services/keepproxy/keepproxy.go

   1 // Copyright (C) The Arvados Authors. All rights reserved.
   2 //
   3 // SPDX-License-Identifier: AGPL-3.0
   4
   5 package main
   6
   7 import (
   8         "errors"
   9         "flag"
  10         "fmt"
  11         "io"
  12         "io/ioutil"
  13         "net"
  14         "net/http"
  15         "os"
  16         "os/signal"
  17         "regexp"
  18         "strings"
  19         "syscall"
  20         "time"
  21
  22         "git.arvados.org/arvados.git/lib/config"
  23         "git.arvados.org/arvados.git/sdk/go/arvados"
  24         "git.arvados.org/arvados.git/sdk/go/arvadosclient"
  25         "git.arvados.org/arvados.git/sdk/go/health"
  26         "git.arvados.org/arvados.git/sdk/go/httpserver"
  27         "git.arvados.org/arvados.git/sdk/go/keepclient"
  28         "github.com/coreos/go-systemd/daemon"
  29         "github.com/ghodss/yaml"
  30         "github.com/gorilla/mux"
  31         lru "github.com/hashicorp/golang-lru"
  32         log "github.com/sirupsen/logrus"
  33 )
  34
  35 var version = "dev"
  36
  37 var (
  38         listener net.Listener
  39         router   http.Handler
  40 )
  41
  42 const rfc3339NanoFixed = "2006-01-02T15:04:05.000000000Z07:00"
  43
  44 func configure(logger log.FieldLogger, args []string) (*arvados.Cluster, error) {
  45         flags := flag.NewFlagSet(args[0], flag.ExitOnError)
  46
  47         dumpConfig := flags.Bool("dump-config", false, "write current configuration to stdout and exit")
  48         getVersion := flags.Bool("version", false, "Print version information and exit.")
  49
  50         loader := config.NewLoader(os.Stdin, logger)
  51         loader.SetupFlags(flags)
  52
  53         args = loader.MungeLegacyConfigArgs(logger, args[1:], "-legacy-keepproxy-config")
  54         flags.Parse(args)
  55
  56         // Print version information if requested
  57         if *getVersion {
  58                 fmt.Printf("keepproxy %s\n", version)
  59                 return nil, nil
  60         }
  61
  62         cfg, err := loader.Load()
  63         if err != nil {
  64                 return nil, err
  65         }
  66         cluster, err := cfg.GetCluster("")
  67         if err != nil {
  68                 return nil, err
  69         }
  70
  71         if *dumpConfig {
  72                 out, err := yaml.Marshal(cfg)
  73                 if err != nil {
  74                         return nil, err
  75                 }
  76                 if _, err := os.Stdout.Write(out); err != nil {
  77                         return nil, err
  78                 }
  79                 return nil, nil
  80         }
  81         return cluster, nil
  82 }
  83
  84 func main() {
  85         logger := log.New()
  86         logger.Formatter = &log.JSONFormatter{
  87                 TimestampFormat: rfc3339NanoFixed,
  88         }
  89
  90         cluster, err := configure(logger, os.Args)
  91         if err != nil {
  92                 log.Fatal(err)
  93         }
  94         if cluster == nil {
  95                 return
  96         }
  97
  98         log.Printf("keepproxy %s started", version)
  99
 100         if err := run(logger, cluster); err != nil {
 101                 log.Fatal(err)
 102         }
 103
 104         log.Println("shutting down")
 105 }
 106
 107 func run(logger log.FieldLogger, cluster *arvados.Cluster) error {
 108         client, err := arvados.NewClientFromConfig(cluster)
 109         if err != nil {
 110                 return err
 111         }
 112         client.AuthToken = cluster.SystemRootToken
 113
 114         arv, err := arvadosclient.New(client)
 115         if err != nil {
 116                 return fmt.Errorf("Error setting up arvados client %v", err)
 117         }
 118
 119         // If a config file is available, use the keepstores defined there
 120         // instead of the legacy autodiscover mechanism via the API server
