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         for _, f1 := range filters {
 168                 if len(f1) != 3 {
 169                         return false
 170                 }
 171                 lhs, ok := f1[0].(string)
 172                 if ok && lhs == "uuid" {
 173                         op, ok := f1[1].(string)
 174                         if !ok {
 175                                 return false
 176                         }
 177
 178                         if op == "in" {
 179                                 rhs, ok := f1[2].([]interface{})
 180                                 if ok {
 181                                         for _, i := range rhs {
 182                                                 u := i.(string)
 183                                                 *clusterId = u[0:5]
 184                                                 queryClusters[u[0:5]] = append(queryClusters[u[0:5]], u)
 185                                         }
 186                                 }
 187                         } else if op == "=" {
 188                                 u, ok := f1[2].(string)
 189                                 if ok {
 190                                         *clusterId = u[0:5]
 191                                         queryClusters[u[0:5]] = append(queryClusters[u[0:5]], u)
 192                                 }
 193                         } else {
 194                                 return false
 195                         }
 196                 } else {
 197                         return false
 198                 }
 199         }
 200
 201         if len(queryClusters) <= 1 {
 202                 // Did not find a list query to search for uuids
 203                 // across multiple clusters.
 204                 return false
 205         }
 206
 207         if !(len(params["count"]) == 1 && (params["count"][0] == `none` ||
 208                 params["count"][0] == `"none"`)) {
 209                 httpserver.Error(w, "Federated multi-object query must have 'count=none'", http.StatusBadRequest)
 210                 return true
 211         }
 212         if len(params["limit"]) != 0 || len(params["offset"]) != 0 || len(params["order"]) != 0 {
 213                 httpserver.Error(w, "Federated multi-object may not provide 'limit', 'offset' or 'order'.", http.StatusBadRequest)
 214                 return true
 215         }
 216
 217         wg := sync.WaitGroup{}
 218
 219         // use channel as a semaphore to limit it to 4
 220         // parallel requests at a time
 221         sem := make(chan bool, 4)
 222         defer close(sem)
 223         req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
 224
 225         rc := multiClusterQueryResponseCollector{}
 226         for k, v := range queryClusters {
 227                 // blocks until it can put a value into the
 228                 // channel (which has a max queue capacity)
 229                 sem <- true
 230                 wg.Add(1)
 231                 go func(k string, v []string) {
 232                         defer func() {
 233                                 wg.Done()
 234                                 <-sem
 235                         }()
 236                         var remoteReq http.Request
 237                         remoteReq.Header = req.Header
 238                         remoteReq.Method = "POST"
 239                         remoteReq.URL = &url.URL{Path: req.URL.Path}
 240                         remoteParams := make(url.Values)
 241                         remoteParams["_method"] = []string{"GET"}
 242                         remoteParams["count"] = []string{"none"}
 243                         if _, ok := params["select"]; ok {
 244                                 remoteParams["select"] = params["select"]
 245                         }
 246                         content, err := json.Marshal(v)
 247                         if err != nil {
 248                                 rc.mtx.Lock()
 249                                 defer rc.mtx.Unlock()
 250                                 rc.errors = append(rc.errors, err)
 251                                 return
 252                         }
 253                         remoteParams["filters"] = []string{fmt.Sprintf(`[["uuid", "in", %s]]`, content)}
 254                         enc := remoteParams.Encode()
 255                         remoteReq.Body = ioutil.NopCloser(bytes.NewBufferString(enc))
 256
 257                         if k == h.handler.Cluster.ClusterID {
 258                                 h.handler.localClusterRequest(w, &remoteReq,
 259                                         rc.collectResponse)
 260                         } else {
 261                                 h.handler.remoteClusterRequest(k, w, &remoteReq,
 262                                         rc.collectResponse)
 263                         }
 264                 }(k, v)
 265         }
 266         wg.Wait()
 267
 268         if len(rc.errors) > 0 {
 269                 // parallel query
 270                 var strerr []string
 271                 for _, e := range rc.errors {
 272                         strerr = append(strerr, e.Error())
 273                 }
 274                 httpserver.Errors(w, strerr, http.StatusBadGateway)
 275         } else {
 276                 w.Header().Set("Content-Type", "application/json")
 277                 w.WriteHeader(http.StatusOK)
 278                 itemList := make(map[string]interface{})
 279                 itemList["items"] = rc.responses
 280                 itemList["kind"] = rc.kind
 281                 json.NewEncoder(w).Encode(itemList)
 282         }
 283
 284         return true
 285 }
 286
 287 func (h *genericFederatedRequestHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 288         m := h.matcher.FindStringSubmatch(req.URL.Path)
 289         clusterId := ""
 290
 291         if len(m) > 0 && m[2] != "" {
 292                 clusterId = m[2]
 293         }
 294
 295         // First, parse the query portion of the URL.
