Merge pull request #1438 from rabbitmq/rabbitmq-dotnet-client-1434

Pass exception back up to application code

Author: lukebakken

projects/RabbitMQ.Client/client/api/ShutdownEventArgs.cs

@@ -41,27 +41,48 @@ namespace RabbitMQ.Client
     /// </remarks>
     public class ShutdownEventArgs : EventArgs
     {
+        private readonly Exception _exception;
+
         /// <summary>
         /// Construct a <see cref="ShutdownEventArgs"/> with the given parameters and
         ///  0 for <see cref="ClassId"/> and <see cref="MethodId"/>.
         /// </summary>
-        public ShutdownEventArgs(ShutdownInitiator initiator, ushort replyCode, string replyText, object cause = null)
-            : this(initiator, replyCode, replyText, 0, 0, cause)
+        public ShutdownEventArgs(ShutdownInitiator initiator, ushort replyCode, string replyText, object cause = null, Exception exception = null)
+            : this(initiator, replyCode, replyText, 0, 0, cause, exception)
         {
         }
 
         /// <summary>
         /// Construct a <see cref="ShutdownEventArgs"/> with the given parameters.
         /// </summary>
         public ShutdownEventArgs(ShutdownInitiator initiator, ushort replyCode, string replyText,
-            ushort classId, ushort methodId, object cause = null)
+            ushort classId, ushort methodId, object cause = null, Exception exception = null)
         {
             Initiator = initiator;
             ReplyCode = replyCode;
             ReplyText = replyText;
             ClassId = classId;
             MethodId = methodId;
             Cause = cause;
+            _exception = exception;
+        }
+
+        /// <summary>
+        /// Exception causing the shutdown, or null if none.
+        /// </summary>
+        public Exception Exception
+        {
+            get
+            {
+                if (_exception != null)
+                {
+                    return _exception;
+                }
+                else
+                {
+                    return new Exception(ToString());
+                }
+            }
         }
 
         /// <summary>
@@ -98,13 +119,14 @@ public ShutdownEventArgs(ShutdownInitiator initiator, ushort replyCode, string r
         /// Override ToString to be useful for debugging.
         /// </summary>
         public override string ToString()
-        { 
-            return $"AMQP close-reason, initiated by {Initiator}" 
+        {
+            return $"AMQP close-reason, initiated by {Initiator}"
                 + $", code={ReplyCode}"
                 + (ReplyText != null ? $", text='{ReplyText}'" : string.Empty)
                 + $", classId={ClassId}"
                 + $", methodId={MethodId}"
-                + (Cause != null ? $", cause={Cause}" : string.Empty);
+                + (Cause != null ? $", cause={Cause}" : string.Empty)
+                + (_exception != null ? $", exception={_exception}" : string.Empty);
         }
     }
 }

projects/RabbitMQ.Client/client/impl/Connection.cs

@@ -457,13 +457,14 @@ public void HandleMainLoopException(ShutdownEventArgs reason)
         {
             if (!SetCloseReason(reason))
             {
-                LogCloseError("Unexpected Main Loop Exception while closing: "
-                              + reason, new Exception(reason.ToString()));
+                LogCloseError($"Unexpected Main Loop Exception while closing: {reason}", reason.Exception);
                 return;
             }
 
+            _model0.MaybeSetConnectionStartException(reason.Exception);
+
             OnShutdown();
-            LogCloseError($"Unexpected connection closure: {reason}", new Exception(reason.ToString()));
+            LogCloseError($"Unexpected connection closure: {reason}", reason.Exception);
         }
 
