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 // Buffer request body, parse form parameters in request, and then
  77 // replace original body with the buffer so it can be re-read by
  78 // downstream proxy steps.
  79 func loadParamsFromForm(req *http.Request) error {
  80         var postBody *bytes.Buffer
  81         if req.Body != nil && req.Header.Get("Content-Type") == "application/x-www-form-urlencoded" {
  82                 var cl int64
  83                 if req.ContentLength > 0 {
  84                         cl = req.ContentLength
  85                 }
  86                 postBody = bytes.NewBuffer(make([]byte, 0, cl))
  87                 originalBody := req.Body
  88                 defer originalBody.Close()
  89                 req.Body = ioutil.NopCloser(io.TeeReader(req.Body, postBody))
  90         }
  91
  92         err := req.ParseForm()
  93         if err != nil {
  94                 return err
  95         }
  96
  97         if req.Body != nil && postBody != nil {
  98                 req.Body = ioutil.NopCloser(postBody)
  99         }
 100         return nil
 101 }
 102
 103 type multiClusterQueryResponseCollector struct {
 104         responses []map[string]interface{}
 105         error     error
 106         kind      string
 107         clusterID string
 108 }
 109
 110 func (c *multiClusterQueryResponseCollector) collectResponse(resp *http.Response,
 111         requestError error) (newResponse *http.Response, err error) {
 112         if requestError != nil {
 113                 c.error = requestError
 114                 return nil, nil
 115         }
 116
 117         defer resp.Body.Close()
 118         var loadInto struct {
 119                 Kind   string                   `json:"kind"`
 120                 Items  []map[string]interface{} `json:"items"`
 121                 Errors []string                 `json:"errors"`
 122         }
 123         err = json.NewDecoder(resp.Body).Decode(&loadInto)
 124
 125         if err != nil {
 126                 c.error = fmt.Errorf("error fetching from %v (%v): %v", c.clusterID, resp.Status, err)
 127                 return nil, nil
 128         }
 129         if resp.StatusCode != http.StatusOK {
 130                 c.error = fmt.Errorf("error fetching from %v (%v): %v", c.clusterID, resp.Status, loadInto.Errors)
 131                 return nil, nil
 132         }
 133
 134         c.responses = loadInto.Items
 135         c.kind = loadInto.Kind
 136
 137         return nil, nil
 138 }
 139
 140 func (h *genericFederatedRequestHandler) remoteQueryUUIDs(w http.ResponseWriter,
 141         req *http.Request,
 142         clusterID string, uuids []string) (rp []map[string]interface{}, kind string, err error) {
 143
 144         found := make(map[string]bool)
 145         prev_len_uuids := len(uuids) + 1
 146         // Loop while
 147         // (1) there are more uuids to query
 148         // (2) we're making progress - on each iteration the set of
 149         // uuids we are expecting for must shrink.
 150         for len(uuids) > 0 && len(uuids) < prev_len_uuids {
 151                 var remoteReq http.Request
 152                 remoteReq.Header = req.Header
 153                 remoteReq.Method = "POST"
 154                 remoteReq.URL = &url.URL{Path: req.URL.Path}
 155                 remoteParams := make(url.Values)
 156                 remoteParams.Set("_method", "GET")
 157                 remoteParams.Set("count", "none")
 158                 if req.Form.Get("select") != "" {
 159                         remoteParams.Set("select", req.Form.Get("select"))
 160                 }
 161                 content, err := json.Marshal(uuids)
 162                 if err != nil {
 163                         return nil, "", err
 164                 }
 165                 remoteParams["filters"] = []string{fmt.Sprintf(`[["uuid", "in", %s]]`, content)}
 166                 enc := remoteParams.Encode()
 167                 remoteReq.Body = ioutil.NopCloser(bytes.NewBufferString(enc))
 168
 169                 rc := multiClusterQueryResponseCollector{clusterID: clusterID}
 170
 171                 if clusterID == h.handler.Cluster.ClusterID {
 172                         h.handler.localClusterRequest(w, &remoteReq,
 173                                 rc.collectResponse)
 174                 } else {
 175                         h.handler.remoteClusterRequest(clusterID, w, &remoteReq,
 176                                 rc.collectResponse)
 177                 }
 178                 if rc.error != nil {
 179                         return nil, "", rc.error
 180                 }
 181
 182                 kind = rc.kind
 183
 184                 if len(rc.responses) == 0 {
 185                         // We got zero responses, no point in doing
 186                         // another query.
