From 6e2cb00008cbf09e556b00f87603797fcaa47e09 Mon Sep 17 00:00:00 2001
From: Christopher Speller Welcome to the Go language's HTTP/2 demo & interop server. Unfortunately, you're not using HTTP/2 right now. To do so: See code & instructions for connecting at https://github.com/golang/net/tree/master/http2. Welcome to the Go language's HTTP/2 demo & interop server. Congratulations, you're using HTTP/2 right now. This server exists for others in the HTTP/2 community to test their HTTP/2 client implementations and point out flaws in our server.
-The code is at golang.org/x/net/http2 and
-is used transparently by the Go standard library from Go 1.6 and later.
- Contact info: bradfitz@golang.org, or file a bug. ", xt*yt)
- for _, ms := range []int{0, 30, 200, 1000} {
- d := time.Duration(ms) * nanosPerMilli
- fmt.Fprintf(w, "[HTTP/2, %v latency] [HTTP/1, %v latency] \n")
- cacheBust := time.Now().UnixNano()
- for y := 0; y < yt; y++ {
- for x := 0; x < xt; x++ {
- fmt.Fprintf(w, "",
- tileSize, tileSize, x, y, cacheBust, ms)
- }
- io.WriteString(w, "Go + HTTP/2
-
-
-Go + HTTP/2
-
-Handlers for testing
-
-
-
-`)
-}
-
-func reqInfoHandler(w http.ResponseWriter, r *http.Request) {
- w.Header().Set("Content-Type", "text/plain")
- fmt.Fprintf(w, "Method: %s\n", r.Method)
- fmt.Fprintf(w, "Protocol: %s\n", r.Proto)
- fmt.Fprintf(w, "Host: %s\n", r.Host)
- fmt.Fprintf(w, "RemoteAddr: %s\n", r.RemoteAddr)
- fmt.Fprintf(w, "RequestURI: %q\n", r.RequestURI)
- fmt.Fprintf(w, "URL: %#v\n", r.URL)
- fmt.Fprintf(w, "Body.ContentLength: %d (-1 means unknown)\n", r.ContentLength)
- fmt.Fprintf(w, "Close: %v (relevant for HTTP/1 only)\n", r.Close)
- fmt.Fprintf(w, "TLS: %#v\n", r.TLS)
- fmt.Fprintf(w, "\nHeaders:\n")
- r.Header.Write(w)
-}
-
-func crcHandler(w http.ResponseWriter, r *http.Request) {
- if r.Method != "PUT" {
- http.Error(w, "PUT required.", 400)
- return
- }
- crc := crc32.NewIEEE()
- n, err := io.Copy(crc, r.Body)
- if err == nil {
- w.Header().Set("Content-Type", "text/plain")
- fmt.Fprintf(w, "bytes=%d, CRC32=%x", n, crc.Sum(nil))
- }
-}
-
-type capitalizeReader struct {
- r io.Reader
-}
-
-func (cr capitalizeReader) Read(p []byte) (n int, err error) {
- n, err = cr.r.Read(p)
- for i, b := range p[:n] {
- if b >= 'a' && b <= 'z' {
- p[i] = b - ('a' - 'A')
- }
- }
- return
-}
-
-type flushWriter struct {
- w io.Writer
-}
-
-func (fw flushWriter) Write(p []byte) (n int, err error) {
- n, err = fw.w.Write(p)
- if f, ok := fw.w.(http.Flusher); ok {
- f.Flush()
- }
- return
-}
-
-func echoCapitalHandler(w http.ResponseWriter, r *http.Request) {
- if r.Method != "PUT" {
- http.Error(w, "PUT required.", 400)
- return
- }
- io.Copy(flushWriter{w}, capitalizeReader{r.Body})
-}
-
-var (
- fsGrp singleflight.Group
- fsMu sync.Mutex // guards fsCache
- fsCache = map[string]http.Handler{}
-)
-
-// fileServer returns a file-serving handler that proxies URL.
-// It lazily fetches URL on the first access and caches its contents forever.
-func fileServer(url string, latency time.Duration) http.Handler {
- return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
- if latency > 0 {
- time.Sleep(latency)
- }
- hi, err := fsGrp.Do(url, func() (interface{}, error) {
- fsMu.Lock()
- if h, ok := fsCache[url]; ok {
- fsMu.Unlock()
- return h, nil
- }
- fsMu.Unlock()
-
- res, err := http.Get(url)
- if err != nil {
- return nil, err
- }
- defer res.Body.Close()
- slurp, err := ioutil.ReadAll(res.Body)
- if err != nil {
- return nil, err
- }
-
- modTime := time.Now()
- var h http.Handler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
- http.ServeContent(w, r, path.Base(url), modTime, bytes.NewReader(slurp))
- })
- fsMu.Lock()
- fsCache[url] = h
- fsMu.Unlock()
- return h, nil
- })
- if err != nil {
- http.Error(w, err.Error(), 500)
- return
- }
- hi.(http.Handler).ServeHTTP(w, r)
- })
-}
-
-func clockStreamHandler(w http.ResponseWriter, r *http.Request) {
- clientGone := w.(http.CloseNotifier).CloseNotify()
- w.Header().Set("Content-Type", "text/plain")
- ticker := time.NewTicker(1 * time.Second)
- defer ticker.Stop()
- fmt.Fprintf(w, "# ~1KB of junk to force browsers to start rendering immediately: \n")
- io.WriteString(w, strings.Repeat("# xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\n", 13))
-
- for {
- fmt.Fprintf(w, "%v\n", time.Now())
- w.(http.Flusher).Flush()
- select {
- case <-ticker.C:
- case <-clientGone:
- log.Printf("Client %v disconnected from the clock", r.RemoteAddr)
- return
- }
- }
-}
-
-func registerHandlers() {
- tiles := newGopherTilesHandler()
- push := newPushHandler()
-
- mux2 := http.NewServeMux()
- http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
- switch {
- case r.URL.Path == "/gophertiles":
- tiles.ServeHTTP(w, r) // allow HTTP/2 + HTTP/1.x
- return
- case strings.HasPrefix(r.URL.Path, "/serverpush"):
- push.ServeHTTP(w, r) // allow HTTP/2 + HTTP/1.x
- return
- case r.TLS == nil: // do not allow HTTP/1.x for anything else
- http.Redirect(w, r, "https://"+httpsHost()+"/", http.StatusFound)
- return
- }
- if r.ProtoMajor == 1 {
- if r.URL.Path == "/reqinfo" {
- reqInfoHandler(w, r)
- return
- }
- homeOldHTTP(w, r)
- return
- }
- mux2.ServeHTTP(w, r)
- })
- mux2.HandleFunc("/", home)
- mux2.Handle("/file/gopher.png", fileServer("https://golang.org/doc/gopher/frontpage.png", 0))
- mux2.Handle("/file/go.src.tar.gz", fileServer("https://storage.googleapis.com/golang/go1.4.1.src.tar.gz", 0))
- mux2.HandleFunc("/reqinfo", reqInfoHandler)
- mux2.HandleFunc("/crc32", crcHandler)
- mux2.HandleFunc("/ECHO", echoCapitalHandler)
- mux2.HandleFunc("/clockstream", clockStreamHandler)
- mux2.Handle("/gophertiles", tiles)
- mux2.HandleFunc("/redirect", func(w http.ResponseWriter, r *http.Request) {
- http.Redirect(w, r, "/", http.StatusFound)
- })
- stripHomedir := regexp.MustCompile(`/(Users|home)/\w+`)
- mux2.HandleFunc("/goroutines", func(w http.ResponseWriter, r *http.Request) {
- w.Header().Set("Content-Type", "text/plain; charset=utf-8")
- buf := make([]byte, 2<<20)
- w.Write(stripHomedir.ReplaceAll(buf[:runtime.Stack(buf, true)], nil))
- })
-}
-
-var pushResources = map[string]http.Handler{
- "/serverpush/static/jquery.min.js": fileServer("https://ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js", 100*time.Millisecond),
- "/serverpush/static/godocs.js": fileServer("https://golang.org/lib/godoc/godocs.js", 100*time.Millisecond),
- "/serverpush/static/playground.js": fileServer("https://golang.org/lib/godoc/playground.js", 100*time.Millisecond),
- "/serverpush/static/style.css": fileServer("https://golang.org/lib/godoc/style.css", 100*time.Millisecond),
-}
-
-func newPushHandler() http.Handler {
- return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
- for path, handler := range pushResources {
- if r.URL.Path == path {
- handler.ServeHTTP(w, r)
- return
- }
- }
-
- cacheBust := time.Now().UnixNano()
- if pusher, ok := w.(http.Pusher); ok {
- for path := range pushResources {
- url := fmt.Sprintf("%s?%d", path, cacheBust)
- if err := pusher.Push(url, nil); err != nil {
- log.Printf("Failed to push %v: %v", path, err)
- }
- }
- }
- time.Sleep(100 * time.Millisecond) // fake network latency + parsing time
- if err := pushTmpl.Execute(w, struct {
- CacheBust int64
- HTTPSHost string
- HTTPHost string
- }{
- CacheBust: cacheBust,
- HTTPSHost: httpsHost(),
- HTTPHost: httpHost(),
- }); err != nil {
- log.Printf("Executing server push template: %v", err)
- }
- })
-}
-
-func newGopherTilesHandler() http.Handler {
- const gopherURL = "https://blog.golang.org/go-programming-language-turns-two_gophers.jpg"
- res, err := http.Get(gopherURL)
- if err != nil {
- log.Fatal(err)
- }
- if res.StatusCode != 200 {
- log.Fatalf("Error fetching %s: %v", gopherURL, res.Status)
- }
- slurp, err := ioutil.ReadAll(res.Body)
- res.Body.Close()
- if err != nil {
- log.Fatal(err)
- }
- im, err := jpeg.Decode(bytes.NewReader(slurp))
- if err != nil {
- if len(slurp) > 1024 {
- slurp = slurp[:1024]
- }
- log.Fatalf("Failed to decode gopher image: %v (got %q)", err, slurp)
- }
-
- type subImager interface {
- SubImage(image.Rectangle) image.Image
- }
- const tileSize = 32
- xt := im.Bounds().Max.X / tileSize
- yt := im.Bounds().Max.Y / tileSize
- var tile [][][]byte // y -> x -> jpeg bytes
