1// Copyright 2009 The Go Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style 3// license that can be found in the LICENSE file. 4 5// godoc: Go Documentation Server 6 7// Web server tree: 8// 9// http://godoc/ redirect to /pkg/ 10// http://godoc/src/ serve files from $GOROOT/src; .go gets pretty-printed 11// http://godoc/cmd/ serve documentation about commands 12// http://godoc/pkg/ serve documentation about packages 13// (idea is if you say import "compress/zlib", you go to 14// http://godoc/pkg/compress/zlib) 15// 16 17package main 18 19import ( 20 "archive/zip" 21 "bytes" 22 "context" 23 "encoding/json" 24 _ "expvar" // to serve /debug/vars 25 "flag" 26 "fmt" 27 "go/build" 28 exec "golang.org/x/sys/execabs" 29 "io" 30 "log" 31 "net/http" 32 _ "net/http/pprof" // to serve /debug/pprof/* 33 "net/url" 34 "os" 35 "path" 36 "path/filepath" 37 "regexp" 38 "runtime" 39 "strings" 40 41 "golang.org/x/tools/godoc" 42 "golang.org/x/tools/godoc/analysis" 43 "golang.org/x/tools/godoc/static" 44 "golang.org/x/tools/godoc/vfs" 45 "golang.org/x/tools/godoc/vfs/gatefs" 46 "golang.org/x/tools/godoc/vfs/mapfs" 47 "golang.org/x/tools/godoc/vfs/zipfs" 48 "golang.org/x/tools/internal/gocommand" 49 "golang.org/x/xerrors" 50) 51 52const defaultAddr = "localhost:6060" // default webserver address 53 54var ( 55 // file system to serve 56 // (with e.g.: zip -r go.zip $GOROOT -i \*.go -i \*.html -i \*.css -i \*.js -i \*.txt -i \*.c -i \*.h -i \*.s -i \*.png -i \*.jpg -i \*.sh -i favicon.ico) 57 zipfile = flag.String("zip", "", "zip file providing the file system to serve; disabled if empty") 58 59 // file-based index 60 writeIndex = flag.Bool("write_index", false, "write index to a file; the file name must be specified with -index_files") 61 62 analysisFlag = flag.String("analysis", "", `comma-separated list of analyses to perform when in GOPATH mode (supported: type, pointer). See https://golang.org/lib/godoc/analysis/help.html`) 63 64 // network 65 httpAddr = flag.String("http", defaultAddr, "HTTP service address") 66 67 // layout control 68 urlFlag = flag.String("url", "", "print HTML for named URL") 69 70 verbose = flag.Bool("v", false, "verbose mode") 71 72 // file system roots 73 // TODO(gri) consider the invariant that goroot always end in '/' 74 goroot = flag.String("goroot", findGOROOT(), "Go root directory") 75 76 // layout control 77 showTimestamps = flag.Bool("timestamps", false, "show timestamps with directory listings") 78 templateDir = flag.String("templates", "", "load templates/JS/CSS from disk in this directory") 79 showPlayground = flag.Bool("play", false, "enable playground") 80 declLinks = flag.Bool("links", true, "link identifiers to their declarations") 81 82 // search index 83 indexEnabled = flag.Bool("index", false, "enable search index") 84 indexFiles = flag.String("index_files", "", "glob pattern specifying index files; if not empty, the index is read from these files in sorted order") 85 indexInterval = flag.Duration("index_interval", 0, "interval of indexing; 0 for default (5m), negative to only index once at startup") 86 maxResults = flag.Int("maxresults", 10000, "maximum number of full text search results shown") 87 indexThrottle = flag.Float64("index_throttle", 0.75, "index throttle value; 0.0 = no time allocated, 1.0 = full throttle") 88 89 // source code notes 90 notesRx = flag.String("notes", "BUG", "regular expression matching note markers to show") 91) 92 93// An httpResponseRecorder is an http.ResponseWriter 94type