static async Task RunStateChecker()
{
using var context = new AccountDbContext();
await context.Database.EnsureCreatedAsync();
using var connection = await EventStoreHelpers.CreateConnection();
await ProcessLastEvents(connection, context);
}
static async Task UpdateState(StreamEventsSlice oldEvents, AccountDbContext context)
{
foreach (var evt in oldEvents.Events)
{
if (evt.Event is null)
{
continue;
}
var accountIdStr = evt.Event.EventStreamId.Replace("account-", "");
var accountId = new Guid(accountIdStr);
var accountStateCheckpoint = await GetOrCreateAccount(accountId, context);
var accountState = accountStateCheckpoint.AccountState;
accountState.Update(evt);
accountStateCheckpoint.LastProcessedEventNumber = evt.Event.EventNumber;
await context.SaveChangesAsync();
}
}
static async Task ProcessLastEvents(IEventStoreConnection connection, AccountDbContext context)
{
var isEndOfStream = false;
var lastProcessEventNumber = 0;
var batchSize = 2;
while (!isEndOfStream)
{
var oldEvents = await connection.ReadStreamEventsForwardAsync(
StreamName,
lastProcessEventNumber,
batchSize,
true,
EventStoreHelpers.GetCredentials());
await UpdateState(oldEvents, context);
lastProcessEventNumber += batchSize;
isEndOfStream = oldEvents.IsEndOfStream;
}
}
static async Task <AccountStateCheckpoint> GetOrCreateAccount(Guid accountId, AccountDbContext context)
{
var accountStateCheckpoint = await context.AccountStateCheckpoints
.Include(checkpoint => checkpoint.AccountState)
.FirstOrDefaultAsync(checkpoint => checkpoint.AccountStateId == accountId);
if (accountStateCheckpoint != null)
{
return(accountStateCheckpoint);
}
var accountState = new AccountState
{
Id = accountId
};
accountStateCheckpoint = new AccountStateCheckpoint
{
AccountState = accountState
};
await context.AccountStateCheckpoints.AddAsync(accountStateCheckpoint);
return(accountStateCheckpoint);
}