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                 err := fmt.Errorf("no proxy available for cluster %v", remoteID)
  51                 if filter != nil {
  52                         _, err = filter(nil, err)
  53                 }
  54                 if err != nil {
  55                         httpserver.Error(w, err.Error(), http.StatusNotFound)
  56                 }
  57                 return
  58         }
  59         scheme := remote.Scheme
  60         if scheme == "" {
  61                 scheme = "https"
  62         }
  63         saltedReq, err := h.saltAuthToken(req, remoteID)
  64         if err != nil {
  65                 if filter != nil {
  66                         _, err = filter(nil, err)
  67                 }
  68                 if err != nil {
  69                         httpserver.Error(w, err.Error(), http.StatusBadRequest)
  70                 }
  71                 return
  72         }
  73         urlOut := &url.URL{
  74                 Scheme:   scheme,
  75                 Host:     remote.Host,
  76                 Path:     saltedReq.URL.Path,
  77                 RawPath:  saltedReq.URL.RawPath,
  78                 RawQuery: saltedReq.URL.RawQuery,
  79         }
  80         client := h.secureClient
  81         if remote.Insecure {
  82                 client = h.insecureClient
  83         }
  84         h.proxy.Do(w, saltedReq, urlOut, client, filter)
  85 }
  86
  87 // Buffer request body, parse form parameters in request, and then
  88 // replace original body with the buffer so it can be re-read by
  89 // downstream proxy steps.
  90 func loadParamsFromForm(req *http.Request) error {
  91         var postBody *bytes.Buffer
  92         if req.Body != nil && req.Header.Get("Content-Type") == "application/x-www-form-urlencoded" {
  93                 var cl int64
  94                 if req.ContentLength > 0 {
  95                         cl = req.ContentLength
  96                 }
  97                 postBody = bytes.NewBuffer(make([]byte, 0, cl))
  98                 originalBody := req.Body
  99                 defer originalBody.Close()
 100                 req.Body = ioutil.NopCloser(io.TeeReader(req.Body, postBody))
 101         }
 102
 103         err := req.ParseForm()
 104         if err != nil {
 105                 return err
 106         }
 107
 108         if req.Body != nil && postBody != nil {
 109                 req.Body = ioutil.NopCloser(postBody)
 110         }
 111         return nil
 112 }
 113
 114 type multiClusterQueryResponseCollector struct {
 115         responses []map[string]interface{}
 116         error     error
 117         kind      string
 118         clusterID string
 119 }
 120
 121 func (c *multiClusterQueryResponseCollector) collectResponse(resp *http.Response,
 122         requestError error) (newResponse *http.Response, err error) {
 123         if requestError != nil {
 124                 c.error = requestError
 125                 return nil, nil
 126         }
 127
 128         defer resp.Body.Close()
 129         var loadInto struct {
 130                 Kind   string                   `json:"kind"`
 131                 Items  []map[string]interface{} `json:"items"`
 132                 Errors []string                 `json:"errors"`
 133         }
 134         err = json.NewDecoder(resp.Body).Decode(&loadInto)
 135
 136         if err != nil {
 137                 c.error = fmt.Errorf("error fetching from %v (%v): %v", c.clusterID, resp.Status, err)
 138                 return nil, nil
 139         }
 140         if resp.StatusCode != http.StatusOK {
 141                 c.error = fmt.Errorf("error fetching from %v (%v): %v", c.clusterID, resp.Status, loadInto.Errors)
 142                 return nil, nil
 143         }
 144
 145         c.responses = loadInto.Items
 146         c.kind = loadInto.Kind
 147
 148         return nil, nil
 149 }
 150
 151 func (h *genericFederatedRequestHandler) remoteQueryUUIDs(w http.ResponseWriter,
 152         req *http.Request,
 153         clusterID string, uuids []string) (rp []map[string]interface{}, kind string, err error) {
 154
 155         found := make(map[string]bool)
 156         prev_len_uuids := len(uuids) + 1
 157         // Loop while
 158         // (1) there are more uuids to query
 159         // (2) we're making progress - on each iteration the set of
 160         // uuids we are expecting for must shrink.