 187                         return rp, kind, nil
 188                 }
 189
 190                 rp = append(rp, rc.responses...)
 191
 192                 // Go through the responses and determine what was
 193                 // returned.  If there are remaining items, loop
 194                 // around and do another request with just the
 195                 // stragglers.
 196                 for _, i := range rc.responses {
 197                         uuid, ok := i["uuid"].(string)
 198                         if ok {
 199                                 found[uuid] = true
 200                         }
 201                 }
 202
 203                 l := []string{}
 204                 for _, u := range uuids {
 205                         if !found[u] {
 206                                 l = append(l, u)
 207                         }
 208                 }
 209                 prev_len_uuids = len(uuids)
 210                 uuids = l
 211         }
 212
 213         return rp, kind, nil
 214 }
 215
 216 func (h *Handler) FederatedRequestConcurrency() int {
 217         if h.Cluster.FederatedRequestConcurrency == 0 {
 218                 return 4
 219         }
 220         return h.Cluster.FederatedRequestConcurrency
 221 }
 222
 223 func (h *Handler) MaxItemsPerResponse() int {
 224         if h.Cluster.MaxItemsPerResponse == 0 {
 225                 return 1000
 226         }
 227         return h.Cluster.MaxItemsPerResponse
 228 }
 229
 230 func (h *genericFederatedRequestHandler) handleMultiClusterQuery(w http.ResponseWriter,
 231         req *http.Request, clusterId *string) bool {
 232
 233         var filters [][]interface{}
 234         err := json.Unmarshal([]byte(req.Form.Get("filters")), &filters)
 235         if err != nil {
 236                 httpserver.Error(w, err.Error(), http.StatusBadRequest)
 237                 return true
 238         }
 239
 240         // Split the list of uuids by prefix
 241         queryClusters := make(map[string][]string)
 242         expectCount := 0
 243         for _, filter := range filters {
 244                 if len(filter) != 3 {
 245                         return false
 246                 }
 247
 248                 if lhs, ok := filter[0].(string); !ok || lhs != "uuid" {
 249                         return false
 250                 }
 251
 252                 op, ok := filter[1].(string)
 253                 if !ok {
 254                         return false
 255                 }
 256
 257                 if op == "in" {
 258                         if rhs, ok := filter[2].([]interface{}); ok {
 259                                 for _, i := range rhs {
 260                                         if u, ok := i.(string); ok {
 261                                                 *clusterId = u[0:5]
 262                                                 queryClusters[u[0:5]] = append(queryClusters[u[0:5]], u)
 263                                                 expectCount += 1
 264                                         }
 265                                 }
 266                         }
 267                 } else if op == "=" {
 268                         if u, ok := filter[2].(string); ok {
 269                                 *clusterId = u[0:5]
 270                                 queryClusters[u[0:5]] = append(queryClusters[u[0:5]], u)
 271                                 expectCount += 1
 272                         }
 273                 } else {
 274                         return false
 275                 }
 276
 277         }
 278
 279         if len(queryClusters) <= 1 {
 280                 // Query does not search for uuids across multiple
 281                 // clusters.
