Fixed: Workaround for mono 5.16+ bug preventing the closure of sockets on timeouts (Jackett connections)

ref #2802

src/NzbDrone.Common/Http/Dispatchers/ManagedHttpDispatcher.cs

@@ -2,9 +2,13 @@ using System;
 using System.IO;
 using System.IO.Compression;
 using System.Net;
+using System.Reflection;
+using NLog;
+using NLog.Fluent;
 using NzbDrone.Common.EnvironmentInfo;
 using NzbDrone.Common.Extensions;
 using NzbDrone.Common.Http.Proxy;
+using NzbDrone.Common.Instrumentation.Extensions;
 using NzbDrone.Common.Security;
 
 namespace NzbDrone.Common.Http.Dispatchers
@@ -14,12 +18,16 @@ namespace NzbDrone.Common.Http.Dispatchers
         private readonly IHttpProxySettingsProvider _proxySettingsProvider;
         private readonly ICreateManagedWebProxy _createManagedWebProxy;
         private readonly IUserAgentBuilder _userAgentBuilder;
+        private readonly IPlatformInfo _platformInfo;
+        private readonly Logger _logger;
 
-        public ManagedHttpDispatcher(IHttpProxySettingsProvider proxySettingsProvider, ICreateManagedWebProxy createManagedWebProxy, IUserAgentBuilder userAgentBuilder)
+        public ManagedHttpDispatcher(IHttpProxySettingsProvider proxySettingsProvider, ICreateManagedWebProxy createManagedWebProxy, IUserAgentBuilder userAgentBuilder, IPlatformInfo platformInfo, Logger logger)
         {
             _proxySettingsProvider = proxySettingsProvider;
             _createManagedWebProxy = createManagedWebProxy;
             _userAgentBuilder = userAgentBuilder;
+            _platformInfo = platformInfo;
+            _logger = logger;
         }
 
         public HttpResponse GetResponse(HttpRequest request, CookieContainer cookies)
@@ -84,6 +92,9 @@ namespace NzbDrone.Common.Http.Dispatchers
 
                 if (httpWebResponse == null)
                 {
+                    // Workaround for mono not closing connections properly in certain situations.
+                    AbortWebRequest(webRequest);
+
                     // The default messages for WebException on mono are pretty horrible.
                     if (e.Status == WebExceptionStatus.NameResolutionFailure)
                     {
@@ -198,5 +209,36 @@ namespace NzbDrone.Common.Http.Dispatchers
                 }
             }
         }
+
+        // Workaround for mono not closing connections properly on timeouts
+        private void AbortWebRequest(HttpWebRequest webRequest)
+        {
+            // First affected version was mono 5.16
+            if (OsInfo.IsNotWindows && _platformInfo.Version >= new Version(5, 16))
+            {
+                try
+                {
+                    var currentOperationInfo = webRequest.GetType().GetField("currentOperation", BindingFlags.NonPublic | BindingFlags.Instance);
+                    var currentOperation = currentOperationInfo.GetValue(webRequest);
+
+                    if (currentOperation != null)
+                    {
+                        var responseStreamInfo = currentOperation.GetType().GetField("responseStream", BindingFlags.NonPublic | BindingFlags.Instance);
+                        var responseStream = responseStreamInfo.GetValue(currentOperation) as Stream;
+                        // Note that responseStream will likely be null once mono fixes it.
+                        responseStream?.Dispose();
+                    }
+                }
+                catch (Exception ex)
+                {
+                    // This can fail randomly on future mono versions that have been changed/fixed. Log to sentry and ignore.
+                    _logger.Trace()
+                           .Exception(ex)
+                           .Message("Unable to dispose responseStream on mono {0}", _platformInfo.Version)
+                           .WriteSentryWarn("MonoCloseWaitPatchFailed", ex.Message)
+                           .Write();
+                }
+            }
+        }
     }
 }

src/NzbDrone.Core.Test/Framework/CoreTest.cs

@@ -24,8 +24,8 @@ namespace NzbDrone.Core.Test.Framework
 
             Mocker.SetConstant<IHttpProxySettingsProvider>(new HttpProxySettingsProvider(Mocker.Resolve<ConfigService>()));
             Mocker.SetConstant<ICreateManagedWebProxy>(new ManagedWebProxyFactory(Mocker.Resolve<CacheManager>()));
-            Mocker.SetConstant<ManagedHttpDispatcher>(new ManagedHttpDispatcher(Mocker.Resolve<IHttpProxySettingsProvider>(), Mocker.Resolve<ICreateManagedWebProxy>(), Mocker.Resolve<UserAgentBuilder>()));
+            Mocker.SetConstant<ManagedHttpDispatcher>(new ManagedHttpDispatcher(Mocker.Resolve<IHttpProxySettingsProvider>(), Mocker.Resolve<ICreateManagedWebProxy>(), Mocker.Resolve<UserAgentBuilder>(), Mocker.Resolve<IPlatformInfo>(), TestLogger));
-            Mocker.SetConstant<CurlHttpDispatcher>(new CurlHttpDispatcher(Mocker.Resolve<IHttpProxySettingsProvider>(), Mocker.Resolve<UserAgentBuilder>(), Mocker.Resolve<NLog.Logger>()));
+            Mocker.SetConstant<CurlHttpDispatcher>(new CurlHttpDispatcher(Mocker.Resolve<IHttpProxySettingsProvider>(), Mocker.Resolve<UserAgentBuilder>(), TestLogger));
             Mocker.SetConstant<IHttpProvider>(new HttpProvider(TestLogger));
             Mocker.SetConstant<IHttpClient>(new HttpClient(new IHttpRequestInterceptor[0], Mocker.Resolve<CacheManager>(), Mocker.Resolve<RateLimitService>(), Mocker.Resolve<FallbackHttpDispatcher>(), Mocker.Resolve<UserAgentBuilder>(), TestLogger));
             Mocker.SetConstant<ILidarrCloudRequestBuilder>(new LidarrCloudRequestBuilder());