public async Task<Guid> PostCheckout(List<CustomerOrderItem> cart)
{
ServiceEventSource.Current.Message("Now printing cart for POSTCHECKOUT...");
foreach (CustomerOrderItem item in cart)
{
ServiceEventSource.Current.Message("Guid {0}, quantity {1}", item.ItemId.ToString(), item.Quantity.ToString());
}
Guid orderId = Guid.NewGuid();
ServiceUriBuilder builder = new ServiceUriBuilder(CustomerOrderServiceName);
//We create a unique Guid that is associated with a customer order, as well as with the actor that represents that order's state.
ICustomerOrderActor customerOrder = ActorProxy.Create<ICustomerOrderActor>(new ActorId(orderId), builder.ToUri());
try
{
await customerOrder.SubmitOrderAsync(cart);
ServiceEventSource.Current.Message("Customer order submitted successfully. ActorOrderID: {0} created", orderId);
}
catch (InvalidOperationException ex)
{
ServiceEventSource.Current.Message("Web Service: Actor rejected {0}: {1}", customerOrder, ex);
throw;
}
catch (Exception ex)
{
ServiceEventSource.Current.Message("Web Service: Exception {0}: {1}", customerOrder, ex);
throw;
}
return orderId;
}
public Task<string> GetOrderStatus(Guid customerOrderId)
{
ServiceUriBuilder builder = new ServiceUriBuilder(CustomerOrderServiceName);
ICustomerOrderActor customerOrder = ActorProxy.Create<ICustomerOrderActor>(new ActorId(customerOrderId), builder.ToUri());
try
{
return customerOrder.GetStatusAsync();
}
catch (Exception ex)
{
ServiceEventSource.Current.Message("Web Service: Exception {0}: {1}", customerOrder, ex);
throw;
}
}
public Task<bool> CreateInventoryItem(string description, decimal price, int number, int reorderThreshold, int max)
{
InventoryItem i = new InventoryItem(description, price, number, reorderThreshold, max);
ServiceUriBuilder builder = new ServiceUriBuilder(InventoryServiceName);
IInventoryService inventoryServiceClient = ServiceProxy.Create<IInventoryService>(builder.ToUri(), i.Id.GetPartitionKey());
try
{
return inventoryServiceClient.CreateInventoryItemAsync(i);
}
catch (Exception ex)
{
ServiceEventSource.Current.Message("Web Service: Exception creating {0}: {1}", i, ex);
throw;
}
}
public async Task<IEnumerable<InventoryItemView>> GetStore()
{
ServiceUriBuilder builder = new ServiceUriBuilder(InventoryServiceName);
Uri serviceName = builder.ToUri();
List<InventoryItemView> itemList = new List<InventoryItemView>();
ServicePartitionList partitions = await fc.QueryManager.GetPartitionListAsync(serviceName);
foreach(Partition p in partitions)
{
long minKey = (p.PartitionInformation as Int64RangePartitionInformation).LowKey;
IInventoryService inventoryServiceClient = ServiceProxy.Create<IInventoryService>(minKey, serviceName);
itemList.AddRange(await inventoryServiceClient.GetCustomerInventoryAsync());
}
return itemList;
}
/// <summary>
/// Drains the queue of completed restock requests sends them to InventoryService.
/// </summary>
/// <param name="cancellationToken"></param>
/// <returns></returns>
protected override async Task RunAsync(CancellationToken cancellationToken)
{
IReliableQueue<RestockRequest> completedRequests = await this.StateManager.GetOrAddAsync<IReliableQueue<RestockRequest>>(CompletedRequestsQueueName);
while (!cancellationToken.IsCancellationRequested)
{
using (ITransaction tx = this.StateManager.CreateTransaction())
{
ConditionalResult<RestockRequest> result = await completedRequests.TryDequeueAsync(tx, TxTimeout, cancellationToken);
if (result.HasValue)
{
ServiceUriBuilder builder = new ServiceUriBuilder(InventoryServiceName);
IInventoryService inventoryService = ServiceProxy.Create<IInventoryService>(result.Value.ItemId.GetPartitionKey(), builder.ToUri());
await inventoryService.AddStockAsync(result.Value.ItemId, result.Value.Quantity);
ServiceEventSource.Current.ServiceMessage(
this,
"Adding stock to inventory service. ID: {0}. Quantity: {1}",
result.Value.ItemId,
result.Value.Quantity);
}
// This commits the dequeue operations.
