nil {
 382                                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 383                                 }
 384
 385                                 // for hash checking, ignore signatures
 386                                 n, err = fmt.Fprintf(hasher, "%s%s", m[1], m[2])
 387                                 if err != nil {
 388                                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 389                                 }
 390                                 sz += n
 391                         } else {
 392                                 n, err = mw.Write([]byte(token))
 393                                 if err != nil {
 394                                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 395                                 }
 396                                 sz += n
 397                         }
 398                 }
 399                 n, err = mw.Write([]byte("\n"))
 400                 if err != nil {
 401                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 402                 }
 403                 sz += n
 404         }
 405
 406         // Check that expected hash is consistent with
 407         // portable_data_hash field of the returned record
 408         if rw.expectHash == "" {
 409                 rw.expectHash = col.PortableDataHash
 410         } else if rw.expectHash != col.PortableDataHash {
 411                 return nil, fmt.Errorf("portable_data_hash %q on returned record did not match expected hash %q ", rw.expectHash, col.PortableDataHash)
 412         }
 413
 414         // Certify that the computed hash of the manifest_text matches our expectation
 415         sum := hasher.Sum(nil)
 416         computedHash := fmt.Sprintf("%x+%v", sum, sz)
 417         if computedHash != rw.expectHash {
 418                 return nil, fmt.Errorf("Computed manifest_text hash %q did not match expected hash %q", computedHash, rw.expectHash)
 419         }
 420
 421         col.ManifestText = updatedManifest.String()
 422
 423         newbody, err := json.Marshal(col)
 424         if err != nil {
 425                 return nil, err
 426         }
 427
 428         buf := bytes.NewBuffer(newbody)
 429         resp.Body = ioutil.NopCloser(buf)
 430         resp.ContentLength = int64(buf.Len())
 431         resp.Header.Set("Content-Length", fmt.Sprintf("%v", buf.Len()))
 432
 433         return resp, nil
 434 }
 435
 436 func filterLocalClusterResponse(resp *http.Response, requestError error) (newResponse *http.Response, err error) {
 437         if requestError != nil {
 438                 return resp, requestError
 439         }
 440
 441         if resp.StatusCode == 404 {
 442                 // Suppress returning this result, because we want to
 443                 // search the federation.
 444                 return nil, nil
 445         }
 446         return resp, nil
 447 }
 448
 449 type searchRemoteClusterForPDH struct {
 450         pdh           string
 451         remoteID      string
 452         mtx           *sync.Mutex
 453         sentResponse  *bool
 454         sharedContext *context.Context
 455         cancelFunc    func()
 456         errors        *[]string
 457         statusCode    *int
 458 }
 459
 460 func (s *searchRemoteClusterForPDH) filterRemoteClusterResponse(resp *http.Response, requestError error) (newResponse *http.Response, err error) {
 461         s.mtx.Lock()
 462         defer s.mtx.Unlock()
 463
 464         if *s.sentResponse {
 465                 // Another request already returned a response
 466                 return nil, nil
 467         }
 468
 469         if requestError != nil {
 470                 *s.errors = append(*s.errors, fmt.Sprintf("Request error contacting %q: %v", s.remoteID, requestError))
 471                 // Record the error and suppress response
 472                 return nil, nil
 473         }
 474
 475         if resp.StatusCode != 200 {
 476                 // Suppress returning unsuccessful result.  Maybe
 477                 // another request will find it.
 478                 // TODO collect and return error responses.
 479                 *s.errors = append(*s.errors, fmt.Sprintf("Response from %q: %v", s.remoteID, resp.Status))
 480                 if resp.StatusCode != 404 {
 481                         // Got a non-404 error response, convert into BadGateway
 482                         *s.statusCode = http.StatusBadGateway
 483                 }
 484                 return nil, nil
 485         }
 486
 487         s.mtx.Unlock()
 488
 489         // This reads the response body.  We don't want to hold the
 490         // lock while doing this because other remote requests could
 491         // also have made it to this point, and we don't want a
 492         // slow response holding the lock to block a faster response
 493         // that is waiting on the lock.