- for yi := 0; yi < yt; yi++ {
- var row [][]byte
- for xi := 0; xi < xt; xi++ {
- si := im.(subImager).SubImage(image.Rectangle{
- Min: image.Point{xi * tileSize, yi * tileSize},
- Max: image.Point{(xi + 1) * tileSize, (yi + 1) * tileSize},
- })
- buf := new(bytes.Buffer)
- if err := jpeg.Encode(buf, si, &jpeg.Options{Quality: 90}); err != nil {
- log.Fatal(err)
- }
- row = append(row, buf.Bytes())
- }
- tile = append(tile, row)
- }
- return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
- ms, _ := strconv.Atoi(r.FormValue("latency"))
- const nanosPerMilli = 1e6
- if r.FormValue("x") != "" {
- x, _ := strconv.Atoi(r.FormValue("x"))
- y, _ := strconv.Atoi(r.FormValue("y"))
- if ms <= 1000 {
- time.Sleep(time.Duration(ms) * nanosPerMilli)
- }
- if x >= 0 && x < xt && y >= 0 && y < yt {
- http.ServeContent(w, r, "", time.Time{}, bytes.NewReader(tile[y][x]))
- return
- }
- }
- io.WriteString(w, "")
- fmt.Fprintf(w, "A grid of %d tiled images is below. Compare:
\n",
- httpsHost(), ms, d,
- httpHost(), ms, d,
- )
- }
- io.WriteString(w, "
\n")
- }
- io.WriteString(w, `
-Go is a tool for managing Go source code. -
--Usage: -
-go command [arguments] --
-The commands are: -
-build compile packages and dependencies -clean remove object files -doc show documentation for package or symbol -env print Go environment information -bug start a bug report -fix run go tool fix on packages -fmt run gofmt on package sources -generate generate Go files by processing source -get download and install packages and dependencies -install compile and install packages and dependencies -list list packages -run compile and run Go program -test test packages -tool run specified go tool -version print Go version -vet run go tool vet on packages --
-Use "go help [command]" for more information about a command. -
--Additional help topics: -
-c calling between Go and C -buildmode description of build modes -filetype file types -gopath GOPATH environment variable -environment environment variables -importpath import path syntax -packages description of package lists -testflag description of testing flags -testfunc description of testing functions --
-Use "go help [topic]" for more information about that topic. -
--Usage: -
-go build [-o output] [-i] [build flags] [packages] --
-Build compiles the packages named by the import paths, -along with their dependencies, but it does not install the results. -
--If the arguments to build are a list of .go files, build treats -them as a list of source files specifying a single package. -
--When compiling a single main package, build writes -the resulting executable to an output file named after -the first source file ('go build ed.go rx.go' writes 'ed' or 'ed.exe') -or the source code directory ('go build unix/sam' writes 'sam' or 'sam.exe'). -The '.exe' suffix is added when writing a Windows executable. -
--When compiling multiple packages or a single non-main package, -build compiles the packages but discards the resulting object, -serving only as a check that the packages can be built. -
--When compiling packages, build ignores files that end in '_test.go'. -
--The -o flag, only allowed when compiling a single package, -forces build to write the resulting executable or object -to the named output file, instead of the default behavior described -in the last two paragraphs. -
--The -i flag installs the packages that are dependencies of the target. -
--The build flags are shared by the build, clean, get, install, list, run, -and test commands: -
--a - force rebuilding of packages that are already up-to-date. --n - print the commands but do not run them. --p n - the number of programs, such as build commands or - test binaries, that can be run in parallel. - The default is the number of CPUs available. --race - enable data race detection. - Supported only on linux/amd64, freebsd/amd64, darwin/amd64 and windows/amd64. --msan - enable interoperation with memory sanitizer. - Supported only on linux/amd64, - and only with Clang/LLVM as the host C compiler. --v - print the names of packages as they are compiled. --work - print the name of the temporary work directory and - do not delete it when exiting. --x - print the commands. - --asmflags 'flag list' - arguments to pass on each go tool asm invocation. --buildmode mode - build mode to use. See 'go help buildmode' for more. --compiler name - name of compiler to use, as in runtime.Compiler (gccgo or gc). --gccgoflags 'arg list' - arguments to pass on each gccgo compiler/linker invocation. --gcflags 'arg list' - arguments to pass on each go tool compile invocation. --installsuffix suffix - a suffix to use in the name of the package installation directory, - in order to keep output separate from default builds. - If using the -race flag, the install suffix is automatically set to race - or, if set explicitly, has _race appended to it. Likewise for the -msan - flag. Using a -buildmode option that requires non-default compile flags - has a similar effect. --ldflags 'flag list' - arguments to pass on each go tool link invocation. --linkshared - link against shared libraries previously created with - -buildmode=shared. --pkgdir dir - install and load all packages from dir instead of the usual locations. - For example, when building with a non-standard configuration, - use -pkgdir to keep generated packages in a separate location. --tags 'tag list' - a list of build tags to consider satisfied during the build. - For more information about build tags, see the description of - build constraints in the documentation for the go/build package. --toolexec 'cmd args' - a program to use to invoke toolchain programs like vet and asm. - For example, instead of running asm, the go command will run - 'cmd args /path/to/asm <arguments for asm>'. --
-The list flags accept a space-separated list of strings. To embed spaces -in an element in the list, surround it with either single or double quotes. -
--For more about specifying packages, see 'go help packages'. -For more about where packages and binaries are installed, -run 'go help gopath'. -For more about calling between Go and C/C++, run 'go help c'. -
--Note: Build adheres to certain conventions such as those described -by 'go help gopath'. Not all projects can follow these conventions, -however. Installations that have their own conventions or that use -a separate software build system may choose to use lower-level -invocations such as 'go tool compile' and 'go tool link' to avoid -some of the overheads and design decisions of the build tool. -
--See also: go install, go get, go clean. -
--Usage: -
-go clean [-i] [-r] [-n] [-x] [build flags] [packages] --
-Clean removes object files from package source directories. -The go command builds most objects in a temporary directory, -so go clean is mainly concerned with object files left by other -tools or by manual invocations of go build. -
--Specifically, clean removes the following files from each of the -source directories corresponding to the import paths: -
-_obj/ old object directory, left from Makefiles -_test/ old test directory, left from Makefiles -_testmain.go old gotest file, left from Makefiles -test.out old test log, left from Makefiles -build.out old test log, left from Makefiles -*.[568ao] object files, left from Makefiles - -DIR(.exe) from go build -DIR.test(.exe) from go test -c -MAINFILE(.exe) from go build MAINFILE.go -*.so from SWIG --
-In the list, DIR represents the final path element of the -directory, and MAINFILE is the base name of any Go source -file in the directory that is not included when building -the package. -
--The -i flag causes clean to remove the corresponding installed -archive or binary (what 'go install' would create). -
--The -n flag causes clean to print the remove commands it would execute, -but not run them. -
--The -r flag causes clean to be applied recursively to all the -dependencies of the packages named by the import paths. -
--The -x flag causes clean to print remove commands as it executes them. -
--For more about build flags, see 'go help build'. -
--For more about specifying packages, see 'go help packages'. -
--Usage: -
-go doc [-u] [-c] [package|[package.]symbol[.method]] --
