fix #2448 favor publish_address in 5.x

Now that 5.x no longer returns http_address we need to give precedence
to `publish_address` over `bound_address`

Author: Mpdreamz

src/Elasticsearch.Net/Transport/Sniff/SniffResponse.cs

@@ -5,13 +5,29 @@
 
 namespace Elasticsearch.Net
 {
-	public class SniffResponse
+	public static class SniffParser
 	{
-		//internal ctor  - so that only Elasticsearch.Net can instantiate it
-		internal SniffResponse() { }
-
 		public static Regex AddressRegex { get; } = new Regex(@"^((?<fqdn>[^/]+)/)?(?<ip>[^:]+|\[[\da-fA-F:\.]+\]):(?<port>\d+)$");
+		public static Uri ParseToUri(string boundAddress, bool forceHttp)
+		{
+			if (boundAddress == null) throw new ArgumentNullException(nameof(boundAddress));
+			var suffix = forceHttp ? "s" : string.Empty;
+			var match = AddressRegex.Match(boundAddress);
+			if (!match.Success) throw new Exception($"Can not parse bound_address: {boundAddress} to Uri");
+
+			var fqdn = match.Groups["fqdn"].Value?.Trim();
+			var ip = match.Groups["ip"].Value?.Trim();
+			var port = match.Groups["port"].Value?.Trim();
+			var host = !fqdn.IsNullOrEmpty() ? fqdn : ip;
+
+			return new Uri($"http{suffix}://{host}:{port}");
+		}
+	}
+	internal class SniffResponse
+	{
 
+		// ReSharper disable InconsistentNaming
+		// this uses simplejsons bindings
 		public string cluster_name { get; set; }
 
 		public Dictionary<string, NodeInfo> nodes { get; set; }
@@ -20,34 +36,29 @@ public IEnumerable<Node> ToNodes(bool forceHttp = false)
 		{
 			foreach (var kv in nodes.Where(n => n.Value.HttpEnabled))
 			{
-				yield return new Node(this.ParseToUri(kv.Value.http?.bound_address.FirstOrDefault(), forceHttp))
+				var info = kv.Value;
+				var httpEndpoint = info.http?.publish_address;
+				if (string.IsNullOrWhiteSpace(httpEndpoint))
+					httpEndpoint = kv.Value.http?.bound_address.FirstOrDefault();
+				if (string.IsNullOrWhiteSpace(httpEndpoint))
+					continue;
+
+				var uri = SniffParser.ParseToUri(httpEndpoint, forceHttp);
+				var node = new Node(uri)
 				{
 					Name = kv.Value.name,
 					Id = kv.Key,
 					MasterEligible = kv.Value.MasterEligible,
 					HoldsData = kv.Value.HoldsData,
 					HttpEnabled = kv.Value.HttpEnabled
 				};
+				//TODO selector
+				yield return node;
 			}
 		}
-
-		private Uri ParseToUri(string boundAddress, bool forceHttp)
-		{
-			if (boundAddress.IsNullOrEmpty()) return null;
-			var suffix = forceHttp ? "s" : string.Empty;
-			var match = AddressRegex.Match(boundAddress);
-			if (!match.Success) throw new Exception($"Can not parse bound_address: {boundAddress} to Uri");
-
-			var fqdn = match.Groups["fqdn"].Value?.Trim();
-			var ip = match.Groups["ip"].Value?.Trim();
-			var port = match.Groups["port"].Value?.Trim();
-			var host = !fqdn.IsNullOrEmpty() ? fqdn : ip;
-
-			return new Uri($"http{suffix}://{host}:{port}");
-		}
 	}
 
-	public class NodeInfo
+	internal class NodeInfo
 	{
 		public string name { get; set; }
 		public string transport_address { get; set; }
@@ -72,8 +83,9 @@ internal bool HttpEnabled
 		}
 	}
 
-	public class NodeInfoHttp
+	internal class NodeInfoHttp
 	{
 		public IList<string> bound_address { get; set; }
+		public string publish_address { get; set; }
 	}
 }