addressed PR feedback, added unit tests

release_notes.md

@@ -18,6 +18,8 @@
 
 ### New Features
 
+- Update MaxQueuePollingInterval default for Flex Consumption apps #2953
+
 ### Bug Fixes
 
 ### Breaking Changes

src/WebJobs.Extensions.DurableTask/Options/AzureStorageOptions.cs

@@ -161,19 +161,26 @@ public string TrackingStoreConnectionStringName
 
         /// <summary>
         /// Gets or sets the maximum queue polling interval.
+        /// We update the default value to 1 second for the Flex Consumption SKU
+        /// because of a known cold start latency with Flex Consumption
+        /// and Durable Functions.
+        /// The default value is 30 seconds for all other SKUs.
         /// </summary>
         /// <value>Maximum interval for polling control and work-item queues.</value>
         public TimeSpan MaxQueuePollingInterval
         {
             get
             {
-                if (string.Equals(Environment.GetEnvironmentVariable("WEBSITE_SKU"), "FlexConsumption", StringComparison.OrdinalIgnoreCase))
+                if (this.maxQueuePollingInterval == TimeSpan.Zero)
                 {
-                    this.maxQueuePollingInterval = TimeSpan.FromSeconds(1);
-                }
-                else
-                {
-                    this.maxQueuePollingInterval = TimeSpan.FromSeconds(30);
+                    if (string.Equals(Environment.GetEnvironmentVariable("WEBSITE_SKU"), "FlexConsumption", StringComparison.OrdinalIgnoreCase))
+                    {
+                        this.maxQueuePollingInterval = TimeSpan.FromSeconds(1);
+                    }
+                    else
+                    {
+                        this.maxQueuePollingInterval = TimeSpan.FromSeconds(30);
+                    }
                 }
 
                 return this.maxQueuePollingInterval;

test/FunctionsV2/AzureStorageOptionsTests.cs

@@ -0,0 +1,56 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace Microsoft.Azure.WebJobs.Extensions.DurableTask.Tests
+{
+    public class AzureStorageOptionsTests
+    {
+#if !FUNCTIONS_V1
+        [Fact]
+        [Trait("Category", PlatformSpecificHelpers.TestCategory)]
+        public void MaxQueuePollingInterval_NonFlexConsumption_DefaultValue()
+        {
+            Environment.SetEnvironmentVariable("WEBSITE_SKU", "Free");
+
+            var options = new AzureStorageOptions();
+            Assert.Equal(TimeSpan.FromSeconds(30), options.MaxQueuePollingInterval);
+        }
+
+        [Fact]
+        [Trait("Category", PlatformSpecificHelpers.TestCategory)]
+        public void MaxQueuePollingInterval_NonFlexConsumption_SetCustomValue()
+        {
+            Environment.SetEnvironmentVariable("WEBSITE_SKU", "Free");
+
+            var options = new AzureStorageOptions();
+            options.MaxQueuePollingInterval = TimeSpan.FromSeconds(4);
+            Assert.Equal(TimeSpan.FromSeconds(4), options.MaxQueuePollingInterval);
+        }
+
+        [Fact]
+        [Trait("Category", PlatformSpecificHelpers.TestCategory)]
+        public void MaxQueuePollingInterval_FlexConsumption_DefaultValue()
+        {
+            Environment.SetEnvironmentVariable("WEBSITE_SKU", "FlexConsumption");
+
+            var options = new AzureStorageOptions();
+            Assert.Equal(TimeSpan.FromSeconds(1), options.MaxQueuePollingInterval);
+        }
+
+        [Fact]
+        [Trait("Category", PlatformSpecificHelpers.TestCategory)]
+        public void MaxQueuePollingInterval_FlexConsumption_SetCustomValue()
+        {
+            Environment.SetEnvironmentVariable("WEBSITE_SKU", "FlexConsumption");
+
+            var options = new AzureStorageOptions();
+            options.MaxQueuePollingInterval = TimeSpan.FromSeconds(6);
+            Assert.Equal(TimeSpan.FromSeconds(6), options.MaxQueuePollingInterval);
+        }
+#endif
+    }
+}