[wildfly-dev] Automatically resolving expressions in the CLI

[Brian Stansberry]

Thanks, Joe, for looking into this.

I'm curious what you've done so far with your 'ls --resolve-expressions' 
work. Did you use the existing ':resolve-expression(expression=___)' low 
level operation to process any expressions found in the :read-resource 
response?

There are a few aspects of this I'd like to explore.

One is the UX one. Is allowing 'resolve-expressions' in some contexts 
and not others a good UX? Will users understand that? I'm ambivalent 
about that, and am interested in others' opinions.

If it can work for a server and for anything under /host=*, then I'm 
ambivalent. Any restriction at all is unintuitive, but once the user 
learns that there is a restriction, that's a pretty understandable one. 
If it only works for a patchwork of stuff under /host=* then I'm real 
negative about it. An area of concern is /host=*/server-config=*, where 
an expression might be irrelevant to the host, only resolving correctly 
on the server that is created using that server-config. That will need 
careful examination.

A second one is how this data would be displayed with 'ls'. A separate 
additional column? Or replacing the current data? The answer to this 
might impact how it would be implemented server side.

The third aspect is the technical issue of how to make any 
'resolve-expressions' param or CLI argument available in certain 
contexts and not in others. That's very likely solvable on the server 
side; not sure how difficult it would be in the CLI high-level command.

FYI, for others reading this, offline Joe pointed out there's a related 
JIRA for this: https://issues.jboss.org/browse/WFLY-1069.

On 6/26/14, 5:41 AM, Edward Wertz wrote:
> I'm looking into whether it's possible to automatically resolve expressions when executing operations and commands in the CLI.
>
>>From my understanding, there are two variations of the problem.
>
>   * Operations are server-side processes that are accessed via ':' in the CLI and, currently, the CLI presents the results returned as-is to the users. ex: ':read-resource'
>
>   * Commands are processes that get manipulated by the CLI before getting presented to users. ex: 'ls'
>
> I've been experimenting with adding arguments to the CLI commands, like 'ls --resolve-expressions', and gotten it working for the standalone and domain side of things. However, I can't control the scope of the argument, so it's available in situations that cannot accurately resolve expressions like the 'profile=full' section of the domain tree. The results wouldn't be reliable.
>
> The same problem would apply to adding parameters to the server-side operations. The scope of the operations themselves can be controlled, but not their parameters. An execution like ':read-resource(recursive=true resolve-expressions=true)' can't resolve expressions unless it's used against an actual server or host, but the operation is available almost everywhere. Again, the results wouldn't be reliable.
>
> I'm wondering if anyone can suggest a way to attack this problem? There is already a ':resolve-expression(expression=___)' operation, so users can somewhat laboriously get the runtime values they want, but I can't figure out a way to integrate the values into the existing framework successfully. Other than creating entirely new operations and commands, like 'ls-resolve' and ':read-resource-resolve', which seems like an unsustainable way to solve the problem.
>
> Thanks,
>
> Joe Wertz
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-- 
Brian Stansberry
Senior Principal Software Engineer
JBoss by Red Hat