httpResponseRecorder struct { 95 body *bytes.Buffer 96 header http.Header 97 code int 98} 99 100func (w *httpResponseRecorder) Header() http.Header { return w.header } 101func (w *httpResponseRecorder) Write(b []byte) (int, error) { return w.body.Write(b) } 102func (w *httpResponseRecorder) WriteHeader(code int) { w.code = code } 103 104func usage() { 105 fmt.Fprintf(os.Stderr, "usage: godoc -http="+defaultAddr+"\n") 106 flag.PrintDefaults() 107 os.Exit(2) 108} 109 110func loggingHandler(h http.Handler) http.Handler { 111 return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) { 112 log.Printf("%s\t%s", req.RemoteAddr, req.URL) 113 h.ServeHTTP(w, req) 114 }) 115} 116 117func handleURLFlag() { 118 // Try up to 10 fetches, following redirects. 119 urlstr := *urlFlag 120 for i := 0; i < 10; i++ { 121 // Prepare request. 122 u, err := url.Parse(urlstr) 123 if err != nil { 124 log.Fatal(err) 125 } 126 req := &http.Request{ 127 URL: u, 128 } 129 130 // Invoke default HTTP handler to serve request 131 // to our buffering httpWriter. 132 w := &httpResponseRecorder{code: 200, header: make(http.Header), body: new(bytes.Buffer)} 133 http.DefaultServeMux.ServeHTTP(w, req) 134 135 // Return data, error, or follow redirect. 136 switch w.code { 137 case 200: // ok 138 os.Stdout.Write(w.body.Bytes()) 139 return 140 case 301, 302, 303, 307: // redirect 141 redirect := w.header.Get("Location") 142 if redirect == "" { 143 log.Fatalf("HTTP %d without Location header", w.code) 144 } 145 urlstr = redirect 146 default: 147 log.Fatalf("HTTP error %d", w.code) 148 } 149 } 150 log.Fatalf("too many redirects") 151} 152 153func initCorpus(corpus *godoc.Corpus) { 154 err := corpus.Init() 155 if err != nil { 156 log.Fatal(err) 157 } 158} 159 160func main() { 161 flag.Usage = usage 162 flag.Parse() 163 164 // Check usage. 165 if flag.NArg() > 0 { 166 fmt.Fprintln(os.Stderr, `Unexpected arguments. Use "go doc" for command-line help output instead. For example, "go doc fmt.Printf".`) 167 usage() 168 } 169 if *httpAddr == "" && *urlFlag == "" && !*writeIndex { 170 fmt.Fprintln(os.Stderr, "At least one of -http, -url, or -write_index must be set to a non-zero value.") 171 usage() 172 } 173 174 // Set the resolved goroot. 175 vfs.GOROOT = *goroot 176 177 fsGate := make(chan bool, 20) 178 179 // Determine file system to use. 180 if *zipfile == "" { 181 // use file system of underlying OS 182 rootfs := gatefs.New(vfs.OS(*goroot), fsGate) 183 fs.Bind("/", rootfs, "/", vfs.BindReplace) 184 } else { 185 // use file system specified via .zip file (path separator must be '/') 186 rc, err := zip.OpenReader(*zipfile) 187 if err != nil { 188 log.Fatalf("%s: %s\n", *zipfile, err) 189 } 190 defer rc.Close() // be nice (e.g., -writeIndex mode) 191 fs.Bind("/", zipfs.New(rc, *zipfile), *goroot, vfs.BindReplace) 192 } 193 if *templateDir != "" { 194 fs.Bind("/lib/godoc", vfs.OS(*templateDir), "/", vfs.BindBefore) 195 fs.Bind("/favicon.ico", vfs.OS(*templateDir), "/favicon.ico", vfs.BindReplace) 196 } else { 197 fs.Bind("/lib/godoc", mapfs.New(static.Files), "/", vfs.BindReplace) 198 fs.Bind("/favicon.ico", mapfs.New(static.Files), "/favicon.ico", vfs.BindReplace) 199 } 200 201 // Get the GOMOD value, use it to determine if godoc is being invoked in module mode. 202 goModFile, err := goMod() 203 if err != nil { 204 fmt.Fprintf(os.Stderr, "failed to determine go env GOMOD value: %v", err) 205 goModFile = "" // Fall back to GOPATH mode. 206 } 207 208 if goModFile != "" { 209 fmt.Printf("using module mode; GOMOD=%s\n", goModFile) 210 211 if *analysisFlag != "" { 212 fmt.Fprintln(os.Stderr, "The -analysis flag is supported only in GOPATH mode at this time.") 213 fmt.Fprintln(os.Stderr, "See https://golang.org/issue/34473.") 