[Yum] Showing rpm messages before rpm completes

[Eric Shubert]

On 01/02/2014 11:34 AM, James Antill wrote:
> Eric Shubert <ejs at shubes.net> writes:
>
>> Let me try to explain a little better what's going on. For example, my
>> clamav package runs "freshclam" during the %post section, in order to
>> update virus definitions. The freshclam program outputs a progress
>> bar, so you can see how the download is going as it progresses. This
>> works fine when using the rpm command.
>
>   This is broken, it's an error for rpm packages to output anything in
> %post/%postun ...

Since when is output from an rpm script considered an error? That's news 
to me (which is, ironically, nothing new). ;) Can you point me to some 
documentation which explains this?

If %post scripts are prohibited from using stdout/stderr, how then are 
such scripts supposed to report progress (and/or problems)?

> and you'll see that "yum history" will flag any
> transaction without output as problematic.

Why exactly is that?
What purpose does this serve?

>> When the package is installed with yum though, yum shows no progress
>> bar during the download. The %post section appears to run silently
>> until the very end, at which time it duly spits out all of the output
>> created by the %post script(s). My objective here is to have yum show
>> these messages as they happen, same as what occurs when running rpm.
>
>   Even if we wanted to change this behaviour the API interface between
> rpm and yum doesn't make this easy.

Sounds to me like the API interface is a bit lacking. :(

I could of course remove the pertinent %post processing from the rpm and 
run it external to yum, but that sort of defeats the purpose of having 
%post processing in general.

Out of curiosity, how does (or doesn't) yum handle %verify script output?

Is there any sort of best practice (I'm likely missing) for 
accomplishing this sort of thing? I'd like to do things in a typical 
manner, but I'm finding yum to be somewhat prohibitive in this area.

Thanks for your patience and guidance.


-- 
-Eric 'shubes'