 121         for k := range cluster.Services.Keepstore.InternalURLs {
 122                 arv.KeepServiceURIs = append(arv.KeepServiceURIs, strings.TrimRight(k.String(), "/"))
 123         }
 124
 125         if cluster.SystemLogs.LogLevel == "debug" {
 126                 keepclient.DebugPrintf = log.Printf
 127         }
 128         kc, err := keepclient.MakeKeepClient(arv)
 129         if err != nil {
 130                 return fmt.Errorf("Error setting up keep client %v", err)
 131         }
 132         keepclient.RefreshServiceDiscoveryOnSIGHUP()
 133
 134         if cluster.Collections.DefaultReplication > 0 {
 135                 kc.Want_replicas = cluster.Collections.DefaultReplication
 136         }
 137
 138         var listen arvados.URL
 139         for listen = range cluster.Services.Keepproxy.InternalURLs {
 140                 break
 141         }
 142
 143         var lErr error
 144         listener, lErr = net.Listen("tcp", listen.Host)
 145         if lErr != nil {
 146                 return fmt.Errorf("listen(%s): %v", listen.Host, lErr)
 147         }
 148
 149         if _, err := daemon.SdNotify(false, "READY=1"); err != nil {
 150                 log.Printf("Error notifying init daemon: %v", err)
 151         }
 152         log.Println("listening at", listener.Addr())
 153
 154         // Shut down the server gracefully (by closing the listener)
 155         // if SIGTERM is received.
 156         term := make(chan os.Signal, 1)
 157         go func(sig <-chan os.Signal) {
 158                 s := <-sig
 159                 log.Println("caught signal:", s)
 160                 listener.Close()
 161         }(term)
 162         signal.Notify(term, syscall.SIGTERM)
 163         signal.Notify(term, syscall.SIGINT)
 164
 165         // Start serving requests.
 166         router, err = MakeRESTRouter(kc, time.Duration(keepclient.DefaultProxyRequestTimeout), cluster, logger)
 167         if err != nil {
 168                 return err
 169         }
 170         return http.Serve(listener, httpserver.AddRequestIDs(httpserver.LogRequests(router)))
 171 }
 172
 173 type TokenCacheEntry struct {
 174         expire int64
 175         user   *arvados.User
 176 }
 177
 178 type APITokenCache struct {
 179         tokens     *lru.TwoQueueCache
 180         expireTime int64
 181 }
 182
 183 // RememberToken caches the token and set an expire time.  If the
 184 // token is already in the cache, it is not updated.
 185 func (cache *APITokenCache) RememberToken(token string, user *arvados.User) {
 186         now := time.Now().Unix()
 187         _, ok := cache.tokens.Get(token)
 188         if !ok {
 189                 cache.tokens.Add(token, TokenCacheEntry{
 190                         expire: now + cache.expireTime,
 191                         user:   user,
 192                 })
 193         }
 194 }
 195
 196 // RecallToken checks if the cached token is known and still believed to be
 197 // valid.
 198 func (cache *APITokenCache) RecallToken(token string) (bool, *arvados.User) {
 199         val, ok := cache.tokens.Get(token)
 200         if !ok {
 201                 return false, nil
 202         }
 203
 204         cacheEntry := val.(TokenCacheEntry)
 205         now := time.Now().Unix()
 206         if now < cacheEntry.expire {
 207                 // Token is known and still valid
 208                 return true, cacheEntry.user
 209         } else {
 210                 // Token is expired
 211                 cache.tokens.Remove(token)
 212                 return false, nil
 213         }
 214 }
 215
 216 // GetRemoteAddress returns a string with the remote address for the request.
 217 // If the X-Forwarded-For header is set and has a non-zero length, it returns a
 218 // string made from a comma separated list of all the remote addresses,
 219 // starting with the one(s) from the X-Forwarded-For header.