-Doc prints the documentation comments associated with the item identified by its -arguments (a package, const, func, type, var, or method) followed by a one-line -summary of each of the first-level items "under" that item (package-level -declarations for a package, methods for a type, etc.). -
--Doc accepts zero, one, or two arguments. -
--Given no arguments, that is, when run as -
-go doc --
-it prints the package documentation for the package in the current directory. -If the package is a command (package main), the exported symbols of the package -are elided from the presentation unless the -cmd flag is provided. -
--When run with one argument, the argument is treated as a Go-syntax-like -representation of the item to be documented. What the argument selects depends -on what is installed in GOROOT and GOPATH, as well as the form of the argument, -which is schematically one of these: -
-go doc <pkg> -go doc <sym>[.<method>] -go doc [<pkg>.]<sym>[.<method>] -go doc [<pkg>.][<sym>.]<method> --
-The first item in this list matched by the argument is the one whose documentation -is printed. (See the examples below.) However, if the argument starts with a capital -letter it is assumed to identify a symbol or method in the current directory. -
--For packages, the order of scanning is determined lexically in breadth-first order. -That is, the package presented is the one that matches the search and is nearest -the root and lexically first at its level of the hierarchy. The GOROOT tree is -always scanned in its entirety before GOPATH. -
--If there is no package specified or matched, the package in the current -directory is selected, so "go doc Foo" shows the documentation for symbol Foo in -the current package. -
--The package path must be either a qualified path or a proper suffix of a -path. The go tool's usual package mechanism does not apply: package path -elements like . and ... are not implemented by go doc. -
--When run with two arguments, the first must be a full package path (not just a -suffix), and the second is a symbol or symbol and method; this is similar to the -syntax accepted by godoc: -
-go doc <pkg> <sym>[.<method>] --
-In all forms, when matching symbols, lower-case letters in the argument match -either case but upper-case letters match exactly. This means that there may be -multiple matches of a lower-case argument in a package if different symbols have -different cases. If this occurs, documentation for all matches is printed. -
--Examples: -
-go doc - Show documentation for current package. -go doc Foo - Show documentation for Foo in the current package. - (Foo starts with a capital letter so it cannot match - a package path.) -go doc encoding/json - Show documentation for the encoding/json package. -go doc json - Shorthand for encoding/json. -go doc json.Number (or go doc json.number) - Show documentation and method summary for json.Number. -go doc json.Number.Int64 (or go doc json.number.int64) - Show documentation for json.Number's Int64 method. -go doc cmd/doc - Show package docs for the doc command. -go doc -cmd cmd/doc - Show package docs and exported symbols within the doc command. -go doc template.new - Show documentation for html/template's New function. - (html/template is lexically before text/template) -go doc text/template.new # One argument - Show documentation for text/template's New function. -go doc text/template new # Two arguments - Show documentation for text/template's New function. - -At least in the current tree, these invocations all print the -documentation for json.Decoder's Decode method: - -go doc json.Decoder.Decode -go doc json.decoder.decode -go doc json.decode -cd go/src/encoding/json; go doc decode --
-Flags: -
--c - Respect case when matching symbols. --cmd - Treat a command (package main) like a regular package. - Otherwise package main's exported symbols are hidden - when showing the package's top-level documentation. --u - Show documentation for unexported as well as exported - symbols and methods. --
-Usage: -
-go env [var ...] --
-Env prints Go environment information. -
--By default env prints information as a shell script -(on Windows, a batch file). If one or more variable -names is given as arguments, env prints the value of -each named variable on its own line. -
--Usage: -
-go bug --
-Bug opens the default browser and starts a new bug report. -The report includes useful system information. -
--Usage: -
-go fix [packages] --
-Fix runs the Go fix command on the packages named by the import paths. -
--For more about fix, see 'go doc cmd/fix'. -For more about specifying packages, see 'go help packages'. -
--To run fix with specific options, run 'go tool fix'. -
--See also: go fmt, go vet. -
--Usage: -
-go fmt [-n] [-x] [packages] --
-Fmt runs the command 'gofmt -l -w' on the packages named -by the import paths. It prints the names of the files that are modified. -
--For more about gofmt, see 'go doc cmd/gofmt'. -For more about specifying packages, see 'go help packages'. -
--The -n flag prints commands that would be executed. -The -x flag prints commands as they are executed. -
--To run gofmt with specific options, run gofmt itself. -
--See also: go fix, go vet. -
--Usage: -
-go generate [-run regexp] [-n] [-v] [-x] [build flags] [file.go... | packages] --
-Generate runs commands described by directives within existing -files. Those commands can run any process but the intent is to -create or update Go source files. -
--Go generate is never run automatically by go build, go get, go test, -and so on. It must be run explicitly. -
--Go generate scans the file for directives, which are lines of -the form, -
-//go:generate command argument... --
-(note: no leading spaces and no space in "//go") where command -is the generator to be run, corresponding to an executable file -that can be run locally. It must either be in the shell path -(gofmt), a fully qualified path (/usr/you/bin/mytool), or a -command alias, described below. -
--Note that go generate does not parse the file, so lines that look -like directives in comments or multiline strings will be treated -as directives. -
--The arguments to the directive are space-separated tokens or -double-quoted strings passed to the generator as individual -arguments when it is run. -
--Quoted strings use Go syntax and are evaluated before execution; a -quoted string appears as a single argument to the generator. -
--Go generate sets several variables when it runs the generator: -
-$GOARCH - The execution architecture (arm, amd64, etc.) -$GOOS - The execution operating system (linux, windows, etc.) -$GOFILE - The base name of the file. -$GOLINE - The line number of the directive in the source file. -$GOPACKAGE - The name of the package of the file containing the directive. -$DOLLAR - A dollar sign. --
-Other than variable substitution and quoted-string evaluation, no -special processing such as "globbing" is performed on the command -line. -
--As a last step before running the command, any invocations of any -environment variables with alphanumeric names, such as $GOFILE or -$HOME, are expanded throughout the command line. The syntax for -variable expansion is $NAME on all operating systems. Due to the -order of evaluation, variables are expanded even inside quoted -strings. If the variable NAME is not set, $NAME expands to the -empty string. -
--A directive of the form, -
-//go:generate -command xxx args... --
-specifies, for the remainder of this source file only, that the -string xxx represents the command identified by the arguments. This -can be used to create aliases or to handle multiword generators. -For example, -
-//go:generate -command foo go tool foo --
-specifies that the command "foo" represents the generator -"go tool foo". -
--Generate processes packages in the order given on the command line, -one at a time. If the command line lists .go files, they are treated -as a single package. Within a package, generate processes the -source files in a package in file name order, one at a time. Within -a source file, generate runs generators in the order they appear -in the file, one at a time. -
--If any generator returns an error exit status, "go generate" skips -all further processing for that package. -
--The generator is run in the package's source directory. -
