Detect STDOUT isn't a TTY and disable color

This PR disables color output when the STDOUT is not a TTY. This makes
running commands under `watch` or other commands nicer.

command/meta.go

@@ -8,6 +8,7 @@ import (
 	"strings"
 
 	"github.com/hashicorp/nomad/api"
+	isatty "github.com/mattn/go-isatty"
 	"github.com/mitchellh/cli"
 	"github.com/mitchellh/colorstring"
 )
@@ -126,7 +127,7 @@ func (m *Meta) Client() (*api.Client, error) {
 func (m *Meta) Colorize() *colorstring.Colorize {
 	return &colorstring.Colorize{
 		Colors:  colorstring.DefaultColors,
-		Disable: m.noColor,
+		Disable: m.noColor || !isatty.IsTerminal(os.Stdout.Fd()),
 		Reset:   true,
 	}
 }

vendor/github.com/mattn/go-isatty/README.md

@@ -1,5 +1,10 @@
 # go-isatty
 
+[![Godoc Reference](https://godoc.org/github.com/mattn/go-isatty?status.svg)](http://godoc.org/github.com/mattn/go-isatty)
+[![Build Status](https://travis-ci.org/mattn/go-isatty.svg?branch=master)](https://travis-ci.org/mattn/go-isatty)
+[![Coverage Status](https://coveralls.io/repos/github/mattn/go-isatty/badge.svg?branch=master)](https://coveralls.io/github/mattn/go-isatty?branch=master)
+[![Go Report Card](https://goreportcard.com/badge/mattn/go-isatty)](https://goreportcard.com/report/mattn/go-isatty)
+
 isatty for golang
 
 ## Usage
@@ -16,6 +21,8 @@ import (
 func main() {
 	if isatty.IsTerminal(os.Stdout.Fd()) {
 		fmt.Println("Is Terminal")
+	} else if isatty.IsCygwinTerminal(os.Stdout.Fd()) {
+		fmt.Println("Is Cygwin/MSYS2 Terminal")
 	} else {
 		fmt.Println("Is Not Terminal")
 	}
@@ -28,10 +35,16 @@ func main() {
 $ go get github.com/mattn/go-isatty
 ```
 
-# License
+## License
 
 MIT
 
-# Author
+## Author
 
 Yasuhiro Matsumoto (a.k.a mattn)
+
+## Thanks
+
+* k-takata: base idea for IsCygwinTerminal
+
+    https://github.com/k-takata/go-iscygpty

vendor/github.com/mattn/go-isatty/isatty_appengine.go

@@ -1,9 +0,0 @@
-// +build appengine
-
-package isatty
-
-// IsTerminal returns true if the file descriptor is terminal which
-// is always false on on appengine classic which is a sandboxed PaaS.
-func IsTerminal(fd uintptr) bool {
-	return false
-}

vendor/github.com/mattn/go-isatty/isatty_bsd.go

@@ -1,4 +1,4 @@
-// +build darwin freebsd openbsd netbsd
+// +build darwin freebsd openbsd netbsd dragonfly
 // +build !appengine
 
 package isatty

vendor/github.com/mattn/go-isatty/isatty_others.go

@@ -0,0 +1,10 @@
+// +build !windows
+// +build !appengine
+
+package isatty
+
+// IsCygwinTerminal() return true if the file descriptor is a cygwin or msys2
+// terminal. This is also always false on this environment.
+func IsCygwinTerminal(fd uintptr) bool {
+	return false
+}

vendor/github.com/mattn/go-isatty/isatty_windows.go

@@ -4,12 +4,30 @@
 package isatty
 
 import (
+	"strings"
 	"syscall"
+	"unicode/utf16"
 	"unsafe"
 )
 
-var kernel32 = syscall.NewLazyDLL("kernel32.dll")
-var procGetConsoleMode = kernel32.NewProc("GetConsoleMode")
+const (
+	fileNameInfo uintptr = 2
+	fileTypePipe         = 3
+)
+
+var (
+	kernel32                         = syscall.NewLazyDLL("kernel32.dll")
+	procGetConsoleMode               = kernel32.NewProc("GetConsoleMode")
+	procGetFileInformationByHandleEx = kernel32.NewProc("GetFileInformationByHandleEx")
+	procGetFileType                  = kernel32.NewProc("GetFileType")
+)
+
+func init() {
+	// Check if GetFileInformationByHandleEx is available.
+	if procGetFileInformationByHandleEx.Find() != nil {
+		procGetFileInformationByHandleEx = nil
+	}
+}
 
 // IsTerminal return true if the file descriptor is terminal.
 func IsTerminal(fd uintptr) bool {
@@ -17,3 +35,60 @@ func IsTerminal(fd uintptr) bool {
 	r, _, e := syscall.Syscall(procGetConsoleMode.Addr(), 2, fd, uintptr(unsafe.Pointer(&st)), 0)
 	return r != 0 && e == 0
 }
+
+// Check pipe name is used for cygwin/msys2 pty.
+// Cygwin/MSYS2 PTY has a name like:
+//   \{cygwin,msys}-XXXXXXXXXXXXXXXX-ptyN-{from,to}-master
+func isCygwinPipeName(name string) bool {
+	token := strings.Split(name, "-")
+	if len(token) < 5 {
+		return false
+	}
+
+	if token[0] != `\msys` && token[0] != `\cygwin` {
+		return false
+	}
+
+	if token[1] == "" {
+		return false
+	}
+
+	if !strings.HasPrefix(token[2], "pty") {
+		return false
+	}
+
+	if token[3] != `from` && token[3] != `to` {
+		return false
+	}
+
+	if token[4] != "master" {
+		return false
+	}
+
+	return true
+}
+
+// IsCygwinTerminal() return true if the file descriptor is a cygwin or msys2
+// terminal.
+func IsCygwinTerminal(fd uintptr) bool {
+	if procGetFileInformationByHandleEx == nil {
+		return false
+	}
+
+	// Cygwin/msys's pty is a pipe.
+	ft, _, e := syscall.Syscall(procGetFileType.Addr(), 1, fd, 0, 0)
+	if ft != fileTypePipe || e != 0 {
+		return false
+	}
+
+	var buf [2 + syscall.MAX_PATH]uint16
+	r, _, e := syscall.Syscall6(procGetFileInformationByHandleEx.Addr(),
+		4, fd, fileNameInfo, uintptr(unsafe.Pointer(&buf)),
+		uintptr(len(buf)*2), 0, 0)
+	if r == 0 || e != 0 {
+		return false
+	}
+
+	l := *(*uint32)(unsafe.Pointer(&buf))
+	return isCygwinPipeName(string(utf16.Decode(buf[2 : 2+l/2])))
+}

vendor/vendor.json

@@ -980,8 +980,10 @@
 			"revisionTime": "2016-05-04T02:26:26Z"
 		},
 		{
+			"checksumSHA1": "trzmsZQDCc13zk/6qANox7Z/KCg=",
 			"path": "github.com/mattn/go-isatty",
-			"revision": "56b76bdf51f7708750eac80fa38b952bb9f32639"
+			"revision": "fc9e8d8ef48496124e79ae0df75490096eccf6fe",
+			"revisionTime": "2017-03-22T23:44:13Z"
 		},
 		{
 			"checksumSHA1": "ajImwVZHzsI+aNwsgzCSFSbmJqs=",