Added AppServicesHostingUtility to calculate process memory for each plan

src/WebJobs.Extensions.DurableTask/AppServicesHostingUtility.cs

@@ -0,0 +1,93 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License. See LICENSE in the project root for license information.
+
+using System;
+
+namespace Microsoft.Azure.WebJobs.Extensions.DurableTask
+{
+    // Taken from Microsoft.Azure.WebJobs.Host https://github.com/Azure/azure-webjobs-sdk/commit/7442bed629d15b4837cd8d18c302381b34f3ddac
+    internal static class AppServicesHostingUtility
+    {
+        private const int BytesPerGB = 1024 * 1024 * 1024;
+
+        public static long GetMemoryLimitBytes(string sku = null, int? numCores = null)
+        {
+            sku ??= GetWebsiteSku();
+            numCores ??= GetEffectiveCoresCount();
+
+            if (!string.IsNullOrEmpty(sku))
+            {
+                float memoryGBPerCore = GetMemoryGBPerCore(sku);
+
+                if (memoryGBPerCore > 0)
+                {
+                    double memoryLimitBytes = memoryGBPerCore * numCores.Value * BytesPerGB;
+
+                    if (string.Equals(sku, "IsolatedV2", StringComparison.OrdinalIgnoreCase) && numCores == 8)
+                    {
+                        // special case for upper tier IsolatedV2 where GB per Core
+                        // isn't cleanly linear
+                        memoryLimitBytes = 23F * BytesPerGB;
+                    }
+
+                    return (long)memoryLimitBytes;
+                }
+            }
+
+            // unable to determine memory limit
+            return -1;
+        }
+
+        private static int GetEffectiveCoresCount()
+        {
+            // The dynamic plan has some limits that mean that a given instance is using effectively a single core,
+            // so we should not use Environment.Processor count in this case.
+            var effectiveCores = IsConsumptionSku() ? 1 : Environment.ProcessorCount;
+            return effectiveCores;
+        }
+
+        private static string GetWebsiteSku()
+        {
+            return Environment.GetEnvironmentVariable("WEBSITE_SKU");
+        }
+
+        private static bool IsConsumptionSku()
+        {
+            string value = GetWebsiteSku();
+            return string.Equals(value, "Dynamic", StringComparison.OrdinalIgnoreCase);
+        }
+
+        internal static float GetMemoryGBPerCore(string sku)
+        {
+            if (string.IsNullOrEmpty(sku))
+            {
+                return -1;
+            }
+
+            // These memory allowances are based on published limits:
+            // Dynamic SKU: https://docs.microsoft.com/en-us/azure/azure-functions/functions-scale#service-limits
+            // Premium SKU: https://docs.microsoft.com/en-us/azure/azure-functions/functions-premium-plan?tabs=portal#available-instance-skus
+            // Dedicated SKUs: https://azure.microsoft.com/en-us/pricing/details/app-service/windows/
+            switch (sku.ToLower())
+            {
+                case "free":
+                case "shared":
+                    return 1;
+                case "dynamic":
+                    return 1.5F;
+                case "basic":
+                case "standard":
+                    return 1.75F;
+                case "premiumv2":
+                case "isolated":
+                case "elasticpremium":
+                    return 3.5F;
+                case "premiumv3":
+                case "isolatedv2":
+                    return 4;
+                default:
+                    return -1;
+            }
+        }
+    }
+}

src/WebJobs.Extensions.DurableTask/AzureStorageDurabilityProviderFactory.cs

@@ -201,6 +201,8 @@ internal AzureStorageOrchestrationServiceSettings GetAzureStorageOrchestrationSe
                 AppName = EndToEndTraceHelper.LocalAppName,
                 LoggerFactory = this.loggerFactory,
                 UseLegacyPartitionManagement = this.azureStorageOptions.UseLegacyPartitionManagement,
+                UseOrchestrationHistoryLoadThrottle = true,
+                TotalProcessMemoryBytes = AppServicesHostingUtility.GetMemoryLimitBytes(),
             };
 
             if (this.inConsumption)