gocheese.go

   1 /*
   2 GoCheese -- Python private package repository and caching proxy
   3 Copyright (C) 2019 Sergey Matveev <stargrave@stargrave.org>
   4               2019 Elena Balakhonova <balakhonova_e@riseup.net>
   5
   6 This program is free software: you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation, version 3 of the License.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17 */
  18
  19 // Python private package repository and caching proxy
  20 package main
  21
  22 import (
  23         "bytes"
  24         "context"
  25         "crypto/sha256"
  26         "encoding/hex"
  27         "flag"
  28         "fmt"
  29         "io"
  30         "io/ioutil"
  31         "log"
  32         "net"
  33         "net/http"
  34         "net/url"
  35         "os"
  36         "os/signal"
  37         "path/filepath"
  38         "regexp"
  39         "runtime"
  40         "strings"
  41         "syscall"
  42         "time"
  43
  44         "golang.org/x/net/netutil"
  45 )
  46
  47 const (
  48         HTMLBegin = `<!DOCTYPE html>
  49 <html>
  50   <head>
  51     <title>Links for %s</title>
  52   </head>
  53   <body>
  54 `
  55         HTMLEnd      = "  </body>\n</html>\n"
  56         HTMLElement  = "    <a href=\"%s\"%s>%s</a><br/>\n"
  57         SHA256Prefix = "sha256="
  58         SHA256Ext    = ".sha256"
  59         InternalFlag = ".internal"
  60         GPGSigExt    = ".asc"
  61         GPGSigAttr   = " data-gpg-sig=true"
  62
  63         Warranty = `This program is free software: you can redistribute it and/or modify
  64 it under the terms of the GNU General Public License as published by
  65 the Free Software Foundation, version 3 of the License.
  66
  67 This program is distributed in the hope that it will be useful,
  68 but WITHOUT ANY WARRANTY; without even the implied warranty of
  69 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  70 GNU General Public License for more details.
  71
  72 You should have received a copy of the GNU General Public License
  73 along with this program.  If not, see <http://www.gnu.org/licenses/>.`
  74 )
  75
  76 var (
  77         pkgPyPI        = regexp.MustCompile(`^.*<a href="([^"]+)"[^>]*>(.+)</a><br/>.*$`)
  78         Version string = "UNKNOWN"
  79
  80         root             = flag.String("root", "./packages", "Path to packages directory")
  81         bind             = flag.String("bind", "[::]:8080", "Address to bind to")
  82         tlsCert          = flag.String("tls-cert", "", "Path to TLS X.509 certificate")
  83         tlsKey           = flag.String("tls-key", "", "Path to TLS X.509 private key")
  84         norefreshURLPath = flag.String("norefresh", "/norefresh/", "Non-refreshing URL path")
  85         refreshURLPath   = flag.String("refresh", "/simple/", "Auto-refreshing URL path")
  86         gpgUpdateURLPath = flag.String("gpgupdate", "/gpgupdate/", "GPG forceful refreshing URL path")
  87         pypiURL          = flag.String("pypi", "https://pypi.org/simple/", "Upstream PyPI URL")
  88         passwdPath       = flag.String("passwd", "passwd", "Path to file with authenticators")
  89         passwdCheck      = flag.Bool("passwd-check", false, "Test the -passwd file for syntax errors and exit")
  90         fsck             = flag.Bool("fsck", false, "Check integrity of all packages")
  91         maxClients       = flag.Int("maxclients", 128, "Maximal amount of simultaneous clients")
  92         version          = flag.Bool("version", false, "Print version information")
  93         warranty         = flag.Bool("warranty", false, "Print warranty information")
  94
  95         killed bool
  96
  97         normalizationRe *regexp.Regexp = regexp.MustCompilePOSIX("[-_.]+")
  98 )
  99
 100 func mkdirForPkg(w http.ResponseWriter, r *http.Request, dir string) bool {
 101         path := filepath.Join(*root, dir)
 102         if _, err := os.Stat(path); os.IsNotExist(err) {
 103                 if err = os.Mkdir(path, os.FileMode(0777)); err != nil {
 104                         http.Error(w, err.Error(), http.StatusInternalServerError)
 105                         return false
 106                 }
 107                 log.Println(r.RemoteAddr, "mkdir", dir)
 108         }
 109         return true
 110 }
 111
 112 func refreshDir(
 113         w http.ResponseWriter,
 114         r *http.Request,
 115         dir,
 116         filenameGet string,
 117         gpgUpdate bool,
 118 ) bool {
 119         if _, err := os.Stat(filepath.Join(*root, dir, InternalFlag)); err == nil {
 120                 return true
 121         }
 122         resp, err := http.Get(*pypiURL + dir + "/")
 123         if err != nil {
 124                 http.Error(w, err.Error(), http.StatusBadGateway)
 125                 return false