 161         for len(uuids) > 0 && len(uuids) < prev_len_uuids {
 162                 var remoteReq http.Request
 163                 remoteReq.Header = req.Header
 164                 remoteReq.Method = "POST"
 165                 remoteReq.URL = &url.URL{Path: req.URL.Path}
 166                 remoteParams := make(url.Values)
 167                 remoteParams.Set("_method", "GET")
 168                 remoteParams.Set("count", "none")
 169                 if req.Form.Get("select") != "" {
 170                         remoteParams.Set("select", req.Form.Get("select"))
 171                 }
 172                 content, err := json.Marshal(uuids)
 173                 if err != nil {
 174                         return nil, "", err
 175                 }
 176                 remoteParams["filters"] = []string{fmt.Sprintf(`[["uuid", "in", %s]]`, content)}
 177                 enc := remoteParams.Encode()
 178                 remoteReq.Body = ioutil.NopCloser(bytes.NewBufferString(enc))
 179
 180                 rc := multiClusterQueryResponseCollector{clusterID: clusterID}
 181
 182                 if clusterID == h.handler.Cluster.ClusterID {
 183                         h.handler.localClusterRequest(w, &remoteReq,
 184                                 rc.collectResponse)
 185                 } else {
 186                         h.handler.remoteClusterRequest(clusterID, w, &remoteReq,
 187                                 rc.collectResponse)
 188                 }
 189                 if rc.error != nil {
 190                         return nil, "", rc.error
 191                 }
 192
 193                 kind = rc.kind
 194
 195                 if len(rc.responses) == 0 {
 196                         // We got zero responses, no point in doing
 197                         // another query.
 198                         return rp, kind, nil
 199                 }
 200
 201                 rp = append(rp, rc.responses...)
 202
 203                 // Go through the responses and determine what was
 204                 // returned.  If there are remaining items, loop
 205                 // around and do another request with just the
 206                 // stragglers.
 207                 for _, i := range rc.responses {
 208                         uuid, ok := i["uuid"].(string)
 209                         if ok {
 210                                 found[uuid] = true
 211                         }
 212                 }
 213
 214                 l := []string{}
 215                 for _, u := range uuids {
 216                         if !found[u] {
 217                                 l = append(l, u)
 218                         }
 219                 }
 220                 prev_len_uuids = len(uuids)
 221                 uuids = l
 222         }
 223
 224         return rp, kind, nil
 225 }
 226
 227 func (h *genericFederatedRequestHandler) handleMultiClusterQuery(w http.ResponseWriter,
 228         req *http.Request, clusterId *string) bool {
 229
 230         var filters [][]interface{}
 231         err := json.Unmarshal([]byte(req.Form.Get("filters")), &filters)
 232         if err != nil {
 233                 httpserver.Error(w, err.Error(), http.StatusBadRequest)
 234                 return true
 235         }
 236
 237         // Split the list of uuids by prefix
 238         queryClusters := make(map[string][]string)
 239         expectCount := 0
 240         for _, filter := range filters {
 241                 if len(filter) != 3 {
 242                         return false
 243                 }
 244
 245                 if lhs, ok := filter[0].(string); !ok || lhs != "uuid" {
 246                         return false
 247                 }
 248
 249                 op, ok := filter[1].(string)
 250                 if !ok {
 251                         return false
 252                 }
 253
 254                 if op == "in" {
 255                         if rhs, ok := filter[2].([]interface{}); ok {
 256                                 for _, i := range rhs {
 257                                         if u, ok := i.(string); ok {
 258                                                 *clusterId = u[0:5]
 259                                                 queryClusters[u[0:5]] = append(queryClusters[u[0:5]], u)
 260                                                 expectCount += 1
 261                                         }
 262                                 }
 263                         }
 264                 } else if op == "=" {
 265                         if u, ok := filter[2].(string); ok {
 266                                 *clusterId = u[0:5]
 267                                 queryClusters[u[0:5]] = append(queryClusters[u[0:5]], u)
 268                                 expectCount += 1
 269                         }
 270                 } else {
 271                         return false
 272                 }
 273
 274         }
 275
 276         if len(queryClusters) <= 1 {
 277                 // Query does not search for uuids across multiple
 278                 // clusters.
