private static async void AddRestockRequestsAsync()
{
// TODO: need to go to correct partition
// For now, the inventory is not partitioned, so always go to first partition
IRestockRequestManager restockRequestService = ServiceProxy.Create <IRestockRequestManager>(0, RestockRequestManagerServiceName);
IList <Task> tasks = new List <Task>();
for (int i = 0; i < ParallelRequests; i++)
{
RestockRequest request = GenerateRandomRequest();
Console.WriteLine("Add request {0}", request);
tasks.Add(restockRequestService.AddRestockRequestAsync(request));
}
await Task.WhenAll(tasks);
}
private async Task PeriodicInventoryCheck(CancellationToken cancellationToken)
{
IReliableDictionary <InventoryItemId, InventoryItem> inventoryItems =
await this.stateManager.GetOrAddAsync <IReliableDictionary <InventoryItemId, InventoryItem> >(InventoryItemDictionaryName);
if (this.storageType == StorageTypes.Azure)
{
await this.InitializeAsync(cancellationToken);
}
while (!cancellationToken.IsCancellationRequested)
{
ServiceEventSource.Current.ServiceMessage(this, "Checking inventory stock for {0} items.", await inventoryItems.GetCountAsync());
foreach (InventoryItem item in inventoryItems.Select(x => x.Value))
{
cancellationToken.ThrowIfCancellationRequested();
try
{
//Check if stock is below restockThreshold and if the item is not already on reorder
if ((item.AvailableStock <= item.RestockThreshold) && !item.OnReorder)
{
ServiceUriBuilder builder = new ServiceUriBuilder(RestockRequestManagerServiceName);
IRestockRequestManager restockRequestManagerClient = ServiceProxy.Create <IRestockRequestManager>(0, builder.ToUri());
// we reduce the quantity passed in to RestockRequest to ensure we don't overorder
RestockRequest newRequest = new RestockRequest(item.Id, (item.MaxStockThreshold - item.AvailableStock));
InventoryItem updatedItem = new InventoryItem(
item.Description,
item.Price,
item.AvailableStock,
item.RestockThreshold,
item.MaxStockThreshold,
item.Id,
true);
// TODO: this call needs to be idempotent in case we fail to update the InventoryItem after this completes.
await restockRequestManagerClient.AddRestockRequestAsync(newRequest);
// Write operations take an exclusive lock on an item, which means we can't do anything else with that item while the transaction is open.
// If something blocks before the transaction is committed, the open transaction on the item will prevent all operations on it, including reads.
// Once the transaction commits, the lock is released and other operations on the item can proceed.
// Operations on the transaction all have timeouts to prevent deadlocking an item,
// but we should do as little work inside the transaction as possible that is not related to the transaction itself.
using (ITransaction tx = this.stateManager.CreateTransaction())
{
await inventoryItems.TryUpdateAsync(tx, item.Id, updatedItem, item);
await tx.CommitAsync();
}
ServiceEventSource.Current.ServiceMessage(
this,
"Restock order placed. Item ID: {0}. Quantity: {1}",
newRequest.ItemId,
newRequest.Quantity);
}
}
catch (Exception e)
{
ServiceEventSource.Current.ServiceMessage(this, "Failed to place restock order for item {0}. {1}", item.Id, e.ToString());
}
if (this.storageType == StorageTypes.Local)
{
await this.StateManager.BackupAsync(this.BackupCallbackAsync);
}
else
{
await this.StateManager.BackupAsync(this.BackupCallbackAzureAsync);
}
}
await Task.Delay(TimeSpan.FromSeconds(30), cancellationToken);
}
}
