[Engine-devel] Jar versions in ovirt-engine

Thu Apr 19 14:21:26 UTC 2012

On 19/04/12 17:17, Juan Hernandez wrote:
> On 04/19/2012 04:10 PM, Doron Fediuck wrote:
>> On 19/04/12 16:53, Juan Hernandez wrote:
>>> On 04/19/2012 03:22 PM, Doron Fediuck wrote:
>>>> On 19/04/12 13:26, Juan Hernandez wrote:
>>>>> On 04/19/2012 12:00 PM, Doron Fediuck wrote:
>>>>>> On 18/04/12 14:04, Juan Hernandez wrote:
>>>>>>> On 04/18/2012 09:51 AM, Ofer Schreiber wrote:
>>>>>>>> Ever wondered why the version of oVirt's first release is 3.0.0_0001?
>>>>>>>> The answer is simple - We use ovirt-engine jar's version as our "main" release version.
>>>>>>>>
>>>>>>>> Personally, I think the current versioning scheme is ugly. Actually, I can't name even one open-source project using "_" in it's version.
>>>>>>>>
>>>>>>>> What can we do about it? We have couple of options:
>>>>>>>> 1. Leave the engine alone, and use a separate versioning scheme (e.g - use just 3.1.0 as the main version for next release)
>>>>>>>> 2. Remove "_" from engine jars
>>>>>>>> 3. Do nothing.
>>>>>>>>
>>>>>>>> I'd like to hear your thoughts, as well as the reasons to use such an unusual versioning scheme.
>>>>>>>>
>>>>>>>> ---
>>>>>>>> Ofer Schreiber
>>>>>>>> oVirt Release Manager
>>>>>>>> _______________________________________________
>>>>>>>> Arch mailing list
>>>>>>>> Arch at ovirt.org
>>>>>>>> http://lists.ovirt.org/mailman/listinfo/arch
>>>>>>>
>>>>>>> From my point of view using the 0001 suffix in the names of the jar
>>>>>>> files is not a big problem, but I agree that using it in the release
>>>>>>> number is ugly, and it produces issues/discussions during packaging. I
>>>>>>> vote for option #1: use 3.1.0 for the next main version.
>>>>>>>
>>>>>>
>>>>>> The original versioning scheme was due to a bug in maven2.
>>>>>>
>>>>>> Juan, I've read some of the Java packaging concepts, but didn't see
>>>>>> (or missed) thoughts about modular versioning (ie- artifacts).
>>>>>>
>>>>>> Here are the things to consider here;
>>>>>>
>>>>>> - Current RPM's are using the version declared in the POM files.
>>>>>> Should this concept remain?
>>>>>> * I think it should remain, as other packaging systems should
>>>>>> be able to use it as well and end-up is the similar project version.
>>>>>
>>>>> I can talk from the Fedora point of view only, as that is what I know a bit.
>>>>>
>>>>> In Fedora there can be only one version of a given jar file installed in
>>>>> the system, so there is no point in adding a version number to the name
>>>>> of that jar file: the version number is already in the package
>>>>> containing that jar file. In fact if the build generates jar files with
>>>>> version numbers in the name the RPM should remove those jar files. That
>>>>> is why I say that having any kind of numbers in the names of the jars is
>>>>> not important: we have to remove them anyway.
>>>>>
>>>>> Packaging guidelines (see [1]) recommend to avoid version numbers in the
>>>>> jar files, and I think that makes sense.
>>>>>
>>>> This would be the easy solution.
>>>
>>> Again talking only about Fedora:
>>>
>>> Having just one version of every jar is not simple at all, in fact it
>>> requires a lot of work to make sure that the selected versions work
>>> properly together.
>>>
>> See below, we actually share the same view...
>>
>>>> What happens when you have more than a single Java app, and both
>>>> using different versions of the same jar file? This means that one
>>>> of the app's will need to bring it along and use it locally, rather
>>>> than system-level usage.
>>>
>>> What happens is that both applications have to be patched so that they
>>> work correctly with the same version of that jar file. If possible the
>>> patches are pushed upstream, if not they applied as part of the package.
>>> Embedding another version of that jar file in one of the applications is
>>> not allowed, in fact that is something that packagers have to undo quite
>>> often.
>>>
>> See below... converging into the latest jar is what I figured that
>> will happen. Still, as I see it such constraints are not really needed.
>>>> I'm guessing if we assume such a constraint the solution will be
>>>> to force all app's to use latest jar version, which isn't trivial.
>>>
>>> I agree completely, it is not trivial at all, that is where packagers
>>> expend most of their time.
>>>
>>>> So some distro's will allow of concept of slotted installation.
>>>> This means I currently /have/ 2 working versions of postgres in
>>>> my laptop (using Gentoo)-
>>>>
>>>> equery l postgresql-server
>>>>  * Searching for postgresql-server ...
>>>> [IP-] [  ] dev-db/postgresql-server-8.4.11:8.4
>>>> [IP-] [  ] dev-db/postgresql-server-9.1.3:9.1
>>>>
>>>> The same works on my laptop for Maven, Java, Python and many others.
>>>> If you think about it, Fedora supports slotted installation for
>>>> kernels, and then added alternatives to do that with other packages
>>>> as well (mta, Java..). So there's a need and a way to handle several
>>>> versions of the same library (regardless of the language), and
>>>> we should be careful when taking such assumptions. At least try
>>>> to be as flexible as possible, to allow others to join in.
>>>
>>> In Fedora that is allowed only for major versions: java-1.7.0 and
>>> java-1.6.0, maven 2 and maven 3, so on, but not usually for minor
>>> versions (there are exceptions).
>>>
>> It's a good start.
>>
>>>> So learning from Fedora I'd say- let the RPM install in a versioned
>>>> folder (ie- /usr/lib/jvm/jre-1.5.0-gcj/..), and leave the jar
>>>> files without versions for now. In the future we may need to change it
>>>> as some disrto's may use sym links to indicate the latest jar.
>>>> In such a case the RPM will stripdown the version from the artifact.
>>>
>>> What we are currently doing with the Fedora ovirt-engine package is that
>>> jar files are installed to /usr/share/java/ovirt-engine, with names like
>>> bll.jar, common.jar, compat.jar, etc. The RPM takes care of stripping
>>> the version numbers generated by the upstream build. This doesn't
>>> preclude other distros from doing it in a different way, using version
>>> numbers or symlinks.
>>>
>> Why not /usr/share/java/ovirt-engine-3/ ? I do not see someone using
>> engine3 and engine4 on the same machine, but he may need to have
>> engine-config v3 to handle previous instance and engine-config v4
>> to handle current instance, so we could have a good infra if we
>> keep the major version.
> 
> The only thing I have against ovirt-engine-3 is that the packaging
> guidelines recommend to use /usr/share/java/%{name}, where %{name} is
> the name of the package, and the package has already been approved with
> the name ovirt-engine. Next major version (not 3.1, that is a minor
> version) can perfectly be named ovirt-engine4 or ovirt4-engine.

Maybe open a bz for it so we'll remember?
Make sure to add this thread so we'll know what happened....
-- 

/d

"Air conditioned environment - Do NOT open Windows!"