 279                 return false
 280         }
 281
 282         // Validations
 283         count := req.Form.Get("count")
 284         if count != "" && count != `none` && count != `"none"` {
 285                 httpserver.Error(w, "Federated multi-object query must have 'count=none'", http.StatusBadRequest)
 286                 return true
 287         }
 288         if req.Form.Get("limit") != "" || req.Form.Get("offset") != "" || req.Form.Get("order") != "" {
 289                 httpserver.Error(w, "Federated multi-object may not provide 'limit', 'offset' or 'order'.", http.StatusBadRequest)
 290                 return true
 291         }
 292         if expectCount > h.handler.Cluster.RequestLimits.GetMaxItemsPerResponse() {
 293                 httpserver.Error(w, fmt.Sprintf("Federated multi-object request for %v objects which is more than max page size %v.",
 294                         expectCount, h.handler.Cluster.RequestLimits.GetMaxItemsPerResponse()), http.StatusBadRequest)
 295                 return true
 296         }
 297         if req.Form.Get("select") != "" {
 298                 foundUUID := false
 299                 var selects []string
 300                 err := json.Unmarshal([]byte(req.Form.Get("select")), &selects)
 301                 if err != nil {
 302                         httpserver.Error(w, err.Error(), http.StatusBadRequest)
 303                         return true
 304                 }
 305
 306                 for _, r := range selects {
 307                         if r == "uuid" {
 308                                 foundUUID = true
 309                                 break
 310                         }
 311                 }
 312                 if !foundUUID {
 313                         httpserver.Error(w, "Federated multi-object request must include 'uuid' in 'select'", http.StatusBadRequest)
 314                         return true
 315                 }
 316         }
 317
 318         // Perform concurrent requests to each cluster
 319
 320         // use channel as a semaphore to limit the number of concurrent
 321         // requests at a time
 322         sem := make(chan bool, h.handler.Cluster.RequestLimits.GetMultiClusterRequestConcurrency())
 323         defer close(sem)
 324         wg := sync.WaitGroup{}
 325
 326         req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
 327         mtx := sync.Mutex{}
 328         errors := []error{}
 329         var completeResponses []map[string]interface{}
 330         var kind string
 331
 332         for k, v := range queryClusters {
 333                 if len(v) == 0 {
 334                         // Nothing to query
 335                         continue
 336                 }
 337
 338                 // blocks until it can put a value into the
 339                 // channel (which has a max queue capacity)
 340                 sem <- true
 341                 wg.Add(1)
 342                 go func(k string, v []string) {
 343                         rp, kn, err := h.remoteQueryUUIDs(w, req, k, v)
 344                         mtx.Lock()
 345                         if err == nil {
 346                                 completeResponses = append(completeResponses, rp...)
 347                                 kind = kn
 348                         } else {
 349                                 errors = append(errors, err)
 350                         }
 351                         mtx.Unlock()
 352                         wg.Done()
 353                         <-sem
 354                 }(k, v)
 355         }
 356         wg.Wait()
 357
 358         if len(errors) > 0 {
 359                 var strerr []string
 360                 for _, e := range errors {
 361                         strerr = append(strerr, e.Error())
 362                 }
 363                 httpserver.Errors(w, strerr, http.StatusBadGateway)
 364                 return true
 365         }
 366
 367         w.Header().Set("Content-Type", "application/json")
 368         w.WriteHeader(http.StatusOK)
 369         itemList := make(map[string]interface{})
 370         itemList["items"] = completeResponses
 371         itemList["kind"] = kind
 372         json.NewEncoder(w).Encode(itemList)
 373
 374         return true
 375 }
 376
 377 func (h *genericFederatedRequestHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 378         m := h.matcher.FindStringSubmatch(req.URL.Path)
 379         clusterId := ""
 380
 381         if len(m) > 0 && m[2] != "" {
 382                 clusterId = m[2]
 383         }
 384
 385         // Get form parameters from URL and form body (if POST).
