Bugfix: enforce minimum retry interval for subscriptions with no TTL

sweetlandj · Aug 31, 2017 · 3088c64 · 3088c64
1 parent 733fa63
commit 3088c64
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Showing 2 changed files with 37 additions and 5 deletions.
diff --git a/Source/Platibus.UnitTests/Http/HttpSubscriptionMetadataTests.cs b/Source/Platibus.UnitTests/Http/HttpSubscriptionMetadataTests.cs
@@ -60,7 +60,7 @@ public void SubscriptionExpiresIfTTLGiven()
         }
 
         [Fact]
-        public void TTLAlwaysBeGreaterThanOrEqualToMinTTL()
+        public void TTLAlwaysNeverLessThanMinTTL()
         {
             GivenEndpoint();
             GivenTopic();
@@ -71,7 +71,7 @@ public void TTLAlwaysBeGreaterThanOrEqualToMinTTL()
         }
 
         [Fact]
-        public void RenewalIntervalAlwaysLessThanMaxRenewalInterval()
+        public void RenewalIntervalNeverExceedsMaxRenewalInterval()
         {
             GivenEndpoint();
             GivenTopic();
@@ -82,7 +82,7 @@ public void RenewalIntervalAlwaysLessThanMaxRenewalInterval()
         }
 
         [Fact]
-        public void RetrIntervalAlwaysLessThanMaxRetryInterval()
+        public void RetryIntervalNeverExceedsMaxRetryInterval()
         {
             GivenEndpoint();
             GivenTopic();
@@ -92,6 +92,21 @@ public void RetrIntervalAlwaysLessThanMaxRetryInterval()
             Assert.Equal(HttpSubscriptionMetadata.MaxRetryInterval, Metadata.RetryInterval);
         }
 
+        [Theory]
+        [InlineData("00:00:00")]
+        [InlineData("00:00:01")]
+        [InlineData("00:00:00.001")]
+        public void RetryIntervalNeverLessThanMinRetryInterval(string ttl)
+        {
+            GivenEndpoint();
+            GivenTopic();
+            GivenTTL(TimeSpan.Parse(ttl));
+            WhenInitializingMetadata();
+
+            Assert.Equal(HttpSubscriptionMetadata.MinRetryInterval, Metadata.RetryInterval);
+            Assert.True(Metadata.RetryInterval > TimeSpan.Zero);
+        }
+
         protected void GivenEndpoint()
         {
             Endpoint = new Endpoint(new Uri("http://localhost/platibus"));
@@ -107,6 +122,11 @@ protected void GivenTTL()
             TTL = TimeSpan.FromHours(1);
         }
 
+        protected void GivenTTL(TimeSpan ttl)
+        {
+            TTL = ttl;
+        }
+
         protected void GivenNegativeTTL()
         {
             TTL = TimeSpan.FromSeconds(-1);

diff --git a/Source/Platibus/Http/HttpSubscriptionMetadata.cs b/Source/Platibus/Http/HttpSubscriptionMetadata.cs
@@ -12,7 +12,12 @@ public class HttpSubscriptionMetadata
         /// the TTL on the subscription
         /// </summary>
         public static readonly TimeSpan MaxRenewalInterval = TimeSpan.FromMinutes(5);
-
+
+        /// <summary>
+        /// The minimum amount of time that can elapse before retrying a failed subscription request
+        /// </summary>
+        public static readonly TimeSpan MinRetryInterval = TimeSpan.FromSeconds(5);
+
         /// <summary>
         /// The maximum amount of time that can elapse before retrying a failed subscription request
         /// </summary>
@@ -91,7 +96,7 @@ public HttpSubscriptionMetadata(IEndpoint endpoint, TopicName topic, TimeSpan tt
             if (ttl > TimeSpan.Zero)
             {
                 _ttl = ttl > MinTTL ? ttl : MinTTL;
-                _expires = true;
+                _expires = true;    
             }
 
             // Attempt to renew after half of the TTL or 5 minutes (whichever is less)
@@ -110,6 +115,13 @@ public HttpSubscriptionMetadata(IEndpoint endpoint, TopicName topic, TimeSpan tt
             {
                 _retryInterval = MaxRetryInterval;
             }
+
+            // Ensure a minimum amount of time elapses between retries to avoid overloading
+            // both the subscriber and publisher with requests
+            if (_retryInterval < MinRetryInterval)
+            {
+                _retryInterval = MinRetryInterval;
+            }
         }
     }
 }