Re: [Apiman-dev] Feedback wanted: Allowing policies to modify PolicyFailures emitted by *other* policies in chain

Hi, I have a prototype of this available for people to try (forgive any scrappiness, this will be tidied before the final version is merged): https://github.com/apiman/apiman/pull/686/files It works as follows: Let's imagine our policy chain again. [CORS, PolicyA, PolicyB] * If a policy failure occurs in the *request* chain, the entire response chain will be executed (in the usual reverse order) with #processFailure Imagine PolicyA throws a failure on the request leg, then each of the policies will have a chance to modify the failure object in the following order: [PolicyB, PolicyA, CORS] * If a policy failure occurs during the *response* chain, then only the remaining policies will have a chance to process the failure. This seemed like the most sensible/practical design to me -- happy to hear feedback, though. Here's an example of a policy using this proposed functionality: https://gist.github.com/msavy/b872efa7f08929d19a420ea68ec3f584 Regards, Marc On 12 April 2018 at 19:42, Marc Savy <marc.savy(a)redhat.com&gt; wrote: > Marvin Oßwald filed a really interesting issue: > https://issues.jboss.org/browse/APIMAN-1300 > > In short, if we imagine a policy chain like this: > > [CORS, PolicyA, PolicyB] > > Even if PolicyB emits a failure, then the CORS policy would likely > still want to be able to process the PolicyFailure to add the relevant > headers (otherwise a SPA type app like Angular would break). > > This seems like a valid use-case. > > Ideally I'd like to tackle this without breaking any existing interfaces. > > A couple of quick ideas: > > * Add a new interface that policies like CORS could implement that > indicates it wants to do this kind of processing. E.g. > IFailureProcessor or similar with a simple method signature like > #process(PolicyFailure failureToModify). > > * An annotation: essentially the same as above, but with a > @WhateverWeCallIt annotation on the method that does the processing.