 296         var params url.Values
 297         var err error
 298         if params, err = url.ParseQuery(req.URL.RawQuery); err != nil {
 299                 httpserver.Error(w, err.Error(), http.StatusBadRequest)
 300                 return
 301         }
 302
 303         // Next, if appropriate, merge in parameters from the form POST body.
 304         if req.Method == "POST" && req.Header.Get("Content-Type") == "application/x-www-form-urlencoded" {
 305                 if err = loadParamsFromForm(req, params); err != nil {
 306                         httpserver.Error(w, err.Error(), http.StatusBadRequest)
 307                         return
 308                 }
 309         }
 310
 311         // Check if the parameters have an explicit cluster_id
 312         if len(params["cluster_id"]) == 1 {
 313                 clusterId = params["cluster_id"][0]
 314         }
 315
 316         // Handle the POST-as-GET special case (workaround for large
 317         // GET requests that potentially exceed maximum URL length,
 318         // like multi-object queries where the filter has 100s of
 319         // items)
 320         effectiveMethod := req.Method
 321         if req.Method == "POST" && len(params["_method"]) == 1 {
 322                 effectiveMethod = params["_method"][0]
 323         }
 324
 325         if effectiveMethod == "GET" && clusterId == "" && len(params["filters"]) == 1 {
 326                 if h.handleMultiClusterQuery(w, req, params, &clusterId) {
 327                         return
 328                 }
 329         }
 330
 331         if clusterId == "" || clusterId == h.handler.Cluster.ClusterID {
 332                 h.next.ServeHTTP(w, req)
 333         } else {
 334                 h.handler.remoteClusterRequest(clusterId, w, req, nil)
 335         }
 336 }
 337
 338 type rewriteSignaturesClusterId struct {
 339         clusterID  string
 340         expectHash string
 341 }
 342
 343 func (rw rewriteSignaturesClusterId) rewriteSignatures(resp *http.Response, requestError error) (newResponse *http.Response, err error) {
 344         if requestError != nil {
 345                 return resp, requestError
 346         }
 347
 348         if resp.StatusCode != 200 {
 349                 return resp, nil
 350         }
 351
 352         originalBody := resp.Body
 353         defer originalBody.Close()
 354
 355         var col arvados.Collection
 356         err = json.NewDecoder(resp.Body).Decode(&col)
 357         if err != nil {
 358                 return nil, err
 359         }
 360
 361         // rewriting signatures will make manifest text 5-10% bigger so calculate
 362         // capacity accordingly
 363         updatedManifest := bytes.NewBuffer(make([]byte, 0, int(float64(len(col.ManifestText))*1.1)))
 364
 365         hasher := md5.New()
 366         mw := io.MultiWriter(hasher, updatedManifest)
 367         sz := 0
 368
 369         scanner := bufio.NewScanner(strings.NewReader(col.ManifestText))
 370         scanner.Buffer(make([]byte, 1048576), len(col.ManifestText))
 371         for scanner.Scan() {
 372                 line := scanner.Text()
 373                 tokens := strings.Split(line, " ")
 374                 if len(tokens) < 3 {
 375                         return nil, fmt.Errorf("Invalid stream (<3 tokens): %q", line)
 376                 }
 377
 378                 n, err := mw.Write([]byte(tokens[0]))
 379                 if err != nil {
 380                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 381                 }
 382                 sz += n
 383                 for _, token := range tokens[1:] {
 384                         n, err = mw.Write([]byte(" "))
 385                         if err != nil {
 386                                 return nil, fmt.Errorf("Error updating manifest: %v", err)
 387                         }
 388                         sz += n
 389
 390                         m := keepclient.SignedLocatorRe.FindStringSubmatch(token)
 391                         if m != nil {
 392                                 // Rewrite the block signature to be a remote signature
 393                                 _, err = fmt.Fprintf(updatedManifest, "%s%s%s+R%s-%s%s", m[1], m[2], m[3], rw.clusterID, m[5][2:], m[8])
 394                                 if err != nil {
 395                                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 396                                 }
 397
 398                                 // for hash checking, ignore signatures
 399                                 n, err = fmt.Fprintf(hasher, "%s%s", m[1], m[2])