214 usage() 215 } 216 217 // Detect whether to use vendor mode or not. 218 mainMod, vendorEnabled, err := gocommand.VendorEnabled(context.Background(), gocommand.Invocation{}, &gocommand.Runner{}) 219 if err != nil { 220 fmt.Fprintf(os.Stderr, "failed to determine if vendoring is enabled: %v", err) 221 os.Exit(1) 222 } 223 if vendorEnabled { 224 // Bind the root directory of the main module. 225 fs.Bind(path.Join("/src", mainMod.Path), gatefs.New(vfs.OS(mainMod.Dir), fsGate), "/", vfs.BindAfter) 226 227 // Bind the vendor directory. 228 // 229 // Note that in module mode, vendor directories in locations 230 // other than the main module's root directory are ignored. 231 // See https://golang.org/ref/mod#vendoring. 232 vendorDir := filepath.Join(mainMod.Dir, "vendor") 233 fs.Bind("/src", gatefs.New(vfs.OS(vendorDir), fsGate), "/", vfs.BindAfter) 234 235 } else { 236 // Try to download dependencies that are not in the module cache in order to 237 // to show their documentation. 238 // This may fail if module downloading is disallowed (GOPROXY=off) or due to 239 // limited connectivity, in which case we print errors to stderr and show 240 // documentation only for packages that are available. 241 fillModuleCache(os.Stderr, goModFile) 242 243 // Determine modules in the build list. 244 mods, err := buildList(goModFile) 245 if err != nil { 246 fmt.Fprintf(os.Stderr, "failed to determine the build list of the main module: %v", err) 247 os.Exit(1) 248 } 249 250 // Bind module trees into Go root. 251 for _, m := range mods { 252 if m.Dir == "" { 253 // Module is not available in the module cache, skip it. 254 continue 255 } 256 dst := path.Join("/src", m.Path) 257 fs.Bind(dst, gatefs.New(vfs.OS(m.Dir), fsGate), "/", vfs.BindAfter) 258 } 259 } 260 } else { 261 fmt.Println("using GOPATH mode") 262 263 // Bind $GOPATH trees into Go root. 264 for _, p := range filepath.SplitList(build.Default.GOPATH) { 265 fs.Bind("/src", gatefs.New(vfs.OS(p), fsGate), "/src", vfs.BindAfter) 266 } 267 } 268 269 var typeAnalysis, pointerAnalysis bool 270 if *analysisFlag != "" { 271 for _, a := range strings.Split(*analysisFlag, ",") { 272 switch a { 273 case "type": 274 typeAnalysis = true 275 case "pointer": 276 pointerAnalysis = true 277 default: 278 log.Fatalf("unknown analysis: %s", a) 279 } 280 } 281 } 282 283 var corpus *godoc.Corpus 284 if goModFile != "" { 285 corpus = godoc.NewCorpus(moduleFS{fs}) 286 } else { 287 corpus = godoc.NewCorpus(fs) 288 } 289 corpus.Verbose = *verbose 290 corpus.MaxResults = *maxResults 291 corpus.IndexEnabled = *indexEnabled 292 if *maxResults == 0 { 293 corpus.IndexFullText = false 294 } 295 corpus.IndexFiles = *indexFiles 296 corpus.IndexDirectory = func(dir string) bool { 297 return dir != "/pkg" && !strings.HasPrefix(dir, "/pkg/") 298 } 299 corpus.IndexThrottle = *indexThrottle 300 corpus.IndexInterval = *indexInterval 301 if *writeIndex || *urlFlag != "" { 302 corpus.IndexThrottle = 1.0 303 corpus.IndexEnabled = true 304 initCorpus(corpus) 305 } else { 306 go initCorpus(corpus) 307 } 308 309 // Initialize the version info before readTemplates, which saves 310 // the map value in a method value. 