From c39c4d535cb32fabaab9ce892b1c039f21068bd2 Mon Sep 17 00:00:00 2001
From: Richard Ramos <info@richardramos.me>
Date: Wed, 14 Sep 2022 15:19:11 -0400
Subject: [PATCH] feat: support multiple DNS discovery URLs (#309)

---
 waku.go         |  4 ++--
 waku/node.go    | 24 +++++++++++++-----------
 waku/options.go |  2 +-
 3 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/waku.go b/waku.go
index 3736a6e8..0540dfa1 100644
--- a/waku.go
+++ b/waku.go
@@ -354,10 +354,10 @@ func main() {
 			Usage:       "Enable DNS discovery",
 			Destination: &options.DNSDiscovery.Enable,
 		},
-		&cli.StringFlag{
+		&cli.StringSliceFlag{
 			Name:        "dns-discovery-url",
 			Usage:       "URL for DNS node list in format 'enrtree://<key>@<fqdn>'",
-			Destination: &options.DNSDiscovery.URL,
+			Destination: &options.DNSDiscovery.URLs,
 		},
 		&cli.StringFlag{
 			Name:        "dns-discovery-name-server",
diff --git a/waku/node.go b/waku/node.go
index 7a0286f9..2aa5c1f8 100644
--- a/waku/node.go
+++ b/waku/node.go
@@ -226,18 +226,20 @@ func Execute(options Options) {
 
 	var discoveredNodes []dnsdisc.DiscoveredNode
 	if options.DNSDiscovery.Enable {
-		if options.DNSDiscovery.URL != "" {
-			logger.Info("attempting DNS discovery with ", zap.String("URL", options.DNSDiscovery.URL))
-			nodes, err := dnsdisc.RetrieveNodes(ctx, options.DNSDiscovery.URL, dnsdisc.WithNameserver(options.DNSDiscovery.Nameserver))
-			if err != nil {
-				logger.Warn("dns discovery error ", zap.Error(err))
-			} else {
-				var discAddresses []multiaddr.Multiaddr
-				for _, n := range nodes {
-					discAddresses = append(discAddresses, n.Addresses...)
+		if len(options.DNSDiscovery.URLs.Value()) != 0 {
+			for _, url := range options.DNSDiscovery.URLs.Value() {
+				logger.Info("attempting DNS discovery with ", zap.String("URL", url))
+				nodes, err := dnsdisc.RetrieveNodes(ctx, url, dnsdisc.WithNameserver(options.DNSDiscovery.Nameserver))
+				if err != nil {
+					logger.Warn("dns discovery error ", zap.Error(err))
+				} else {
+					var discAddresses []multiaddr.Multiaddr
+					for _, n := range nodes {
+						discAddresses = append(discAddresses, n.Addresses...)
+					}
+					logger.Info("found dns entries ", logging.MultiAddrs("nodes", discAddresses...))
+					discoveredNodes = nodes
 				}
-				logger.Info("found dns entries ", logging.MultiAddrs("nodes", discAddresses...))
-				discoveredNodes = nodes
 			}
 		} else {
 			logger.Fatal("DNS discovery URL is required")
diff --git a/waku/options.go b/waku/options.go
index 3f861679..339eda6c 100644
--- a/waku/options.go
+++ b/waku/options.go
@@ -103,7 +103,7 @@ type SwapOptions struct {
 // information for nodes. It's very useful for bootstrapping a p2p network.
 type DNSDiscoveryOptions struct {
 	Enable     bool
-	URL        string
+	URLs       cli.StringSlice
 	Nameserver string
 }