package command import ( "bufio" "bytes" "errors" "fmt" "io" "log" "os" "os/signal" "strings" "sync" "unicode" "github.com/hashicorp/terraform/terraform" "github.com/mitchellh/colorstring" ) var defaultInputReader io.Reader var defaultInputWriter io.Writer // UIInput is an implementation of terraform.UIInput that asks the CLI // for input stdin. type UIInput struct { // Colorize will color the output. Colorize *colorstring.Colorize // Reader and Writer for IO. If these aren't set, they will default to // Stdout and Stderr respectively. Reader io.Reader Writer io.Writer interrupted bool l sync.Mutex once sync.Once } func (i *UIInput) Input(opts *terraform.InputOpts) (string, error) { i.once.Do(i.init) r := i.Reader w := i.Writer if r == nil { r = defaultInputReader } if w == nil { w = defaultInputWriter } if r == nil { r = os.Stdin } if w == nil { w = os.Stdout } // Make sure we only ask for input once at a time. Terraform // should enforce this, but it doesn't hurt to verify. i.l.Lock() defer i.l.Unlock() // If we're interrupted, then don't ask for input if i.interrupted { return "", errors.New("interrupted") } // Listen for interrupts so we can cancel the input ask sigCh := make(chan os.Signal, 1) signal.Notify(sigCh, os.Interrupt) defer signal.Stop(sigCh) // Build the output format for asking var buf bytes.Buffer buf.WriteString("[reset]") buf.WriteString(fmt.Sprintf("[bold]%s[reset]\n", opts.Query)) if opts.Description != "" { s := bufio.NewScanner(strings.NewReader(opts.Description)) for s.Scan() { buf.WriteString(fmt.Sprintf(" %s\n", s.Text())) } buf.WriteString("\n") } if opts.Default != "" { buf.WriteString(" [bold]Default:[reset] ") buf.WriteString(opts.Default) buf.WriteString("\n") } buf.WriteString(" [bold]Enter a value:[reset] ") // Ask the user for their input if _, err := fmt.Fprint(w, i.Colorize.Color(buf.String())); err != nil { return "", err } // Listen for the input in a goroutine. This will allow us to // interrupt this if we are interrupted (SIGINT) result := make(chan string, 1) go func() { buf := bufio.NewReader(r) line, err := buf.ReadString('\n') if err != nil { log.Printf("[ERR] UIInput scan err: %s", err) } result <- strings.TrimRightFunc(line, unicode.IsSpace) }() select { case line := <-result: fmt.Fprint(w, "\n") if line == "" { line = opts.Default } return line, nil case <-sigCh: // Print a newline so that any further output starts properly // on a new line. fmt.Fprintln(w) // Mark that we were interrupted so future Ask calls fail. i.interrupted = true return "", errors.New("interrupted") } } func (i *UIInput) init() { if i.Colorize == nil { i.Colorize = &colorstring.Colorize{ Colors: colorstring.DefaultColors, Disable: true, } } }