Added PartitionCount lookup from host.json (#3027)

Co-authored-by: gorillapower <[email protected]>

Author: gorillapower

src/Azure.Functions.Cli/Common/DurableManager.cs

@@ -30,6 +30,8 @@ internal class DurableManager : IDurableManager
 
         private string _connectionStringKey;
 
+        private int? _partitionCount;
+
         public const string DefaultConnectionStringKey = "AzureWebJobsStorage";
 
         public const string DefaultTaskHubName = "DurableFunctionsHub";
@@ -80,6 +82,12 @@ private void SetConnectionStringAndTaskHubName()
                             ?? _connectionStringKey;
                         _taskHubName = durableTask.GetValue("HubName", StringComparison.OrdinalIgnoreCase)?.ToString()
                             ?? _taskHubName;
+
+                        if (durableTask.TryGetValue("storageProvider", StringComparison.OrdinalIgnoreCase, out JToken storageProviderToken))
+                        {
+                            JObject storageProviderObject = storageProviderToken as JObject;
+                            _partitionCount = storageProviderObject?.GetValue("partitionCount", StringComparison.OrdinalIgnoreCase)?.Value<int?>();
+                        }
                     }
                 }
                 else
@@ -110,6 +118,11 @@ private void SetStorageServiceAndTaskHubClient(out AzureStorageOrchestrationServ
                     StorageConnectionString = connectionString,
                 };
 
+                if (_partitionCount.HasValue)
+                {
+                    settings.PartitionCount = _partitionCount.Value;
+                }
+
                 orchestrationService = new AzureStorageOrchestrationService(settings);
                 taskHubClient = new TaskHubClient(orchestrationService);
             }