TUN-881: Display trial zone URL upon successful registration

origin/tunnel.go

@@ -342,6 +342,14 @@ func RegisterTunnel(ctx context.Context, muxer *h2mux.Muxer, config *TunnelConfi
 	if registration.TunnelID != "" {
 		config.Logger.Info("Tunnel ID: " + registration.TunnelID)
 	}
+
+	// Print out the user's trial zone URL in a nice box (if they requested and got one)
+	if isTrialTunnel := config.Hostname == "" && registration.Url != ""; isTrialTunnel {
+		for _, line := range asciiBox(trialZoneMsg(registration.Url), 2) {
+			config.Logger.Infoln(line)
+		}
+	}
+
 	config.Logger.Infof("Route propagating, it may take up to 1 minute for your new route to become functional")
 	return nil
 }
@@ -632,3 +640,35 @@ func uint8ToString(input uint8) string {
 func isLBProbeRequest(req *http.Request) bool {
 	return strings.HasPrefix(req.UserAgent(), lbProbeUserAgentPrefix)
 }
+
+// Print out the given lines in a nice ASCII box.
+func asciiBox(lines []string, padding int) (box []string) {
+	maxLen := maxLen(lines)
+	spacer := strings.Repeat(" ", padding)
+
+	border := "+" + strings.Repeat("-", maxLen+(padding*2)) + "+"
+
+	box = append(box, border)
+	for _, line := range lines {
+		box = append(box, "|"+spacer+line+strings.Repeat(" ", maxLen-len(line))+spacer+"|")
+	}
+	box = append(box, border)
+	return
+}
+
+func maxLen(lines []string) int {
+	max := 0
+	for _, line := range lines {
+		if len(line) > max {
+			max = len(line)
+		}
+	}
+	return max
+}
+
+func trialZoneMsg(url string) []string {
+	return []string{
+		"Your free tunnel has started! Visit it:",
+		"  " + url,
+	}
+}