Strip ANSI color codes from notifications (#2508)

Co-authored-by: Tom Limoncelli <tlimoncelli@stackoverflow.com>

pkg/notifications/notifications.go

@@ -1,5 +1,7 @@
 package notifications
 
+import "regexp"
+
 // Notifier is a type that can send a notification
 type Notifier interface {
 	// Notify will be called after a correction is performed.
@@ -14,6 +16,9 @@ type Notifier interface {
 // new notification types should add themselves to this array
 var initers = []func(map[string]string) Notifier{}
 
+// matches ansi color codes
+var ansiColorRegex = regexp.MustCompile(`\x1b\[[0-9;]*m`)
+
 // Init will take the given config map (from creds.json notifications key) and create a single Notifier with
 // all notifications it has full config for.
 func Init(config map[string]string) Notifier {
@@ -29,9 +34,20 @@ func Init(config map[string]string) Notifier {
 
 type multiNotifier []Notifier
 
+// removes any ansi color codes from a given string
+func stripAnsiColors(colored string) string {
+	return ansiColorRegex.ReplaceAllString(colored, "")
+}
+
 func (m multiNotifier) Notify(domain, provider string, message string, err error, preview bool) {
+
+	// force-remove ansi colors that might come with the message from dnscontrol.
+	// These usually don't render well in notifiers, outputting escape codes.
+	// If a notifier wants to output colors, they should probably implement
+	// them natively.
+	nMsg := stripAnsiColors(message)
 	for _, n := range m {
-		n.Notify(domain, provider, message, err, preview)
+		n.Notify(domain, provider, nMsg, err, preview)
 	}
 }
 func (m multiNotifier) Done() {

pkg/notifications/notifications_test.go

@@ -0,0 +1,25 @@
+package notifications
+
+import "testing"
+
+func Test_stripAnsiColorsValid(t *testing.T) {
+
+	coloredStr := "\x1b[0133myellow\x1b[0m" // 33 == yellow
+	nonColoredStr := "yellow"
+
+	s := stripAnsiColors(coloredStr)
+	if s != nonColoredStr {
+		t.Errorf("stripAnsiColors() stripped %q different from %q", coloredStr, nonColoredStr)
+	}
+}
+
+func Test_stripAnsiColorsInvalid(t *testing.T) {
+
+	coloredStr := "\x1b[01AAmyellow\x1b[0m" // AA not a real color
+	nonColoredStr := "yellow"
+
+	s := stripAnsiColors(coloredStr)
+	if s == nonColoredStr {
+		t.Errorf("stripAnsiColors() stripped %q should be different from %q", coloredStr, nonColoredStr)
+	}
+}