This adds the ability to force colored output

Feature suggested in #87

main.go

@@ -9,6 +9,7 @@ import (
 	"path/filepath"
 	"runtime"
 
+	"github.com/fatih/color"
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
 
@@ -22,6 +23,10 @@ var (
 	date    = "unknown"
 )
 
+// forceColor tells kubeval to use colored output even if
+// stdout is not a TTY
+var forceColor bool
+
 // RootCmd represents the the command to run when kubeval is run
 var RootCmd = &cobra.Command{
 	Use:     "kubeval <file> [file...]",
@@ -43,6 +48,10 @@ var RootCmd = &cobra.Command{
 				windowsStdinIssue = true
 			}
 		}
+		// Assert that colors will definitely be used if requested
+		if forceColor {
+			color.NoColor = false
+		}
 		// We detect whether we have anything on stdin to process if we have no arguments
 		// or if the argument is a -
 		if (len(args) < 1 || args[0] == "-") && !windowsStdinIssue && ((stat.Mode() & os.ModeCharDevice) == 0) {
@@ -119,6 +128,7 @@ func init() {
 	RootCmd.Flags().BoolVarP(&kubeval.OpenShift, "openshift", "", false, "Use OpenShift schemas instead of upstream Kubernetes")
 	RootCmd.Flags().BoolVarP(&kubeval.Strict, "strict", "", false, "Disallow additional properties not in schema")
 	RootCmd.Flags().BoolVarP(&kubeval.IgnoreMissingSchemas, "ignore-missing-schemas", "", false, "Skip validation for resource definitions without a schema")
+	RootCmd.Flags().BoolVarP(&forceColor, "force-color", "", false, "Force colored output even if stdout is not a TTY")
 	RootCmd.SetVersionTemplate(`{{.Version}}`)
 	viper.BindPFlag("schema_location", RootCmd.Flags().Lookup("schema-location"))
 	RootCmd.PersistentFlags().StringP("filename", "f", "stdin", "filename to be displayed when testing manifests read from stdin")