--Go generate accepts one specific flag: -
--run="" - if non-empty, specifies a regular expression to select - directives whose full original source text (excluding - any trailing spaces and final newline) matches the - expression. --
-It also accepts the standard build flags including -v, -n, and -x. -The -v flag prints the names of packages and files as they are -processed. -The -n flag prints commands that would be executed. -The -x flag prints commands as they are executed. -
--For more about build flags, see 'go help build'. -
--For more about specifying packages, see 'go help packages'. -
--Usage: -
-go get [-d] [-f] [-fix] [-insecure] [-t] [-u] [build flags] [packages] --
-Get downloads the packages named by the import paths, along with their -dependencies. It then installs the named packages, like 'go install'. -
--The -d flag instructs get to stop after downloading the packages; that is, -it instructs get not to install the packages. -
--The -f flag, valid only when -u is set, forces get -u not to verify that -each package has been checked out from the source control repository -implied by its import path. This can be useful if the source is a local fork -of the original. -
--The -fix flag instructs get to run the fix tool on the downloaded packages -before resolving dependencies or building the code. -
--The -insecure flag permits fetching from repositories and resolving -custom domains using insecure schemes such as HTTP. Use with caution. -
--The -t flag instructs get to also download the packages required to build -the tests for the specified packages. -
--The -u flag instructs get to use the network to update the named packages -and their dependencies. By default, get uses the network to check out -missing packages but does not use it to look for updates to existing packages. -
--The -v flag enables verbose progress and debug output. -
--Get also accepts build flags to control the installation. See 'go help build'. -
--When checking out a new package, get creates the target directory -GOPATH/src/<import-path>. If the GOPATH contains multiple entries, -get uses the first one. For more details see: 'go help gopath'. -
--When checking out or updating a package, get looks for a branch or tag -that matches the locally installed version of Go. The most important -rule is that if the local installation is running version "go1", get -searches for a branch or tag named "go1". If no such version exists it -retrieves the most recent version of the package. -
--When go get checks out or updates a Git repository, -it also updates any git submodules referenced by the repository. -
--Get never checks out or updates code stored in vendor directories. -
--For more about specifying packages, see 'go help packages'. -
--For more about how 'go get' finds source code to -download, see 'go help importpath'. -
--See also: go build, go install, go clean. -
--Usage: -
-go install [build flags] [packages] --
-Install compiles and installs the packages named by the import paths, -along with their dependencies. -
--For more about the build flags, see 'go help build'. -For more about specifying packages, see 'go help packages'. -
--See also: go build, go get, go clean. -
--Usage: -
-go list [-e] [-f format] [-json] [build flags] [packages] --
-List lists the packages named by the import paths, one per line. -
--The default output shows the package import path: -
-bytes -encoding/json -github.com/gorilla/mux -golang.org/x/net/html --
-The -f flag specifies an alternate format for the list, using the -syntax of package template. The default output is equivalent to -f -''. The struct being passed to the template is: -
-type Package struct { - Dir string // directory containing package sources - ImportPath string // import path of package in dir - ImportComment string // path in import comment on package statement - Name string // package name - Doc string // package documentation string - Target string // install path - Shlib string // the shared library that contains this package (only set when -linkshared) - Goroot bool // is this package in the Go root? - Standard bool // is this package part of the standard Go library? - Stale bool // would 'go install' do anything for this package? - StaleReason string // explanation for Stale==true - Root string // Go root or Go path dir containing this package - ConflictDir string // this directory shadows Dir in $GOPATH - BinaryOnly bool // binary-only package: cannot be recompiled from sources - - // Source files - GoFiles []string // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles) - CgoFiles []string // .go sources files that import "C" - IgnoredGoFiles []string // .go sources ignored due to build constraints - CFiles []string // .c source files - CXXFiles []string // .cc, .cxx and .cpp source files - MFiles []string // .m source files - HFiles []string // .h, .hh, .hpp and .hxx source files - FFiles []string // .f, .F, .for and .f90 Fortran source files - SFiles []string // .s source files - SwigFiles []string // .swig files - SwigCXXFiles []string // .swigcxx files - SysoFiles []string // .syso object files to add to archive - TestGoFiles []string // _test.go files in package - XTestGoFiles []string // _test.go files outside package - - // Cgo directives - CgoCFLAGS []string // cgo: flags for C compiler - CgoCPPFLAGS []string // cgo: flags for C preprocessor - CgoCXXFLAGS []string // cgo: flags for C++ compiler - CgoFFLAGS []string // cgo: flags for Fortran compiler - CgoLDFLAGS []string // cgo: flags for linker - CgoPkgConfig []string // cgo: pkg-config names - - // Dependency information - Imports []string // import paths used by this package - Deps []string // all (recursively) imported dependencies - TestImports []string // imports from TestGoFiles - XTestImports []string // imports from XTestGoFiles - - // Error information - Incomplete bool // this package or a dependency has an error - Error *PackageError // error loading package - DepsErrors []*PackageError // errors loading dependencies -} --
-Packages stored in vendor directories report an ImportPath that includes the -path to the vendor directory (for example, "d/vendor/p" instead of "p"), -so that the ImportPath uniquely identifies a given copy of a package. -The Imports, Deps, TestImports, and XTestImports lists also contain these -expanded imports paths. See golang.org/s/go15vendor for more about vendoring. -
--The error information, if any, is -
-type PackageError struct { - ImportStack []string // shortest path from package named on command line to this one - Pos string // position of error (if present, file:line:col) - Err string // the error itself -} --
-The template function "join" calls strings.Join. -
--The template function "context" returns the build context, defined as: -
-type Context struct { - GOARCH string // target architecture - GOOS string // target operating system - GOROOT string // Go root - GOPATH string // Go path - CgoEnabled bool // whether cgo can be used - UseAllFiles bool // use files regardless of +build lines, file names - Compiler string // compiler to assume when computing target paths - BuildTags []string // build constraints to match in +build lines - ReleaseTags []string // releases the current release is compatible with - InstallSuffix string // suffix to use in the name of the install dir -} --
-For more information about the meaning of these fields see the documentation -for the go/build package's Context type. -
--The -json flag causes the package data to be printed in JSON format -instead of using the template format. -
--The -e flag changes the handling of erroneous packages, those that -cannot be found or are malformed. By default, the list command -prints an error to standard error for each erroneous package and -omits the packages from consideration during the usual printing. -With the -e flag, the list command never prints errors to standard -error and instead processes the erroneous packages with the usual -printing. Erroneous packages will have a non-empty ImportPath and -a non-nil Error field; other information may or may not be missing -(zeroed). -
--For more about build flags, see 'go help build'. -