         public bool HardProtocolExceptionHandler(HardProtocolException hpe)
@@ -540,22 +541,33 @@ public void MainLoop()
                 catch (EndOfStreamException eose)
                 {
                     // Possible heartbeat exception
-                    HandleMainLoopException(new ShutdownEventArgs(
-                        ShutdownInitiator.Library,
-                        0,
-                        "End of stream",
-                        eose));
+                    var ea = new ShutdownEventArgs(ShutdownInitiator.Library,
+                        0, "End of stream",
+                        cause: null, exception: eose);
+                    HandleMainLoopException(ea);
                 }
                 catch (HardProtocolException hpe)
                 {
                     shutdownCleanly = HardProtocolExceptionHandler(hpe);
                 }
+                catch (FileLoadException fileLoadException)
+                {
+                    /*
+                     * https://github.com/rabbitmq/rabbitmq-dotnet-client/issues/1434
+                     * Ensure that these exceptions eventually make it to application code
+                     */
+                    var ea = new ShutdownEventArgs(ShutdownInitiator.Library,
+                        Constants.InternalError, fileLoadException.Message,
+                        cause: null, exception: fileLoadException);
+                    HandleMainLoopException(ea);
+                }
                 catch (Exception ex)
                 {
-                    HandleMainLoopException(new ShutdownEventArgs(ShutdownInitiator.Library,
+                    var ea = new ShutdownEventArgs(ShutdownInitiator.Library,
                         Constants.InternalError,
-                        "Unexpected Exception",
-                        ex));
+                        $"Unexpected Exception: {ex.Message}",
+                        cause: null, exception: ex);
+                    HandleMainLoopException(ea);
                 }
 
                 // If allowed for clean shutdown, run main loop until the
@@ -1104,7 +1116,8 @@ private void StartAndTune()
 
             if (connectionStart == null)
             {
-                throw new IOException("connection.start was never received, likely due to a network timeout");
+                const string msg = "connection.start was never received, likely due to a network timeout";
+                throw new IOException(msg, _model0.ConnectionStartException);
             }
 
             ServerProperties = connectionStart.m_serverProperties;

projects/RabbitMQ.Client/client/impl/ModelBase.cs

@@ -48,7 +48,9 @@ abstract class ModelBase : IFullModel, IRecoverable
     {
         ///<summary>Only used to kick-start a connection open
         ///sequence. See <see cref="Connection.Open"/> </summary>
-        public BlockingCell<ConnectionStartDetails> m_connectionStartCell = null;
+        internal BlockingCell<ConnectionStartDetails> m_connectionStartCell = null;
+        private Exception m_connectionStartException = null;
+
         internal readonly IBasicProperties _emptyBasicProperties;
 
         private readonly Dictionary<string, IBasicConsumer> _consumers = new Dictionary<string, IBasicConsumer>();
@@ -174,6 +176,19 @@ public bool IsOpen
 
         public ISession Session { get; private set; }
 
+        public Exception ConnectionStartException
+        {
+            get { return m_connectionStartException; }
+        }
+
+        public void MaybeSetConnectionStartException(Exception ex)
+        {
+            if (m_connectionStartCell != null)
+            {
+                m_connectionStartException = ex;
+            }
+        }
+
         public Task Close(ushort replyCode, string replyText, bool abort)
         {
             return Close(new ShutdownEventArgs(ShutdownInitiator.Application,

projects/Unit/APIApproval.Approve.verified.txt

@@ -609,10 +609,11 @@ namespace RabbitMQ.Client
     }
     public class ShutdownEventArgs : System.EventArgs
     {
-        public ShutdownEventArgs(RabbitMQ.Client.ShutdownInitiator initiator, ushort replyCode, string replyText, object cause = null) { }
-        public ShutdownEventArgs(RabbitMQ.Client.ShutdownInitiator initiator, ushort replyCode, string replyText, ushort classId, ushort methodId, object cause = null) { }
+        public ShutdownEventArgs(RabbitMQ.Client.ShutdownInitiator initiator, ushort replyCode, string replyText, object cause = null, System.Exception exception = null) { }
+        public ShutdownEventArgs(RabbitMQ.Client.ShutdownInitiator initiator, ushort replyCode, string replyText, ushort classId, ushort methodId, object cause = null, System.Exception exception = null) { }
         public object Cause { get; }
         public ushort ClassId { get; }
+        public System.Exception Exception { get; }
         public RabbitMQ.Client.ShutdownInitiator Initiator { get; }
         public ushort MethodId { get; }
         public ushort ReplyCode { get; }