 282                 return false
 283         }
 284
 285         // Validations
 286         count := req.Form.Get("count")
 287         if count != "" && count != `none` && count != `"none"` {
 288                 httpserver.Error(w, "Federated multi-object query must have 'count=none'", http.StatusBadRequest)
 289                 return true
 290         }
 291         if req.Form.Get("limit") != "" || req.Form.Get("offset") != "" || req.Form.Get("order") != "" {
 292                 httpserver.Error(w, "Federated multi-object may not provide 'limit', 'offset' or 'order'.", http.StatusBadRequest)
 293                 return true
 294         }
 295         if expectCount > h.handler.MaxItemsPerResponse() {
 296                 httpserver.Error(w, fmt.Sprintf("Federated multi-object request for %v objects which is more than max page size %v.",
 297                         expectCount, h.handler.MaxItemsPerResponse()), http.StatusBadRequest)
 298                 return true
 299         }
 300         if req.Form.Get("select") != "" {
 301                 foundUUID := false
 302                 var selects []string
 303                 err := json.Unmarshal([]byte(req.Form.Get("select")), &selects)
 304                 if err != nil {
 305                         httpserver.Error(w, err.Error(), http.StatusBadRequest)
 306                         return true
 307                 }
 308
 309                 for _, r := range selects {
 310                         if r == "uuid" {
 311                                 foundUUID = true
 312                                 break
 313                         }
 314                 }
 315                 if !foundUUID {
 316                         httpserver.Error(w, "Federated multi-object request must include 'uuid' in 'select'", http.StatusBadRequest)
 317                         return true
 318                 }
 319         }
 320
 321         // Perform concurrent requests to each cluster
 322
 323         // use channel as a semaphore to limit the number of concurrent
 324         // requests at a time
 325         sem := make(chan bool, h.handler.FederatedRequestConcurrency())
 326         defer close(sem)
 327         wg := sync.WaitGroup{}
 328
 329         req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
 330         mtx := sync.Mutex{}
 331         errors := []error{}
 332         var completeResponses []map[string]interface{}
 333         var kind string
 334
 335         for k, v := range queryClusters {
 336                 if len(v) == 0 {
 337                         // Nothing to query
 338                         continue
 339                 }
 340
 341                 // blocks until it can put a value into the
 342                 // channel (which has a max queue capacity)
 343                 sem <- true
 344                 wg.Add(1)
 345                 go func(k string, v []string) {
 346                         rp, kn, err := h.remoteQueryUUIDs(w, req, k, v)
 347                         mtx.Lock()
 348                         if err == nil {
 349                                 completeResponses = append(completeResponses, rp...)
 350                                 kind = kn
 351                         } else {
 352                                 errors = append(errors, err)
 353                         }
 354                         mtx.Unlock()
 355                         wg.Done()
 356                         <-sem
 357                 }(k, v)
 358         }
 359         wg.Wait()
 360
 361         if len(errors) > 0 {
 362                 var strerr []string
 363                 for _, e := range errors {
 364                         strerr = append(strerr, e.Error())
 365                 }
 366                 httpserver.Errors(w, strerr, http.StatusBadGateway)
 367                 return true
 368         }
 369
 370         w.Header().Set("Content-Type", "application/json")
 371         w.WriteHeader(http.StatusOK)
 372         itemList := make(map[string]interface{})
 373         itemList["items"] = completeResponses
 374         itemList["kind"] = kind
 375         json.NewEncoder(w).Encode(itemList)
 376
 377         return true
 378 }
 379
 380 func (h *genericFederatedRequestHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 381         m := h.matcher.FindStringSubmatch(req.URL.Path)
 382         clusterId := ""
 383
 384         if len(m) > 0 && m[2] != "" {
 385                 clusterId = m[2]
 386         }
 387
 388         // Get form parameters from URL and form body (if POST).