--For more about specifying packages, see 'go help packages'. -
--Usage: -
-go run [build flags] [-exec xprog] gofiles... [arguments...] --
-Run compiles and runs the main package comprising the named Go source files. -A Go source file is defined to be a file ending in a literal ".go" suffix. -
--By default, 'go run' runs the compiled binary directly: 'a.out arguments...'. -If the -exec flag is given, 'go run' invokes the binary using xprog: -
-'xprog a.out arguments...'. --
-If the -exec flag is not given, GOOS or GOARCH is different from the system -default, and a program named go_$GOOS_$GOARCH_exec can be found -on the current search path, 'go run' invokes the binary using that program, -for example 'go_nacl_386_exec a.out arguments...'. This allows execution of -cross-compiled programs when a simulator or other execution method is -available. -
--For more about build flags, see 'go help build'. -
--See also: go build. -
--Usage: -
-go test [build/test flags] [packages] [build/test flags & test binary flags] --
-'Go test' automates testing the packages named by the import paths. -It prints a summary of the test results in the format: -
-ok archive/tar 0.011s -FAIL archive/zip 0.022s -ok compress/gzip 0.033s -... --
-followed by detailed output for each failed package. -
--'Go test' recompiles each package along with any files with names matching -the file pattern "*_test.go". -Files whose names begin with "_" (including "_test.go") or "." are ignored. -These additional files can contain test functions, benchmark functions, and -example functions. See 'go help testfunc' for more. -Each listed package causes the execution of a separate test binary. -
--Test files that declare a package with the suffix "_test" will be compiled as a -separate package, and then linked and run with the main test binary. -
--The go tool will ignore a directory named "testdata", making it available -to hold ancillary data needed by the tests. -
--By default, go test needs no arguments. It compiles and tests the package -with source in the current directory, including tests, and runs the tests. -
--The package is built in a temporary directory so it does not interfere with the -non-test installation. -
--In addition to the build flags, the flags handled by 'go test' itself are: -
--args - Pass the remainder of the command line (everything after -args) - to the test binary, uninterpreted and unchanged. - Because this flag consumes the remainder of the command line, - the package list (if present) must appear before this flag. - --c - Compile the test binary to pkg.test but do not run it - (where pkg is the last element of the package's import path). - The file name can be changed with the -o flag. - --exec xprog - Run the test binary using xprog. The behavior is the same as - in 'go run'. See 'go help run' for details. - --i - Install packages that are dependencies of the test. - Do not run the test. - --o file - Compile the test binary to the named file. - The test still runs (unless -c or -i is specified). --
-The test binary also accepts flags that control execution of the test; these -flags are also accessible by 'go test'. See 'go help testflag' for details. -
--For more about build flags, see 'go help build'. -For more about specifying packages, see 'go help packages'. -
--See also: go build, go vet. -
--Usage: -
-go tool [-n] command [args...] --
-Tool runs the go tool command identified by the arguments. -With no arguments it prints the list of known tools. -
--The -n flag causes tool to print the command that would be -executed but not execute it. -
--For more about each tool command, see 'go tool command -h'. -
--Usage: -
-go version --
-Version prints the Go version, as reported by runtime.Version. -
--Usage: -
-go vet [-n] [-x] [build flags] [packages] --
-Vet runs the Go vet command on the packages named by the import paths. -
--For more about vet, see 'go doc cmd/vet'. -For more about specifying packages, see 'go help packages'. -
--To run the vet tool with specific options, run 'go tool vet'. -
--The -n flag prints commands that would be executed. -The -x flag prints commands as they are executed. -
--For more about build flags, see 'go help build'. -
--See also: go fmt, go fix. -
--There are two different ways to call between Go and C/C++ code. -
--The first is the cgo tool, which is part of the Go distribution. For -information on how to use it see the cgo documentation (go doc cmd/cgo). -
--The second is the SWIG program, which is a general tool for -interfacing between languages. For information on SWIG see -http://swig.org/. When running go build, any file with a .swig -extension will be passed to SWIG. Any file with a .swigcxx extension -will be passed to SWIG with the -c++ option. -
--When either cgo or SWIG is used, go build will pass any .c, .m, .s, -or .S files to the C compiler, and any .cc, .cpp, .cxx files to the C++ -compiler. The CC or CXX environment variables may be set to determine -the C or C++ compiler, respectively, to use. -
--The 'go build' and 'go install' commands take a -buildmode argument which -indicates which kind of object file is to be built. Currently supported values -are: -
--buildmode=archive - Build the listed non-main packages into .a files. Packages named - main are ignored. - --buildmode=c-archive - Build the listed main package, plus all packages it imports, - into a C archive file. The only callable symbols will be those - functions exported using a cgo //export comment. Requires - exactly one main package to be listed. - --buildmode=c-shared - Build the listed main packages, plus all packages that they - import, into C shared libraries. The only callable symbols will - be those functions exported using a cgo //export comment. - Non-main packages are ignored. - --buildmode=default - Listed main packages are built into executables and listed - non-main packages are built into .a files (the default - behavior). - --buildmode=shared - Combine all the listed non-main packages into a single shared - library that will be used when building with the -linkshared - option. Packages named main are ignored. - --buildmode=exe - Build the listed main packages and everything they import into - executables. Packages not named main are ignored. - --buildmode=pie - Build the listed main packages and everything they import into - position independent executables (PIE). Packages not named - main are ignored. - --buildmode=plugin - Build the listed main packages, plus all packages that they - import, into a Go plugin. Packages not named main are ignored. --
-The go command examines the contents of a restricted set of files -in each directory. It identifies which files to examine based on -the extension of the file name. These extensions are: -
-.go - Go source files. -.c, .h - C source files. - If the package uses cgo or SWIG, these will be compiled with the - OS-native compiler (typically gcc); otherwise they will - trigger an error. -.cc, .cpp, .cxx, .hh, .hpp, .hxx - C++ source files. Only useful with cgo or SWIG, and always - compiled with the OS-native compiler. -.m - Objective-C source files. Only useful with cgo, and always - compiled with the OS-native compiler. -.s, .S - Assembler source files. - If the package uses cgo or SWIG, these will be assembled with the - OS-native assembler (typically gcc (sic)); otherwise they - will be assembled with the Go assembler. -.swig, .swigcxx - SWIG definition files. -.syso - System object files. --
-Files of each of these types except .syso may contain build -constraints, but the go command stops scanning for build constraints -at the first item in the file that is not a blank line or //-style -line comment. See the go/build package documentation for -more details. -
--Non-test Go source files can also include a //go:binary-only-package -comment, indicating that the package sources are included -for documentation only and must not be used to build the -package binary. This enables distribution of Go packages in -their compiled form alone. See the go/build package documentation -for more details. -
--The Go path is used to resolve import statements. -It is implemented by and documented in the go/build package. -