 386         if err := loadParamsFromForm(req); err != nil {
 387                 httpserver.Error(w, err.Error(), http.StatusBadRequest)
 388                 return
 389         }
 390
 391         // Check if the parameters have an explicit cluster_id
 392         if req.Form.Get("cluster_id") != "" {
 393                 clusterId = req.Form.Get("cluster_id")
 394         }
 395
 396         // Handle the POST-as-GET special case (workaround for large
 397         // GET requests that potentially exceed maximum URL length,
 398         // like multi-object queries where the filter has 100s of
 399         // items)
 400         effectiveMethod := req.Method
 401         if req.Method == "POST" && req.Form.Get("_method") != "" {
 402                 effectiveMethod = req.Form.Get("_method")
 403         }
 404
 405         if effectiveMethod == "GET" &&
 406                 clusterId == "" &&
 407                 req.Form.Get("filters") != "" &&
 408                 h.handleMultiClusterQuery(w, req, &clusterId) {
 409                 return
 410         }
 411
 412         if clusterId == "" || clusterId == h.handler.Cluster.ClusterID {
 413                 h.next.ServeHTTP(w, req)
 414         } else {
 415                 h.handler.remoteClusterRequest(clusterId, w, req, nil)
 416         }
 417 }
 418
 419 type rewriteSignaturesClusterId struct {
 420         clusterID  string
 421         expectHash string
 422 }
 423
 424 func (rw rewriteSignaturesClusterId) rewriteSignatures(resp *http.Response, requestError error) (newResponse *http.Response, err error) {
 425         if requestError != nil {
 426                 return resp, requestError
 427         }
 428
 429         if resp.StatusCode != 200 {
 430                 return resp, nil
 431         }
 432
 433         originalBody := resp.Body
 434         defer originalBody.Close()
 435
 436         var col arvados.Collection
 437         err = json.NewDecoder(resp.Body).Decode(&col)
 438         if err != nil {
 439                 return nil, err
 440         }
 441
 442         // rewriting signatures will make manifest text 5-10% bigger so calculate
 443         // capacity accordingly
 444         updatedManifest := bytes.NewBuffer(make([]byte, 0, int(float64(len(col.ManifestText))*1.1)))
 445
 446         hasher := md5.New()
 447         mw := io.MultiWriter(hasher, updatedManifest)
 448         sz := 0
 449
 450         scanner := bufio.NewScanner(strings.NewReader(col.ManifestText))
 451         scanner.Buffer(make([]byte, 1048576), len(col.ManifestText))
 452         for scanner.Scan() {
 453                 line := scanner.Text()
 454                 tokens := strings.Split(line, " ")
 455                 if len(tokens) < 3 {
 456                         return nil, fmt.Errorf("Invalid stream (<3 tokens): %q", line)
 457                 }
 458
 459                 n, err := mw.Write([]byte(tokens[0]))
 460                 if err != nil {
 461                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 462                 }
 463                 sz += n
 464                 for _, token := range tokens[1:] {
 465                         n, err = mw.Write([]byte(" "))
 466                         if err != nil {
 467                                 return nil, fmt.Errorf("Error updating manifest: %v", err)
 468                         }
 469                         sz += n
 470
 471                         m := keepclient.SignedLocatorRe.FindStringSubmatch(token)
 472                         if m != nil {
 473                                 // Rewrite the block signature to be a remote signature
 474                                 _, err = fmt.Fprintf(updatedManifest, "%s%s%s+R%s-%s%s", m[1], m[2], m[3], rw.clusterID, m[5][2:], m[8])
 475                                 if err != nil {
 476                                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 477                                 }
 478
 479                                 // for hash checking, ignore signatures
 480                                 n, err = fmt.Fprintf(hasher, "%s%s", m[1], m[2])
 481                                 if err != nil {
 482                                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 483                                 }
 484                                 sz += n
 485                         } else {
 486                                 n, err = mw.Write([]byte(token))
 487                                 if err != nil {
 488                                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 489                                 }
 490                                 sz += n
 491                         }
 492                 }
 493                 n, err = mw.Write([]byte("\n"))
 494                 if err != nil {
 495                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 496                 }
 497                 sz += n
 498         }
 499
 500         // Check that expected hash is consistent with
 501         // portable_data_hash field of the returned record
 502         if rw.expectHash == "" {
 503                 rw.expectHash = col.PortableDataHash
 504         } else if rw.expectHash != col.PortableDataHash {
 505                 return nil, fmt.Errorf("portable_data_hash %q on returned record did not match expected hash %q ", rw.expectHash, col.PortableDataHash)
 506         }
 507
 508         // Certify that the computed hash of the manifest_text matches our expectation
 509         sum := hasher.Sum(nil)
 510         computedHash := fmt.Sprintf("%x+%v", sum, sz)
 511         if computedHash != rw.expectHash {
 512                 return nil, fmt.Errorf("Computed manifest_text hash %q did not match expected hash %q", computedHash, rw.expectHash)
 513         }
 514
 515         col.ManifestText = updatedManifest.String()
 516
 517         newbody, err := json.Marshal(col)
 518         if err != nil {
 519                 return nil, err
 520         }
 521
 522         buf := bytes.NewBuffer(newbody)
 523         resp.Body = ioutil.NopCloser(buf)
 524         resp.ContentLength = int64(buf.Len())
 525         resp.Header.Set("Content-Length", fmt.Sprintf("%v", buf.Len()))
 526
 527         return resp, nil
 528 }
 529
 530 func filterLocalClusterResponse(resp *http.Response, requestError error) (newResponse *http.Response, err error) {
 531         if requestError != nil {
 532                 return resp, requestError
 533         }
 534
 535         if resp.StatusCode == 404 {
 536                 // Suppress returning this result, because we want to
 537                 // search the federation.