 389         if err := loadParamsFromForm(req); err != nil {
 390                 httpserver.Error(w, err.Error(), http.StatusBadRequest)
 391                 return
 392         }
 393
 394         // Check if the parameters have an explicit cluster_id
 395         if req.Form.Get("cluster_id") != "" {
 396                 clusterId = req.Form.Get("cluster_id")
 397         }
 398
 399         // Handle the POST-as-GET special case (workaround for large
 400         // GET requests that potentially exceed maximum URL length,
 401         // like multi-object queries where the filter has 100s of
 402         // items)
 403         effectiveMethod := req.Method
 404         if req.Method == "POST" && req.Form.Get("_method") != "" {
 405                 effectiveMethod = req.Form.Get("_method")
 406         }
 407
 408         if effectiveMethod == "GET" &&
 409                 clusterId == "" &&
 410                 req.Form.Get("filters") != "" &&
 411                 h.handleMultiClusterQuery(w, req, &clusterId) {
 412                 return
 413         }
 414
 415         if clusterId == "" || clusterId == h.handler.Cluster.ClusterID {
 416                 h.next.ServeHTTP(w, req)
 417         } else {
 418                 h.handler.remoteClusterRequest(clusterId, w, req, nil)
 419         }
 420 }
 421
 422 type rewriteSignaturesClusterId struct {
 423         clusterID  string
 424         expectHash string
 425 }
 426
 427 func (rw rewriteSignaturesClusterId) rewriteSignatures(resp *http.Response, requestError error) (newResponse *http.Response, err error) {
 428         if requestError != nil {
 429                 return resp, requestError
 430         }
 431
 432         if resp.StatusCode != 200 {
 433                 return resp, nil
 434         }
 435
 436         originalBody := resp.Body
 437         defer originalBody.Close()
 438
 439         var col arvados.Collection
 440         err = json.NewDecoder(resp.Body).Decode(&col)
 441         if err != nil {
 442                 return nil, err
 443         }
 444
 445         // rewriting signatures will make manifest text 5-10% bigger so calculate
 446         // capacity accordingly
 447         updatedManifest := bytes.NewBuffer(make([]byte, 0, int(float64(len(col.ManifestText))*1.1)))
 448
 449         hasher := md5.New()
 450         mw := io.MultiWriter(hasher, updatedManifest)
 451         sz := 0
 452
 453         scanner := bufio.NewScanner(strings.NewReader(col.ManifestText))
 454         scanner.Buffer(make([]byte, 1048576), len(col.ManifestText))
 455         for scanner.Scan() {
 456                 line := scanner.Text()
 457                 tokens := strings.Split(line, " ")
 458                 if len(tokens) < 3 {
 459                         return nil, fmt.Errorf("Invalid stream (<3 tokens): %q", line)
 460                 }
 461
 462                 n, err := mw.Write([]byte(tokens[0]))
 463                 if err != nil {
 464                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 465                 }
 466                 sz += n
 467                 for _, token := range tokens[1:] {
 468                         n, err = mw.Write([]byte(" "))
 469                         if err != nil {
 470                                 return nil, fmt.Errorf("Error updating manifest: %v", err)
 471                         }
 472                         sz += n
 473
 474                         m := keepclient.SignedLocatorRe.FindStringSubmatch(token)
 475                         if m != nil {
 476                                 // Rewrite the block signature to be a remote signature
 477                                 _, err = fmt.Fprintf(updatedManifest, "%s%s%s+R%s-%s%s", m[1], m[2], m[3], rw.clusterID, m[5][2:], m[8])
 478                                 if err != nil {
 479                                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 480                                 }
 481
 482                                 // for hash checking, ignore signatures
 483                                 n, err = fmt.Fprintf(hasher, "%s%s", m[1], m[2])
 484                                 if err != nil {
 485                                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 486                                 }
 487                                 sz += n
 488                         } else {
 489                                 n, err = mw.Write([]byte(token))
 490                                 if err != nil {
 491                                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 492                                 }
 493                                 sz += n
 494                         }
 495                 }