--The GOPATH environment variable lists places to look for Go code. -On Unix, the value is a colon-separated string. -On Windows, the value is a semicolon-separated string. -On Plan 9, the value is a list. -
--If the environment variable is unset, GOPATH defaults -to a subdirectory named "go" in the user's home directory -($HOME/go on Unix, %USERPROFILE%\go on Windows), -unless that directory holds a Go distribution. -Run "go env GOPATH" to see the current GOPATH. -
--See https://golang.org/wiki/SettingGOPATH to set a custom GOPATH. -
--Each directory listed in GOPATH must have a prescribed structure: -
--The src directory holds source code. The path below src -determines the import path or executable name. -
--The pkg directory holds installed package objects. -As in the Go tree, each target operating system and -architecture pair has its own subdirectory of pkg -(pkg/GOOS_GOARCH). -
--If DIR is a directory listed in the GOPATH, a package with -source in DIR/src/foo/bar can be imported as "foo/bar" and -has its compiled form installed to "DIR/pkg/GOOS_GOARCH/foo/bar.a". -
--The bin directory holds compiled commands. -Each command is named for its source directory, but only -the final element, not the entire path. That is, the -command with source in DIR/src/foo/quux is installed into -DIR/bin/quux, not DIR/bin/foo/quux. The "foo/" prefix is stripped -so that you can add DIR/bin to your PATH to get at the -installed commands. If the GOBIN environment variable is -set, commands are installed to the directory it names instead -of DIR/bin. GOBIN must be an absolute path. -
--Here's an example directory layout: -
-GOPATH=/home/user/go - -/home/user/go/ - src/ - foo/ - bar/ (go code in package bar) - x.go - quux/ (go code in package main) - y.go - bin/ - quux (installed command) - pkg/ - linux_amd64/ - foo/ - bar.a (installed package object) --
-Go searches each directory listed in GOPATH to find source code, -but new packages are always downloaded into the first directory -in the list. -
--See https://golang.org/doc/code.html for an example. -
--Code in or below a directory named "internal" is importable only -by code in the directory tree rooted at the parent of "internal". -Here's an extended version of the directory layout above: -
-/home/user/go/ - src/ - crash/ - bang/ (go code in package bang) - b.go - foo/ (go code in package foo) - f.go - bar/ (go code in package bar) - x.go - internal/ - baz/ (go code in package baz) - z.go - quux/ (go code in package main) - y.go --
-The code in z.go is imported as "foo/internal/baz", but that -import statement can only appear in source files in the subtree -rooted at foo. The source files foo/f.go, foo/bar/x.go, and -foo/quux/y.go can all import "foo/internal/baz", but the source file -crash/bang/b.go cannot. -
--See https://golang.org/s/go14internal for details. -
--Go 1.6 includes support for using local copies of external dependencies -to satisfy imports of those dependencies, often referred to as vendoring. -
--Code below a directory named "vendor" is importable only -by code in the directory tree rooted at the parent of "vendor", -and only using an import path that omits the prefix up to and -including the vendor element. -
--Here's the example from the previous section, -but with the "internal" directory renamed to "vendor" -and a new foo/vendor/crash/bang directory added: -
-/home/user/go/ - src/ - crash/ - bang/ (go code in package bang) - b.go - foo/ (go code in package foo) - f.go - bar/ (go code in package bar) - x.go - vendor/ - crash/ - bang/ (go code in package bang) - b.go - baz/ (go code in package baz) - z.go - quux/ (go code in package main) - y.go --
-The same visibility rules apply as for internal, but the code -in z.go is imported as "baz", not as "foo/vendor/baz". -
--Code in vendor directories deeper in the source tree shadows -code in higher directories. Within the subtree rooted at foo, an import -of "crash/bang" resolves to "foo/vendor/crash/bang", not the -top-level "crash/bang". -
--Code in vendor directories is not subject to import path -checking (see 'go help importpath'). -
--When 'go get' checks out or updates a git repository, it now also -updates submodules. -
--Vendor directories do not affect the placement of new repositories -being checked out for the first time by 'go get': those are always -placed in the main GOPATH, never in a vendor subtree. -
--See https://golang.org/s/go15vendor for details. -
--The go command, and the tools it invokes, examine a few different -environment variables. For many of these, you can see the default -value of on your system by running 'go env NAME', where NAME is the -name of the variable. -
--General-purpose environment variables: -
-GCCGO - The gccgo command to run for 'go build -compiler=gccgo'. -GOARCH - The architecture, or processor, for which to compile code. - Examples are amd64, 386, arm, ppc64. -GOBIN - The directory where 'go install' will install a command. -GOOS - The operating system for which to compile code. - Examples are linux, darwin, windows, netbsd. -GOPATH - For more details see: 'go help gopath'. -GORACE - Options for the race detector. - See https://golang.org/doc/articles/race_detector.html. -GOROOT - The root of the go tree. --
-Environment variables for use with cgo: -
-CC - The command to use to compile C code. -CGO_ENABLED - Whether the cgo command is supported. Either 0 or 1. -CGO_CFLAGS - Flags that cgo will pass to the compiler when compiling - C code. -CGO_CPPFLAGS - Flags that cgo will pass to the compiler when compiling - C or C++ code. -CGO_CXXFLAGS - Flags that cgo will pass to the compiler when compiling - C++ code. -CGO_FFLAGS - Flags that cgo will pass to the compiler when compiling - Fortran code. -CGO_LDFLAGS - Flags that cgo will pass to the compiler when linking. -CXX - The command to use to compile C++ code. -PKG_CONFIG - Path to pkg-config tool. --
-Architecture-specific environment variables: -
-GOARM - For GOARCH=arm, the ARM architecture for which to compile. - Valid values are 5, 6, 7. -GO386 - For GOARCH=386, the floating point instruction set. - Valid values are 387, sse2. --
-Special-purpose environment variables: -
-GOROOT_FINAL - The root of the installed Go tree, when it is - installed in a location other than where it is built. - File names in stack traces are rewritten from GOROOT to - GOROOT_FINAL. -GO_EXTLINK_ENABLED - Whether the linker should use external linking mode - when using -linkmode=auto with code that uses cgo. - Set to 0 to disable external linking mode, 1 to enable it. -GIT_ALLOW_PROTOCOL - Defined by Git. A colon-separated list of schemes that are allowed to be used - with git fetch/clone. If set, any scheme not explicitly mentioned will be - considered insecure by 'go get'. --
-An import path (see 'go help packages') denotes a package stored in the local -file system. In general, an import path denotes either a standard package (such -as "unicode/utf8") or a package found in one of the work spaces (For more -details see: 'go help gopath'). -
--An import path beginning with ./ or ../ is called a relative path. -The toolchain supports relative import paths as a shortcut in two ways. -
--First, a relative path can be used as a shorthand on the command line. -If you are working in the directory containing the code imported as -"unicode" and want to run the tests for "unicode/utf8", you can type -"go test ./utf8" instead of needing to specify the full path. -Similarly, in the reverse situation, "go test .." will test "unicode" from -the "unicode/utf8" directory. Relative patterns are also allowed, like -"go test ./..." to test all subdirectories. See 'go help packages' for details -on the pattern syntax. -
--Second, if you are compiling a Go program not in a work space, -you can use a relative path in an import statement in that program -to refer to nearby code also not in a work space. -This makes it easy to experiment with small multipackage programs -outside of the usual work spaces, but such programs cannot be -installed with "go install" (there is no work space in which to install them), -so they are rebuilt from scratch each time they are built. -To avoid ambiguity, Go programs cannot use relative import paths -within a work space. -