 220 func GetRemoteAddress(req *http.Request) string {
 221         if xff := req.Header.Get("X-Forwarded-For"); xff != "" {
 222                 return xff + "," + req.RemoteAddr
 223         }
 224         return req.RemoteAddr
 225 }
 226
 227 func (h *proxyHandler) CheckAuthorizationHeader(req *http.Request) (pass bool, tok string, user *arvados.User) {
 228         parts := strings.SplitN(req.Header.Get("Authorization"), " ", 2)
 229         if len(parts) < 2 || !(parts[0] == "OAuth2" || parts[0] == "Bearer") || len(parts[1]) == 0 {
 230                 return false, "", nil
 231         }
 232         tok = parts[1]
 233
 234         // Tokens are validated differently depending on what kind of
 235         // operation is being performed. For example, tokens in
 236         // collection-sharing links permit GET requests, but not
 237         // PUT requests.
 238         var op string
 239         if req.Method == "GET" || req.Method == "HEAD" {
 240                 op = "read"
 241         } else {
 242                 op = "write"
 243         }
 244
 245         if ok, user := h.APITokenCache.RecallToken(op + ":" + tok); ok {
 246                 // Valid in the cache, short circuit
 247                 return true, tok, user
 248         }
 249
 250         var err error
 251         arv := *h.KeepClient.Arvados
 252         arv.ApiToken = tok
 253         arv.RequestID = req.Header.Get("X-Request-Id")
 254         user = &arvados.User{}
 255         userCurrentError := arv.Call("GET", "users", "", "current", nil, user)
 256         err = userCurrentError
 257         if err != nil && op == "read" {
 258                 apiError, ok := err.(arvadosclient.APIServerError)
 259                 if ok && apiError.HttpStatusCode == http.StatusForbidden {
 260                         // If it was a scoped "sharing" token it will
 261                         // return 403 instead of 401 for the current
 262                         // user check.  If it is a download operation
 263                         // and they have permission to read the
 264                         // keep_services table, we can allow it.
 265                         err = arv.Call("HEAD", "keep_services", "", "accessible", nil, nil)
 266                 }
 267         }
 268         if err != nil {
 269                 log.Printf("%s: CheckAuthorizationHeader error: %v", GetRemoteAddress(req), err)
 270                 return false, "", nil
 271         }
 272
 273         if userCurrentError == nil && user.IsAdmin {
 274                 // checking userCurrentError is probably redundant,
 275                 // IsAdmin would be false anyway. But can't hurt.
 276                 if op == "read" && !h.cluster.Collections.KeepproxyPermission.Admin.Download {
 277                         return false, "", nil
 278                 }
 279                 if op == "write" && !h.cluster.Collections.KeepproxyPermission.Admin.Upload {
 280                         return false, "", nil
 281                 }
 282         } else {
 283                 if op == "read" && !h.cluster.Collections.KeepproxyPermission.User.Download {
 284                         return false, "", nil
 285                 }
 286                 if op == "write" && !h.cluster.Collections.KeepproxyPermission.User.Upload {
 287                         return false, "", nil
 288                 }
 289         }
 290
 291         // Success!  Update cache
 292         h.APITokenCache.RememberToken(op+":"+tok, user)
 293
 294         return true, tok, user
 295 }
 296
 297 // We need to make a private copy of the default http transport early
 298 // in initialization, then make copies of our private copy later. It
 299 // won't be safe to copy http.DefaultTransport itself later, because
 300 // its private mutexes might have already been used. (Without this,
 301 // the test suite sometimes panics "concurrent map writes" in
 302 // net/http.(*Transport).removeIdleConnLocked().)
 303 var defaultTransport = *(http.DefaultTransport.(*http.Transport))
 304
 305 type proxyHandler struct {
 306         http.Handler
 307         *keepclient.KeepClient
 308         *APITokenCache
 309         timeout   time.Duration
 310         transport *http.Transport
 311         logger    log.FieldLogger
 312         cluster   *arvados.Cluster
 313 }
 314
 315 // MakeRESTRouter returns an http.Handler that passes GET and PUT
 316 // requests to the appropriate handlers.