 126         }
 127         body, err := ioutil.ReadAll(resp.Body)
 128         resp.Body.Close()
 129         if err != nil {
 130                 http.Error(w, err.Error(), http.StatusBadGateway)
 131                 return false
 132         }
 133         if !mkdirForPkg(w, r, dir) {
 134                 return false
 135         }
 136         dirPath := filepath.Join(*root, dir)
 137         var submatches []string
 138         var uri string
 139         var filename string
 140         var path string
 141         var pkgURL *url.URL
 142         var digest []byte
 143         for _, lineRaw := range bytes.Split(body, []byte("\n")) {
 144                 submatches = pkgPyPI.FindStringSubmatch(string(lineRaw))
 145                 if len(submatches) == 0 {
 146                         continue
 147                 }
 148                 uri = submatches[1]
 149                 filename = submatches[2]
 150                 if pkgURL, err = url.Parse(uri); err != nil {
 151                         http.Error(w, err.Error(), http.StatusInternalServerError)
 152                         return false
 153                 }
 154                 if !strings.HasPrefix(pkgURL.Fragment, SHA256Prefix) {
 155                         log.Println(r.RemoteAddr, "pypi", filename, "no SHA256 digest provided")
 156                         http.Error(w, "no SHA256 digest provided", http.StatusBadGateway)
 157                         return false
 158                 }
 159                 digest, err = hex.DecodeString(strings.TrimPrefix(pkgURL.Fragment, SHA256Prefix))
 160                 if err != nil {
 161                         http.Error(w, err.Error(), http.StatusBadGateway)
 162                         return false
 163                 }
 164                 pkgURL.Fragment = ""
 165                 path = filepath.Join(dirPath, filename)
 166                 if filename == filenameGet {
 167                         if killed {
 168                                 // Skip heavy remote call, when shutting down
 169                                 http.Error(w, "shutting down", http.StatusInternalServerError)
 170                                 return false
 171                         }
 172                         log.Println(r.RemoteAddr, "pypi download", filename)
 173                         resp, err = http.Get(pkgURL.String())
 174                         if err != nil {
 175                                 http.Error(w, err.Error(), http.StatusBadGateway)
 176                                 return false
 177                         }
 178                         defer resp.Body.Close()
 179                         hasher := sha256.New()
 180                         dst, err := TempFile(dirPath)
 181                         if err != nil {
 182                                 http.Error(w, err.Error(), http.StatusInternalServerError)
 183                                 return false
 184                         }
 185                         wr := io.MultiWriter(hasher, dst)
 186                         if _, err = io.Copy(wr, resp.Body); err != nil {
 187                                 os.Remove(dst.Name())
 188                                 dst.Close()
 189                                 http.Error(w, err.Error(), http.StatusInternalServerError)
 190                                 return false
 191                         }
 192                         if bytes.Compare(hasher.Sum(nil), digest) != 0 {
 193                                 log.Println(r.RemoteAddr, "pypi", filename, "digest mismatch")
 194                                 os.Remove(dst.Name())
 195                                 dst.Close()
 196                                 http.Error(w, err.Error(), http.StatusBadGateway)
 197                                 return false
 198                         }
 199                         if err = dst.Sync(); err != nil {
 200                                 os.Remove(dst.Name())
 201                                 dst.Close()
 202                                 http.Error(w, err.Error(), http.StatusInternalServerError)
 203                                 return false
 204                         }
 205                         dst.Close()
 206                         if err = os.Rename(dst.Name(), path); err != nil {
 207                                 http.Error(w, err.Error(), http.StatusInternalServerError)
 208                                 return false
 209                         }
 210                         if err = DirSync(dirPath); err != nil {
 211                                 http.Error(w, err.Error(), http.StatusInternalServerError)
 212                                 return false
 213                         }
 214                 }
 215                 if filename == filenameGet || gpgUpdate {
