ReBus: Unable to use sagas with handlers decorator - decorator

Question

I use Rebus 3.0.1 with Simpleinjector. I have registered a decorator, for logging, of all the handlers, this way:
container.RegisterDecorator(typeof(IHandleMessages<>), typeof(HandlerLogDecorator<>));
Everything works fine, except the Sagas: because, in LoadSagaDataStep, the following code
var handlerInvokersForSagas = context.Load<HandlerInvokers>()
.Where(l => l.HasSaga)
.ToList();
is not able to find the Saga under the covers.
If I unregister the decorators, saga starts working again.
Any suggestion to conciliate sagas and handlers decorators?

Answer 1

Unfortunately, as you have discovered, Rebus does not expect handlers (including sagas) to be wrapped in decorators.
It uses decorators a lot for various things internally, and it encourages the use of decorators as an extension point for developers, but that only goes for all of Rebus' services like IPipeline, ISubscriptionStorage, etc.
If you want to log stuff in relation to message handling, a better extension point would be to either
a) use Rebus.Events and simply install an event handler like this:
Configure.With(...)
.(...)
.Events(e => {
e.AfterMessageHandled += (bus, headers, message, context, args) => {
// log stuff in here :)
};
})
.Start();
or
b) create an incoming pipeline step that logs what you want to log like this:
Configure.With(...)
.(...)
.Options(o => {
o.Decorate<IPipeline>(c => {
var step = new YourLoggingStep();
var pipeline = c.Get<IPipeline>();
return new PipelineStepInjector(pipeline)
.OnReceive(step, PipelineRelativePosition.After, typeof(DeserializeIncomingMessageStep));
});
})
.Start();
probably wrapping all of the ugly stuff in an extension method that makes usage look more like this:
Configure.With(...)
.(...)
.Options(o => {
o.LogHandledMessages();
})
.Start();