#2080 Adds parameters (in this case those of Polly V8) to fine-tune circuit-breaker behavior

Author: RaynaldM

src/Ocelot.Provider.Polly/PollyQoSResiliencePipelineProvider.cs

@@ -32,7 +32,7 @@ public ResiliencePipeline<HttpResponseMessage> GetResiliencePipeline(DownstreamR
         var options = route.QosOptions;
 
         // Check if we need pipeline at all before calling GetOrAddPipeline
-        if (options is null ||
+        if (options is null || options.UseQos == false ||
             (options.ExceptionsAllowedBeforeBreaking == 0 && options.TimeoutValue is int.MaxValue))
         {
             return null; // shortcut > no qos
@@ -48,6 +48,8 @@ private void PollyResiliencePipelineWrapperFactory(ResiliencePipelineBuilder<Htt
     {
         var options = route.QosOptions;
 
+        if(!options.UseQos) return; // shortcut > no qos
+
         // Add TimeoutStrategy if TimeoutValue is not int.MaxValue and greater than 0
         if (options.TimeoutValue != int.MaxValue && options.TimeoutValue > 0)
         {
@@ -64,8 +66,8 @@ private void PollyResiliencePipelineWrapperFactory(ResiliencePipelineBuilder<Htt
 
         var circuitBreakerStrategyOptions = new CircuitBreakerStrategyOptions<HttpResponseMessage>
         {
-            FailureRatio = 0.8,
-            SamplingDuration = TimeSpan.FromSeconds(10),
+            FailureRatio = options.FailureRatio,
+            SamplingDuration = TimeSpan.FromSeconds(options.SamplingDuration),
             MinimumThroughput = options.ExceptionsAllowedBeforeBreaking, 
             BreakDuration = TimeSpan.FromMilliseconds(options.DurationOfBreak),
             ShouldHandle = new PredicateBuilder<HttpResponseMessage>()

src/Ocelot/Configuration/QoSOptions.cs

@@ -23,7 +23,7 @@ public QoSOptions(FileQoSOptions from)
         public QoSOptions(
             int exceptionsAllowedBeforeBreaking,
             int durationOfBreak,
-            int timeoutValue, 
+            int timeoutValue,
             string key)
         {
             DurationOfBreak = durationOfBreak;
@@ -32,6 +32,36 @@ public QoSOptions(
             TimeoutValue = timeoutValue;
         }
 
+        public QoSOptions(
+            int exceptionsAllowedBeforeBreaking,
+            int durationOfBreak,
+            double failureRatio,
+            int timeoutValue,
+            string key)
+        {
+            DurationOfBreak = durationOfBreak;
+            ExceptionsAllowedBeforeBreaking = exceptionsAllowedBeforeBreaking;
+            Key = key;
+            TimeoutValue = timeoutValue;
+            FailureRatio = failureRatio;
+        }
+
+        public QoSOptions(
+            int exceptionsAllowedBeforeBreaking,
+            int durationOfBreak,
+            double failureRatio,
+            int samplingDuration,
+            int timeoutValue,
+           string key)
+        {
+            DurationOfBreak = durationOfBreak;
+            ExceptionsAllowedBeforeBreaking = exceptionsAllowedBeforeBreaking;
+            Key = key;
+            TimeoutValue = timeoutValue;
+            FailureRatio = failureRatio;
+            SamplingDuration = samplingDuration;
+        }
+
         /// <summary>
         /// How long the circuit should stay open before resetting in milliseconds.
         /// </summary>
@@ -54,6 +84,22 @@ public QoSOptions(
         /// </value>
         public int ExceptionsAllowedBeforeBreaking { get; }
 
+        /// <summary>
+        /// The failure-success ratio that will cause the circuit to break/open. 
+        /// </summary>
+        /// <value>
+        /// An <see cref="double"/> 0.8 means 80% failed of all sampled executions.
+        /// </value>
+        public double FailureRatio { get; } = .8;
+
+        /// <summary>
+        /// The time period over which the failure-success ratio is calculated (in seconds).
+        /// </summary>
+        /// <value>
+        /// An <see cref="int"/> Time period in seconds, 10 means 10 seconds.
+        /// </value>
+        public int SamplingDuration { get; } = 10;
+
         public string Key { get; }
 
         /// <summary>

test/Ocelot.AcceptanceTests/PollyQoSTests.cs

@@ -44,7 +44,7 @@ public override void Dispose()
         public void Should_not_timeout()
         {
             var port = PortFinder.GetRandomPort();
-            var configuration = FileConfigurationFactory(port, new QoSOptions(10, 500, 1000, null), HttpMethods.Post);
+            var configuration = FileConfigurationFactory(port, new QoSOptions(10, 500,.5,5, 1000, null), HttpMethods.Post);
 
             this.Given(x => x.GivenThereIsAServiceRunningOn($"http://localhost:{port}", 200, string.Empty, 10))
                 .And(x => GivenThereIsAConfiguration(configuration))