 216                         if _, err = os.Stat(path); err != nil {
 217                                 goto GPGSigSkip
 218                         }
 219                         resp, err := http.Get(pkgURL.String() + GPGSigExt)
 220                         if err != nil {
 221                                 goto GPGSigSkip
 222                         }
 223                         if resp.StatusCode != http.StatusOK {
 224                                 resp.Body.Close()
 225                                 goto GPGSigSkip
 226                         }
 227                         sig, err := ioutil.ReadAll(resp.Body)
 228                         resp.Body.Close()
 229                         if err != nil {
 230                                 goto GPGSigSkip
 231                         }
 232                         if err = WriteFileSync(dirPath, path+GPGSigExt, sig); err != nil {
 233                                 http.Error(w, err.Error(), http.StatusInternalServerError)
 234                                 return false
 235                         }
 236                         log.Println(r.RemoteAddr, "pypi downloaded signature", filename)
 237                 }
 238         GPGSigSkip:
 239                 path = path + SHA256Ext
 240                 _, err = os.Stat(path)
 241                 if err == nil {
 242                         continue
 243                 }
 244                 if !os.IsNotExist(err) {
 245                         http.Error(w, err.Error(), http.StatusInternalServerError)
 246                         return false
 247                 }
 248                 log.Println(r.RemoteAddr, "pypi touch", filename)
 249                 if err = WriteFileSync(dirPath, path, digest); err != nil {
 250                         http.Error(w, err.Error(), http.StatusInternalServerError)
 251                         return false
 252                 }
 253         }
 254         return true
 255 }
 256
 257 func listRoot(w http.ResponseWriter, r *http.Request) {
 258         files, err := ioutil.ReadDir(*root)
 259         if err != nil {
 260                 http.Error(w, err.Error(), http.StatusInternalServerError)
 261                 return
 262         }
 263         var result bytes.Buffer
 264         result.WriteString(fmt.Sprintf(HTMLBegin, "root"))
 265         for _, file := range files {
 266                 if file.Mode().IsDir() {
 267                         result.WriteString(fmt.Sprintf(
 268                                 HTMLElement,
 269                                 *refreshURLPath+file.Name()+"/",
 270                                 file.Name(),
 271                         ))
 272                 }
 273         }
 274         result.WriteString(HTMLEnd)
 275         w.Write(result.Bytes())
 276 }
 277
 278 func listDir(
 279         w http.ResponseWriter,
 280         r *http.Request,
 281         dir string,
 282         autorefresh,
 283         gpgUpdate bool,
 284 ) {
 285         dirPath := filepath.Join(*root, dir)
 286         if autorefresh {
 287                 if !refreshDir(w, r, dir, "", gpgUpdate) {
 288                         return
 289                 }
 290         } else if _, err := os.Stat(dirPath); os.IsNotExist(err) && !refreshDir(w, r, dir, "", false) {
 291                 return
 292         }
 293         files, err := ioutil.ReadDir(dirPath)
 294         if err != nil {
 295                 http.Error(w, err.Error(), http.StatusInternalServerError)
 296                 return
 297         }
 298         var result bytes.Buffer
 299         result.WriteString(fmt.Sprintf(HTMLBegin, dir))
 300         var data []byte
 301         var gpgSigAttr string
 302         var filenameClean string
 303         for _, file := range files {
 304                 if !strings.HasSuffix(file.Name(), SHA256Ext) {
 305                         continue
 306                 }
 307                 if killed {
 308                         // Skip expensive I/O when shutting down
 309                         http.Error(w, "shutting down", http.StatusInternalServerError)
 310                         return
 311                 }
 312                 data, err = ioutil.ReadFile(filepath.Join(dirPath, file.Name()))
 313                 if err != nil {
 314                         http.Error(w, err.Error(), http.StatusInternalServerError)
 315                         return
 316                 }
 317                 filenameClean = strings.TrimSuffix(file.Name(), SHA256Ext)
 318                 if _, err = os.Stat(filepath.Join(dirPath, filenameClean+GPGSigExt)); os.IsNotExist(err) {
 319                         gpgSigAttr = ""
 320                 } else {
 321                         gpgSigAttr = GPGSigAttr
 322                 }
 323                 result.WriteString(fmt.Sprintf(