311 corpus.InitVersionInfo() 312 313 pres = godoc.NewPresentation(corpus) 314 pres.ShowTimestamps = *showTimestamps 315 pres.ShowPlayground = *showPlayground 316 pres.DeclLinks = *declLinks 317 if *notesRx != "" { 318 pres.NotesRx = regexp.MustCompile(*notesRx) 319 } 320 321 readTemplates(pres) 322 registerHandlers(pres) 323 324 if *writeIndex { 325 // Write search index and exit. 326 if *indexFiles == "" { 327 log.Fatal("no index file specified") 328 } 329 330 log.Println("initialize file systems") 331 *verbose = true // want to see what happens 332 333 corpus.UpdateIndex() 334 335 log.Println("writing index file", *indexFiles) 336 f, err := os.Create(*indexFiles) 337 if err != nil { 338 log.Fatal(err) 339 } 340 index, _ := corpus.CurrentIndex() 341 _, err = index.WriteTo(f) 342 if err != nil { 343 log.Fatal(err) 344 } 345 346 log.Println("done") 347 return 348 } 349 350 // Print content that would be served at the URL *urlFlag. 351 if *urlFlag != "" { 352 handleURLFlag() 353 return 354 } 355 356 var handler http.Handler = http.DefaultServeMux 357 if *verbose { 358 log.Printf("Go Documentation Server") 359 log.Printf("version = %s", runtime.Version()) 360 log.Printf("address = %s", *httpAddr) 361 log.Printf("goroot = %s", *goroot) 362 switch { 363 case !*indexEnabled: 364 log.Print("search index disabled") 365 case *maxResults > 0: 366 log.Printf("full text index enabled (maxresults = %d)", *maxResults) 367 default: 368 log.Print("identifier search index enabled") 369 } 370 fs.Fprint(os.Stderr) 371 handler = loggingHandler(handler) 372 } 373 374 // Initialize search index. 375 if *indexEnabled { 376 go corpus.RunIndexer() 377 } 378 379 // Start type/pointer analysis. 380 if typeAnalysis || pointerAnalysis { 381 go analysis.Run(pointerAnalysis, &corpus.Analysis) 382 } 383 384 // Start http server. 385 if *verbose { 386 log.Println("starting HTTP server") 387 } 388 if err := http.ListenAndServe(*httpAddr, handler); err != nil { 389 log.Fatalf("ListenAndServe %s: %v", *httpAddr, err) 390 } 391} 392 393// goMod returns the go env GOMOD value in the current directory 394// by invoking the go command. 395// 396// GOMOD is documented at https://golang.org/cmd/go/#hdr-Environment_variables: 397// 398// The absolute path to the go.mod of the main module, 399// or the empty string if not using modules. 400// 401func goMod() (string, error) { 402 out, err := exec.Command("go", "env", "-json", "GOMOD").Output() 403 if ee := (*exec.ExitError)(nil); xerrors.As(err, &ee) { 404 return "", fmt.Errorf("go command exited unsuccessfully: %v\n%s", ee.ProcessState.String(), ee.Stderr) 405 } else if err != nil { 406 return "", err 407 } 408 var env struct { 409 GoMod string 410 } 411 err = json.Unmarshal(out, &env) 412 if err != nil { 413 return "", err 414 } 415 return env.GoMod, nil 416} 417 418// fillModuleCache does a best-effort attempt to fill the module cache 419// with all dependencies of the main module in the current directory 420// by invoking the go command. Module download logs are streamed to w. 421// If there are any problems encountered, they are also written to w. 422// It should only be used in module mode, when vendor mode isn't on. 423// 424// See https://golang.org/cmd/go/#hdr-Download_modules_to_local_cache. 