 317 func MakeRESTRouter(kc *keepclient.KeepClient, timeout time.Duration, cluster *arvados.Cluster, logger log.FieldLogger) (http.Handler, error) {
 318         rest := mux.NewRouter()
 319
 320         transport := defaultTransport
 321         transport.DialContext = (&net.Dialer{
 322                 Timeout:   keepclient.DefaultConnectTimeout,
 323                 KeepAlive: keepclient.DefaultKeepAlive,
 324                 DualStack: true,
 325         }).DialContext
 326         transport.TLSClientConfig = arvadosclient.MakeTLSConfig(kc.Arvados.ApiInsecure)
 327         transport.TLSHandshakeTimeout = keepclient.DefaultTLSHandshakeTimeout
 328
 329         cacheQ, err := lru.New2Q(500)
 330         if err != nil {
 331                 return nil, fmt.Errorf("Error from lru.New2Q: %v", err)
 332         }
 333
 334         h := &proxyHandler{
 335                 Handler:    rest,
 336                 KeepClient: kc,
 337                 timeout:    timeout,
 338                 transport:  &transport,
 339                 APITokenCache: &APITokenCache{
 340                         tokens:     cacheQ,
 341                         expireTime: 300,
 342                 },
 343                 logger:  logger,
 344                 cluster: cluster,
 345         }
 346
 347         rest.HandleFunc(`/{locator:[0-9a-f]{32}\+.*}`, h.Get).Methods("GET", "HEAD")
 348         rest.HandleFunc(`/{locator:[0-9a-f]{32}}`, h.Get).Methods("GET", "HEAD")
 349
 350         // List all blocks
 351         rest.HandleFunc(`/index`, h.Index).Methods("GET")
 352
 353         // List blocks whose hash has the given prefix
 354         rest.HandleFunc(`/index/{prefix:[0-9a-f]{0,32}}`, h.Index).Methods("GET")
 355
 356         rest.HandleFunc(`/{locator:[0-9a-f]{32}\+.*}`, h.Put).Methods("PUT")
 357         rest.HandleFunc(`/{locator:[0-9a-f]{32}}`, h.Put).Methods("PUT")
 358         rest.HandleFunc(`/`, h.Put).Methods("POST")
 359         rest.HandleFunc(`/{any}`, h.Options).Methods("OPTIONS")
 360         rest.HandleFunc(`/`, h.Options).Methods("OPTIONS")
 361
 362         rest.Handle("/_health/{check}", &health.Handler{
 363                 Token:  cluster.ManagementToken,
 364                 Prefix: "/_health/",
 365         }).Methods("GET")
 366
 367         rest.NotFoundHandler = InvalidPathHandler{}
 368         return h, nil
 369 }
 370
 371 var errLoopDetected = errors.New("loop detected")
 372
 373 func (h *proxyHandler) checkLoop(resp http.ResponseWriter, req *http.Request) error {
 374         if via := req.Header.Get("Via"); strings.Index(via, " "+viaAlias) >= 0 {
 375                 h.logger.Printf("proxy loop detected (request has Via: %q): perhaps keepproxy is misidentified by gateway config as an external client, or its keep_services record does not have service_type=proxy?", via)
 376                 http.Error(resp, errLoopDetected.Error(), http.StatusInternalServerError)
 377                 return errLoopDetected
 378         }
 379         return nil
 380 }
 381
 382 func SetCorsHeaders(resp http.ResponseWriter) {
 383         resp.Header().Set("Access-Control-Allow-Methods", "GET, HEAD, POST, PUT, OPTIONS")
 384         resp.Header().Set("Access-Control-Allow-Origin", "*")
 385         resp.Header().Set("Access-Control-Allow-Headers", "Authorization, Content-Length, Content-Type, X-Keep-Desired-Replicas")
 386         resp.Header().Set("Access-Control-Max-Age", "86486400")
 387 }
 388
 389 type InvalidPathHandler struct{}
 390
 391 func (InvalidPathHandler) ServeHTTP(resp http.ResponseWriter, req *http.Request) {
 392         log.Printf("%s: %s %s unroutable", GetRemoteAddress(req), req.Method, req.URL.Path)
 393         http.Error(resp, "Bad request", http.StatusBadRequest)
 394 }
 395
 396 func (h *proxyHandler) Options(resp http.ResponseWriter, req *http.Request) {
 397         log.Printf("%s: %s %s", GetRemoteAddress(req), req.Method, req.URL.Path)
 398         SetCorsHeaders(resp)
 399 }
 400
 401 var errBadAuthorizationHeader = errors.New("Missing or invalid Authorization header, or method not allowed")
