diff options
Diffstat (limited to 'local.go')
| -rw-r--r-- | local.go | 77 |
1 files changed, 37 insertions, 40 deletions
@@ -5,8 +5,8 @@ package main import ( + "encoding/json" "flag" - "fmt" "go/build" "html/template" "io" @@ -18,6 +18,7 @@ import ( "os/exec" "path/filepath" "runtime" + "runtime/debug" "strings" "time" @@ -30,7 +31,6 @@ import ( ) const ( - basePkg = "golang.org/x/tour" socketPath = "/socket" ) @@ -40,9 +40,6 @@ var ( ) var ( - // GOPATH containing the tour packages - gopath = os.Getenv("GOPATH") - httpAddr string ) @@ -56,20 +53,41 @@ func isRoot(path string) bool { return err == nil } -func findRoot() (string, error) { - ctx := build.Default - p, err := ctx.Import(basePkg, "", build.FindOnly) +// findRoot is a best-effort attempt to find a tour directory +// that contains the files it needs. It may not always work. +// +// TODO: Delete after Go 1.17 is out and we can just use embed; see CL 291849. +func findRoot() (string, bool) { + // Try finding the golang.org/x/tour package in the + // legacy GOPATH mode workspace or in build list. + p, err := build.Import("golang.org/x/tour", "", build.FindOnly) if err == nil && isRoot(p.Dir) { - return p.Dir, nil + return p.Dir, true } - tourRoot := filepath.Join(runtime.GOROOT(), "misc", "tour") - ctx.GOPATH = tourRoot - p, err = ctx.Import(basePkg, "", build.FindOnly) - if err == nil && isRoot(tourRoot) { - gopath = tourRoot - return tourRoot, nil + // If that didn't work, perhaps we're not inside any module + // and the binary was built in module mode (e.g., 'go install + // golang.org/x/tour@latest' or 'go get golang.org/x/tour' + // outside a module). + // In that's the case, find out what version it is, + // and access its content from the module cache. + if info, ok := debug.ReadBuildInfo(); ok && + info.Main.Path == "golang.org/x/tour" && + info.Main.Replace == nil && + info.Main.Version != "(devel)" { + // Make some assumptions for brevity: + // • the 'go' binary is in $PATH + // • the main module isn't replaced + // • the version isn't "(devel)" + // They should hold for the use cases we care about, until this + // entire mechanism is obsoleted by file embedding. + out, execError := exec.Command("go", "mod", "download", "-json", "--", "golang.org/x/tour@"+info.Main.Version).Output() + var tourRoot struct{ Dir string } + jsonError := json.Unmarshal(out, &tourRoot) + if execError == nil && jsonError == nil && isRoot(tourRoot.Dir) { + return tourRoot.Dir, true + } } - return "", fmt.Errorf("could not find go-tour content; check $GOROOT and $GOPATH") + return "", false } func main() { @@ -82,9 +100,9 @@ func main() { } // find and serve the go tour files - root, err := findRoot() - if err != nil { - log.Fatalf("Couldn't find tour files: %v", err) + root, ok := findRoot() + if !ok { + log.Fatalln("Couldn't find files for the Go tour. Try reinstalling it.") } log.Println("Serving content from", root) @@ -166,27 +184,6 @@ If you don't understand this message, hit Control-C to terminate this process. WARNING! WARNING! WARNING! ` -type response struct { - Output string `json:"output"` - Errors string `json:"compile_errors"` -} - -func init() { - socket.Environ = environ -} - -// environ returns the original execution environment with GOPATH -// replaced (or added) with the value of the global var gopath. -func environ() (env []string) { - for _, v := range os.Environ() { - if !strings.HasPrefix(v, "GOPATH=") { - env = append(env, v) - } - } - env = append(env, "GOPATH="+gopath) - return -} - // waitServer waits some time for the http Server to start // serving url. The return value reports whether it starts. func waitServer(url string) bool { |