 400                                 if err != nil {
 401                                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 402                                 }
 403                                 sz += n
 404                         } else {
 405                                 n, err = mw.Write([]byte(token))
 406                                 if err != nil {
 407                                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 408                                 }
 409                                 sz += n
 410                         }
 411                 }
 412                 n, err = mw.Write([]byte("\n"))
 413                 if err != nil {
 414                         return nil, fmt.Errorf("Error updating manifest: %v", err)
 415                 }
 416                 sz += n
 417         }
 418
 419         // Check that expected hash is consistent with
 420         // portable_data_hash field of the returned record
 421         if rw.expectHash == "" {
 422                 rw.expectHash = col.PortableDataHash
 423         } else if rw.expectHash != col.PortableDataHash {
 424                 return nil, fmt.Errorf("portable_data_hash %q on returned record did not match expected hash %q ", rw.expectHash, col.PortableDataHash)
 425         }
 426
 427         // Certify that the computed hash of the manifest_text matches our expectation
 428         sum := hasher.Sum(nil)
 429         computedHash := fmt.Sprintf("%x+%v", sum, sz)
 430         if computedHash != rw.expectHash {
 431                 return nil, fmt.Errorf("Computed manifest_text hash %q did not match expected hash %q", computedHash, rw.expectHash)
 432         }
 433
 434         col.ManifestText = updatedManifest.String()
 435
 436         newbody, err := json.Marshal(col)
 437         if err != nil {
 438                 return nil, err
 439         }
 440
 441         buf := bytes.NewBuffer(newbody)
 442         resp.Body = ioutil.NopCloser(buf)
 443         resp.ContentLength = int64(buf.Len())
 444         resp.Header.Set("Content-Length", fmt.Sprintf("%v", buf.Len()))
 445
 446         return resp, nil
 447 }
 448
 449 func filterLocalClusterResponse(resp *http.Response, requestError error) (newResponse *http.Response, err error) {
 450         if requestError != nil {
 451                 return resp, requestError
 452         }
 453
 454         if resp.StatusCode == 404 {
 455                 // Suppress returning this result, because we want to
 456                 // search the federation.
 457                 return nil, nil
 458         }
 459         return resp, nil
 460 }
 461
 462 type searchRemoteClusterForPDH struct {
 463         pdh           string
 464         remoteID      string
 465         mtx           *sync.Mutex
 466         sentResponse  *bool
 467         sharedContext *context.Context
 468         cancelFunc    func()
 469         errors        *[]string
 470         statusCode    *int
 471 }
 472
 473 func (s *searchRemoteClusterForPDH) filterRemoteClusterResponse(resp *http.Response, requestError error) (newResponse *http.Response, err error) {
 474         s.mtx.Lock()
 475         defer s.mtx.Unlock()
 476
 477         if *s.sentResponse {
 478                 // Another request already returned a response
 479                 return nil, nil
 480         }
 481
 482         if requestError != nil {
 483                 *s.errors = append(*s.errors, fmt.Sprintf("Request error contacting %q: %v", s.remoteID, requestError))
 484                 // Record the error and suppress response
 485                 return nil, nil
 486         }
 487
 488         if resp.StatusCode != 200 {
 489                 // Suppress returning unsuccessful result.  Maybe
 490                 // another request will find it.
 491                 // TODO collect and return error responses.
 492                 *s.errors = append(*s.errors, fmt.Sprintf("Response from %q: %v", s.remoteID, resp.Status))
 493                 if resp.StatusCode != 404 {
 494                         // Got a non-404 error response, convert into BadGateway
 495                         *s.statusCode = http.StatusBadGateway
 496                 }
 497                 return nil, nil
 498         }
 499
 500         s.mtx.Unlock()
 501
 502         // This reads the response body.  We don't want to hold the
 503         // lock while doing this because other remote requests could
 504         // also have made it to this point, and we don't want a
 505         // slow response holding the lock to block a faster response
 506         // that is waiting on the lock.
