🎁 Add FORCE_COLOR support

README.md

@@ -130,7 +130,9 @@ There might be a case where you want to explicitly disable/enable color output.
 (for example if the output were piped directly to `less`).
 
 The `color` package also disables color output if the [`NO_COLOR`](https://no-color.org) environment
-variable is set (regardless of its value).
+variable is set (regardless of its value). Setting the `FORCE_COLOR` 
+environment variable to value different from `0` will force enable color 
+output, even for non-tty output streams.
 
 `Color` has support to disable/enable colors programatically both globally and
 for single color definitions. For example suppose you have a CLI app and a
@@ -160,7 +162,16 @@ c.Println("This prints again cyan...")
 
 ## GitHub Actions
 
-To output color in GitHub Actions (or other CI systems that support ANSI colors), make sure to set `color.NoColor = false` so that it bypasses the check for non-tty output streams. 
+To output color in GitHub Actions (or other CI systems that support ANSI 
+colors), make sure to set `color.NoColor = false` so that it bypasses the check
+for non-tty output streams.
+
+Easiest way to do it can be leveraging the `FORCE_COLOR` environment variable:
+
+```yaml
+env:
+  FORCE_COLOR: true
+```
 
 ## Todo
 

color.go

@@ -19,8 +19,7 @@ var (
 	// set (regardless of its value). This is a global option and affects all
 	// colors. For more control over each color block use the methods
 	// DisableColor() individually.
-	NoColor = noColorExists() || os.Getenv("TERM") == "dumb" ||
-		(!isatty.IsTerminal(os.Stdout.Fd()) && !isatty.IsCygwinTerminal(os.Stdout.Fd()))
+	NoColor = calculateNoColor()
 
 	// Output defines the standard output of the print functions. By default
 	// os.Stdout is used.
@@ -35,6 +34,47 @@ var (
 	colorsCacheMu sync.Mutex // protects colorsCache
 )
 
+func calculateNoColor() bool {
+	mode := resolveColorMode()
+	if mode.set() {
+		return !mode.colored()
+	}
+	return noColorExists() || os.Getenv("TERM") == "dumb" ||
+		(!isatty.IsTerminal(os.Stdout.Fd()) && !isatty.IsCygwinTerminal(os.Stdout.Fd()))
+}
+
+type colorMode int
+
+const notForcedColor colorMode = -1
+const (
+	noColor colorMode = iota
+	color16
+	color256
+	color16M
+)
+
+func (c colorMode) set() bool {
+	return c != notForcedColor
+}
+
+func (c colorMode) colored() bool {
+	return c > noColor
+}
+
+func resolveColorMode() colorMode {
+	if ev, set := os.LookupEnv("FORCE_COLOR"); set {
+		ev = strings.ToLower(ev)
+		if mode, err := strconv.Atoi(ev); err == nil {
+			return colorMode(mode)
+		}
+		if ev == "yes" || ev == "true" {
+			return color256
+		}
+		return noColor
+	}
+	return notForcedColor
+}
+
 // noColorExists returns true if the environment variable NO_COLOR exists.
 func noColorExists() bool {
 	_, exists := os.LookupEnv("NO_COLOR")
@@ -124,6 +164,10 @@ func New(value ...Attribute) *Color {
 		c.noColor = boolPtr(true)
 	}
 
+	if mode := resolveColorMode(); mode.set() {
+		c.noColor = boolPtr(!mode.colored())
+	}
+
 	c.Add(value...)
 	return c
 }

color_test.go

@@ -200,6 +200,25 @@ func TestNoColor_Env(t *testing.T) {
 
 }
 
+func TestForceColorEnv(t *testing.T) {
+	_ = os.Setenv("FORCE_COLOR", "1")
+	t.Cleanup(func() {
+		_ = os.Unsetenv("FORCE_COLOR")
+	})
+
+	rb := new(bytes.Buffer)
+	Output = rb
+
+	p := New(FgHiCyan)
+	text := "text to be colored"
+	_, _ = p.Print(text)
+
+	line, _ := rb.ReadString('\n')
+	if line == text {
+		t.Errorf("Expecting '%s' be colored\n", line)
+	}
+}
+
 func TestColorVisual(t *testing.T) {
 	// First Visual Test
 	Output = colorable.NewColorableStdout()