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