 538                 return nil, nil
 539         }
 540         return resp, nil
 541 }
 542
 543 type searchRemoteClusterForPDH struct {
 544         pdh           string
 545         remoteID      string
 546         mtx           *sync.Mutex
 547         sentResponse  *bool
 548         sharedContext *context.Context
 549         cancelFunc    func()
 550         errors        *[]string
 551         statusCode    *int
 552 }
 553
 554 func (s *searchRemoteClusterForPDH) filterRemoteClusterResponse(resp *http.Response, requestError error) (newResponse *http.Response, err error) {
 555         s.mtx.Lock()
 556         defer s.mtx.Unlock()
 557
 558         if *s.sentResponse {
 559                 // Another request already returned a response
 560                 return nil, nil
 561         }
 562
 563         if requestError != nil {
 564                 *s.errors = append(*s.errors, fmt.Sprintf("Request error contacting %q: %v", s.remoteID, requestError))
 565                 // Record the error and suppress response
 566                 return nil, nil
 567         }
 568
 569         if resp.StatusCode != 200 {
 570                 // Suppress returning unsuccessful result.  Maybe
 571                 // another request will find it.
 572                 // TODO collect and return error responses.
 573                 *s.errors = append(*s.errors, fmt.Sprintf("Response from %q: %v", s.remoteID, resp.Status))
 574                 if resp.StatusCode != 404 {
 575                         // Got a non-404 error response, convert into BadGateway
 576                         *s.statusCode = http.StatusBadGateway
 577                 }
 578                 return nil, nil
 579         }
 580
 581         s.mtx.Unlock()
 582
 583         // This reads the response body.  We don't want to hold the
 584         // lock while doing this because other remote requests could
 585         // also have made it to this point, and we don't want a
 586         // slow response holding the lock to block a faster response
 587         // that is waiting on the lock.
 588         newResponse, err = rewriteSignaturesClusterId{s.remoteID, s.pdh}.rewriteSignatures(resp, nil)
 589
 590         s.mtx.Lock()
 591
 592         if *s.sentResponse {
 593                 // Another request already returned a response
 594                 return nil, nil
 595         }
 596
 597         if err != nil {
 598                 // Suppress returning unsuccessful result.  Maybe
 599                 // another request will be successful.
 600                 *s.errors = append(*s.errors, fmt.Sprintf("Error parsing response from %q: %v", s.remoteID, err))
 601                 return nil, nil
 602         }
 603
 604         // We have a successful response.  Suppress/cancel all the
 605         // other requests/responses.
 606         *s.sentResponse = true
 607         s.cancelFunc()
 608
 609         return newResponse, nil
 610 }
 611
 612 func (h *collectionFederatedRequestHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 613         if req.Method != "GET" {
 614                 // Only handle GET requests right now
 615                 h.next.ServeHTTP(w, req)
 616                 return
 617         }
 618
 619         m := collectionByPDHRe.FindStringSubmatch(req.URL.Path)
 620         if len(m) != 2 {
 621                 // Not a collection PDH GET request
 622                 m = collectionRe.FindStringSubmatch(req.URL.Path)
 623                 clusterId := ""
 624
 625                 if len(m) > 0 {
 626                         clusterId = m[2]
 627                 }
 628
 629                 if clusterId != "" && clusterId != h.handler.Cluster.ClusterID {
 630                         // request for remote collection by uuid
 631                         h.handler.remoteClusterRequest(clusterId, w, req,
 632                                 rewriteSignaturesClusterId{clusterId, ""}.rewriteSignatures)
 633                         return
 634                 }
 635                 // not a collection UUID request, or it is a request
 636                 // for a local UUID, either way, continue down the
 637                 // handler stack.
