color

command/commands.go

@@ -9,6 +9,11 @@ import (
 	"github.com/mitchellh/cli"
 )
 
+const (
+	// EnvNomadCLINoColor is an env var that toggles colored UI output.
+	EnvNomadCLINoColor = `NOMAD_CLI_NO_COLOR`
+)
+
 // DeprecatedCommand is a command that wraps an existing command and prints a
 // deprecation notice and points the user to the new command. Deprecated
 // commands are always hidden from help output.

command/meta.go

@@ -181,7 +181,8 @@ func generalOptionsUsage() string {
     Defaults to the "default" namespace.
 
   -no-color
-    Disables colored command output.
+    Disables colored command output. Alternatively, NOMAD_CLI_NO_COLOR may be
+    set.
 
   -ca-cert=<path>
     Path to a PEM encoded CA cert file to use to verify the

main.go

@@ -13,6 +13,7 @@ import (
 	"github.com/hashicorp/nomad/version"
 	"github.com/mitchellh/cli"
 	"github.com/sean-/seed"
+	"golang.org/x/crypto/ssh/terminal"
 )
 
 var (
@@ -63,10 +64,39 @@ func main() {
 }
 
 func Run(args []string) int {
-	return RunCustom(args, command.Commands(nil))
+	return RunCustom(args)
 }
 
-func RunCustom(args []string, commands map[string]cli.CommandFactory) int {
+func RunCustom(args []string) int {
+	// Parse flags into env vars for global use
+	args = setupEnv(args)
+
+	// Create the meta object
+	metaPtr := new(command.Meta)
+
+	// Don't use color if disabled
+	color := true
+	if os.Getenv(command.EnvNomadCLINoColor) != "" {
+		color = false
+	}
+
+	isTerminal := terminal.IsTerminal(int(os.Stdout.Fd()))
+	metaPtr.Ui = &cli.BasicUi{
+		Reader:      os.Stdin,
+		Writer:      os.Stdout,
+		ErrorWriter: os.Stderr,
+	}
+
+	// Only use colored UI if stdout is a tty, and not disabled
+	if isTerminal && color {
+		metaPtr.Ui = &cli.ColoredUi{
+			ErrorColor: cli.UiColorRed,
+			WarnColor:  cli.UiColorYellow,
+			Ui:         metaPtr.Ui,
+		}
+	}
+
+	commands := command.Commands(metaPtr)
 	cli := &cli.CLI{
 		Name:                       "nomad",
 		Version:                    version.GetVersion().FullVersionNumber(true),
@@ -78,6 +108,7 @@ func RunCustom(args []string, commands map[string]cli.CommandFactory) int {
 		HelpFunc: groupedHelpFunc(
 			cli.BasicHelpFunc("nomad"),
 		),
+		HelpWriter: os.Stdout,
 	}
 
 	exitCode, err := cli.Run()
@@ -177,3 +208,22 @@ func printCommand(w io.Writer, name string, cmdFn cli.CommandFactory) {
 	}
 	fmt.Fprintf(w, "    %s\t%s\n", name, cmd.Synopsis())
 }
+
+// setupEnv parses args and may replace them and sets some env vars to known
+// values based on format options
+func setupEnv(args []string) []string {
+	noColor := false
+	for _, arg := range args {
+		// Check if color is set
+		if arg == "-no-color" || arg == "--no-color" {
+			noColor = true
+		}
+	}
+
+	// Put back into the env for later
+	if noColor {
+		os.Setenv(command.EnvNomadCLINoColor, "true")
+	}
+
+	return args
+}

website/source/docs/commands/_general_options.html.md

@@ -5,7 +5,8 @@
   Overrides the `NOMAD_REGION` environment variable if set. Defaults to the
   Agent's local region.
 
-- `-no-color`: Disables colored command output.
+- `-no-color`: Disables colored command output. Alternatively,
+  `NOMAD_CLI_NO_COLOR` may be set.
 
 - `-ca-cert=<path>`: Path to a PEM encoded CA cert file to use to verify the
   Nomad server SSL certificate. Overrides the `NOMAD_CACERT` environment