 494         newResponse, err = rewriteSignaturesClusterId{s.remoteID, s.pdh}.rewriteSignatures(resp, nil)
 495
 496         s.mtx.Lock()
 497
 498         if *s.sentResponse {
 499                 // Another request already returned a response
 500                 return nil, nil
 501         }
 502
 503         if err != nil {
 504                 // Suppress returning unsuccessful result.  Maybe
 505                 // another request will be successful.
 506                 *s.errors = append(*s.errors, fmt.Sprintf("Error parsing response from %q: %v", s.remoteID, err))
 507                 return nil, nil
 508         }
 509
 510         // We have a successful response.  Suppress/cancel all the
 511         // other requests/responses.
 512         *s.sentResponse = true
 513         s.cancelFunc()
 514
 515         return newResponse, nil
 516 }
 517
 518 func (h *collectionFederatedRequestHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 519         if req.Method != "GET" {
 520                 // Only handle GET requests right now
 521                 h.next.ServeHTTP(w, req)
 522                 return
 523         }
 524
 525         m := collectionByPDHRe.FindStringSubmatch(req.URL.Path)
 526         if len(m) != 2 {
 527                 // Not a collection PDH GET request
 528                 m = collectionRe.FindStringSubmatch(req.URL.Path)
 529                 clusterId := ""
 530
 531                 if len(m) > 0 {
 532                         clusterId = m[2]
 533                 }
 534
 535                 if clusterId != "" && clusterId != h.handler.Cluster.ClusterID {
 536                         // request for remote collection by uuid
 537                         h.handler.remoteClusterRequest(clusterId, w, req,
 538                                 rewriteSignaturesClusterId{clusterId, ""}.rewriteSignatures)
 539                         return
 540                 }
 541                 // not a collection UUID request, or it is a request
 542                 // for a local UUID, either way, continue down the
 543                 // handler stack.
 544                 h.next.ServeHTTP(w, req)
 545                 return
 546         }
 547
 548         // Request for collection by PDH.  Search the federation.
 549
 550         // First, query the local cluster.
 551         if h.handler.localClusterRequest(w, req, filterLocalClusterResponse) {
 552                 return
 553         }
 554
 555         sharedContext, cancelFunc := context.WithCancel(req.Context())
 556         defer cancelFunc()
 557         req = req.WithContext(sharedContext)
 558
 559         // Create a goroutine for each cluster in the
 560         // RemoteClusters map.  The first valid result gets
 561         // returned to the client.  When that happens, all
 562         // other outstanding requests are cancelled or
 563         // suppressed.
 564         sentResponse := false
 565         mtx := sync.Mutex{}
 566         wg := sync.WaitGroup{}
 567         var errors []string
 568         var errorCode int = 404
 569
 570         // use channel as a semaphore to limit it to 4
 571         // parallel requests at a time
 572         sem := make(chan bool, 4)
 573         defer close(sem)
 574         for remoteID := range h.handler.Cluster.RemoteClusters {
 575                 // blocks until it can put a value into the
 576                 // channel (which has a max queue capacity)
 577                 sem <- true
 578                 if sentResponse {
 579                         break
 580                 }
 581                 search := &searchRemoteClusterForPDH{m[1], remoteID, &mtx, &sentResponse,
 582                         &sharedContext, cancelFunc, &errors, &errorCode}
 583                 wg.Add(1)
 584                 go func() {
 585                         h.handler.remoteClusterRequest(search.remoteID, w, req, search.filterRemoteClusterResponse)
 586                         wg.Done()
 587                         <-sem
 588                 }()
 589         }
 590         wg.Wait()
 591
 592         if sentResponse {
 593                 return
 594         }
 595
 596         // No successful responses, so return the error
 597         httpserver.Errors(w, errors, errorCode)
 598 }
 599
 600 func (h *Handler) setupProxyRemoteCluster(next http.Handler) http.Handler {
 601         mux := http.NewServeMux()
 602         mux.Handle("/arvados/v1/workflows", &genericFederatedRequestHandler{next, h, wfRe})
 603         mux.Handle("/arvados/v1/workflows/", &genericFederatedRequestHandler{next, h, wfRe})
 604         mux.Handle("/arvados/v1/containers", &genericFederatedRequestHandler{next, h, containersRe})
 605         mux.Handle("/arvados/v1/containers/", &genericFederatedRequestHandler{next, h, containersRe})
 606         mux.Handle("/arvados/v1/container_requests", &genericFederatedRequestHandler{next, h, containerRequestsRe})
 607         mux.Handle("/arvados/v1/container_requests/", &genericFederatedRequestHandler{next, h, containerRequestsRe})
 608         mux.Handle("/arvados/v1/collections", next)
 609         mux.Handle("/arvados/v1/collections/", &collectionFederatedRequestHandler{next, h})
 610         mux.Handle("/", next)
 611
 612         return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
 613                 parts := strings.Split(req.Header.Get("Authorization"), "/")
 614                 alreadySalted := (len(parts) == 3 && parts[0] == "Bearer v2" && len(parts[2]) == 40)
 615
 616                 if alreadySalted ||
 617                         strings.Index(req.Header.Get("Via"), "arvados-controller") != -1 {
 618                         // The token is already salted, or this is a
 619                         // request from another instance of
 620                         // arvados-controller.  In either case, we
 621                         // don't want to proxy this query, so just
 622                         // continue down the instance handler stack.