// If the request to add the stock to the inventory service throws, this commit will not execute
// and the items will remain on the queue, so we can be sure that we didn't dequeue items
// that didn't get saved successfully in the inventory service.
// However there is a very small chance that the stock was added to the inventory service successfully,
// but service execution stopped before reaching this commit (machine crash, for example).
await tx.CommitAsync();
}
await Task.Delay(CompletedRequestsBatchInterval, cancellationToken);
}
}
private async Task PeriodicInventoryCheck(CancellationToken cancellationToken)
{
IReliableDictionary<InventoryItemId, InventoryItem> inventoryItems =
await this.stateManager.GetOrAddAsync<IReliableDictionary<InventoryItemId, InventoryItem>>(InventoryItemDictionaryName);
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());
}
}
await Task.Delay(TimeSpan.FromSeconds(30), cancellationToken);
}
}
/// <summary>
/// This method takes in a list of CustomerOrderItem objects. Using a Service Proxy to access the Inventory Service,
/// the method iterates onces through the order and tries to remove the quantity specified in the order from inventory.
/// If the inventory has insufficient stock to remove the requested amount for a particular item, the entire order is
/// marked as backordered and the item in question is added to a "backordered" item list, which is fulfilled in a separate
/// method.
///
/// In its current form, this application addresses the question of race conditions to remove the same item by making a rule
/// that no order ever fails. While an item that is displayed in the store may not be available any longer by the time an order is placed,
/// the automatic restock policy instituted in the Inventory Service means that our FulfillOrder method and its sub-methods can continue to
/// query the Inventory Service on repeat (with a timer in between each cycle) until the order is fulfilled.
///
/// </summary>
/// <returns>The number of items put on backorder after fulfilling the order.</returns>
internal async Task FulfillOrderAsync()
{
ServiceUriBuilder builder = new ServiceUriBuilder(InventoryServiceName);
await this.SetOrderStatusAsync(CustomerOrderStatus.InProcess);
IList<CustomerOrderItem> orderedItems = await this.StateManager.GetStateAsync<IList<CustomerOrderItem>>(OrderItemListPropertyName);
ActorEventSource.Current.ActorMessage(this, "Fullfilling customer order. ID: {0}. Items: {1}", this.Id.GetGuidId(), orderedItems.Count);
foreach (CustomerOrderItem tempitem in orderedItems)
{
ActorEventSource.Current.Message("OrderContains:{0}", tempitem);
}
//We loop through the customer order list.
//For every item that cannot be fulfilled, we add to backordered.
foreach (CustomerOrderItem item in orderedItems.Where(x => x.FulfillmentRemaining > 0))
{
IInventoryService inventoryService = ServiceProxy.Create<IInventoryService>(builder.ToUri(), item.ItemId.GetPartitionKey());
//First, check the item is listed in inventory.
//This will avoid infinite backorder status.
if ((await inventoryService.IsItemInInventoryAsync(item.ItemId, this.tokenSource.Token)) == false)
{
await this.SetOrderStatusAsync(CustomerOrderStatus.Canceled);
return;
}
int numberItemsRemoved =
await
inventoryService.RemoveStockAsync(
item.ItemId,
item.Quantity,
new CustomerOrderActorMessageId(
new ActorId(this.Id.GetGuidId()),
await this.StateManager.GetStateAsync<long>(RequestIdPropertyName)));
item.FulfillmentRemaining -= numberItemsRemoved;
}
IList<CustomerOrderItem> items = await this.StateManager.GetStateAsync<IList<CustomerOrderItem>>(OrderItemListPropertyName);
bool backordered = false;
// Set the status appropriately
foreach (CustomerOrderItem item in items)
{
if (item.FulfillmentRemaining > 0)
{
backordered = true;
break;
}
}
if (backordered)
{
await this.SetOrderStatusAsync(CustomerOrderStatus.Backordered);
}
else
{
await this.SetOrderStatusAsync(CustomerOrderStatus.Shipped);
}
ActorEventSource.Current.ActorMessage(
this,
"{0}; Fulfilled: {1}. Backordered: {2}",
await this.GetOrderStatusAsStringAsync(),
items.Count(x => x.FulfillmentRemaining == 0),
items.Count(x => x.FulfillmentRemaining > 0));
long messageRequestId = await this.StateManager.GetStateAsync<long>(RequestIdPropertyName);
await this.StateManager.SetStateAsync<long>(RequestIdPropertyName, ++messageRequestId);
}