 324                         HTMLElement,
 325                         strings.Join([]string{
 326                                 *refreshURLPath, dir, "/",
 327                                 filenameClean, "#", SHA256Prefix, hex.EncodeToString(data),
 328                         }, ""),
 329                         gpgSigAttr,
 330                         filenameClean,
 331                 ))
 332         }
 333         result.WriteString(HTMLEnd)
 334         w.Write(result.Bytes())
 335 }
 336
 337 func servePkg(w http.ResponseWriter, r *http.Request, dir, filename string) {
 338         log.Println(r.RemoteAddr, "get", filename)
 339         path := filepath.Join(*root, dir, filename)
 340         if _, err := os.Stat(path); os.IsNotExist(err) {
 341                 if !refreshDir(w, r, dir, filename, false) {
 342                         return
 343                 }
 344         }
 345         http.ServeFile(w, r, path)
 346 }
 347
 348 func serveUpload(w http.ResponseWriter, r *http.Request) {
 349         // Authentication
 350         username, password, ok := r.BasicAuth()
 351         if !ok {
 352                 log.Println(r.RemoteAddr, "unauthenticated", username)
 353                 http.Error(w, "unauthenticated", http.StatusUnauthorized)
 354                 return
 355         }
 356         auther, ok := passwords[username]
 357         if !ok || !auther.Auth(password) {
 358                 log.Println(r.RemoteAddr, "unauthenticated", username)
 359                 http.Error(w, "unauthenticated", http.StatusUnauthorized)
 360                 return
 361         }
 362
 363         // Form parsing
 364         var err error
 365         if err = r.ParseMultipartForm(1 << 20); err != nil {
 366                 http.Error(w, err.Error(), http.StatusBadRequest)
 367                 return
 368         }
 369         pkgNames, exists := r.MultipartForm.Value["name"]
 370         if !exists || len(pkgNames) != 1 {
 371                 http.Error(w, "single name is expected in request", http.StatusBadRequest)
 372                 return
 373         }
 374         dir := normalizationRe.ReplaceAllString(pkgNames[0], "-")
 375         dirPath := filepath.Join(*root, dir)
 376         var digestExpected []byte
 377         if digestExpectedHex, exists := r.MultipartForm.Value["sha256_digest"]; exists {
 378                 digestExpected, err = hex.DecodeString(digestExpectedHex[0])
 379                 if err != nil {
 380                         http.Error(w, "bad sha256_digest: "+err.Error(), http.StatusBadRequest)
 381                         return
 382                 }
 383         }
 384         gpgSigsExpected := make(map[string]struct{})
 385
 386         // Checking is it internal package
 387         if _, err = os.Stat(filepath.Join(dirPath, InternalFlag)); err != nil {
 388                 log.Println(r.RemoteAddr, "non-internal package", dir)
 389                 http.Error(w, "unknown internal package", http.StatusUnauthorized)
 390                 return
 391         }
 392
 393         for _, file := range r.MultipartForm.File["content"] {
 394                 filename := file.Filename
 395                 gpgSigsExpected[filename+GPGSigExt] = struct{}{}
 396                 log.Println(r.RemoteAddr, "put", filename, "by", username)
 397                 path := filepath.Join(dirPath, filename)
 398                 if _, err = os.Stat(path); err == nil {
 399                         log.Println(r.RemoteAddr, "already exists", filename)
 400                         http.Error(w, "already exists", http.StatusBadRequest)
 401                         return
 402                 }
 403                 if !mkdirForPkg(w, r, dir) {
 404                         return
 405                 }
 406                 src, err := file.Open()
 407                 defer src.Close()
 408                 if err != nil {
 409                         http.Error(w, err.Error(), http.StatusInternalServerError)
 410                         return
 411                 }
 412                 dst, err := TempFile(dirPath)
 413                 if err != nil {
 414                         http.Error(w, err.Error(), http.StatusInternalServerError)
 415                         return
 416                 }
 417                 hasher := sha256.New()
 418                 wr := io.MultiWriter(hasher, dst)
 419                 if _, err = io.Copy(wr, src); err != nil {
 420                         os.Remove(dst.Name())
 421                         dst.Close()
 422                         http.Error(w, err.Error(), http.StatusInternalServerError)
 423                         return
 424                 }
 425                 if err = dst.Sync(); err != nil {
 426                         os.Remove(dst.Name())