--Certain import paths also -describe how to obtain the source code for the package using -a revision control system. -
--A few common code hosting sites have special syntax: -
-Bitbucket (Git, Mercurial) - - import "bitbucket.org/user/project" - import "bitbucket.org/user/project/sub/directory" - -GitHub (Git) - - import "github.com/user/project" - import "github.com/user/project/sub/directory" - -Launchpad (Bazaar) - - import "launchpad.net/project" - import "launchpad.net/project/series" - import "launchpad.net/project/series/sub/directory" - - import "launchpad.net/~user/project/branch" - import "launchpad.net/~user/project/branch/sub/directory" - -IBM DevOps Services (Git) - - import "hub.jazz.net/git/user/project" - import "hub.jazz.net/git/user/project/sub/directory" --
-For code hosted on other servers, import paths may either be qualified -with the version control type, or the go tool can dynamically fetch -the import path over https/http and discover where the code resides -from a <meta> tag in the HTML. -
--To declare the code location, an import path of the form -
-repository.vcs/path --
-specifies the given repository, with or without the .vcs suffix, -using the named version control system, and then the path inside -that repository. The supported version control systems are: -
-Bazaar .bzr -Git .git -Mercurial .hg -Subversion .svn --
-For example, -
-import "example.org/user/foo.hg" --
-denotes the root directory of the Mercurial repository at -example.org/user/foo or foo.hg, and -
-import "example.org/repo.git/foo/bar" --
-denotes the foo/bar directory of the Git repository at -example.org/repo or repo.git. -
--When a version control system supports multiple protocols, -each is tried in turn when downloading. For example, a Git -download tries https://, then git+ssh://. -
--By default, downloads are restricted to known secure protocols -(e.g. https, ssh). To override this setting for Git downloads, the -GIT_ALLOW_PROTOCOL environment variable can be set (For more details see: -'go help environment'). -
--If the import path is not a known code hosting site and also lacks a -version control qualifier, the go tool attempts to fetch the import -over https/http and looks for a <meta> tag in the document's HTML -<head>. -
--The meta tag has the form: -
-<meta name="go-import" content="import-prefix vcs repo-root"> --
-The import-prefix is the import path corresponding to the repository -root. It must be a prefix or an exact match of the package being -fetched with "go get". If it's not an exact match, another http -request is made at the prefix to verify the <meta> tags match. -
--The meta tag should appear as early in the file as possible. -In particular, it should appear before any raw JavaScript or CSS, -to avoid confusing the go command's restricted parser. -
--The vcs is one of "git", "hg", "svn", etc, -
--The repo-root is the root of the version control system -containing a scheme and not containing a .vcs qualifier. -
--For example, -
-import "example.org/pkg/foo" --
-will result in the following requests: -
-https://example.org/pkg/foo?go-get=1 (preferred) -http://example.org/pkg/foo?go-get=1 (fallback, only with -insecure) --
-If that page contains the meta tag -
-<meta name="go-import" content="example.org git https://code.org/r/p/exproj"> --
-the go tool will verify that https://example.org/?go-get=1 contains the -same meta tag and then git clone https://code.org/r/p/exproj into -GOPATH/src/example.org. -
--New downloaded packages are written to the first directory listed in the GOPATH -environment variable (For more details see: 'go help gopath'). -
--The go command attempts to download the version of the -package appropriate for the Go release being used. -Run 'go help get' for more. -
--When the custom import path feature described above redirects to a -known code hosting site, each of the resulting packages has two possible -import paths, using the custom domain or the known hosting site. -
--A package statement is said to have an "import comment" if it is immediately -followed (before the next newline) by a comment of one of these two forms: -
-package math // import "path" -package math /* import "path" */ --
-The go command will refuse to install a package with an import comment -unless it is being referred to by that import path. In this way, import comments -let package authors make sure the custom import path is used and not a -direct path to the underlying code hosting site. -
--Import path checking is disabled for code found within vendor trees. -This makes it possible to copy code into alternate locations in vendor trees -without needing to update import comments. -
--See https://golang.org/s/go14customimport for details. -
--Many commands apply to a set of packages: -
-go action [packages] --
-Usually, [packages] is a list of import paths. -
--An import path that is a rooted path or that begins with -a . or .. element is interpreted as a file system path and -denotes the package in that directory. -
--Otherwise, the import path P denotes the package found in -the directory DIR/src/P for some DIR listed in the GOPATH -environment variable (For more details see: 'go help gopath'). -
--If no import paths are given, the action applies to the -package in the current directory. -
--There are four reserved names for paths that should not be used -for packages to be built with the go tool: -
--- "main" denotes the top-level package in a stand-alone executable. -
--- "all" expands to all package directories found in all the GOPATH -trees. For example, 'go list all' lists all the packages on the local -system. -
--- "std" is like all but expands to just the packages in the standard -Go library. -
--- "cmd" expands to the Go repository's commands and their -internal libraries. -
--Import paths beginning with "cmd/" only match source code in -the Go repository. -
--An import path is a pattern if it includes one or more "..." wildcards, -each of which can match any string, including the empty string and -strings containing slashes. Such a pattern expands to all package -directories found in the GOPATH trees with names matching the -patterns. As a special case, x/... matches x as well as x's subdirectories. -For example, net/... expands to net and packages in its subdirectories. -
--An import path can also name a package to be downloaded from -a remote repository. Run 'go help importpath' for details. -
--Every package in a program must have a unique import path. -By convention, this is arranged by starting each path with a -unique prefix that belongs to you. For example, paths used -internally at Google all begin with 'google', and paths -denoting remote repositories begin with the path to the code, -such as 'github.com/user/repo'. -
--Packages in a program need not have unique package names, -but there are two reserved package names with special meaning. -The name main indicates a command, not a library. -Commands are built into binaries and cannot be imported. -The name documentation indicates documentation for -a non-Go program in the directory. Files in package documentation -are ignored by the go command. -
--As a special case, if the package list is a list of .go files from a -single directory, the command is applied to a single synthesized -package made up of exactly those files, ignoring any build constraints -in those files and ignoring any other files in the directory. -
--Directory and file names that begin with "." or "_" are ignored -by the go tool, as are directories named "testdata". -
--The 'go test' command takes both flags that apply to 'go test' itself -and flags that apply to the resulting test binary. -
--Several of the flags control profiling and write an execution profile -suitable for "go tool pprof"; run "go tool pprof -h" for more -information. The --alloc_space, --alloc_objects, and --show_bytes -options of pprof control how the information is presented. -
--The following flags are recognized by the 'go test' command and -control the execution of any test: -