 402 var errContentLengthMismatch = errors.New("Actual length != expected content length")
 403 var errMethodNotSupported = errors.New("Method not supported")
 404
 405 var removeHint, _ = regexp.Compile("\\+K@[a-z0-9]{5}(\\+|$)")
 406
 407 func (h *proxyHandler) Get(resp http.ResponseWriter, req *http.Request) {
 408         if err := h.checkLoop(resp, req); err != nil {
 409                 return
 410         }
 411         SetCorsHeaders(resp)
 412         resp.Header().Set("Via", req.Proto+" "+viaAlias)
 413
 414         locator := mux.Vars(req)["locator"]
 415         var err error
 416         var status int
 417         var expectLength, responseLength int64
 418         var proxiedURI = "-"
 419
 420         defer func() {
 421                 log.Println(GetRemoteAddress(req), req.Method, req.URL.Path, status, expectLength, responseLength, proxiedURI, err)
 422                 if status != http.StatusOK {
 423                         http.Error(resp, err.Error(), status)
 424                 }
 425         }()
 426
 427         kc := h.makeKeepClient(req)
 428
 429         var pass bool
 430         var tok string
 431         var user *arvados.User
 432         if pass, tok, user = h.CheckAuthorizationHeader(req); !pass {
 433                 status, err = http.StatusForbidden, errBadAuthorizationHeader
 434                 return
 435         }
 436
 437         // Copy ArvadosClient struct and use the client's API token
 438         arvclient := *kc.Arvados
 439         arvclient.ApiToken = tok
 440         kc.Arvados = &arvclient
 441
 442         var reader io.ReadCloser
 443
 444         locator = removeHint.ReplaceAllString(locator, "$1")
 445
 446         if locator != "" {
 447                 parts := strings.SplitN(locator, "+", 3)
 448                 if len(parts) >= 2 {
 449                         logger := h.logger
 450                         if user != nil {
 451                                 logger = logger.WithField("user_uuid", user.UUID).
 452                                         WithField("user_full_name", user.FullName)
 453                         }
 454                         logger.WithField("locator", fmt.Sprintf("%s+%s", parts[0], parts[1])).Infof("Block download")
 455                 }
 456         }
 457
 458         switch req.Method {
 459         case "HEAD":
 460                 expectLength, proxiedURI, err = kc.Ask(locator)
 461         case "GET":
 462                 reader, expectLength, proxiedURI, err = kc.Get(locator)
 463                 if reader != nil {
 464                         defer reader.Close()
 465                 }
 466         default:
 467                 status, err = http.StatusNotImplemented, errMethodNotSupported
 468                 return
 469         }
 470
 471         if expectLength == -1 {
 472                 log.Println("Warning:", GetRemoteAddress(req), req.Method, proxiedURI, "Content-Length not provided")
 473         }
 474
 475         switch respErr := err.(type) {
 476         case nil:
 477                 status = http.StatusOK
 478                 resp.Header().Set("Content-Length", fmt.Sprint(expectLength))
 479                 switch req.Method {
 480                 case "HEAD":
 481                         responseLength = 0
 482                 case "GET":
 483                         responseLength, err = io.Copy(resp, reader)
 484                         if err == nil && expectLength > -1 && responseLength != expectLength {
 485                                 err = errContentLengthMismatch
 486                         }
 487                 }
 488         case keepclient.Error:
 489                 if respErr == keepclient.BlockNotFound {
 490                         status = http.StatusNotFound
 491                 } else if respErr.Temporary() {
 492                         status = http.StatusBadGateway
 493                 } else {
 494                         status = 422
 495                 }
 496         default:
 497                 status = http.StatusInternalServerError
 498         }
 499 }
 500
 501 var errLengthRequired = errors.New(http.StatusText(http.StatusLengthRequired))
