make pkg_install suite reusable, please

[Garrett Cooper]

On Mon, Apr 12, 2010 at 9:07 AM, Leinier Cruz Salfran
<salfrancl.listas at gmail.com> wrote:
> On Sun, Apr 11, 2010 at 8:34 PM, Marcin Wisnicki
> <mwisnicki+freebsd at gmail.com> wrote:
>> On Sun, 11 Apr 2010 12:37:27 +0100, Robert Watson wrote:
>>
>>> On Fri, 9 Apr 2010, Alexander Churanov wrote:
>>>
>>>> 2010/4/9 Leinier Cruz Salfran <salfrancl.listas at gmail.com>
>>>>
>>>>> i want to ask you one thing: can you make the 'pkg_install' suite
>>>>> reusable .. means install 'libinstall.a' as a shared object in order
>>>>> to make it reusable by others devs
>>>>
>>>> I'd like to add my 50 cents. From my point of view, the true UNIX way
>>>> is re-using whole programs. This provides unbelievable isolation and
>>>> correctness. If you don't want to fork myriads of processes each
>>>> second, then, it's, probably, better to ask for pipe mode of pkg_*
>>>> tools. For example, aspell works that way. You start a process, write
>>>> commands and queries and read results.
>>>
>>> While there are clearly benefits to process isolation, there are
>>> countless situations in UNIX where I've said to myself "Oh, I wish I had
>>> a lib<foo> not just a <foo> command".  This is particularly the case for
>>> monitoring tools, where third-party applications have a lot of trouble
>>> parsing and tracking the output of tools like ps(1), etc.  This is why
>>> recently we've been working on libmemstat(3), libprocstat(3),
>>> libnetstat(3), etc -- so that tools can avoid rewriting that code as
>>> well as avoid the parsing problem.
>>
>> A middle-ground solution to this is to standardise on a common data
>> exchange format with a schema definition language. With schema you can
>> autogenerate high level parsers and generators, validators and other things
>> for free. It does not have to be XML with XML-Schema (though there are good
>> plaintext schema languages like RelaxNG-compact and you could possibly find
>> less verbose text encoding for XML).
>>
>> If, say ps or ipfw, had a switch like '--format-output-yaml' and
>> '--print-output-schema' (alternatively schema files could be stored
>> somewhere in $prefix/share) it would be trivial to use them anywhere.
>>
>> The only problem I see is agreeing on a single format and forcing everyone
>> to use it. Which is probably why it will never happen :(
>>
>
> hello marcin
>
> that can be a smart solution but i prefer to use functions directly
> from library .. i think it's better
>
> well, alexander .. i must to follow your first suggestion: use 'pkg_*'
> commands (meanwhile) .. i plan to make this software usable to netbsd
> and openbsd too ..  i'm not sure but maybe they have the same
> situation and for that reason i think use the commands is the way to
> follow

Just to give you an idea of what's out there... NetBSD used the same
basic solution that FreeBSD did, but they diverged about 3 years ago
and they have their own library based solution. I think that OpenBSD
has their own package maintenance tool written in perl.

As for us, we're going the libpkg direction-ish AFAIK, but it's going
to take time before we get there.

In the meantime, there's also a tool named pkgin which does similar to
what you describe and it's portable between pkg_install on FreeBSD and
the libpkg-ish solution on NetBSD.

HTH,
-Garrett