 496                 n, err = mw.Write([]byte("\n"))
 497                 if err != nil {
 498                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 499                 }
 500                 sz += n
 501         }
 502
 503         // Check that expected hash is consistent with
 504         // portable_data_hash field of the returned record
 505         if rw.expectHash == "" {
 506                 rw.expectHash = col.PortableDataHash
 507         } else if rw.expectHash != col.PortableDataHash {
 508                 return nil, fmt.Errorf("portable_data_hash %q on returned record did not match expected hash %q ", rw.expectHash, col.PortableDataHash)
 509         }
 510
 511         // Certify that the computed hash of the manifest_text matches our expectation
 512         sum := hasher.Sum(nil)
 513         computedHash := fmt.Sprintf("%x+%v", sum, sz)
 514         if computedHash != rw.expectHash {
 515                 return nil, fmt.Errorf("Computed manifest_text hash %q did not match expected hash %q", computedHash, rw.expectHash)
 516         }
 517
 518         col.ManifestText = updatedManifest.String()
 519
 520         newbody, err := json.Marshal(col)
 521         if err != nil {
 522                 return nil, err
 523         }
 524
 525         buf := bytes.NewBuffer(newbody)
 526         resp.Body = ioutil.NopCloser(buf)
 527         resp.ContentLength = int64(buf.Len())
 528         resp.Header.Set("Content-Length", fmt.Sprintf("%v", buf.Len()))
 529
 530         return resp, nil
 531 }
 532
 533 func filterLocalClusterResponse(resp *http.Response, requestError error) (newResponse *http.Response, err error) {
 534         if requestError != nil {
 535                 return resp, requestError
 536         }
 537
 538         if resp.StatusCode == 404 {
 539                 // Suppress returning this result, because we want to
 540                 // search the federation.
 541                 return nil, nil
 542         }
 543         return resp, nil
 544 }
 545
 546 type searchRemoteClusterForPDH struct {
 547         pdh           string
 548         remoteID      string
 549         mtx           *sync.Mutex
 550         sentResponse  *bool
 551         sharedContext *context.Context
 552         cancelFunc    func()
 553         errors        *[]string
 554         statusCode    *int
 555 }
 556
 557 func (s *searchRemoteClusterForPDH) filterRemoteClusterResponse(resp *http.Response, requestError error) (newResponse *http.Response, err error) {
 558         s.mtx.Lock()
 559         defer s.mtx.Unlock()
 560
 561         if *s.sentResponse {
 562                 // Another request already returned a response
 563                 return nil, nil
 564         }
 565
 566         if requestError != nil {
 567                 *s.errors = append(*s.errors, fmt.Sprintf("Request error contacting %q: %v", s.remoteID, requestError))
 568                 // Record the error and suppress response
 569                 return nil, nil
 570         }
 571
 572         if resp.StatusCode != 200 {
 573                 // Suppress returning unsuccessful result.  Maybe
 574                 // another request will find it.
 575                 // TODO collect and return error responses.
 576                 *s.errors = append(*s.errors, fmt.Sprintf("Response from %q: %v", s.remoteID, resp.Status))
 577                 if resp.StatusCode != 404 {
 578                         // Got a non-404 error response, convert into BadGateway
 579                         *s.statusCode = http.StatusBadGateway
 580                 }
 581                 return nil, nil
 582         }
 583
 584         s.mtx.Unlock()
 585
 586         // This reads the response body.  We don't want to hold the
 587         // lock while doing this because other remote requests could
 588         // also have made it to this point, and we don't want a
 589         // slow response holding the lock to block a faster response
 590         // that is waiting on the lock.
 591         newResponse, err = rewriteSignaturesClusterId{s.remoteID, s.pdh}.rewriteSignatures(resp, nil)
 592
 593         s.mtx.Lock()
 594
 595         if *s.sentResponse {
 596                 // Another request already returned a response
 597                 return nil, nil
 598         }
 599
 600         if err != nil {
 601                 // Suppress returning unsuccessful result.  Maybe
 602                 // another request will be successful.
 603                 *s.errors = append(*s.errors, fmt.Sprintf("Error parsing response from %q: %v", s.remoteID, err))
 604                 return nil, nil
 605         }
 606
 607         // We have a successful response.  Suppress/cancel all the
 608         // other requests/responses.