--bench regexp - Run (sub)benchmarks matching a regular expression. - The given regular expression is split into smaller ones by - top-level '/', where each must match the corresponding part of a - benchmark's identifier. - By default, no benchmarks run. To run all benchmarks, - use '-bench .' or '-bench=.'. - --benchtime t - Run enough iterations of each benchmark to take t, specified - as a time.Duration (for example, -benchtime 1h30s). - The default is 1 second (1s). - --count n - Run each test and benchmark n times (default 1). - If -cpu is set, run n times for each GOMAXPROCS value. - Examples are always run once. - --cover - Enable coverage analysis. - --covermode set,count,atomic - Set the mode for coverage analysis for the package[s] - being tested. The default is "set" unless -race is enabled, - in which case it is "atomic". - The values: - set: bool: does this statement run? - count: int: how many times does this statement run? - atomic: int: count, but correct in multithreaded tests; - significantly more expensive. - Sets -cover. - --coverpkg pkg1,pkg2,pkg3 - Apply coverage analysis in each test to the given list of packages. - The default is for each test to analyze only the package being tested. - Packages are specified as import paths. - Sets -cover. - --cpu 1,2,4 - Specify a list of GOMAXPROCS values for which the tests or - benchmarks should be executed. The default is the current value - of GOMAXPROCS. - --parallel n - Allow parallel execution of test functions that call t.Parallel. - The value of this flag is the maximum number of tests to run - simultaneously; by default, it is set to the value of GOMAXPROCS. - Note that -parallel only applies within a single test binary. - The 'go test' command may run tests for different packages - in parallel as well, according to the setting of the -p flag - (see 'go help build'). - --run regexp - Run only those tests and examples matching the regular expression. - For tests the regular expression is split into smaller ones by - top-level '/', where each must match the corresponding part of a - test's identifier. - --short - Tell long-running tests to shorten their run time. - It is off by default but set during all.bash so that installing - the Go tree can run a sanity check but not spend time running - exhaustive tests. - --timeout t - If a test runs longer than t, panic. - The default is 10 minutes (10m). - --v - Verbose output: log all tests as they are run. Also print all - text from Log and Logf calls even if the test succeeds. --
-The following flags are also recognized by 'go test' and can be used to -profile the tests during execution: -
--benchmem - Print memory allocation statistics for benchmarks. - --blockprofile block.out - Write a goroutine blocking profile to the specified file - when all tests are complete. - Writes test binary as -c would. - --blockprofilerate n - Control the detail provided in goroutine blocking profiles by - calling runtime.SetBlockProfileRate with n. - See 'go doc runtime.SetBlockProfileRate'. - The profiler aims to sample, on average, one blocking event every - n nanoseconds the program spends blocked. By default, - if -test.blockprofile is set without this flag, all blocking events - are recorded, equivalent to -test.blockprofilerate=1. - --coverprofile cover.out - Write a coverage profile to the file after all tests have passed. - Sets -cover. - --cpuprofile cpu.out - Write a CPU profile to the specified file before exiting. - Writes test binary as -c would. - --memprofile mem.out - Write a memory profile to the file after all tests have passed. - Writes test binary as -c would. - --memprofilerate n - Enable more precise (and expensive) memory profiles by setting - runtime.MemProfileRate. See 'go doc runtime.MemProfileRate'. - To profile all memory allocations, use -test.memprofilerate=1 - and pass --alloc_space flag to the pprof tool. - --mutexprofile mutex.out - Write a mutex contention profile to the specified file - when all tests are complete. - Writes test binary as -c would. - --mutexprofilefraction n - Sample 1 in n stack traces of goroutines holding a - contended mutex. - --outputdir directory - Place output files from profiling in the specified directory, - by default the directory in which "go test" is running. - --trace trace.out - Write an execution trace to the specified file before exiting. --
-Each of these flags is also recognized with an optional 'test.' prefix, -as in -test.v. When invoking the generated test binary (the result of -'go test -c') directly, however, the prefix is mandatory. -
--The 'go test' command rewrites or removes recognized flags, -as appropriate, both before and after the optional package list, -before invoking the test binary. -
--For instance, the command -
-go test -v -myflag testdata -cpuprofile=prof.out -x --
-will compile the test binary and then run it as -
-pkg.test -test.v -myflag testdata -test.cpuprofile=prof.out --
-(The -x flag is removed because it applies only to the go command's -execution, not to the test itself.) -
--The test flags that generate profiles (other than for coverage) also -leave the test binary in pkg.test for use when analyzing the profiles. -
--When 'go test' runs a test binary, it does so from within the -corresponding package's source code directory. Depending on the test, -it may be necessary to do the same when invoking a generated test -binary directly. -
--The command-line package list, if present, must appear before any -flag not known to the go test command. Continuing the example above, -the package list would have to appear before -myflag, but could appear -on either side of -v. -
--To keep an argument for a test binary from being interpreted as a -known flag or a package name, use -args (see 'go help test') which -passes the remainder of the command line through to the test binary -uninterpreted and unaltered. -
--For instance, the command -
-go test -v -args -x -v --
-will compile the test binary and then run it as -
-pkg.test -test.v -x -v --
-Similarly, -
-go test -args math --
-will compile the test binary and then run it as -
-pkg.test math --
-In the first example, the -x and the second -v are passed through to the -test binary unchanged and with no effect on the go command itself. -In the second example, the argument math is passed through to the test -binary, instead of being interpreted as the package list. -
--The 'go test' command expects to find test, benchmark, and example functions -in the "*_test.go" files corresponding to the package under test. -
--A test function is one named TestXXX (where XXX is any alphanumeric string -not starting with a lower case letter) and should have the signature, -
-func TestXXX(t *testing.T) { ... } --
-A benchmark function is one named BenchmarkXXX and should have the signature, -
-func BenchmarkXXX(b *testing.B) { ... } --
-An example function is similar to a test function but, instead of using -*testing.T to report success or failure, prints output to os.Stdout. -If the last comment in the function starts with "Output:" then the output -is compared exactly against the comment (see examples below). If the last -comment begins with "Unordered output:" then the output is compared to the -comment, however the order of the lines is ignored. An example with no such -comment is compiled but not executed. An example with no text after -"Output:" is compiled, executed, and expected to produce no output. -
--Godoc displays the body of ExampleXXX to demonstrate the use -of the function, constant, or variable XXX. An example of a method M with -receiver type T or *T is named ExampleT_M. There may be multiple examples -for a given function, constant, or variable, distinguished by a trailing _xxx, -where xxx is a suffix not beginning with an upper case letter. -
--Here is an example of an example: -
-func ExamplePrintln() { - Println("The output of\nthis example.") - // Output: The output of - // this example. -} --
-Here is another example where the ordering of the output is ignored: -
-func ExamplePerm() { - for _, value := range Perm(4) { - fmt.Println(value) - } - - // Unordered output: 4 - // 2 - // 1 - // 3 - // 0 -} --
-The entire test file is presented as the example when it contains a single -example function, at least one other function, type, variable, or constant -declaration, and no test or benchmark functions. -
--See the documentation of the testing package for more information. -
- - - -