 638                 h.next.ServeHTTP(w, req)
 639                 return
 640         }
 641
 642         // Request for collection by PDH.  Search the federation.
 643
 644         // First, query the local cluster.
 645         if h.handler.localClusterRequest(w, req, filterLocalClusterResponse) {
 646                 return
 647         }
 648
 649         sharedContext, cancelFunc := context.WithCancel(req.Context())
 650         defer cancelFunc()
 651         req = req.WithContext(sharedContext)
 652
 653         // Create a goroutine for each cluster in the
 654         // RemoteClusters map.  The first valid result gets
 655         // returned to the client.  When that happens, all
 656         // other outstanding requests are cancelled or
 657         // suppressed.
 658         sentResponse := false
 659         mtx := sync.Mutex{}
 660         wg := sync.WaitGroup{}
 661         var errors []string
 662         var errorCode int = 404
 663
 664         // use channel as a semaphore to limit the number of concurrent
 665         // requests at a time
 666         sem := make(chan bool, h.handler.Cluster.RequestLimits.GetMultiClusterRequestConcurrency())
 667         defer close(sem)
 668         for remoteID := range h.handler.Cluster.RemoteClusters {
 669                 if remoteID == h.handler.Cluster.ClusterID {
 670                         // No need to query local cluster again
 671                         continue
 672                 }
 673                 // blocks until it can put a value into the
 674                 // channel (which has a max queue capacity)
 675                 sem <- true
 676                 if sentResponse {
 677                         break
 678                 }
 679                 search := &searchRemoteClusterForPDH{m[1], remoteID, &mtx, &sentResponse,
 680                         &sharedContext, cancelFunc, &errors, &errorCode}
 681                 wg.Add(1)
 682                 go func() {
 683                         h.handler.remoteClusterRequest(search.remoteID, w, req, search.filterRemoteClusterResponse)
 684                         wg.Done()
 685                         <-sem
 686                 }()
 687         }
 688         wg.Wait()
 689
 690         if sentResponse {
 691                 return
 692         }
 693
 694         // No successful responses, so return the error
 695         httpserver.Errors(w, errors, errorCode)
 696 }
 697
 698 func (h *Handler) setupProxyRemoteCluster(next http.Handler) http.Handler {
 699         mux := http.NewServeMux()
 700         mux.Handle("/arvados/v1/workflows", &genericFederatedRequestHandler{next, h, wfRe})
 701         mux.Handle("/arvados/v1/workflows/", &genericFederatedRequestHandler{next, h, wfRe})
 702         mux.Handle("/arvados/v1/containers", &genericFederatedRequestHandler{next, h, containersRe})
 703         mux.Handle("/arvados/v1/containers/", &genericFederatedRequestHandler{next, h, containersRe})
 704         mux.Handle("/arvados/v1/container_requests", &genericFederatedRequestHandler{next, h, containerRequestsRe})
 705         mux.Handle("/arvados/v1/container_requests/", &genericFederatedRequestHandler{next, h, containerRequestsRe})
 706         mux.Handle("/arvados/v1/collections", next)
 707         mux.Handle("/arvados/v1/collections/", &collectionFederatedRequestHandler{next, h})
 708         mux.Handle("/", next)
 709
 710         return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
 711                 parts := strings.Split(req.Header.Get("Authorization"), "/")
 712                 alreadySalted := (len(parts) == 3 && parts[0] == "Bearer v2" && len(parts[2]) == 40)
 713
 714                 if alreadySalted ||
 715                         strings.Index(req.Header.Get("Via"), "arvados-controller") != -1 {
 716                         // The token is already salted, or this is a
 717                         // request from another instance of
 718                         // arvados-controller.  In either case, we
 719                         // don't want to proxy this query, so just
 720                         // continue down the instance handler stack.