 507         newResponse, err = rewriteSignaturesClusterId{s.remoteID, s.pdh}.rewriteSignatures(resp, nil)
 508
 509         s.mtx.Lock()
 510
 511         if *s.sentResponse {
 512                 // Another request already returned a response
 513                 return nil, nil
 514         }
 515
 516         if err != nil {
 517                 // Suppress returning unsuccessful result.  Maybe
 518                 // another request will be successful.
 519                 *s.errors = append(*s.errors, fmt.Sprintf("Error parsing response from %q: %v", s.remoteID, err))
 520                 return nil, nil
 521         }
 522
 523         // We have a successful response.  Suppress/cancel all the
 524         // other requests/responses.
 525         *s.sentResponse = true
 526         s.cancelFunc()
 527
 528         return newResponse, nil
 529 }
 530
 531 func (h *collectionFederatedRequestHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 532         if req.Method != "GET" {
 533                 // Only handle GET requests right now
 534                 h.next.ServeHTTP(w, req)
 535                 return
 536         }
 537
 538         m := collectionByPDHRe.FindStringSubmatch(req.URL.Path)
 539         if len(m) != 2 {
 540                 // Not a collection PDH GET request
 541                 m = collectionRe.FindStringSubmatch(req.URL.Path)
 542                 clusterId := ""
 543
 544                 if len(m) > 0 {
 545                         clusterId = m[2]
 546                 }
 547
 548                 if clusterId != "" && clusterId != h.handler.Cluster.ClusterID {
 549                         // request for remote collection by uuid
 550                         h.handler.remoteClusterRequest(clusterId, w, req,
 551                                 rewriteSignaturesClusterId{clusterId, ""}.rewriteSignatures)
 552                         return
 553                 }
 554                 // not a collection UUID request, or it is a request
 555                 // for a local UUID, either way, continue down the
 556                 // handler stack.
 557                 h.next.ServeHTTP(w, req)
 558                 return
 559         }
 560
 561         // Request for collection by PDH.  Search the federation.
 562
 563         // First, query the local cluster.
 564         if h.handler.localClusterRequest(w, req, filterLocalClusterResponse) {
 565                 return
 566         }
 567
 568         sharedContext, cancelFunc := context.WithCancel(req.Context())
 569         defer cancelFunc()
 570         req = req.WithContext(sharedContext)
 571
 572         // Create a goroutine for each cluster in the
 573         // RemoteClusters map.  The first valid result gets
 574         // returned to the client.  When that happens, all
 575         // other outstanding requests are cancelled or
 576         // suppressed.
 577         sentResponse := false
 578         mtx := sync.Mutex{}
 579         wg := sync.WaitGroup{}
 580         var errors []string
 581         var errorCode int = 404
 582
 583         // use channel as a semaphore to limit it to 4
 584         // parallel requests at a time
 585         sem := make(chan bool, 4)
 586         defer close(sem)
 587         for remoteID := range h.handler.Cluster.RemoteClusters {
 588                 // blocks until it can put a value into the
 589                 // channel (which has a max queue capacity)
 590                 sem <- true
 591                 if sentResponse {
 592                         break
 593                 }
 594                 search := &searchRemoteClusterForPDH{m[1], remoteID, &mtx, &sentResponse,
 595                         &sharedContext, cancelFunc, &errors, &errorCode}
 596                 wg.Add(1)
 597                 go func() {
 598                         h.handler.remoteClusterRequest(search.remoteID, w, req, search.filterRemoteClusterResponse)
 599                         wg.Done()
 600                         <-sem
 601                 }()
 602         }
 603         wg.Wait()
 604
 605         if sentResponse {
 606                 return
 607         }
 608
 609         // No successful responses, so return the error
 610         httpserver.Errors(w, errors, errorCode)
 611 }
 612
 613 func (h *Handler) setupProxyRemoteCluster(next http.Handler) http.Handler {
 614         mux := http.NewServeMux()
 615         mux.Handle("/arvados/v1/workflows", &genericFederatedRequestHandler{next, h, wfRe})
 616         mux.Handle("/arvados/v1/workflows/", &genericFederatedRequestHandler{next, h, wfRe})
 617         mux.Handle("/arvados/v1/containers", &genericFederatedRequestHandler{next, h, containersRe})
 618         mux.Handle("/arvados/v1/containers/", &genericFederatedRequestHandler{next, h, containersRe})
 619         mux.Handle("/arvados/v1/container_requests", &genericFederatedRequestHandler{next, h, containerRequestsRe})
 620         mux.Handle("/arvados/v1/container_requests/", &genericFederatedRequestHandler{next, h, containerRequestsRe})
 621         mux.Handle("/arvados/v1/collections", next)
 622         mux.Handle("/arvados/v1/collections/", &collectionFederatedRequestHandler{next, h})
 623         mux.Handle("/", next)
 624
 625         return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
 626                 parts := strings.Split(req.Header.Get("Authorization"), "/")
 627                 alreadySalted := (len(parts) == 3 && parts[0] == "Bearer v2" && len(parts[2]) == 40)
 628
 629                 if alreadySalted ||
 630                         strings.Index(req.Header.Get("Via"), "arvados-controller") != -1 {
 631                         // The token is already salted, or this is a
 632                         // request from another instance of
 633                         // arvados-controller.  In either case, we
 634                         // don't want to proxy this query, so just
 635                         // continue down the instance handler stack.
