Msg Bus pipeline.onFail()

[pchainho]

Currently msg bus pipeline onFail() handler is receiving a string describing the reason of the failure from the handlers, notably from the Policy Engine eg see here.

However, these failures should result on responding with an Error Response Message to the message source that caused the failure.

Thus, the promise.reject from Msg Bus Handlers should return a well formatted Response Message with the most appropriate response code and associated description eg "403" , "Blocked by Policy". Then, the default msg bus Fail handler will post the message in the bus.

In case, the promise.reject from Msg Bus Handlers does not return a well formatted Response Message a default response message with code "403" and description "reject" is responded.

These failures should can be looged with warnings but not with erros