public bool PreInsertInstance(ConsumeContext <TMessage> context, out TSaga instance)
{
if (_insertOnInitial)
{
instance = _sagaFactory.Create(context);
return(true);
}
instance = null;
return(false);
}
IOrderFulfillmentSaga GetSaga(IOrder order)
{
if (!_sagas.Keys.Exists(k => k == order.Id))
{
_sagas.Add(order.Id, _sagaFactory.Create(order));
}
var saga = _sagas[order.Id];
return(saga);
}
public void Register <TMessage>(ISagaFactory <TSaga, TMessage> factory)
{
Register(typeof(TMessage), m => factory.Create((TMessage)m));
}
public async Task RunAsync <TM>(IMessageContext <TM> messageContext, CancellationToken cancellationToken = default)
where TM : IMessage
{
var(state, lockId) = await GetStateAsync(messageContext, cancellationToken);
if (state.IsCompleted())
{
_logger.LogWarning($"Stopped processing message '{messageContext.Message.Id}', Saga '{state.Id}' was already marked as completed");
return;
}
if (state.CheckWasProcessed(messageContext.Message))
{
_logger.LogWarning($"message '{messageContext.Message.Id}' was already processed by saga '{state.Id}'");
return;
}
var saga = _sagaFactory.Create(state);
if (null == saga)
{
throw new SagaException($"unable to create Saga of type '{typeof(TS).FullName}'");
}
if (saga is not IHandleMessage <TM> handler)
{
throw new ConsumerNotFoundException(typeof(TM));
}
var transaction = await _transactionManager.StartTransactionAsync(cancellationToken);
try
{
var policy = _policyFactory.Create <TM>();
if (policy is null)
{
await handler.HandleAsync(messageContext, cancellationToken);
}
else
{
await policy.WrapAsync(() => handler.HandleAsync(messageContext, cancellationToken));
}
state.SetAsProcessed(messageContext.Message);
await _sagaStateService.SaveAsync(state, lockId, cancellationToken);
await transaction.CommitAsync(cancellationToken);
}
catch (Exception ex)
{
await transaction.RollbackAsync(cancellationToken);
if (saga is not ICompensateMessage <TM> compensatingHandler)
{
throw;
}
await ExecuteCompensationAsync(compensatingHandler, messageContext, ex, state, lockId, cancellationToken);
}
}