Merge pull request #76 from cnblogs/improvement-for-issue-70

 Resolve hostname to IP address in MemcachedClientConfiguration

Author: cnblogs-dudu

Enyim.Caching/Configuration/MemcachedClientConfiguration.cs

@@ -7,6 +7,8 @@
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
 using Microsoft.Extensions.Configuration;
+using System.Linq;
+using System.Net.Sockets;
 
 namespace Enyim.Caching.Configuration
 {
@@ -41,23 +43,19 @@ public MemcachedClientConfiguration(
             var options = optionsAccessor.Value;
             if ((options == null || options.Servers.Count == 0) && configuration != null)
             {
-                var section = configuration.GetSection("enyimMemcached");                
+                var section = configuration.GetSection("enyimMemcached");
                 if (section.Exists())
                 {
-                    section.Bind(options);                    
+                    section.Bind(options);
                 }
                 else
                 {
                     _logger.LogWarning($"No enyimMemcached setting in appsetting.json. Use default configuration");
                     options.AddDefaultServer();
-                }                
+                }
             }
 
-            Servers = new List<DnsEndPoint>();
-            foreach (var server in options.Servers)
-            {
-                Servers.Add(new DnsEndPoint(server.Address, server.Port));
-            }
+            ConfigureServers(options);
 
             SocketPool = new SocketPoolConfiguration();
             if (options.SocketPool != null)
@@ -172,6 +170,35 @@ public MemcachedClientConfiguration(
             }
         }
 
+        private void ConfigureServers(MemcachedClientOptions options)
+        {
+            Servers = new List<DnsEndPoint>();
+            foreach (var server in options.Servers)
+            {
+                if (!IPAddress.TryParse(server.Address, out var address))
+                {
+                    var ip = Dns.GetHostAddresses(server.Address)
+                        .FirstOrDefault(i => i.AddressFamily == AddressFamily.InterNetwork)?.ToString();
+
+                    if (ip == null)
+                    {
+                        _logger.LogError($"Could not resolve host '{server.Address}'.");
+                    }
+                    else
+                    {
+                        _logger.LogInformation($"Memcached server address - {server.Address }({ip}):{server.Port}");
+                        server.Address = ip;
+                    }
+                }
+                else
+                {
+                    _logger.LogInformation($"Memcached server address - {server.Address }:{server.Port}");
+                }
+
+                Servers.Add(new DnsEndPoint(server.Address, server.Port));
+            }
+        }
+
         /// <summary>
         /// Adds a new server to the pool.
         /// </summary>

Enyim.Caching/EnyimMemcachedApplicationBuilderExtensions.cs

@@ -5,23 +5,27 @@
 using System.Threading.Tasks;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
+using Enyim.Caching.Configuration;
+using Enyim.Caching.Memcached;
 
 namespace Microsoft.AspNetCore.Builder
 {
     public static class EnyimMemcachedApplicationBuilderExtensions
     {
         public static IApplicationBuilder UseEnyimMemcached(this IApplicationBuilder app)
         {
+            var logger = app.ApplicationServices.GetService<ILogger<IMemcachedClient>>();
             try
             {
-                app.ApplicationServices.GetService<IMemcachedClient>()
-                    .GetAsync<string>("EnyimMemcached").Wait();
-                Console.WriteLine("EnyimMemcached Started.");
-            } catch (Exception ex)
+                var client = app.ApplicationServices.GetRequiredService<IMemcachedClient>();
+                client.GetValueAsync<string>("UseEnyimMemcached").Wait();
+                Console.WriteLine("EnyimMemcached connected memcached servers.");
+            }
+            catch (Exception ex)
             {
-                app.ApplicationServices.GetService<ILogger<IMemcachedClient>>()
-                    .LogError(new EventId(), ex, "EnyimMemcached Failed.");
+                logger.LogError(ex, "Failed in UseEnyimMemcached");
             }
+
             return app;
         }
     }

Enyim.Caching/EnyimMemcachedServiceCollectionExtensions.cs

@@ -86,7 +86,7 @@ private static IServiceCollection AddEnyimMemcachedInternal(IServiceCollection s
             services.TryAddSingleton<ITranscoder, DefaultTranscoder>();
             services.TryAddSingleton<IMemcachedKeyTransformer, DefaultKeyTransformer>();
             services.TryAddTransient<IMemcachedClientConfiguration, MemcachedClientConfiguration>();
-            services.AddSingleton<MemcachedClient, MemcachedClient>();
+            services.AddSingleton<MemcachedClient>();
 
             services.AddSingleton<IMemcachedClient>(factory => factory.GetService<MemcachedClient>());
             services.AddSingleton<IDistributedCache>(factory => factory.GetService<MemcachedClient>());

MemcachedTest/MemcachedClientTest.cs

@@ -34,7 +34,7 @@ protected virtual MemcachedClient GetClient(MemcachedProtocol protocol = Memcach
                 services.AddSingleton<ITranscoder,BinaryFormatterTranscoder>();
             }
 
-            services.AddLogging(builder => builder.SetMinimumLevel(LogLevel.Debug).AddConsole());
+            services.AddLogging(builder => builder.SetMinimumLevel(LogLevel.Information).AddConsole());
 
             IServiceProvider serviceProvider = services.BuildServiceProvider();
             var client = serviceProvider.GetService<IMemcachedClient>() as MemcachedClient;