425func fillModuleCache(w io.Writer, goMod string) { 426 if goMod == os.DevNull { 427 // No module requirements, nothing to do. 428 return 429 } 430 431 cmd := exec.Command("go", "mod", "download", "-json") 432 var out bytes.Buffer 433 cmd.Stdout = &out 434 cmd.Stderr = w 435 err := cmd.Run() 436 if ee := (*exec.ExitError)(nil); xerrors.As(err, &ee) && ee.ExitCode() == 1 { 437 // Exit code 1 from this command means there were some 438 // non-empty Error values in the output. Print them to w. 439 fmt.Fprintf(w, "documentation for some packages is not shown:\n") 440 for dec := json.NewDecoder(&out); ; { 441 var m struct { 442 Path string // Module path. 443 Version string // Module version. 444 Error string // Error loading module. 445 } 446 err := dec.Decode(&m) 447 if err == io.EOF { 448 break 449 } else if err != nil { 450 fmt.Fprintf(w, "error decoding JSON object from go mod download -json: %v\n", err) 451 continue 452 } 453 if m.Error == "" { 454 continue 455 } 456 fmt.Fprintf(w, "\tmodule %s@%s is not in the module cache and there was a problem downloading it: %s\n", m.Path, m.Version, m.Error) 457 } 458 } else if err != nil { 459 fmt.Fprintf(w, "there was a problem filling module cache: %v\n", err) 460 } 461} 462 463type mod struct { 464 Path string // Module path. 465 Dir string // Directory holding files for this module, if any. 466} 467 468// buildList determines the build list in the current directory 469// by invoking the go command. It should only be used in module mode, 470// when vendor mode isn't on. 471// 472// See https://golang.org/cmd/go/#hdr-The_main_module_and_the_build_list. 473func buildList(goMod string) ([]mod, error) { 474 if goMod == os.DevNull { 475 // Empty build list. 476 return nil, nil 477 } 478 479 out, err := exec.Command("go", "list", "-m", "-json", "all").Output() 480 if ee := (*exec.ExitError)(nil); xerrors.As(err, &ee) { 481 return nil, fmt.Errorf("go command exited unsuccessfully: %v\n%s", ee.ProcessState.String(), ee.Stderr) 482 } else if err != nil { 483 return nil, err 484 } 485 var mods []mod 486 for dec := json.NewDecoder(bytes.NewReader(out)); ; { 487 var m mod 488 err := dec.Decode(&m) 489 if err == io.EOF { 490 break 491 } else if err != nil { 492 return nil, err 493 } 494 mods = append(mods, m) 495 } 496 return mods, nil 497} 498 499// moduleFS is a vfs.FileSystem wrapper used when godoc is running 500// in module mode. It's needed so that packages inside modules are 501// considered to be third party. 502// 503// It overrides the RootType method of the underlying filesystem 504// and implements it using a heuristic based on the import path. 505// If the first element of the import path does not contain a dot, 506// that package is considered to be inside GOROOT. If it contains 507// a dot, then that package is considered to be third party. 508// 509// TODO(dmitshur): The RootType abstraction works well when GOPATH 510// workspaces are bound at their roots, but scales poorly in the 511// general case. It should be replaced by a more direct solution 512// for determining whether a package is third party or not. 513// 514type moduleFS struct{ vfs.FileSystem } 515 516func (moduleFS) RootType(path string) vfs.RootType { 517 if !strings.HasPrefix(path, "/src/") { 518 return "" 519 } 520 domain := path[len("/src/"):] 521 if i := strings.Index(domain, "/"); i >= 0 { 522 domain = domain[:i] 523 } 524 if !strings.Contains(domain, ".") { 525 // No dot in the first element of import path 526 // suggests this is a package in GOROOT. 527 return vfs.RootTypeGoRoot 528 } else { 529 // A dot in the first element of import path 530 // suggests this is a third party package. 531 return vfs.RootTypeGoPath 532 } 533} 534func (fs moduleFS) String() string { return "module(" + fs.FileSystem.String() + ")" } 535