Standard version specification in Dockerfile's for 'x-pkg verrel'

[James Kunstle]

Hey y'all,

I'm a developer at Red Hat working on adding a user-requested feature to the
'x-pkg' line of products.
Specifically, the user would like the 'x-pkg verrel' command to work for those
projects under the 
container/* branch of Fedora targeted software in the same way that the command works for

rpm/ software.

issue: https://pagure.io/rpkg/issue/547

However, different container maintainers include the metadata about their Dockerfile's
in different ways.
Take nginx for example. Its Dockerfile contains both:

NGINX_VERSION=1.12

and 

VERSION=0

What would be the correct way to solve this collision for a hypothetical workflow that you
might have?
Are there any ad hoc best-practices w.r.t Dockerfile standards involving specifying the
version and release 
number?

Any feedback or suggestions would be helpful.

-jkunstle

[Casper]

James Kunstle a écrit :
>  However, different container maintainers include the metadata about
> their Dockerfile's in different ways.
>  Take nginx for example. Its Dockerfile contains both:
>  
>  NGINX_VERSION=1.12
>  
>  and 
>  
>  VERSION=0
>  
>  What would be the correct way to solve this collision for a hypothetical workflow that
> you might have?
>  Are there any ad hoc best-practices w.r.t Dockerfile standards involving specifying the
> version and release 
>  number?
>   
Hi James,

As far I can see in the Docker images produced by the Cloud SIG
(http://fedoraproject.org/wiki/Cloud), it seems to be this rule:

<PKGNAME>_VERSION=<version>

you saw NGINX_VERSION=1.12

I saw MYSQL_VERSION=10.5.9 because I'm using mariadb Docker image.

But personnaly, I think it is not a good idea to do this. It gives a
lot of issue and make it harder to maintain the Dockerfile.

Perhaps it is useful on database softwares, to keep compatibility, but
for something else, I think it's useless. If you specify the version
in the Dockerfile, this info will be obsolete and false by the
time. If you add tests in your Dockerfile to be sure you're installing
this version exactly, the Docker image will fail to build by the
time... then you need to fix the Dockerfile.

So, where do I specify the version of the software (because I need
this information, anyway) ?

I put it in the tag of the image during the build (or after), like
that:

poezio:0.13.1-9

<pkgname>:<pkgversion>-<image_version>

regards,
Casper
-- 
GnuPG: AE157E0B29F0BEF2 at keys.openpgp.org
CA Cert: https://dl.casperlefantom.net/pub/ssl/root.der
Jabber/XMPP Messaging: casper(a)casperlefantom.net