 609         *s.sentResponse = true
 610         s.cancelFunc()
 611
 612         return newResponse, nil
 613 }
 614
 615 func (h *collectionFederatedRequestHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 616         if req.Method != "GET" {
 617                 // Only handle GET requests right now
 618                 h.next.ServeHTTP(w, req)
 619                 return
 620         }
 621
 622         m := collectionByPDHRe.FindStringSubmatch(req.URL.Path)
 623         if len(m) != 2 {
 624                 // Not a collection PDH GET request
 625                 m = collectionRe.FindStringSubmatch(req.URL.Path)
 626                 clusterId := ""
 627
 628                 if len(m) > 0 {
 629                         clusterId = m[2]
 630                 }
 631
 632                 if clusterId != "" && clusterId != h.handler.Cluster.ClusterID {
 633                         // request for remote collection by uuid
 634                         h.handler.remoteClusterRequest(clusterId, w, req,
 635                                 rewriteSignaturesClusterId{clusterId, ""}.rewriteSignatures)
 636                         return
 637                 }
 638                 // not a collection UUID request, or it is a request
 639                 // for a local UUID, either way, continue down the
 640                 // handler stack.
 641                 h.next.ServeHTTP(w, req)
 642                 return
 643         }
 644
 645         // Request for collection by PDH.  Search the federation.
 646
 647         // First, query the local cluster.
 648         if h.handler.localClusterRequest(w, req, filterLocalClusterResponse) {
 649                 return
 650         }
 651
 652         sharedContext, cancelFunc := context.WithCancel(req.Context())
 653         defer cancelFunc()
 654         req = req.WithContext(sharedContext)
 655
 656         // Create a goroutine for each cluster in the
 657         // RemoteClusters map.  The first valid result gets
 658         // returned to the client.  When that happens, all
 659         // other outstanding requests are cancelled or
 660         // suppressed.
 661         sentResponse := false
 662         mtx := sync.Mutex{}
 663         wg := sync.WaitGroup{}
 664         var errors []string
 665         var errorCode int = 404
 666
 667         // use channel as a semaphore to limit the number of concurrent
 668         // requests at a time
 669         sem := make(chan bool, h.handler.FederatedRequestConcurrency())
 670         defer close(sem)
 671         for remoteID := range h.handler.Cluster.RemoteClusters {
 672                 // blocks until it can put a value into the
 673                 // channel (which has a max queue capacity)
 674                 sem <- true
 675                 if sentResponse {
 676                         break
 677                 }
 678                 search := &searchRemoteClusterForPDH{m[1], remoteID, &mtx, &sentResponse,
 679                         &sharedContext, cancelFunc, &errors, &errorCode}
 680                 wg.Add(1)
 681                 go func() {
 682                         h.handler.remoteClusterRequest(search.remoteID, w, req, search.filterRemoteClusterResponse)
 683                         wg.Done()
 684                         <-sem
 685                 }()
 686         }
 687         wg.Wait()
 688
 689         if sentResponse {
 690                 return
 691         }
 692
 693         // No successful responses, so return the error
 694         httpserver.Errors(w, errors, errorCode)
 695 }
 696
 697 func (h *Handler) setupProxyRemoteCluster(next http.Handler) http.Handler {
 698         mux := http.NewServeMux()
 699         mux.Handle("/arvados/v1/workflows", &genericFederatedRequestHandler{next, h, wfRe})
 700         mux.Handle("/arvados/v1/workflows/", &genericFederatedRequestHandler{next, h, wfRe})
 701         mux.Handle("/arvados/v1/containers", &genericFederatedRequestHandler{next, h, containersRe})
 702         mux.Handle("/arvados/v1/containers/", &genericFederatedRequestHandler{next, h, containersRe})
 703         mux.Handle("/arvados/v1/container_requests", &genericFederatedRequestHandler{next, h, containerRequestsRe})
 704         mux.Handle("/arvados/v1/container_requests/", &genericFederatedRequestHandler{next, h, containerRequestsRe})
 705         mux.Handle("/arvados/v1/collections", next)
 706         mux.Handle("/arvados/v1/collections/", &collectionFederatedRequestHandler{next, h})
 707         mux.Handle("/", next)
 708
 709         return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
 710                 parts := strings.Split(req.Header.Get("Authorization"), "/")
 711                 alreadySalted := (len(parts) == 3 && parts[0] == "Bearer v2" && len(parts[2]) == 40)
 712
 713                 if alreadySalted ||
 714                         strings.Index(req.Header.Get("Via"), "arvados-controller") != -1 {
 715                         // The token is already salted, or this is a
 716                         // request from another instance of
 717                         // arvados-controller.  In either case, we
 718                         // don't want to proxy this query, so just
 719                         // continue down the instance handler stack.
