private async Task ProcessAsync <TMessage>(TMessage message, ISagaAction <TMessage> action,
Func <TMessage, ISagaContext, Task> onCompleted, Func <TMessage, ISagaContext, Task> onRejected,
ISagaContext context = null) where TMessage : class
{
context = context ?? SagaContext.Empty;
var saga = (ISaga)action;
var sagaType = saga.GetType();
var id = saga.ResolveId(message, context);
var dataType = saga.GetSagaDataType();
await Semaphore.WaitAsync();
try
{
var state = await _repository.ReadAsync(id, sagaType).ConfigureAwait(false);
if (state is null)
{
if (!(action is ISagaStartAction <TMessage>))
{
return;
}
state = CreateSagaState(id, sagaType, dataType);
}
else if (state.State == SagaStates.Rejected)
{
return;
}
InitializeSaga(saga, id, state);
try
{
await action.HandleAsync(message, context);
}
catch (Exception e)
{
context.SagaContextError = new SagaContextError(e);
saga.Reject();
}
await UpdateSagaAsync(message, saga, state);
}
finally
{
Semaphore.Release();
}
if (saga.State is SagaStates.Rejected)
{
await onRejected(message, context);
await CompensateAsync(saga, sagaType, context);
}
else if (saga.State is SagaStates.Completed)
{
await onCompleted(message, context);
}
}
private async Task ProcessAsync <TMessage>(Guid?nid, Type sagaType, Type sagaDataType, TMessage message, ISagaAction <TMessage> action, ISagaContext context = null) where TMessage : class
{
context = context ?? SagaContext.Empty;
var saga = (ISaga)action;
var id = nid ?? saga.ResolveId(message, context);
var sagaData = await _repository.ReadAsync(id, sagaType).ConfigureAwait(false);
if (sagaData is null)
{
if (!(action is ISagaStartAction <TMessage>))
{
return;
}
sagaData = SagaData.Create(id, sagaType, SagaStates.Pending, Activator.CreateInstance(sagaDataType));
}
else if (sagaData.State == SagaStates.Rejected)
{
return;
}
saga.Initialize(sagaData.SagaId, sagaData.State, sagaData.Data);
var isError = false;
try
{
await action.HandleAsync(message, context);
}
catch
{
isError = true;
}
var newSagaData = SagaData.Create(id, sagaType, saga.State, saga.Data);
var sagaLogData = SagaLogData.Create(id, sagaType, message);
var persistanceTasks = new Task[2]
{
_repository.WriteAsync(newSagaData),
_sagaLog.SaveAsync(sagaLogData)
};
await Task.WhenAll(persistanceTasks).ConfigureAwait(false);
if (saga.State is SagaStates.Rejected || isError)
{
await CompensateAsync(saga, sagaType, context);
}
}