 721                         next.ServeHTTP(w, req)
 722                         return
 723                 }
 724
 725                 mux.ServeHTTP(w, req)
 726         })
 727
 728         return mux
 729 }
 730
 731 type CurrentUser struct {
 732         Authorization arvados.APIClientAuthorization
 733         UUID          string
 734 }
 735
 736 func (h *Handler) validateAPItoken(req *http.Request, user *CurrentUser) error {
 737         db, err := h.db(req)
 738         if err != nil {
 739                 return err
 740         }
 741         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)
 742 }
 743
 744 // Extract the auth token supplied in req, and replace it with a
 745 // salted token for the remote cluster.
 746 func (h *Handler) saltAuthToken(req *http.Request, remote string) (updatedReq *http.Request, err error) {
 747         updatedReq = (&http.Request{
 748                 Method:        req.Method,
 749                 URL:           req.URL,
 750                 Header:        req.Header,
 751                 Body:          req.Body,
 752                 ContentLength: req.ContentLength,
 753                 Host:          req.Host,
 754         }).WithContext(req.Context())
 755
 756         creds := auth.NewCredentials()
 757         creds.LoadTokensFromHTTPRequest(updatedReq)
 758         if len(creds.Tokens) == 0 && updatedReq.Header.Get("Content-Type") == "application/x-www-form-encoded" {
 759                 // Override ParseForm's 10MiB limit by ensuring
 760                 // req.Body is a *http.maxBytesReader.
 761                 updatedReq.Body = http.MaxBytesReader(nil, updatedReq.Body, 1<<28) // 256MiB. TODO: use MaxRequestSize from discovery doc or config.
 762                 if err := creds.LoadTokensFromHTTPRequestBody(updatedReq); err != nil {
 763                         return nil, err
 764                 }
 765                 // Replace req.Body with a buffer that re-encodes the
 766                 // form without api_token, in case we end up
 767                 // forwarding the request.
 768                 if updatedReq.PostForm != nil {
 769                         updatedReq.PostForm.Del("api_token")
 770                 }
 771                 updatedReq.Body = ioutil.NopCloser(bytes.NewBufferString(updatedReq.PostForm.Encode()))
 772         }
 773         if len(creds.Tokens) == 0 {
 774                 return updatedReq, nil
 775         }
 776
 777         token, err := auth.SaltToken(creds.Tokens[0], remote)
 778
 779         if err == auth.ErrObsoleteToken {
 780                 // If the token exists in our own database, salt it
 781                 // for the remote. Otherwise, assume it was issued by
 782                 // the remote, and pass it through unmodified.
 783                 currentUser := CurrentUser{Authorization: arvados.APIClientAuthorization{APIToken: creds.Tokens[0]}}
 784                 err = h.validateAPItoken(req, &currentUser)
 785                 if err == sql.ErrNoRows {
 786                         // Not ours; pass through unmodified.
 787                         token = currentUser.Authorization.APIToken
 788                 } else if err != nil {
 789                         return nil, err
 790                 } else {
 791                         // Found; make V2 version and salt it.
 792                         token, err = auth.SaltToken(currentUser.Authorization.TokenV2(), remote)
 793                         if err != nil {
 794                                 return nil, err
 795                         }
 796                 }
 797         } else if err != nil {
 798                 return nil, err
 799         }
 800         updatedReq.Header = http.Header{}
 801         for k, v := range req.Header {
 802                 if k != "Authorization" {
 803                         updatedReq.Header[k] = v
 804                 }
 805         }
 806         updatedReq.Header.Set("Authorization", "Bearer "+token)
 807
 808         // Remove api_token=... from the the query string, in case we
 809         // end up forwarding the request.
 810         if values, err := url.ParseQuery(updatedReq.URL.RawQuery); err != nil {
 811                 return nil, err
 812         } else if _, ok := values["api_token"]; ok {
 813                 delete(values, "api_token")
 814                 updatedReq.URL = &url.URL{
 815                         Scheme:   req.URL.Scheme,
 816                         Host:     req.URL.Host,
 817                         Path:     req.URL.Path,
 818                         RawPath:  req.URL.RawPath,
 819                         RawQuery: values.Encode(),
 820                 }
 821         }
 822         return updatedReq, nil
 823 }