 502 var errLengthMismatch = errors.New("Locator size hint does not match Content-Length header")
 503
 504 func (h *proxyHandler) Put(resp http.ResponseWriter, req *http.Request) {
 505         if err := h.checkLoop(resp, req); err != nil {
 506                 return
 507         }
 508         SetCorsHeaders(resp)
 509         resp.Header().Set("Via", "HTTP/1.1 "+viaAlias)
 510
 511         kc := h.makeKeepClient(req)
 512
 513         var err error
 514         var expectLength int64
 515         var status = http.StatusInternalServerError
 516         var wroteReplicas int
 517         var locatorOut string = "-"
 518
 519         defer func() {
 520                 log.Println(GetRemoteAddress(req), req.Method, req.URL.Path, status, expectLength, kc.Want_replicas, wroteReplicas, locatorOut, err)
 521                 if status != http.StatusOK {
 522                         http.Error(resp, err.Error(), status)
 523                 }
 524         }()
 525
 526         locatorIn := mux.Vars(req)["locator"]
 527
 528         // Check if the client specified storage classes
 529         if req.Header.Get("X-Keep-Storage-Classes") != "" {
 530                 var scl []string
 531                 for _, sc := range strings.Split(req.Header.Get("X-Keep-Storage-Classes"), ",") {
 532                         scl = append(scl, strings.Trim(sc, " "))
 533                 }
 534                 kc.SetStorageClasses(scl)
 535         }
 536
 537         _, err = fmt.Sscanf(req.Header.Get("Content-Length"), "%d", &expectLength)
 538         if err != nil || expectLength < 0 {
 539                 err = errLengthRequired
 540                 status = http.StatusLengthRequired
 541                 return
 542         }
 543
 544         if locatorIn != "" {
 545                 var loc *keepclient.Locator
 546                 if loc, err = keepclient.MakeLocator(locatorIn); err != nil {
 547                         status = http.StatusBadRequest
 548                         return
 549                 } else if loc.Size > 0 && int64(loc.Size) != expectLength {
 550                         err = errLengthMismatch
 551                         status = http.StatusBadRequest
 552                         return
 553                 }
 554         }
 555
 556         var pass bool
 557         var tok string
 558         var user *arvados.User
 559         if pass, tok, user = h.CheckAuthorizationHeader(req); !pass {
 560                 err = errBadAuthorizationHeader
 561                 status = http.StatusForbidden
 562                 return
 563         }
 564
 565         // Copy ArvadosClient struct and use the client's API token
 566         arvclient := *kc.Arvados
 567         arvclient.ApiToken = tok
 568         kc.Arvados = &arvclient
 569
 570         // Check if the client specified the number of replicas
 571         if desiredReplicas := req.Header.Get(keepclient.XKeepDesiredReplicas); desiredReplicas != "" {
 572                 var r int
 573                 _, err := fmt.Sscanf(desiredReplicas, "%d", &r)
 574                 if err == nil {
 575                         kc.Want_replicas = r
 576                 }
 577         }
 578
 579         // Now try to put the block through
 580         if locatorIn == "" {
 581                 bytes, err2 := ioutil.ReadAll(req.Body)
 582                 if err2 != nil {
 583                         err = fmt.Errorf("Error reading request body: %s", err2)
 584                         status = http.StatusInternalServerError
 585                         return
 586                 }
 587                 locatorOut, wroteReplicas, err = kc.PutB(bytes)
 588         } else {
 589                 locatorOut, wroteReplicas, err = kc.PutHR(locatorIn, req.Body, expectLength)
 590         }
 591
 592         if locatorOut != "" {
 593                 parts := strings.SplitN(locatorOut, "+", 3)
 594                 if len(parts) >= 2 {
 595                         logger := h.logger
 596                         if user != nil {
 597                                 logger = logger.WithField("user_uuid", user.UUID).
