public async Task Handle(StockReserved @event)
{
var optionsBuilder = new DbContextOptionsBuilder <StockLinesDbContext>();
optionsBuilder.UseSqlServer("Data Source=localhost;Initial Catalog=DBName;Integrated Security=True;");
using (var context = new StockLinesDbContext(optionsBuilder.Options))
{
var available = context.StockLines.Single(p => !p.IsReserved);
var existingReservation = context.StockLines.SingleOrDefault(p => p.Id == @event.ReservationId);
if (existingReservation != null)
{
existingReservation.Quantity += @event.Amount;
}
else
{
var res = new StockLine
{
Id = Guid.NewGuid(),
Quantity = @event.Amount,
IsReserved = true,
ReservationId = @event.ReservationId,
Product = "coke"
};
context.StockLines.Add(res);
}
available.Quantity -= @event.Amount;
var saved = false;
while (!saved)
{
try
{
await context.SaveChangesAsync();
Console.WriteLine("--------------------------------------------------------------------------------------------");
Console.WriteLine(JsonConvert.SerializeObject(available));
Console.WriteLine(JsonConvert.SerializeObject(existingReservation));
Console.WriteLine("-- --");
Console.WriteLine(JsonConvert.SerializeObject(_entity));
Console.WriteLine("--------------------------------------------------------------------------------------------");
saved = true;
}
catch (DbUpdateConcurrencyException ex)
{
foreach (var entry in ex.Entries)
{
if (entry.Entity is StockLine && !((StockLine)entry.Entity).IsReserved)
{
var proposedValues = entry.CurrentValues;
var databaseValues = (StockLine)entry.GetDatabaseValues().ToObject();
((StockLine)entry.Entity).Quantity = databaseValues.Quantity - @event.Amount;
// Refresh original values to bypass next concurrency check
entry.OriginalValues.SetValues(databaseValues);
}
if (entry.Entity is StockLine && ((StockLine)entry.Entity).IsReserved)
{
var proposedValues = entry.CurrentValues;
var databaseValues = (StockLine)entry.GetDatabaseValues().ToObject();
((StockLine)entry.Entity).Quantity = databaseValues.Quantity + @event.Amount;
// Refresh original values to bypass next concurrency check
entry.OriginalValues.SetValues(databaseValues);
_entity = entry.Entity;
}
}
}
}
}
}
static void Main(string[] args)
{
var existingReservations = Enumerable.Range(0, 25).Select(x => (Guid?)Guid.NewGuid()).ToList();
var reservationsToCreate = Enumerable.Range(0, 25).Select(x => Guid.NewGuid()).ToList();
var optionsBuilder = new DbContextOptionsBuilder <StockLinesDbContext>();
optionsBuilder.UseSqlServer("Data Source=localhost;Initial Catalog=DBName;Integrated Security=True;");
using (var context = new StockLinesDbContext(optionsBuilder.Options))
{
var temp = context.StockLines.FirstOrDefault(p => p.Product == "coke");
new Checkpoint {
TablesToInclude = new List <string> {
"StockLines", "Reservations"
}.ToArray()
}.Reset(context.Database.GetDbConnection().ConnectionString).Wait();
var stockLine = new StockLine
{
Id = Guid.NewGuid(),
Product = "coke",
Quantity = 300,
IsReserved = false,
ReservationId = null
};
var existingPerson = context.StockLines.SingleOrDefault(p => p.Product == "coke");
if (existingPerson == null)
{
context.StockLines.Add(stockLine);
context.SaveChanges();
}
var reservs = existingReservations.Select(x => new StockLine
{
Id = x.Value,
Product = "coke",
Quantity = 1,
IsReserved = true,
ReservationId = x
});
context.StockLines.AddRange(reservs);
context.SaveChanges();
}
var tasks = GenerateTasks(reservationsToCreate, existingReservations);
Task.WhenAll(tasks).Wait();
using (var context = new StockLinesDbContext(optionsBuilder.Options))
{
var stockLines = context.StockLines.Where(x => existingReservations.Contains(x.ReservationId)).AsNoTracking().ToList();
var availableStockLine = context.StockLines.SingleOrDefault(x => x.IsReserved == false && x.ReservationId == null);
var createdReservations = context.StockLines.Where(x => reservationsToCreate.Contains(x.ReservationId.Value)).AsNoTracking().ToList();
if (stockLines.All(x => x.Quantity == 4))
{
Console.WriteLine("ALL existing Reservations updated correctly");
}
if (createdReservations.Count == 25 && createdReservations.All(x => x.Quantity == 1))
{
Console.WriteLine("ALL reservations created correctly");
}
if (availableStockLine != null && availableStockLine.Quantity == 200)
{
Console.WriteLine("Available stockline quantity is consistent. ");
}
Console.ReadKey();
}
}
