cli/utils/color.go
Brett Buddin 48e7df2337
Any non-empty value should be a disabling intent.
Conforms to the informal standard proposed in https://no-color.org
2020-04-02 20:31:04 -04:00

75 lines
1.7 KiB
Go

package utils
import (
"io"
"os"
"github.com/mattn/go-colorable"
"github.com/mattn/go-isatty"
"github.com/mgutz/ansi"
)
var _isColorEnabled = true
var _isStdoutTerminal = false
var checkedTerminal = false
var checkedNoColor = false
func isStdoutTerminal() bool {
if !checkedTerminal {
_isStdoutTerminal = IsTerminal(os.Stdout)
checkedTerminal = true
}
return _isStdoutTerminal
}
// IsTerminal reports whether the file descriptor is connected to a terminal
func IsTerminal(f *os.File) bool {
return isatty.IsTerminal(f.Fd()) || isatty.IsCygwinTerminal(f.Fd())
}
// NewColorable returns an output stream that handles ANSI color sequences on Windows
func NewColorable(f *os.File) io.Writer {
return colorable.NewColorable(f)
}
func makeColorFunc(color string) func(string) string {
cf := ansi.ColorFunc(color)
return func(arg string) string {
if isColorEnabled() && isStdoutTerminal() {
return cf(arg)
}
return arg
}
}
func isColorEnabled() bool {
if !checkedNoColor {
_isColorEnabled = os.Getenv("NO_COLOR") == ""
checkedNoColor = true
}
return _isColorEnabled
}
// Magenta outputs ANSI color if stdout is a tty
var Magenta = makeColorFunc("magenta")
// Cyan outputs ANSI color if stdout is a tty
var Cyan = makeColorFunc("cyan")
// Red outputs ANSI color if stdout is a tty
var Red = makeColorFunc("red")
// Yellow outputs ANSI color if stdout is a tty
var Yellow = makeColorFunc("yellow")
// Blue outputs ANSI color if stdout is a tty
var Blue = makeColorFunc("blue")
// Green outputs ANSI color if stdout is a tty
var Green = makeColorFunc("green")
// Gray outputs ANSI color if stdout is a tty
var Gray = makeColorFunc("black+h")
// Bold outputs ANSI color if stdout is a tty
var Bold = makeColorFunc("default+b")