 636                         next.ServeHTTP(w, req)
 637                         return
 638                 }
 639
 640                 mux.ServeHTTP(w, req)
 641         })
 642
 643         return mux
 644 }
 645
 646 type CurrentUser struct {
 647         Authorization arvados.APIClientAuthorization
 648         UUID          string
 649 }
 650
 651 func (h *Handler) validateAPItoken(req *http.Request, user *CurrentUser) error {
 652         db, err := h.db(req)
 653         if err != nil {
 654                 return err
 655         }
 656         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)
 657 }
 658
 659 // Extract the auth token supplied in req, and replace it with a
 660 // salted token for the remote cluster.
 661 func (h *Handler) saltAuthToken(req *http.Request, remote string) error {
 662         creds := auth.NewCredentials()
 663         creds.LoadTokensFromHTTPRequest(req)
 664         if len(creds.Tokens) == 0 && req.Header.Get("Content-Type") == "application/x-www-form-encoded" {
 665                 // Override ParseForm's 10MiB limit by ensuring
 666                 // req.Body is a *http.maxBytesReader.
 667                 req.Body = http.MaxBytesReader(nil, req.Body, 1<<28) // 256MiB. TODO: use MaxRequestSize from discovery doc or config.
 668                 if err := creds.LoadTokensFromHTTPRequestBody(req); err != nil {
 669                         return err
 670                 }
 671                 // Replace req.Body with a buffer that re-encodes the
 672                 // form without api_token, in case we end up
 673                 // forwarding the request.
 674                 if req.PostForm != nil {
 675                         req.PostForm.Del("api_token")
 676                 }
 677                 req.Body = ioutil.NopCloser(bytes.NewBufferString(req.PostForm.Encode()))
 678         }
 679         if len(creds.Tokens) == 0 {
 680                 return nil
 681         }
 682         token, err := auth.SaltToken(creds.Tokens[0], remote)
 683         if err == auth.ErrObsoleteToken {
 684                 // If the token exists in our own database, salt it
 685                 // for the remote. Otherwise, assume it was issued by
 686                 // the remote, and pass it through unmodified.
 687                 currentUser := CurrentUser{Authorization: arvados.APIClientAuthorization{APIToken: creds.Tokens[0]}}
 688                 err = h.validateAPItoken(req, &currentUser)
 689                 if err == sql.ErrNoRows {
 690                         // Not ours; pass through unmodified.
 691                         token = currentUser.Authorization.APIToken
 692                 } else if err != nil {
 693                         return err
 694                 } else {
 695                         // Found; make V2 version and salt it.
 696                         token, err = auth.SaltToken(currentUser.Authorization.TokenV2(), remote)
 697                         if err != nil {
 698                                 return err
 699                         }
 700                 }
 701         } else if err != nil {
 702                 return err
 703         }
 704         req.Header.Set("Authorization", "Bearer "+token)
 705
 706         // Remove api_token=... from the the query string, in case we
 707         // end up forwarding the request.
 708         if values, err := url.ParseQuery(req.URL.RawQuery); err != nil {
 709                 return err
 710         } else if _, ok := values["api_token"]; ok {
 711                 delete(values, "api_token")
 712                 req.URL.RawQuery = values.Encode()
 713         }
 714         return nil
 715 }