Support IP address connection string in Basket.API

Dns.GetHostAddressesAsync can return problematic results when passed an IP address, and if the connection string is already an IP address, we needn't call it anyway.

Author: chlowell

src/Services/Basket/Basket.API/Model/RedisBasketRepository.cs

@@ -94,13 +94,21 @@ private async Task<IServer> GetServer()
 
         private async Task ConnectToRedisAsync()
         {
-            //TODO: Need to make this more robust. Also want to understand why the static connection method cannot accept dns names.
-            var ips = await Dns.GetHostAddressesAsync(_settings.ConnectionString);
-            _logger.LogInformation($"Connecting to database {_settings.ConnectionString} at IP {ips.First().ToString()}");
-            _redis = await ConnectionMultiplexer.ConnectAsync(ips.First().ToString());
+            // TODO: Need to make this more robust. ConnectionMultiplexer.ConnectAsync doesn't like domain names or IPv6 addresses.
+            if (IPAddress.TryParse(_settings.ConnectionString, out var ip))
+            {
+                _redis = await ConnectionMultiplexer.ConnectAsync(ip.ToString());
+                _logger.LogInformation($"Connecting to database at {_settings.ConnectionString}");
+            }
+            else
+            {
+                // workaround for https://github.com/StackExchange/StackExchange.Redis/issues/410
+                var ips = await Dns.GetHostAddressesAsync(_settings.ConnectionString);
+                _logger.LogInformation($"Connecting to database {_settings.ConnectionString} at IP {ips.First().ToString()}");
+                _redis = await ConnectionMultiplexer.ConnectAsync(ips.First().ToString());
+            }
         }
-
-        
+    
     }
 }