 623                         next.ServeHTTP(w, req)
 624                         return
 625                 }
 626
 627                 mux.ServeHTTP(w, req)
 628         })
 629
 630         return mux
 631 }
 632
 633 type CurrentUser struct {
 634         Authorization arvados.APIClientAuthorization
 635         UUID          string
 636 }
 637
 638 func (h *Handler) validateAPItoken(req *http.Request, user *CurrentUser) error {
 639         db, err := h.db(req)
 640         if err != nil {
 641                 return err
 642         }
 643         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)
 644 }
 645
 646 // Extract the auth token supplied in req, and replace it with a
 647 // salted token for the remote cluster.
 648 func (h *Handler) saltAuthToken(req *http.Request, remote string) error {
 649         creds := auth.NewCredentials()
 650         creds.LoadTokensFromHTTPRequest(req)
 651         if len(creds.Tokens) == 0 && req.Header.Get("Content-Type") == "application/x-www-form-encoded" {
 652                 // Override ParseForm's 10MiB limit by ensuring
 653                 // req.Body is a *http.maxBytesReader.
 654                 req.Body = http.MaxBytesReader(nil, req.Body, 1<<28) // 256MiB. TODO: use MaxRequestSize from discovery doc or config.
 655                 if err := creds.LoadTokensFromHTTPRequestBody(req); err != nil {
 656                         return err
 657                 }
 658                 // Replace req.Body with a buffer that re-encodes the
 659                 // form without api_token, in case we end up
 660                 // forwarding the request.
 661                 if req.PostForm != nil {
 662                         req.PostForm.Del("api_token")
 663                 }
 664                 req.Body = ioutil.NopCloser(bytes.NewBufferString(req.PostForm.Encode()))
 665         }
 666         if len(creds.Tokens) == 0 {
 667                 return nil
 668         }
 669         token, err := auth.SaltToken(creds.Tokens[0], remote)
 670         if err == auth.ErrObsoleteToken {
 671                 // If the token exists in our own database, salt it
 672                 // for the remote. Otherwise, assume it was issued by
 673                 // the remote, and pass it through unmodified.
 674                 currentUser := CurrentUser{Authorization: arvados.APIClientAuthorization{APIToken: creds.Tokens[0]}}
 675                 err = h.validateAPItoken(req, &currentUser)
 676                 if err == sql.ErrNoRows {
 677                         // Not ours; pass through unmodified.
 678                         token = currentUser.Authorization.APIToken
 679                 } else if err != nil {
 680                         return err
 681                 } else {
 682                         // Found; make V2 version and salt it.
 683                         token, err = auth.SaltToken(currentUser.Authorization.TokenV2(), remote)
 684                         if err != nil {
 685                                 return err
 686                         }
 687                 }
 688         } else if err != nil {
 689                 return err
 690         }
 691         req.Header.Set("Authorization", "Bearer "+token)
 692
 693         // Remove api_token=... from the the query string, in case we
 694         // end up forwarding the request.
 695         if values, err := url.ParseQuery(req.URL.RawQuery); err != nil {
 696                 return err
 697         } else if _, ok := values["api_token"]; ok {
 698                 delete(values, "api_token")
 699                 req.URL.RawQuery = values.Encode()
 700         }
 701         return nil
 702 }