[wildfly-dev] Add a warning if some configuration change has wider impact and could cause error?

[Brian Stansberry]

Any opinions? This is basically a proposal to provide a formal way of including warning data in operations responses. 

If we did it it would probably be something like:

{
  “outcome”=>”success”,
  “result”=>”foo”,
  “response-headers”=> {
    “warnings”=[
        “blah blah blah”,
       { “some_complex_issue: details”>[“x”,”y”,’z”]}
    ]
  }
}

So a standard response header whose value is a list of ModelNode, different messages using different node structures, but the norm being a simple string.

Probably OperationContext would need to add a method addResponseWarning to take the details of constructing the header out of the hands of the handler authors.

We’d have to make sure these headers propogate properly through the domain, so the effort is more than simply getting standalone.

If the operation is a composite, there are no per-step response headers so the warning should not assume that the context of the warning is obvious. Warning authors forgetting that point is a possible source of UX issues.

Is this worth the effort? This is driven by this one WFCORE-1987 issue, which is a bit unusual and in an ideal world would go away. But here’s the general pattern involved:

2 attributes in separate parts of the model should be consistent or you wil get bad runtime behavior
User can use a CLI batch to set them both atomically, but web console users can’t do that, so even if the user will do the right thing there will be a moment where they are inconsistent
So, failing is not good (forces users to use CLI + batch)
For the same reason a WARN in the log is not great, as unrelated users may be required to react to log warns, and will be annoyed by seeing them just because their colleague didn’t use a batch

Is that last statement enough reason to add this functionality vs just using the server log to warn, or just not warning at all?

In theory we could use the same facility to report management API deprecation warnings back. Doing that might be annoying though. Those are a less serious problem than this WFCORE-1987 thing.


> On Jan 3, 2017, at 1:06 AM, Bartosz Baranowski <bbaranow at redhat.com> wrote:
> 
> Hey guys.
> 
> 
> In some cases there are/will be conf changes that might require user to make additional change, for instance [1]. 
> In this case, if user does not edit the name in two places, when remote client tries to reach out, it will fail.
> 
> As far as I remember, there as of now, there is no formal constraint feature for config values.
> I've talked with Brian about this and it seems and viable option would be to simply add a header to response.
> In CLI, it would be clearly visible, in console, it would require a bit  of hacking to present 
> information/hint what needs to be done to configuration to make it work properly.
> 
> 
> Any thoughts?
> 
> [1] https://issues.jboss.org/browse/WFCORE-1987
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-- 
Brian Stansberry
Manager, Senior Principal Software Engineer
JBoss by Red Hat