 720                         next.ServeHTTP(w, req)
 721                         return
 722                 }
 723
 724                 mux.ServeHTTP(w, req)
 725         })
 726
 727         return mux
 728 }
 729
 730 type CurrentUser struct {
 731         Authorization arvados.APIClientAuthorization
 732         UUID          string
 733 }
 734
 735 func (h *Handler) validateAPItoken(req *http.Request, user *CurrentUser) error {
 736         db, err := h.db(req)
 737         if err != nil {
 738                 return err
 739         }
 740         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)
 741 }
 742
 743 // Extract the auth token supplied in req, and replace it with a
 744 // salted token for the remote cluster.
 745 func (h *Handler) saltAuthToken(req *http.Request, remote string) error {
 746         creds := auth.NewCredentials()
 747         creds.LoadTokensFromHTTPRequest(req)
 748         if len(creds.Tokens) == 0 && req.Header.Get("Content-Type") == "application/x-www-form-encoded" {
 749                 // Override ParseForm's 10MiB limit by ensuring
 750                 // req.Body is a *http.maxBytesReader.
 751                 req.Body = http.MaxBytesReader(nil, req.Body, 1<<28) // 256MiB. TODO: use MaxRequestSize from discovery doc or config.
 752                 if err := creds.LoadTokensFromHTTPRequestBody(req); err != nil {
 753                         return err
 754                 }
 755                 // Replace req.Body with a buffer that re-encodes the
 756                 // form without api_token, in case we end up
 757                 // forwarding the request.
 758                 if req.PostForm != nil {
 759                         req.PostForm.Del("api_token")
 760                 }
 761                 req.Body = ioutil.NopCloser(bytes.NewBufferString(req.PostForm.Encode()))
 762         }
 763         if len(creds.Tokens) == 0 {
 764                 return nil
 765         }
 766         token, err := auth.SaltToken(creds.Tokens[0], remote)
 767         if err == auth.ErrObsoleteToken {
 768                 // If the token exists in our own database, salt it
 769                 // for the remote. Otherwise, assume it was issued by
 770                 // the remote, and pass it through unmodified.
 771                 currentUser := CurrentUser{Authorization: arvados.APIClientAuthorization{APIToken: creds.Tokens[0]}}
 772                 err = h.validateAPItoken(req, &currentUser)
 773                 if err == sql.ErrNoRows {
 774                         // Not ours; pass through unmodified.
 775                         token = currentUser.Authorization.APIToken
 776                 } else if err != nil {
 777                         return err
 778                 } else {
 779                         // Found; make V2 version and salt it.
 780                         token, err = auth.SaltToken(currentUser.Authorization.TokenV2(), remote)
 781                         if err != nil {
 782                                 return err
 783                         }
 784                 }
 785         } else if err != nil {
 786                 return err
 787         }
 788         req.Header.Set("Authorization", "Bearer "+token)
 789
 790         // Remove api_token=... from the the query string, in case we
 791         // end up forwarding the request.
 792         if values, err := url.ParseQuery(req.URL.RawQuery); err != nil {
 793                 return err
 794         } else if _, ok := values["api_token"]; ok {
 795                 delete(values, "api_token")
 796                 req.URL.RawQuery = values.Encode()
 797         }
 798         return nil
 799 }