From 145850c3c2bb5e229194e908b3ac2cb2868bd973 Mon Sep 17 00:00:00 2001
From: Mark van Renswoude <mark@x2software.net>
Date: Tue, 17 Mar 2020 15:21:39 +0100
Subject: [PATCH] Provide a way to disable queue verification

- Backwards compatibility with incompatible queue definitions
---
 Tapeti/Config/ITapetiConfig.cs        |  9 +++++++
 Tapeti/Config/ITapetiConfigBuilder.cs | 18 ++++++++++++++
 Tapeti/Connection/TapetiSubscriber.cs | 35 ++++++++++++++++++++++++---
 Tapeti/TapetiConfig.cs                | 24 +++++++++++++++++-
 4 files changed, 82 insertions(+), 4 deletions(-)

diff --git a/Tapeti/Config/ITapetiConfig.cs b/Tapeti/Config/ITapetiConfig.cs
index 515ea0e..78f4022 100644
--- a/Tapeti/Config/ITapetiConfig.cs
+++ b/Tapeti/Config/ITapetiConfig.cs
@@ -50,6 +50,15 @@ namespace Tapeti.Config
         /// already be present when the connection is made.
         /// </summary>
         bool DeclareDurableQueues { get; }
+
+
+        /// <summary>
+        /// Determines if durable queues are verified at startup if DeclareDurableQueues is disabled.
+        /// Defaults to true. Disable if you have queues with additional properties like a deadletter
+        /// exchange, which do not correspond to Tapeti's configuration, as these will cause an error
+        /// while verifying.
+        /// </summary>
+        bool VerifyDurableQueues { get; }
     }
 
 
diff --git a/Tapeti/Config/ITapetiConfigBuilder.cs b/Tapeti/Config/ITapetiConfigBuilder.cs
index 781648e..87699df 100644
--- a/Tapeti/Config/ITapetiConfigBuilder.cs
+++ b/Tapeti/Config/ITapetiConfigBuilder.cs
@@ -92,6 +92,24 @@ namespace Tapeti.Config
         /// feature to work, since AMQP does not provide a way to query existing bindings.
         /// </remarks>
         ITapetiConfigBuilder SetDeclareDurableQueues(bool enabled);
+
+
+        /// <summary>
+        /// Disables verifying durable queues at startup. Enabled by default.
+        /// Disable if you have queues with additional properties like a deadletter
+        /// exchange, which do not correspond to Tapeti's configuration, as these will cause an error
+        /// while verifying.
+        /// </summary>
+        ITapetiConfigBuilder DisableVerifyDurableQueues();
+
+
+        /// <summary>
+        /// Determines if durable queues are verified at startup if DeclareDurableQueues is disabled.
+        /// Defaults to true. Disable if you have queues with additional properties like a deadletter
+        /// exchange, which do not correspond to Tapeti's configuration, as these will cause an error
+        /// while verifying.
+        /// </summary>
+        ITapetiConfigBuilder SetVerifyDurableQueues(bool enabled);
     }
 
 
diff --git a/Tapeti/Connection/TapetiSubscriber.cs b/Tapeti/Connection/TapetiSubscriber.cs
index c57a424..69be2d0 100644
--- a/Tapeti/Connection/TapetiSubscriber.cs
+++ b/Tapeti/Connection/TapetiSubscriber.cs
@@ -97,9 +97,14 @@ namespace Tapeti.Connection
             var routingKeyStrategy = config.DependencyResolver.Resolve<IRoutingKeyStrategy>();
             var exchangeStrategy = config.DependencyResolver.Resolve<IExchangeStrategy>();
 
-            var bindingTarget = config.Features.DeclareDurableQueues
-                ? (CustomBindingTarget)new DeclareDurableQueuesBindingTarget(clientFactory, routingKeyStrategy, exchangeStrategy, cancellationToken)
-                : new PassiveDurableQueuesBindingTarget(clientFactory, routingKeyStrategy, exchangeStrategy, cancellationToken);
+            CustomBindingTarget bindingTarget;
+
+            if (config.Features.DeclareDurableQueues)
+                bindingTarget = new DeclareDurableQueuesBindingTarget(clientFactory, routingKeyStrategy, exchangeStrategy, cancellationToken);
+            else if (config.Features.VerifyDurableQueues)
+                bindingTarget = new PassiveDurableQueuesBindingTarget(clientFactory, routingKeyStrategy, exchangeStrategy, cancellationToken);
+            else
+                bindingTarget = new NoVerifyBindingTarget(clientFactory, routingKeyStrategy, exchangeStrategy, cancellationToken);
 
             await Task.WhenAll(config.Bindings.Select(binding => binding.Apply(bindingTarget)));
             await bindingTarget.Apply();
@@ -358,5 +363,29 @@ namespace Tapeti.Connection
                 }
             }
         }
+
+
+        private class NoVerifyBindingTarget : CustomBindingTarget
+        {
+            public NoVerifyBindingTarget(Func<ITapetiClient> clientFactory, IRoutingKeyStrategy routingKeyStrategy, IExchangeStrategy exchangeStrategy, CancellationToken cancellationToken) : base(clientFactory, routingKeyStrategy, exchangeStrategy, cancellationToken)
+            {
+            }
+
+
+            public override Task BindDurable(Type messageClass, string queueName)
+            {
+                return Task.CompletedTask;
+            }
+
+            public override Task BindDurableDirect(string queueName)
+            {
+                return Task.CompletedTask;
+            }
+
+            public override Task BindDurableObsolete(string queueName)
+            {
+                return Task.CompletedTask;
+            }
+        }
     }
 }
diff --git a/Tapeti/TapetiConfig.cs b/Tapeti/TapetiConfig.cs
index 6da6fae..2746fbc 100644
--- a/Tapeti/TapetiConfig.cs
+++ b/Tapeti/TapetiConfig.cs
@@ -167,6 +167,22 @@ namespace Tapeti
         }
 
 
+        /// <inheritdoc />
+        public ITapetiConfigBuilder DisableVerifyDurableQueues()
+        {
+            GetConfig().SetVerifyDurableQueues(false);
+            return this;
+        }
+
+
+        /// <inheritdoc />
+        public ITapetiConfigBuilder SetVerifyDurableQueues(bool enabled)
+        {
+            GetConfig().SetVerifyDurableQueues(enabled);
+            return this;
+        }
+
+
         /// <summary>
         /// Registers the default implementation of various Tapeti interfaces into the IoC container.
         /// </summary>
@@ -256,13 +272,19 @@ namespace Tapeti
             {
                 features.DeclareDurableQueues = enabled;
             }
+
+            public void SetVerifyDurableQueues(bool enabled)
+            {
+                features.VerifyDurableQueues = enabled;
+            }
         }
 
 
         internal class ConfigFeatures : ITapetiConfigFeatues
         {
             public bool PublisherConfirms { get; internal set; } = true;
-            public bool DeclareDurableQueues { get; internal set; } = true;
+            public bool DeclareDurableQueues { get; internal set; }
+            public bool VerifyDurableQueues { get; internal set; } = true;
         }