package common import ( "bufio" "fmt" "io" "io/ioutil" "os" "os/exec" "os/signal" "strings" "syscall" ) var gopath string // GoPath returns GOPATH env variable value. If it is not set, this function // will try to call `go env GOPATH` subcommand. func GoPath() string { if gopath != "" { return gopath } path := os.Getenv("GOPATH") if len(path) == 0 { goCmd := exec.Command("go", "env", "GOPATH") out, err := goCmd.Output() if err != nil { panic(fmt.Sprintf("failed to determine gopath: %v", err)) } path = string(out) } gopath = path return path } // TrapSignal catches the SIGTERM and executes cb function. After that it exits // with code 1. func TrapSignal(cb func()) { c := make(chan os.Signal, 1) signal.Notify(c, os.Interrupt, syscall.SIGTERM) go func() { for sig := range c { fmt.Printf("captured %v, exiting...\n", sig) if cb != nil { cb() } os.Exit(1) } }() select {} } // Kill the running process by sending itself SIGTERM. func Kill() error { p, err := os.FindProcess(os.Getpid()) if err != nil { return err } return p.Signal(syscall.SIGTERM) } func Exit(s string) { fmt.Printf(s + "\n") os.Exit(1) } func EnsureDir(dir string, mode os.FileMode) error { if _, err := os.Stat(dir); os.IsNotExist(err) { err := os.MkdirAll(dir, mode) if err != nil { return fmt.Errorf("Could not create directory %v. %v", dir, err) } } return nil } func IsDirEmpty(name string) (bool, error) { f, err := os.Open(name) if err != nil { if os.IsNotExist(err) { return true, err } // Otherwise perhaps a permission // error or some other error. return false, err } defer f.Close() _, err = f.Readdirnames(1) // Or f.Readdir(1) if err == io.EOF { return true, nil } return false, err // Either not empty or error, suits both cases } func FileExists(filePath string) bool { _, err := os.Stat(filePath) return !os.IsNotExist(err) } func ReadFile(filePath string) ([]byte, error) { return ioutil.ReadFile(filePath) } func MustReadFile(filePath string) []byte { fileBytes, err := ioutil.ReadFile(filePath) if err != nil { Exit(Fmt("MustReadFile failed: %v", err)) return nil } return fileBytes } func WriteFile(filePath string, contents []byte, mode os.FileMode) error { return ioutil.WriteFile(filePath, contents, mode) } func MustWriteFile(filePath string, contents []byte, mode os.FileMode) { err := WriteFile(filePath, contents, mode) if err != nil { Exit(Fmt("MustWriteFile failed: %v", err)) } } //-------------------------------------------------------------------------------- func Prompt(prompt string, defaultValue string) (string, error) { fmt.Print(prompt) reader := bufio.NewReader(os.Stdin) line, err := reader.ReadString('\n') if err != nil { return defaultValue, err } line = strings.TrimSpace(line) if line == "" { return defaultValue, nil } return line, nil }