Fix for empty ts name when tailscale isn't running on windows (#370)

* Blind fix of proxy exit without error message

* Reproed on windows and thus updating the message

* Linter fix

Author: ldemailly

config/tailscale.go

@@ -36,6 +36,14 @@ func TailscaleServerName() string {
 		log.Critf("Error getting tailscale status: %v", err)
 		return ""
 	}
+	if status.Self == nil {
+		log.Critf("No self info in tailscale status: %+v", status)
+		return ""
+	}
+	if status.Self.DNSName == "" {
+		log.Critf("No DNSName in tailscale self info - check if tailscale is running?")
+		return ""
+	}
 	// Remove the trailing dot as it's not there in ServerName.
 	return strings.TrimSuffix(status.Self.DNSName, ".")
 }

proxy_main.go

@@ -115,7 +115,8 @@ func main() {
 		ErrorLog: log.NewStdLogger("rp", log.Error),
 	}
 
-	log.Printf("Fortio Proxy %s started - hostid %q - tailscale %t", cli.LongVersion, rp.HostID.Get(), config.HasTailscale)
+	log.Printf("Fortio Proxy %s started - hostid %q - tailscale capable: %t, on: %t",
+		cli.LongVersion, rp.HostID.Get(), config.HasTailscale, *autoTailscale)
 
 	if *httpPort != disabled {
 		fhttp.HTTPServerWithHandler("http-reverse-proxy", *httpPort, hdlr)