 427                         dst.Close()
 428                         http.Error(w, err.Error(), http.StatusInternalServerError)
 429                         return
 430                 }
 431                 dst.Close()
 432                 digest := hasher.Sum(nil)
 433                 if digestExpected != nil {
 434                         if bytes.Compare(digestExpected, digest) == 0 {
 435                                 log.Println(r.RemoteAddr, filename, "good checksum received")
 436                         } else {
 437                                 log.Println(r.RemoteAddr, filename, "bad checksum received")
 438                                 http.Error(w, "bad checksum", http.StatusBadRequest)
 439                                 os.Remove(dst.Name())
 440                                 return
 441                         }
 442                 }
 443                 if err = os.Rename(dst.Name(), path); err != nil {
 444                         http.Error(w, err.Error(), http.StatusInternalServerError)
 445                         return
 446                 }
 447                 if err = DirSync(dirPath); err != nil {
 448                         http.Error(w, err.Error(), http.StatusInternalServerError)
 449                         return
 450                 }
 451                 if err = WriteFileSync(dirPath, path+SHA256Ext, digest); err != nil {
 452                         http.Error(w, err.Error(), http.StatusInternalServerError)
 453                         return
 454                 }
 455         }
 456         for _, file := range r.MultipartForm.File["gpg_signature"] {
 457                 filename := file.Filename
 458                 if _, exists := gpgSigsExpected[filename]; !exists {
 459                         http.Error(w, "unexpected GPG signature filename", http.StatusBadRequest)
 460                         return
 461                 }
 462                 delete(gpgSigsExpected, filename)
 463                 log.Println(r.RemoteAddr, "put", filename, "by", username)
 464                 path := filepath.Join(dirPath, filename)
 465                 if _, err = os.Stat(path); err == nil {
 466                         log.Println(r.RemoteAddr, "already exists", filename)
 467                         http.Error(w, "already exists", http.StatusBadRequest)
 468                         return
 469                 }
 470                 src, err := file.Open()
 471                 if err != nil {
 472                         http.Error(w, err.Error(), http.StatusInternalServerError)
 473                         return
 474                 }
 475                 sig, err := ioutil.ReadAll(src)
 476                 src.Close()
 477                 if err != nil {
 478                         http.Error(w, err.Error(), http.StatusInternalServerError)
 479                         return
 480                 }
 481                 if err = WriteFileSync(dirPath, path, sig); err != nil {
 482                         http.Error(w, err.Error(), http.StatusInternalServerError)
 483                         return
 484                 }
 485         }
 486 }
 487
 488 func handler(w http.ResponseWriter, r *http.Request) {
 489         switch r.Method {
 490         case "GET":
 491                 var path string
 492                 var autorefresh bool
 493                 var gpgUpdate bool
 494                 if strings.HasPrefix(r.URL.Path, *norefreshURLPath) {
 495                         path = strings.TrimPrefix(r.URL.Path, *norefreshURLPath)
 496                 } else if strings.HasPrefix(r.URL.Path, *refreshURLPath) {
 497                         path = strings.TrimPrefix(r.URL.Path, *refreshURLPath)
 498                         autorefresh = true
 499                 } else if strings.HasPrefix(r.URL.Path, *gpgUpdateURLPath) {
 500                         path = strings.TrimPrefix(r.URL.Path, *gpgUpdateURLPath)
 501                         autorefresh = true
 502                         gpgUpdate = true
 503                 } else {
 504                         http.Error(w, "unknown action", http.StatusBadRequest)
 505                         return
 506                 }
 507                 parts := strings.Split(strings.TrimSuffix(path, "/"), "/")
 508                 if len(parts) > 2 {
 509                         http.Error(w, "invalid path", http.StatusBadRequest)
 510                         return
 511                 }
 512                 if len(parts) == 1 {
 513                         if parts[0] == "" {
 514                                 listRoot(w, r)
 515                         } else {
 516                                 listDir(w, r, parts[0], autorefresh, gpgUpdate)
 517                         }
 518                 } else {
 519                         servePkg(w, r, parts[0], parts[1])