 598                                         WithField("user_full_name", user.FullName)
 599                         }
 600                         logger.WithField("locator", fmt.Sprintf("%s+%s", parts[0], parts[1])).Infof("Block upload")
 601                 }
 602         }
 603
 604         // Tell the client how many successful PUTs we accomplished
 605         resp.Header().Set(keepclient.XKeepReplicasStored, fmt.Sprintf("%d", wroteReplicas))
 606
 607         switch err.(type) {
 608         case nil:
 609                 status = http.StatusOK
 610                 if len(kc.StorageClasses) > 0 {
 611                         // A successful PUT request with storage classes means that all
 612                         // storage classes were fulfilled, so the client will get a
 613                         // confirmation via the X-Storage-Classes-Confirmed header.
 614                         hdr := ""
 615                         isFirst := true
 616                         for _, sc := range kc.StorageClasses {
 617                                 if isFirst {
 618                                         hdr = fmt.Sprintf("%s=%d", sc, wroteReplicas)
 619                                         isFirst = false
 620                                 } else {
 621                                         hdr += fmt.Sprintf(", %s=%d", sc, wroteReplicas)
 622                                 }
 623                         }
 624                         resp.Header().Set(keepclient.XKeepStorageClassesConfirmed, hdr)
 625                 }
 626                 _, err = io.WriteString(resp, locatorOut)
 627         case keepclient.OversizeBlockError:
 628                 // Too much data
 629                 status = http.StatusRequestEntityTooLarge
 630         case keepclient.InsufficientReplicasError:
 631                 status = http.StatusServiceUnavailable
 632         default:
 633                 status = http.StatusBadGateway
 634         }
 635 }
 636
 637 // ServeHTTP implementation for IndexHandler
 638 // Supports only GET requests for /index/{prefix:[0-9a-f]{0,32}}
 639 // For each keep server found in LocalRoots:
 640 //   Invokes GetIndex using keepclient
 641 //   Expects "complete" response (terminating with blank new line)
 642 //   Aborts on any errors
 643 // Concatenates responses from all those keep servers and returns
 644 func (h *proxyHandler) Index(resp http.ResponseWriter, req *http.Request) {
 645         SetCorsHeaders(resp)
 646
 647         prefix := mux.Vars(req)["prefix"]
 648         var err error
 649         var status int
 650
 651         defer func() {
 652                 if status != http.StatusOK {
 653                         http.Error(resp, err.Error(), status)
 654                 }
 655         }()
 656
 657         kc := h.makeKeepClient(req)
 658         ok, token, _ := h.CheckAuthorizationHeader(req)
 659         if !ok {
 660                 status, err = http.StatusForbidden, errBadAuthorizationHeader
 661                 return
 662         }
 663
 664         // Copy ArvadosClient struct and use the client's API token
 665         arvclient := *kc.Arvados
 666         arvclient.ApiToken = token
 667         kc.Arvados = &arvclient
 668
 669         // Only GET method is supported
 670         if req.Method != "GET" {
 671                 status, err = http.StatusNotImplemented, errMethodNotSupported
 672                 return
 673         }
 674
 675         // Get index from all LocalRoots and write to resp
 676         var reader io.Reader
 677         for uuid := range kc.LocalRoots() {
 678                 reader, err = kc.GetIndex(uuid, prefix)
 679                 if err != nil {
 680                         status = http.StatusBadGateway
 681                         return
 682                 }
 683
 684                 _, err = io.Copy(resp, reader)
 685                 if err != nil {
 686                         status = http.StatusBadGateway
 687                         return
 688                 }
 689         }
 690
 691         // Got index from all the keep servers and wrote to resp
 692         status = http.StatusOK
 693         resp.Write([]byte("\n"))
 694 }
 695
 696 func (h *proxyHandler) makeKeepClient(req *http.Request) *keepclient.KeepClient {
 697         kc := *h.KeepClient
 698         kc.RequestID = req.Header.Get("X-Request-Id")
 699         kc.HTTPClient = &proxyClient{
 700                 client: &http.Client{
 701                         Timeout:   h.timeout,
 702                         Transport: h.transport,
 703                 },
 704                 proto: req.Proto,
 705         }
 706         return &kc
 707 }