 520                 }
 521         case "POST":
 522                 serveUpload(w, r)
 523         default:
 524                 http.Error(w, "unknown action", http.StatusBadRequest)
 525         }
 526 }
 527
 528 func goodIntegrity() bool {
 529         dirs, err := ioutil.ReadDir(*root)
 530         if err != nil {
 531                 log.Fatal(err)
 532         }
 533         hasher := sha256.New()
 534         digest := make([]byte, sha256.Size)
 535         isGood := true
 536         var data []byte
 537         var pkgName string
 538         for _, dir := range dirs {
 539                 files, err := ioutil.ReadDir(filepath.Join(*root, dir.Name()))
 540                 if err != nil {
 541                         log.Fatal(err)
 542                 }
 543                 for _, file := range files {
 544                         if !strings.HasSuffix(file.Name(), SHA256Ext) {
 545                                 continue
 546                         }
 547                         pkgName = strings.TrimSuffix(file.Name(), SHA256Ext)
 548                         data, err = ioutil.ReadFile(filepath.Join(*root, dir.Name(), pkgName))
 549                         if err != nil {
 550                                 if os.IsNotExist(err) {
 551                                         continue
 552                                 }
 553                                 log.Fatal(err)
 554                         }
 555                         hasher.Write(data)
 556                         data, err = ioutil.ReadFile(filepath.Join(*root, dir.Name(), file.Name()))
 557                         if err != nil {
 558                                 log.Fatal(err)
 559                         }
 560                         if bytes.Compare(hasher.Sum(digest[:0]), data) == 0 {
 561                                 fmt.Println(pkgName, "GOOD")
 562                         } else {
 563                                 isGood = false
 564                                 fmt.Println(pkgName, "BAD")
 565                         }
 566                         hasher.Reset()
 567                 }
 568         }
 569         return isGood
 570 }
 571
 572 func main() {
 573         flag.Parse()
 574         if *warranty {
 575                 fmt.Println(Warranty)
 576                 return
 577         }
 578         if *version {
 579                 fmt.Println("GoCheese version " + Version + " built with " + runtime.Version())
 580                 return
 581         }
 582         if *fsck {
 583                 if !goodIntegrity() {
 584                         os.Exit(1)
 585                 }
 586                 return
 587         }
 588         if *passwdCheck {
 589                 refreshPasswd()
 590                 return
 591         }
 592         if (*tlsCert != "" && *tlsKey == "") || (*tlsCert == "" && *tlsKey != "") {
 593                 log.Fatalln("Both -tls-cert and -tls-key are required")
 594         }
 595         refreshPasswd()
 596         log.Println("root:", *root, "bind:", *bind)
 597
 598         ln, err := net.Listen("tcp", *bind)
 599         if err != nil {
 600                 log.Fatal(err)
 601         }
 602         ln = netutil.LimitListener(ln, *maxClients)
 603         server := &http.Server{
 604                 ReadTimeout:  time.Minute,
 605                 WriteTimeout: time.Minute,
 606         }
 607         http.HandleFunc(*norefreshURLPath, handler)
 608         http.HandleFunc(*refreshURLPath, handler)
 609         http.HandleFunc(*gpgUpdateURLPath, handler)
 610
 611         needsRefreshPasswd := make(chan os.Signal, 0)
 612         needsShutdown := make(chan os.Signal, 0)
 613         exitErr := make(chan error, 0)
 614         signal.Notify(needsRefreshPasswd, syscall.SIGHUP)
 615         signal.Notify(needsShutdown, syscall.SIGTERM, syscall.SIGINT)
 616         go func() {
 617                 for range needsRefreshPasswd {
 618                         log.Println("Refreshing passwords")
 619                         refreshPasswd()
 620                 }
 621         }()
 622         go func(s *http.Server) {
 623                 <-needsShutdown
 624                 killed = true
 625                 log.Println("Shutting down")
 626                 ctx, cancel := context.WithTimeout(context.TODO(), time.Minute)
 627                 exitErr <- s.Shutdown(ctx)
 628                 cancel()
 629         }(server)
 630
 631         if *tlsCert == "" {
 632                 err = server.Serve(ln)
 633         } else {
 634                 err = server.ServeTLS(ln, *tlsCert, *tlsKey)
 635         }
 636         if err != http.ErrServerClosed {
 637                 log.Fatal(err)
 638         }
 639         if err := <-exitErr; err != nil {
 640                 log.Fatal(err)
 641         }
 642 }